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Natural polymers have been revisited as a material which may contribute to a low-carbon society. However, the utilization of such natural polymers is quite limited even now. Previously, we have revealed that double-stranded deoxyribonucleic acid (DNA) is one of promising resources as a structural material having peculiar tensile properties. A self-supported film of DNA prepared by a solvent-casting method can be regulated from glassy to rubbery state via semicrystalline-like by its water content. However, there is a problem that the water evaporation causes changing the tensile properties of the films in a short time. To overcome this problem, in this study, we focused on hydrated ionic liquid as a non-volatile substance to maintain the tensile properties of DNA films for a long time. Tensile properties, aggregation structure, and thermal molecular motion of DNA films blended with hydrated ionic liquid were studied., Natural polymers have been revisited as a material which may contribute to a low-carbon society. However, the utilization of such natural polymers is quite limited even now. Previously, we have revealed that double-stranded deoxyribonucleic acid (DNA) is one of promising resources as a structural material having peculiar tensile properties. A self-supported film of DNA prepared by a solvent-casting method can be regulated from glassy to rubbery state via semicrystalline-like by its water content. However, there is a problem that the water evaporation causes changing the tensile properties of the films in a short time. To overcome this problem, in this study, we focused on hydrated ionic liquid as a non-volatile substance to maintain the tensile properties of DNA films for a long time. Tensile properties, aggregation structure, and thermal molecular motion of DNA films blended with hydrated ionic liquid were studied.

In this presentation an advanced model of sliding friction and dynamic contact of elastomers on rough, self-affine surfaces is presented, which is shown to be useful for the prediction of tire traction on dry and wet roads. It describes the frictional force via the dissipated energy, resulting from sliding stochastic excitations of the rubber by surface asperities on various length scales [1, 2]. The effect of surface roughness is considered by surface descriptors, which are derived from a fractal analysis of the surface interface. The hysteresis response of the rubber enters through viscoelastic master curves of the complex modulus up to high frequencies. Based on this concept, stationary friction curves have been estimated numerically on a broad velocity scale, in dependence of surface roughness, load and temperature. They have been compared to experimental friction data found for filled elastomers under dry and wet conditions. In particular, the investigations have shown to be useful for predicting the traction behaviour of tyres on dry and wet roads during ABS-braking of passenger cars. Furthermore, the obtained results allow for a deeper insight into the role of adhesion in dry friction of elastomers under different contact conditions and give a closer look of the physical mechanisms occurring during a friction process, In this presentation an advanced model of sliding friction and dynamic contact of elastomers on rough, self-affine surfaces is presented, which is shown to be useful for the prediction of tire traction on dry and wet roads. It describes the frictional force via the dissipated energy, resulting from sliding stochastic excitations of the rubber by surface asperities on various length scales [1, 2]. The effect of surface roughness is considered by surface descriptors, which are derived from a fractal analysis of the surface interface. The hysteresis response of the rubber enters through viscoelastic master curves of the complex modulus up to high frequencies. Based on this concept, stationary friction curves have been estimated numerically on a broad velocity scale, in dependence of surface roughness, load and temperature. They have been compared to experimental friction data found for filled elastomers under dry and wet conditions. In particular, the investigations have shown to be useful for predicting the traction behaviour of tyres on dry and wet roads during ABS-braking of passenger cars. Furthermore, the obtained results allow for a deeper insight into the role of adhesion in dry friction of elastomers under different contact conditions and give a closer look of the physical mechanisms occurring during a friction process

The author presents three concerns and possible solutions for the rubber industry, 1) low rolling resistance technology by modified SBR and Ologic, 2) tire raw material in terms of biomaterial development, issues of natural rubber and breaking improvement toward light weight, and 3) rubber technology with IOT and advertisement for CAIS and belt wear detection., The author presents three concerns and possible solutions for the rubber industry, 1) low rolling resistance technology by modified SBR and Ologic, 2) tire raw material in terms of biomaterial development, issues of natural rubber and breaking improvement toward light weight, and 3) rubber technology with IOT and advertisement for CAIS and belt wear detection.

Ethylene propylene rubber（EPDM）which can be used in the range of 100 to 160℃ has good mechanical properties performance. However, the disadvantage that it can’t be used at higher temperature limits its application. Due to the special Si-O bond, vinyl silicone rubber (VMQ) with high temperature resistance was widely used. EPDM/VMQ blends were prepared by mechanical blending. The effects of VMQ content, filler, modifier and phase compatibility agent on mechanical properties and heat resistance were studied. The results show that the VMQ enhaced the aging resistance of EPDM. The retention rate of tensile strength increased from 40% to 60% when the content of VMQ was 20%. By adding modified powder, filler and special structure compatibilizer, the conservation rate of tensile strength could be reach to 100%. Optimization formulation of the ageing resistant EPDM/VMQ blend was proposed in this study., Ethylene propylene rubber（EPDM）which can be used in the range of 100 to 160℃ has good mechanical properties performance. However, the disadvantage that it can’t be used at higher temperature limits its application. Due to the special Si-O bond, vinyl silicone rubber (VMQ) with high temperature resistance was widely used. EPDM/VMQ blends were prepared by mechanical blending. The effects of VMQ content, filler, modifier and phase compatibility agent on mechanical properties and heat resistance were studied. The results show that the VMQ enhaced the aging resistance of EPDM. The retention rate of tensile strength increased from 40% to 60% when the content of VMQ was 20%. By adding modified powder, filler and special structure compatibilizer, the conservation rate of tensile strength could be reach to 100%. Optimization formulation of the ageing resistant EPDM/VMQ blend was proposed in this study.

A new method is researched to simulate the vibration noise of the rolling tyre independently in the paper. By this method, a rolling tyre model is built, by which the acceleration of tyre surface can be obtained on the Laranage mesh. Then these datum are mapped to an Euler mesh, which is fixed in the space without rolling. Finally, the rolling noise can be analyzed based on the acceleration of tire surface. What’s more, with the testing of tyre noise, the tyre noise caused by vibration and airpumping can be separated and researched independently. By this method, an interesting result can also be discovered that air pumping dominant the directivity of tyre noise but vibration has only a little influence., A new method is researched to simulate the vibration noise of the rolling tyre independently in the paper. By this method, a rolling tyre model is built, by which the acceleration of tyre surface can be obtained on the Laranage mesh. Then these datum are mapped to an Euler mesh, which is fixed in the space without rolling. Finally, the rolling noise can be analyzed based on the acceleration of tire surface. What’s more, with the testing of tyre noise, the tyre noise caused by vibration and airpumping can be separated and researched independently. By this method, an interesting result can also be discovered that air pumping dominant the directivity of tyre noise but vibration has only a little influence.

Natural rubber latex (NRL) is a type of high molecular weight polymeric substance. Currently, more than 90% of NRL comes from one single tropical tree species – Hevea brasiliensis (para rubber tree). Recently, promising results in the use of NRL from Hevea brasiliensis rubber tree to produce replacement and regeneration tissues has been reported. Among them, wound healing in cutaneous tissues, eardrum replacement, bone regeneration, and dental alveolus replacement afford a unique means to repair or replace the failing organs or tissues. The primary particle of NRL is around 100-300 nm in diameter, which is promising nanoparticles used in biotechnology including pharmaceutics, tissue engineering and regenerative medicine. In order for NRL nanoparticles to be employed in regenerative medicine, they need to have designed biological interaction with cells as well as favorable mechanical properties. Cells can delicately sense and respond to external nano-scale features in intricate living systems. With this in mind, an in-depth understanding of cell differentiation may bring a new perspective to regenerative medicine including new bone regeneration and cartilage therapy. To the best our knowledge, no attention has been paid to differentiation activity of NRL nanoparticles. In this study, we focused on the surface modification of NRL nanoparticles through the biomineralization of hydroxyapatite (HA) in order to create a better cytocompatibility with controlled cell adhesion and mineralization properties in osteogenic culture to determine the effect on bone outcomes. Using MC3T3-E1 osteoblastic-like cells, we examined the osteogenic differentiation and expressions of multiple proteins and characteristic genes of mature osteoblast., Natural rubber latex (NRL) is a type of high molecular weight polymeric substance. Currently, more than 90% of NRL comes from one single tropical tree species – Hevea brasiliensis (para rubber tree). Recently, promising results in the use of NRL from Hevea brasiliensis rubber tree to produce replacement and regeneration tissues has been reported. Among them, wound healing in cutaneous tissues, eardrum replacement, bone regeneration, and dental alveolus replacement afford a unique means to repair or replace the failing organs or tissues. The primary particle of NRL is around 100-300 nm in diameter, which is promising nanoparticles used in biotechnology including pharmaceutics, tissue engineering and regenerative medicine. In order for NRL nanoparticles to be employed in regenerative medicine, they need to have designed biological interaction with cells as well as favorable mechanical properties. Cells can delicately sense and respond to external nano-scale features in intricate living systems. With this in mind, an in-depth understanding of cell differentiation may bring a new perspective to regenerative medicine including new bone regeneration and cartilage therapy. To the best our knowledge, no attention has been paid to differentiation activity of NRL nanoparticles. In this study, we focused on the surface modification of NRL nanoparticles through the biomineralization of hydroxyapatite (HA) in order to create a better cytocompatibility with controlled cell adhesion and mineralization properties in osteogenic culture to determine the effect on bone outcomes. Using MC3T3-E1 osteoblastic-like cells, we examined the osteogenic differentiation and expressions of multiple proteins and characteristic genes of mature osteoblast.

Modern high-performance tyres are built up of more than 20 components/parts ensuring a well-balanced tyre performance. TREAD profiles have a comparatively complex structure, consisting of up to 5 single components, WING, CAP I, CAP II, BASE and CHIMNEY, to meet the demands of the market and statutory specifications. A further component was added to the new TREAD profiles of PCR in order to achieve selected properties. To be able to extrude these furthermore in one process step, an extension of the extrusion aggregates is necessary., Modern high-performance tyres are built up of more than 20 components/parts ensuring a well-balanced tyre performance. TREAD profiles have a comparatively complex structure, consisting of up to 5 single components, WING, CAP I, CAP II, BASE and CHIMNEY, to meet the demands of the market and statutory specifications. A further component was added to the new TREAD profiles of PCR in order to achieve selected properties. To be able to extrude these furthermore in one process step, an extension of the extrusion aggregates is necessary.

In order to clarify the mechanism of rubbery behavior of thermoplastic vulcanizate (TPV), the deformation and strain recovery behavior of dynamically vulcanized polypropylene (PP)/ethylene-propylene-diene (EPDM) rubber blend was investigated. The deformation of PP matrix in rubber particle circumference was measured in detail by the fixed-region observation of atomic force microscope (AFM) during drawing. Under the small strain, the ligament of plastic phase between rubber particles elastically deformed by bending. Because the bending of thin ligament can be achieved by low stress, it was suggested that the elastic deformation by bending of PP ligament at low stress was the origin of low tensile modulus of TPV. Under the large strain, the PP ligament deformed plastically and buckling of the deformed ligament was observed after releasing the stress. The buckling induced by restorative force of rubber phase was considered to induce the high recovery of TPV., In order to clarify the mechanism of rubbery behavior of thermoplastic vulcanizate (TPV), the deformation and strain recovery behavior of dynamically vulcanized polypropylene (PP)/ethylene-propylene-diene (EPDM) rubber blend was investigated. The deformation of PP matrix in rubber particle circumference was measured in detail by the fixed-region observation of atomic force microscope (AFM) during drawing. Under the small strain, the ligament of plastic phase between rubber particles elastically deformed by bending. Because the bending of thin ligament can be achieved by low stress, it was suggested that the elastic deformation by bending of PP ligament at low stress was the origin of low tensile modulus of TPV. Under the large strain, the PP ligament deformed plastically and buckling of the deformed ligament was observed after releasing the stress. The buckling induced by restorative force of rubber phase was considered to induce the high recovery of TPV.

Rubber compounds used for tyre tread applications are filler-reinforced composite materials of which the dynamic properties can be adjusted over a relatively broad range by modification of the polymer-filler interaction. The replacement of carbon black as reinforcing filler two decades ago by silica-silane systems allowed to reduce the low-frequency hysteresis of the rubber, which resulted in reduction of the Rolling Resistance (RR) when applied in tire treads. Apart from the selection of the proper elastomers and silica’s for this technology, the choice of the coupling agents to chemically link the polar silica to the apolar elastomers is of paramount importance. Next to their reactivities towards the silica-particles and to the elastomer molecules in order to obtain sufficient coupling, the intricate chemical structure of the coupling agents once coupled does still influence the RR and the Wet Skid Resistance (WSR) or Wet Traction of the treads. Coupling agents commonly applied are variants of silane types. Selective changes in the structures of the silane coupling agents, e.g. de number of alkoxy-groups attached to the Si-atom reactive towards silanol-groups on the surface of the silica filler, the length of the aliphatic linker between the Si-atom and the reactive group towards the elastomer, or the bond strength between the coupling agent and the polymer, lead to changes in the microstructure of the silica-elastomer interface. All these changes determine the dynamic properties, as indicative for the RR as well as WSR and Abrasion Resistance of a tire tread. The paper primarily covers the RR and WSR, making use of dynamic mechanical analysis: laboratory scale indications for RR and WSR by means of the dynamic loss angle as a function of temperature, and of a practical laboratory assessment to specifically obtain an indication of WSR by means of a Laboratory Abrasion Tester 100 (LAT100)., Rubber compounds used for tyre tread applications are filler-reinforced composite materials of which the dynamic properties can be adjusted over a relatively broad range by modification of the polymer-filler interaction. The replacement of carbon black as reinforcing filler two decades ago by silica-silane systems allowed to reduce the low-frequency hysteresis of the rubber, which resulted in reduction of the Rolling Resistance (RR) when applied in tire treads. Apart from the selection of the proper elastomers and silica’s for this technology, the choice of the coupling agents to chemically link the polar silica to the apolar elastomers is of paramount importance. Next to their reactivities towards the silica-particles and to the elastomer molecules in order to obtain sufficient coupling, the intricate chemical structure of the coupling agents once coupled does still influence the RR and the Wet Skid Resistance (WSR) or Wet Traction of the treads. Coupling agents commonly applied are variants of silane types. Selective changes in the structures of the silane coupling agents, e.g. de number of alkoxy-groups attached to the Si-atom reactive towards silanol-groups on the surface of the silica filler, the length of the aliphatic linker between the Si-atom and the reactive group towards the elastomer, or the bond strength between the coupling agent and the polymer, lead to changes in the microstructure of the silica-elastomer interface. All these changes determine the dynamic properties, as indicative for the RR as well as WSR and Abrasion Resistance of a tire tread. The paper primarily covers the RR and WSR, making use of dynamic mechanical analysis: laboratory scale indications for RR and WSR by means of the dynamic loss angle as a function of temperature, and of a practical laboratory assessment to specifically obtain an indication of WSR by means of a Laboratory Abrasion Tester 100 (LAT100).

A new highly versatile catalyst system was developed at industrial scale to be used in a slurry process to obtain new EP(D)M grades. The new catalyst system is characterized by higher polymerization yield, improved co-monomer addition to obtain better distribution inside polymer chains and reduced undesirable side reactions compared to the traditional one. Thanks to this new catalyst new EP(D)M grades were obtained suitable to be used in highly demanding application such as Automotive Sponge Profiles, Building Solid Profiles and Thermoplastic Vulcanized (TPV). This new catalyst system demonstrated to be particularly suitable to introduce branching technology in slurry process to get easy processable grades keeping a negligible gel content. The main characteristics of the new EP(D)M grades are described, A new highly versatile catalyst system was developed at industrial scale to be used in a slurry process to obtain new EP(D)M grades. The new catalyst system is characterized by higher polymerization yield, improved co-monomer addition to obtain better distribution inside polymer chains and reduced undesirable side reactions compared to the traditional one. Thanks to this new catalyst new EP(D)M grades were obtained suitable to be used in highly demanding application such as Automotive Sponge Profiles, Building Solid Profiles and Thermoplastic Vulcanized (TPV). This new catalyst system demonstrated to be particularly suitable to introduce branching technology in slurry process to get easy processable grades keeping a negligible gel content. The main characteristics of the new EP(D)M grades are described

The neodymium butadiene rubber (Nd-BR) has been recognized for its particularly suitable use in tread and sidewall of green tires. The homogeneous neodymium-based catalyst systems containing neodymium carboxylate, alkyl aluminium compound and chlorinating agent were successfully developed for the coordination polymerizations of butadiene in our laboratory. The catalyst possessed high catalytic activity to butadiene polymerization in hexane and exhibited high stereo-selectivity to butadiene polymerization in hexane and polybutadienes with extremely high cis-1,4 configuration could be produced under appropriate reaction conditions. Stereo-specificity is a key factor for the performance of Nd-BR product. Nd-BR with high cis-1,4 content behaved low Payne effect and good processing properties, which is mainly attributed to the strong interaction between polymer and filler. Nd-BR vulcanizates with higher cis-1,4 content possess the superior mechanical properties and dynamic mechanical properties, such as modulus at 300%, tensile strength, abrasion resistance, heat build-up, compression properties and rolling resistance and wet-skid resistance. Long chain branched Nd-BR possesses an improved cold flow resistance, processing performance and mixing performance with the filler. The excellent properties of these high cis-1,4 Nd-BR products lead to their especially suitable application in green-tyre components., The neodymium butadiene rubber (Nd-BR) has been recognized for its particularly suitable use in tread and sidewall of green tires. The homogeneous neodymium-based catalyst systems containing neodymium carboxylate, alkyl aluminium compound and chlorinating agent were successfully developed for the coordination polymerizations of butadiene in our laboratory. The catalyst possessed high catalytic activity to butadiene polymerization in hexane and exhibited high stereo-selectivity to butadiene polymerization in hexane and polybutadienes with extremely high cis-1,4 configuration could be produced under appropriate reaction conditions. Stereo-specificity is a key factor for the performance of Nd-BR product. Nd-BR with high cis-1,4 content behaved low Payne effect and good processing properties, which is mainly attributed to the strong interaction between polymer and filler. Nd-BR vulcanizates with higher cis-1,4 content possess the superior mechanical properties and dynamic mechanical properties, such as modulus at 300%, tensile strength, abrasion resistance, heat build-up, compression properties and rolling resistance and wet-skid resistance. Long chain branched Nd-BR possesses an improved cold flow resistance, processing performance and mixing performance with the filler. The excellent properties of these high cis-1,4 Nd-BR products lead to their especially suitable application in green-tyre components.

Kuraray has developed a series of liquid rubber products with molecular weights ranging from a few thousands to a hundred thousand. These polymers, which consist of isoprene, butadiene, styrene and a new, bio-based monomer “Farnesene”, can be used by rubber manufacturers to achieve improvements in processing and physical properties. The most valuable physical property enhancement liquid butadiene rubber offers is a performance improvement in wet and ice grip, as well as plasticizing effect. Moreover, liquid Farnesene rubber contributes to advantaged vehicle fuel economy through reduction in tire rolling resistance. The application of each liquid rubber product in tire formulations is explained., Kuraray has developed a series of liquid rubber products with molecular weights ranging from a few thousands to a hundred thousand. These polymers, which consist of isoprene, butadiene, styrene and a new, bio-based monomer “Farnesene”, can be used by rubber manufacturers to achieve improvements in processing and physical properties. The most valuable physical property enhancement liquid butadiene rubber offers is a performance improvement in wet and ice grip, as well as plasticizing effect. Moreover, liquid Farnesene rubber contributes to advantaged vehicle fuel economy through reduction in tire rolling resistance. The application of each liquid rubber product in tire formulations is explained.

It is important to understand the relationship between structure of elastomeric compounds and their properties under high-pressure hydrogen for designing the suitable rubber composites for high-pressure gas seals. In order to input diverse ideas from industries for the model compounds and hydrogen properties for measurement, in 2012, we established “The Research Group of Elastomers for Hydrogen Equipment” in The Society of Rubber Science and Technology, Japan. In the research group, more than 50 members are active in the fields of materials, elastomeric compounds design and hydrogen equipment design. In this presentation, some research activities of “The Research Group of Elastomers for Hydrogen Equipment” on rubber materials for high-pressure hydrogen gas seal will be introduced. In order to clarify the influence of high-pressure hydrogen on the rubber O-ring, we have developed an O-ring durability tester for 100 MPa hydrogen gas. According to the results, we found the three fracture modes, internal fracture of rubbers originated from inflation of dissolved hydrogen, referred as "Blister Fracture", external fracture in terms of volume increase of rubber in the O-ring gland, referred as "Overflow Fracture" and "Buckling Fracture"., It is important to understand the relationship between structure of elastomeric compounds and their properties under high-pressure hydrogen for designing the suitable rubber composites for high-pressure gas seals. In order to input diverse ideas from industries for the model compounds and hydrogen properties for measurement, in 2012, we established “The Research Group of Elastomers for Hydrogen Equipment” in The Society of Rubber Science and Technology, Japan. In the research group, more than 50 members are active in the fields of materials, elastomeric compounds design and hydrogen equipment design. In this presentation, some research activities of “The Research Group of Elastomers for Hydrogen Equipment” on rubber materials for high-pressure hydrogen gas seal will be introduced. In order to clarify the influence of high-pressure hydrogen on the rubber O-ring, we have developed an O-ring durability tester for 100 MPa hydrogen gas. According to the results, we found the three fracture modes, internal fracture of rubbers originated from inflation of dissolved hydrogen, referred as "Blister Fracture", external fracture in terms of volume increase of rubber in the O-ring gland, referred as "Overflow Fracture" and "Buckling Fracture".

Atomic force microscope (AFM) was employed to solve deformation mechanisms of thermoplastic valcanizates (TPVs). It can visualize their mechanical properties in nano-scale by giving Young’s modulus mapping. It was found that the matrix phase in PP-rich compositions were not PP pure phase but the phase with lower Young’s modulus, which may tell us how TPVs deform., Atomic force microscope (AFM) was employed to solve deformation mechanisms of thermoplastic valcanizates (TPVs). It can visualize their mechanical properties in nano-scale by giving Young’s modulus mapping. It was found that the matrix phase in PP-rich compositions were not PP pure phase but the phase with lower Young’s modulus, which may tell us how TPVs deform.

There is a short history of an evaluation of possibilities to calculate compound properties based on the content of ingredients. Methods included Neuronal Network Mathematics (NNM) and None Linear Regression (NLR) for example. A couple of patents granted on different compounds like recipes for color master batches but on rubber compounds as well. Testing a program based on NNM to predict the properties of a rubber compound formula failed even a larger database was created and implemented. On the other hand, the prediction of compound properties with a much smaller database created with Statistic Experimental Design (DoE) is successful but limited to the boundary conditions of this experiment. In a DoE is it called optimization and the result of the overlay plot. The analysis of the failure to predict even with a larger database is the intolerance of NNM to experimental error or mistype errors in the database and that the data in the database can not be corrected, respective excluded from the calculation. There is no ability to of tracking bag. Any regression model obtained from DoE can not handle any happen stance database. On the other hand most DoEs evaluated during investigations of ingredient / rubber property relation show clearly linear correlations, at least second order type of regression. In particular a more careful investigation of the statistics indicate a data fit with linear regression equations is sufficient. In most cases a none linear regression is indicated by the DoE-program used for evaluation, but in particular under consideration of measurement error in rubber testing and statistical noise in compound mixing it may be an over interpretation. As a consequence the prediction of a compound with its properties should be possible with sufficient precision if an approach is used based on linear regression in combination with iteration. This method is called Multi-Linear-Iteration (MLR). To demonstrate the precision of predictions based on MLR two exp, There is a short history of an evaluation of possibilities to calculate compound properties based on the content of ingredients. Methods included Neuronal Network Mathematics (NNM) and None Linear Regression (NLR) for example. A couple of patents granted on different compounds like recipes for color master batches but on rubber compounds as well. Testing a program based on NNM to predict the properties of a rubber compound formula failed even a larger database was created and implemented. On the other hand, the prediction of compound properties with a much smaller database created with Statistic Experimental Design (DoE) is successful but limited to the boundary conditions of this experiment. In a DoE is it called optimization and the result of the overlay plot. The analysis of the failure to predict even with a larger database is the intolerance of NNM to experimental error or mistype errors in the database and that the data in the database can not be corrected, respective excluded from the calculation. There is no ability to of tracking bag. Any regression model obtained from DoE can not handle any happen stance database. On the other hand most DoEs evaluated during investigations of ingredient / rubber property relation show clearly linear correlations, at least second order type of regression. In particular a more careful investigation of the statistics indicate a data fit with linear regression equations is sufficient. In most cases a none linear regression is indicated by the DoE-program used for evaluation, but in particular under consideration of measurement error in rubber testing and statistical noise in compound mixing it may be an over interpretation. As a consequence the prediction of a compound with its properties should be possible with sufficient precision if an approach is used based on linear regression in combination with iteration. This method is called Multi-Linear-Iteration (MLR). To demonstrate the precision of predictions based on MLR two exp

There is no doubt that rubber products with high abrasion resistance are strongly demanded from a sustainable or economical point of view. It is thought that abrasion loss of rubber during friction is caused by cracks generation at the rubber surface, their propagation, and elimination of rubber pieces. Therefore, investigation on generation and propagation of rubber fracture is important to clarify rubber abrasion mechanisms. In this study, X-ray imaging method at SPring-8 is applied to directly observe crack generation and propagation during friction between rubber and a needle, and origin of rubber abrasion loss will be discussed., There is no doubt that rubber products with high abrasion resistance are strongly demanded from a sustainable or economical point of view. It is thought that abrasion loss of rubber during friction is caused by cracks generation at the rubber surface, their propagation, and elimination of rubber pieces. Therefore, investigation on generation and propagation of rubber fracture is important to clarify rubber abrasion mechanisms. In this study, X-ray imaging method at SPring-8 is applied to directly observe crack generation and propagation during friction between rubber and a needle, and origin of rubber abrasion loss will be discussed.

The rubber materials used as high-pressure hydrogen seal materials in fuel cell vehicle (FCV) and the hydrogen station for high-pressure hydrogen fuelling. In these systems, the rubber materials exposed to high-pressure hydrogen gas pressure cycling. The rubber materials are fractured with internal cracks by the cycling. However, the history of damage evolution until cracking has not been clarified due to the difficulty of in-situ analysis in high-pressure environment. In this study, to evaluate the damage evolution to the cracking, in-situ observation of transparent ethylene propylene diene rubber (EPDM) during 15MPa-atomospheric pressure cycling was conducted and the size estimation of the cavities and the cracks was operated by using obtained images, The rubber materials used as high-pressure hydrogen seal materials in fuel cell vehicle (FCV) and the hydrogen station for high-pressure hydrogen fuelling. In these systems, the rubber materials exposed to high-pressure hydrogen gas pressure cycling. The rubber materials are fractured with internal cracks by the cycling. However, the history of damage evolution until cracking has not been clarified due to the difficulty of in-situ analysis in high-pressure environment. In this study, to evaluate the damage evolution to the cracking, in-situ observation of transparent ethylene propylene diene rubber (EPDM) during 15MPa-atomospheric pressure cycling was conducted and the size estimation of the cavities and the cracks was operated by using obtained images

To develop the efficient reusing method of waste cross-linked ethylene-vinyl acetate copolymer (EVA) foam, the mechanical properties of rubber composite containing the waste EVA foam was investigated. The cross-linked EVA foam was powdered mechanically and mixed into isoprene rubber (IR) matrix as filler. It showed excellent reinforcing ability to low modulus matrix, without silica. Temperature dependence of specimens was also discussed. Due to the suppression of strain-induced crystallization (SIC), breaking elongation of low modulus matrix drastically decreased under high temperature condition, in contrast to high modulus matrix. From these observations of elongated specimens, it was found that many microcracks were generated not only at interface between EVA powder and matrix but also inside of matrix. Based on the above results, it was suggested that growth of microcracks was inhibited by SIC of IR. Therefore it was confirmed that SIC was a key factor of the reinforcing mechanism in the case of EVA powder-filled rubber composite., To develop the efficient reusing method of waste cross-linked ethylene-vinyl acetate copolymer (EVA) foam, the mechanical properties of rubber composite containing the waste EVA foam was investigated. The cross-linked EVA foam was powdered mechanically and mixed into isoprene rubber (IR) matrix as filler. It showed excellent reinforcing ability to low modulus matrix, without silica. Temperature dependence of specimens was also discussed. Due to the suppression of strain-induced crystallization (SIC), breaking elongation of low modulus matrix drastically decreased under high temperature condition, in contrast to high modulus matrix. From these observations of elongated specimens, it was found that many microcracks were generated not only at interface between EVA powder and matrix but also inside of matrix. Based on the above results, it was suggested that growth of microcracks was inhibited by SIC of IR. Therefore it was confirmed that SIC was a key factor of the reinforcing mechanism in the case of EVA powder-filled rubber composite.

Cellular structures with low densities of constituent polymer solids have many physical properties unparalleled in elastomeric materials. Elastomer foams (cellular elastomers) have been widely used in commercial products because of their excellent heat resistance and shock absorbance properties. The finite compressibility of elastomer foams is a key mechanical property that is in contrast with the incompressibility of non-cellular elastomers. The elastomer foams exhibit high reversible deformability like rubber, but unlike rubber, they undergo finite volume change before and after deformation. The values of Poisson's ratio (µ) of low-density elastomer foams are far less than 0.5 for large increase in volume under stretching. A large increase in volume significantly influences multi-axial stress because the volume change has a pronounced effect on dimensional variation under deformation. The mechanical properties of elastomer foams have been mainly investigated in uniaxial compression because of the close relation with their industrial use, but little research has been made to investigate the tensile stress-strain behavior in biaxial deformation. The present work investigate the stress-strain behavior in uniaxial and biaxial extension, and compression of the low-density elastomer foams with open- and closed-cell structures., Cellular structures with low densities of constituent polymer solids have many physical properties unparalleled in elastomeric materials. Elastomer foams (cellular elastomers) have been widely used in commercial products because of their excellent heat resistance and shock absorbance properties. The finite compressibility of elastomer foams is a key mechanical property that is in contrast with the incompressibility of non-cellular elastomers. The elastomer foams exhibit high reversible deformability like rubber, but unlike rubber, they undergo finite volume change before and after deformation. The values of Poisson's ratio (µ) of low-density elastomer foams are far less than 0.5 for large increase in volume under stretching. A large increase in volume significantly influences multi-axial stress because the volume change has a pronounced effect on dimensional variation under deformation. The mechanical properties of elastomer foams have been mainly investigated in uniaxial compression because of the close relation with their industrial use, but little research has been made to investigate the tensile stress-strain behavior in biaxial deformation. The present work investigate the stress-strain behavior in uniaxial and biaxial extension, and compression of the low-density elastomer foams with open- and closed-cell structures.

Research into the fundamentals of interfacial strength improvement of short aramid fibres in carbon black reinforced or silica reinforced elastomer compounds turns out to be very complex. Short fibre reinforcement depends mainly on: 1) fibre concentration; 2) fibre orientation distribution; 3) fibre length and distribution; 4) fibre-matrix interfacial strength and 5) properties of the matrix, respectively on the interdependencies between all these factors. Typical elastomer formulations contain many ingredients such as reinforcing and non-reinforcing fillers and curatives, with the fibres coming in addition, which interact either chemically or physically with each other. Many analytical tests are inconclusive in elucidating these interactions. Because of the need to investigate these interactions as well as the influence of processing, a systematic study was carried out making use of a simplified/basic gum-formulation. Publications showed sometimes large and otherwise small improvements in mechanical properties when the interfacial strength was improved in short fibre reinforced elastomer compounds. These were mainly derived from elementary tensile tests, where the effect of fibres was most conspicuous at low strains as an increase in tensile stress vs. non fibre–containing., Research into the fundamentals of interfacial strength improvement of short aramid fibres in carbon black reinforced or silica reinforced elastomer compounds turns out to be very complex. Short fibre reinforcement depends mainly on: 1) fibre concentration; 2) fibre orientation distribution; 3) fibre length and distribution; 4) fibre-matrix interfacial strength and 5) properties of the matrix, respectively on the interdependencies between all these factors. Typical elastomer formulations contain many ingredients such as reinforcing and non-reinforcing fillers and curatives, with the fibres coming in addition, which interact either chemically or physically with each other. Many analytical tests are inconclusive in elucidating these interactions. Because of the need to investigate these interactions as well as the influence of processing, a systematic study was carried out making use of a simplified/basic gum-formulation. Publications showed sometimes large and otherwise small improvements in mechanical properties when the interfacial strength was improved in short fibre reinforced elastomer compounds. These were mainly derived from elementary tensile tests, where the effect of fibres was most conspicuous at low strains as an increase in tensile stress vs. non fibre–containing.

Ageing processes determining the service life of elastomer components. Over the course of time mechanical-dynamic (fatigue), oxidation processes, temperature, exposition to UV light (photo oxidation) and aggressive media lead to irreversible changes in the physical and chemical properties of an elastomer material, often resulting in premature functional failure of the component concerned. Especially in presence of high temperatures and mineral oils NBR and HNBR are used high performance polymers. The knowledge about chemical ageing mechanisms, kinetics and about the weak parts in the polymer chain and in the chemical network are fundamental for lifetime prediction and measures in stabilizing the polymer matrix. Already in the mixing and vulcanization process during manufacture as well as in a subsequent tempering operation (postcuring), the material undergoes thermo-oxidative stress, resulting in a certain prior deterioration. The oxidation reactions, responsible for the irreversible changes of properties, begin at the surface and are reduced in direction of the bulk of the material. So, the ageing process is a function of time and space. A gradient in hardness and stiffness from the surface into the bulk of the material is the consequence. This effect is described by the DLO-effect (Diffusion Limited Oxidation). Alongside the selection of polymers, the ageing process is determined mainly by the use of anti-ageing agents. The influence of crosslinking and of fillers on thermal-oxidative ageing has scarcely been investigated. Overall, for the prediction of life time of elastomers and for the application of simulation models an high interest is existing in a complete knowledge about the chemical mechanisms and especially in quantifying the ageing processes by means of kinetic data., Ageing processes determining the service life of elastomer components. Over the course of time mechanical-dynamic (fatigue), oxidation processes, temperature, exposition to UV light (photo oxidation) and aggressive media lead to irreversible changes in the physical and chemical properties of an elastomer material, often resulting in premature functional failure of the component concerned. Especially in presence of high temperatures and mineral oils NBR and HNBR are used high performance polymers. The knowledge about chemical ageing mechanisms, kinetics and about the weak parts in the polymer chain and in the chemical network are fundamental for lifetime prediction and measures in stabilizing the polymer matrix. Already in the mixing and vulcanization process during manufacture as well as in a subsequent tempering operation (postcuring), the material undergoes thermo-oxidative stress, resulting in a certain prior deterioration. The oxidation reactions, responsible for the irreversible changes of properties, begin at the surface and are reduced in direction of the bulk of the material. So, the ageing process is a function of time and space. A gradient in hardness and stiffness from the surface into the bulk of the material is the consequence. This effect is described by the DLO-effect (Diffusion Limited Oxidation). Alongside the selection of polymers, the ageing process is determined mainly by the use of anti-ageing agents. The influence of crosslinking and of fillers on thermal-oxidative ageing has scarcely been investigated. Overall, for the prediction of life time of elastomers and for the application of simulation models an high interest is existing in a complete knowledge about the chemical mechanisms and especially in quantifying the ageing processes by means of kinetic data.

Latex-state 13C NMR spectroscopy was applied to determine epoxy group content of epoxidized natural rubber in latex stage. The epoxidized natural rubber latex was prepared by epoxidation of deprotenized natural rubber (DPNR) with freshly prepared peracetic acid in latex stage. The resulting epoxidized DPNR (EDPNR) latex was characterized through latex-state 13C NMR spectroscopy. Signals of latex-state 13C NMR spectrum for EDPNR were similar to those of solution-state 13C NMR spectrum for EDPNR. Resolution of latex-state 13C NMR spectrum was gradually improve as temperature for the NMR measurement increased to 70 °C. Signals to noise (S/N) ratio of latex-state 13C NMR measurement was similar to those of solution-state 13C NMR measurement at temperature above 50 ̊C. The epoxy group content of EDPNR was quantitatively analyzed by latex-state NMR spectroscopy in latex stage, Latex-state 13C NMR spectroscopy was applied to determine epoxy group content of epoxidized natural rubber in latex stage. The epoxidized natural rubber latex was prepared by epoxidation of deprotenized natural rubber (DPNR) with freshly prepared peracetic acid in latex stage. The resulting epoxidized DPNR (EDPNR) latex was characterized through latex-state 13C NMR spectroscopy. Signals of latex-state 13C NMR spectrum for EDPNR were similar to those of solution-state 13C NMR spectrum for EDPNR. Resolution of latex-state 13C NMR spectrum was gradually improve as temperature for the NMR measurement increased to 70 °C. Signals to noise (S/N) ratio of latex-state 13C NMR measurement was similar to those of solution-state 13C NMR measurement at temperature above 50 ̊C. The epoxy group content of EDPNR was quantitatively analyzed by latex-state NMR spectroscopy in latex stage

Natural rubber foam (NRF) was produced by chemical blowing agent technique. The amount of chemical blowing agent was varied at 0-6 phr in sulfur vulcanization. The cure kinetics was observed and calculated from torque difference method from the moving die rheograph. Autocatalytic reaction behavior has been observed due to the characteristic of sulfenamide accelerator. In addition, kinetic parameters such as reaction orders (m, n) and activation energy (Ea) were studied by varying processing temperature and using Arrhenius’ law to calculate the activation energy. It was found that the m order of reaction reduced with increasing the content of chemical blowing agent due to low crosslink density of rubber molecules by sulfur. Natural rubber foam with different types of sulfenamide accelerator was also studied to observe the effect of sulfenamide structure on the cure kinetic of natural rubber foam. It was found that natural rubber foam with N-cyclohexyl benzothiazole-2-sulfenamide (CBS) accelerator showed the fastest cure kinetic with the lowest activation energy because it produced higher level of basicity of amine fragment than other sulfenamide accelerators after breaking and forming with other chemicals in sulfur vulcanization., Natural rubber foam (NRF) was produced by chemical blowing agent technique. The amount of chemical blowing agent was varied at 0-6 phr in sulfur vulcanization. The cure kinetics was observed and calculated from torque difference method from the moving die rheograph. Autocatalytic reaction behavior has been observed due to the characteristic of sulfenamide accelerator. In addition, kinetic parameters such as reaction orders (m, n) and activation energy (Ea) were studied by varying processing temperature and using Arrhenius’ law to calculate the activation energy. It was found that the m order of reaction reduced with increasing the content of chemical blowing agent due to low crosslink density of rubber molecules by sulfur. Natural rubber foam with different types of sulfenamide accelerator was also studied to observe the effect of sulfenamide structure on the cure kinetic of natural rubber foam. It was found that natural rubber foam with N-cyclohexyl benzothiazole-2-sulfenamide (CBS) accelerator showed the fastest cure kinetic with the lowest activation energy because it produced higher level of basicity of amine fragment than other sulfenamide accelerators after breaking and forming with other chemicals in sulfur vulcanization.

In order to improve rolling resistance and wet grip performance for passenger car tires that have been believed as trade-off functions, the block copolymer-coated silica nanoparticle was prepared by an in-situ controlled radical polymerization with particle (CRPwP)1) and the surface character of the modified silica was investigated. The surface energies and polarities of the silica were measured by a sessile drop method. The dynamic mechanical properties, Payne effect of the rubber compounds with the modified silica were investigated and compared with conventional compounds with using a silane coupling agent., In order to improve rolling resistance and wet grip performance for passenger car tires that have been believed as trade-off functions, the block copolymer-coated silica nanoparticle was prepared by an in-situ controlled radical polymerization with particle (CRPwP)1) and the surface character of the modified silica was investigated. The surface energies and polarities of the silica were measured by a sessile drop method. The dynamic mechanical properties, Payne effect of the rubber compounds with the modified silica were investigated and compared with conventional compounds with using a silane coupling agent.

In this work, carbon steel (CS) covered with bronze coating was treated by silane coupling agents with an aim to improve surface adhesion between metal and rubber blend. As we know the silane coupling agents offer the ability to form a durable bond between organic and inorganic materials. Through hydrolysis reaction R- silyl group can form a chemical bond with the inorganic surface. Two different chemical properties of materials provide high adhesive strength or improvement of the adhesion strength 1,2. The surfaces characteristics were analyzed by XPS, FTIR, and Contact angle measurements. Surface morphology of bronze surface treated by APS was investigated by AFM., In this work, carbon steel (CS) covered with bronze coating was treated by silane coupling agents with an aim to improve surface adhesion between metal and rubber blend. As we know the silane coupling agents offer the ability to form a durable bond between organic and inorganic materials. Through hydrolysis reaction R- silyl group can form a chemical bond with the inorganic surface. Two different chemical properties of materials provide high adhesive strength or improvement of the adhesion strength 1,2. The surfaces characteristics were analyzed by XPS, FTIR, and Contact angle measurements. Surface morphology of bronze surface treated by APS was investigated by AFM.

Acrylonitrile-butadiene random copolymer (NBR) rubber is widely used as O-ring, oil hose and so on due to the excellent performance of the rubber on oil and cold resistance. The performance depends on the volume fraction of acrylonitrile (AN) in NBR and the heterogeneous structure in NBR also affects the performance. Nishimura et al. have investigated NBR rubbers by small angle X-ray scattering (SAXS) and found the heterogeneous structure in the order of 10 -100 nm. In this study, we will focus on the heterogeneous structure of NBR rubber in the order of 1-10 nm scale and explore how the heterogeneous structures in NBR rubber with the volume fraction of AN., Acrylonitrile-butadiene random copolymer (NBR) rubber is widely used as O-ring, oil hose and so on due to the excellent performance of the rubber on oil and cold resistance. The performance depends on the volume fraction of acrylonitrile (AN) in NBR and the heterogeneous structure in NBR also affects the performance. Nishimura et al. have investigated NBR rubbers by small angle X-ray scattering (SAXS) and found the heterogeneous structure in the order of 10 -100 nm. In this study, we will focus on the heterogeneous structure of NBR rubber in the order of 1-10 nm scale and explore how the heterogeneous structures in NBR rubber with the volume fraction of AN.

Transient temperature prediction of a cylindrical rubber component under cyclic loading with a constant dynamic displacement and static compression force was performed based on nonlinear viscoelastic theory and coupled thermo-mechanical approach with finite element analysis. Particular attention was given to the material properties and constitutive modelling. The coupled thermo-mechanical approach, which requires an iterative procedure, can be divided into three major modules: deformation, dissipation, and thermal modules. In the deformation module, uniaxial, planar, and equibiaxial tensile stress strain test data were used to select appropriate hyperelastic constitutive equation. In the dissipation module, an analytical method for calculating the thermal source was established according to nonlinear viscoelastic theory of rubber materials. The dynamic properties were updated as a function of strain and temperature as the iterative solution proceeded. Mullins effect on viscoelastic properties and creep effect on deformation behaviours of rubber materials were also considered. For verification of the computed transient temperature, a sophisticated equipment was used to obtain the transient temperature measured both on plate and at the heart of the rubber component. The comparison between analytical results and experimental data shows the proposed method offers a satisfactory way to predict transient temperature distributions of rubber components., Transient temperature prediction of a cylindrical rubber component under cyclic loading with a constant dynamic displacement and static compression force was performed based on nonlinear viscoelastic theory and coupled thermo-mechanical approach with finite element analysis. Particular attention was given to the material properties and constitutive modelling. The coupled thermo-mechanical approach, which requires an iterative procedure, can be divided into three major modules: deformation, dissipation, and thermal modules. In the deformation module, uniaxial, planar, and equibiaxial tensile stress strain test data were used to select appropriate hyperelastic constitutive equation. In the dissipation module, an analytical method for calculating the thermal source was established according to nonlinear viscoelastic theory of rubber materials. The dynamic properties were updated as a function of strain and temperature as the iterative solution proceeded. Mullins effect on viscoelastic properties and creep effect on deformation behaviours of rubber materials were also considered. For verification of the computed transient temperature, a sophisticated equipment was used to obtain the transient temperature measured both on plate and at the heart of the rubber component. The comparison between analytical results and experimental data shows the proposed method offers a satisfactory way to predict transient temperature distributions of rubber components.

In this study, the changes in the cross-linked architectures during tensile deformation are quantitatively evaluated by in-situ measurements combining X-ray and SPM techniques. Here, the silicone elastomer is selected for the targeted material because the lower viscosities of the un-cross-linked raw silicone oligomers allow the desirable blending in the molecular level before cross-linking reaction, giving the homogeneous dispersion of the cross-links in the initial state., In this study, the changes in the cross-linked architectures during tensile deformation are quantitatively evaluated by in-situ measurements combining X-ray and SPM techniques. Here, the silicone elastomer is selected for the targeted material because the lower viscosities of the un-cross-linked raw silicone oligomers allow the desirable blending in the molecular level before cross-linking reaction, giving the homogeneous dispersion of the cross-links in the initial state.

Nowadays, with increasing environmental concern and dwindling fossil resources, more and more attention has been focused on the renewable resources. Bio-based elastomers are a new generation of synthesized elastomers whose raw materials are obtained primarily from renewable biomass feedstock1. In this study, pyridine-modified bio-based elastomer poly(dibutyl itaconate-ter-isoprene-ter-4-vinylpyridine) (PDBIIVP) was prepared for the purpose of designing and preparing green nanocomposites with strong interfacial interaction using green montmorillonite (MMT) and graphene oxide (GO) as the fillers. The ionic bonding interfaces in the nanocomposites were the result of electrostatic attraction between the in situ protonated pyridine groups of PDBIIVP and the electronegative MMT and GO sheets with hydrochloric acid during latex co-coagulation. The effect of pyridine groups was studied. This work of new polymer construction with the functional group targeting the interfacial interaction with filler is believed to be an important strategy for developing polymer nanocomposites with high performance., Nowadays, with increasing environmental concern and dwindling fossil resources, more and more attention has been focused on the renewable resources. Bio-based elastomers are a new generation of synthesized elastomers whose raw materials are obtained primarily from renewable biomass feedstock1. In this study, pyridine-modified bio-based elastomer poly(dibutyl itaconate-ter-isoprene-ter-4-vinylpyridine) (PDBIIVP) was prepared for the purpose of designing and preparing green nanocomposites with strong interfacial interaction using green montmorillonite (MMT) and graphene oxide (GO) as the fillers. The ionic bonding interfaces in the nanocomposites were the result of electrostatic attraction between the in situ protonated pyridine groups of PDBIIVP and the electronegative MMT and GO sheets with hydrochloric acid during latex co-coagulation. The effect of pyridine groups was studied. This work of new polymer construction with the functional group targeting the interfacial interaction with filler is believed to be an important strategy for developing polymer nanocomposites with high performance.

Ion-conductive elastomer blends of commercial acrylonitrile-butadiene rubbers (NBR) rubber with polyether-based electrolyte were prepared as potential antistatic materials. Polyether-based electrolytes are usually very sensitive to humidity because the electrolyte consists of hydrophilic polyether and metal salt. We generated a nano-ordered phase-separated structure in the NBR blends so as to improve their stability against varying humidity environment. For better control of the conductivity in the semi-conductive region under differing humidity conditions, we prepared NBR/polyether-based electrolyte blends with several acrylonitrile (AN) content of NBR, and studied the effects of CN groups on the conductive properties and structures using a DC conductivity system, DSC, FT-IR and TEM. We found that the conductivity of the blends increased with increasing AN content of NBR, implying that CN groups having strong electron withdrawing properties interact with the dissociated K ions. The FT-IR and TEM measurements show that the concentration of the CN groups is a crucial factor in determining the morphology of each blends and the improvement in conductivity between the NBR and polyether phases., Ion-conductive elastomer blends of commercial acrylonitrile-butadiene rubbers (NBR) rubber with polyether-based electrolyte were prepared as potential antistatic materials. Polyether-based electrolytes are usually very sensitive to humidity because the electrolyte consists of hydrophilic polyether and metal salt. We generated a nano-ordered phase-separated structure in the NBR blends so as to improve their stability against varying humidity environment. For better control of the conductivity in the semi-conductive region under differing humidity conditions, we prepared NBR/polyether-based electrolyte blends with several acrylonitrile (AN) content of NBR, and studied the effects of CN groups on the conductive properties and structures using a DC conductivity system, DSC, FT-IR and TEM. We found that the conductivity of the blends increased with increasing AN content of NBR, implying that CN groups having strong electron withdrawing properties interact with the dissociated K ions. The FT-IR and TEM measurements show that the concentration of the CN groups is a crucial factor in determining the morphology of each blends and the improvement in conductivity between the NBR and polyether phases.

In the present contribution, we propose a simulation of tyre shaping into a mould including the prediction of pantographing. When predicting the behaviour of the reinforced layers, an orthotropic fluid model based on superposition principle is invoked, where the orthotropy accounts for the reinforcements. Unreinforced layers of the assembly are described by means of standard models., In the present contribution, we propose a simulation of tyre shaping into a mould including the prediction of pantographing. When predicting the behaviour of the reinforced layers, an orthotropic fluid model based on superposition principle is invoked, where the orthotropy accounts for the reinforcements. Unreinforced layers of the assembly are described by means of standard models.

The surface modification of rubber materials is important for the practical use. However, the simple surface modification method of rubber materials is not established, and it has not been well studied. In this study, the control of the surface properties of rubber materials due to the addition of the fluorine-containing copolymer is investigated. In this paper, fluorine-containing copolymers were synthesized and added to natural rubber [NR] and styrene-butadiene-rubber [SBR]. These surfaces and mechanical properties were evaluated by the contact angle measurement, X-ray photoelectron scopy [XPS], and tensile test., The surface modification of rubber materials is important for the practical use. However, the simple surface modification method of rubber materials is not established, and it has not been well studied. In this study, the control of the surface properties of rubber materials due to the addition of the fluorine-containing copolymer is investigated. In this paper, fluorine-containing copolymers were synthesized and added to natural rubber [NR] and styrene-butadiene-rubber [SBR]. These surfaces and mechanical properties were evaluated by the contact angle measurement, X-ray photoelectron scopy [XPS], and tensile test.

It is known that the heat-resistance of perfluoroelastomers is excellent in comparison with other elastomers. Since the industrial demands are harder and harder year after year, some materials with higher heat-resistance are required. It is important for the additional improvement to know the mechanism of thermal degradation. We have examined gases evolved from perfluoroelastomers at high heating temperature under controlled-gas atmosphere by infrared spectroscopy and mass spectrometry., It is known that the heat-resistance of perfluoroelastomers is excellent in comparison with other elastomers. Since the industrial demands are harder and harder year after year, some materials with higher heat-resistance are required. It is important for the additional improvement to know the mechanism of thermal degradation. We have examined gases evolved from perfluoroelastomers at high heating temperature under controlled-gas atmosphere by infrared spectroscopy and mass spectrometry.

In order to bring reversible addition-fragmentation chain-transfer (RAFT) polymerization in industry, search for cheaper RAFT agent has been awaited to be developed. We perform radical polymerization mediated by Bis(dodecylsulfanylthiocarbonyl) disulfide (BisRAFT) which is less smelly and cheaper than its RAFT agent form: dodecylsulfanylthiocarbonates. It was found that polymerizations of acrylates, methacrylates and styrene with the BisRAFT agent showed living characteristic and polymers with narrow polydispersity index were obtained. As the result, the BisRAFT agent handled in the study can be a good candidate for the RAFT agent in industry, In order to bring reversible addition-fragmentation chain-transfer (RAFT) polymerization in industry, search for cheaper RAFT agent has been awaited to be developed. We perform radical polymerization mediated by Bis(dodecylsulfanylthiocarbonyl) disulfide (BisRAFT) which is less smelly and cheaper than its RAFT agent form: dodecylsulfanylthiocarbonates. It was found that polymerizations of acrylates, methacrylates and styrene with the BisRAFT agent showed living characteristic and polymers with narrow polydispersity index were obtained. As the result, the BisRAFT agent handled in the study can be a good candidate for the RAFT agent in industry

Studies on the toughening mechanism of double network hydrogels (DN gels) show that the internal rupture of the brittle network, which effectively dissipates energy and prevents catastrophic crack propagation upon loading gives the extraordinarily high toughness of the material. Thus, the bonds of brittle network act as ‘sacrificial bonds’, in similar to the proposed model for toughening of bones. This sacrificial bond mechanism, accordingly, suggests a new strategy for designing high-strength materials: incorporating, on purpose, a mechanically fragile structure to toughen the material as a whole. As the internal rupture of DN gels is due to the irreversible breaking of the covalent bonds of the brittle network, a DN gel shows Mullins effect and degenerates gradually after repeated deformation. To address this problem, recent works have replaced the covalent bonds with non-covalent bonds to allow the sacrificial bonds to be reformed. The sacrificial bond concept has been successfully applied to develop tough double network and multiple network elastomer materials. Thus, sacrificial bond concept is proved to be a general approach for developing tough soft materials., Studies on the toughening mechanism of double network hydrogels (DN gels) show that the internal rupture of the brittle network, which effectively dissipates energy and prevents catastrophic crack propagation upon loading gives the extraordinarily high toughness of the material. Thus, the bonds of brittle network act as ‘sacrificial bonds’, in similar to the proposed model for toughening of bones. This sacrificial bond mechanism, accordingly, suggests a new strategy for designing high-strength materials: incorporating, on purpose, a mechanically fragile structure to toughen the material as a whole. As the internal rupture of DN gels is due to the irreversible breaking of the covalent bonds of the brittle network, a DN gel shows Mullins effect and degenerates gradually after repeated deformation. To address this problem, recent works have replaced the covalent bonds with non-covalent bonds to allow the sacrificial bonds to be reformed. The sacrificial bond concept has been successfully applied to develop tough double network and multiple network elastomer materials. Thus, sacrificial bond concept is proved to be a general approach for developing tough soft materials.

Magnetic elastomer is a composite obtained by mixing with magnetic particles, and it demonstrates a magnetic-field response by applying magnetic fields. Under uniform magnetic fields, magnetic particles align to the direction of magnetic fields and form a chain structure, as a result the elastic modulus of magnetic elastomers changes to high modulus. This is called the magnetorheological (MR) effect as well as magnetic fluids [1-7]. Considering the industrial application of magnetic elastomers, the most important factor on the MR property would be the absolute change in the storage/loss modulus by magnetic fields. The absolute change in the storage/loss modulus can be easily varied by the volume fraction of magnetic particles or the softness of the matrix. For example, the absolute change in storage modulus for a magnetic elastomer with 80% magnetic particles was 650 folds higher than that for 20% magnetic particles. The absolute change in storage modulus for a magnetic elastomer with 65% plasticizer was 50 times higher than that for 0% plasticizer. Another important factor on the MR property is the magnetic-field sensitivity of the storage modulus against magnetic fields. This factor will be very important for a practical use since the magnetic-field sensitivity closely relates to the response time for changing the viscoelastic properties of magnetic elastomers. Here, the magnetic-field sensitivity is defined by the increment in the storage modulus against the magnetic field at low magnetic fields. The value of magnetic-field sensitivity distributes widely depending on the kind of magnetic elastomers. It can be considered that the magnetic-field sensitivity mainly depends on the mobility of magnetic particles within a cross-linked network. Moreover, the mobility of magnetic particles would be affected by the diameter of magnetic particle size, small magnetic particles can be easily move in the network and easily make a chain structure under magnetic fields. The vis, Magnetic elastomer is a composite obtained by mixing with magnetic particles, and it demonstrates a magnetic-field response by applying magnetic fields. Under uniform magnetic fields, magnetic particles align to the direction of magnetic fields and form a chain structure, as a result the elastic modulus of magnetic elastomers changes to high modulus. This is called the magnetorheological (MR) effect as well as magnetic fluids [1-7]. Considering the industrial application of magnetic elastomers, the most important factor on the MR property would be the absolute change in the storage/loss modulus by magnetic fields. The absolute change in the storage/loss modulus can be easily varied by the volume fraction of magnetic particles or the softness of the matrix. For example, the absolute change in storage modulus for a magnetic elastomer with 80% magnetic particles was 650 folds higher than that for 20% magnetic particles. The absolute change in storage modulus for a magnetic elastomer with 65% plasticizer was 50 times higher than that for 0% plasticizer. Another important factor on the MR property is the magnetic-field sensitivity of the storage modulus against magnetic fields. This factor will be very important for a practical use since the magnetic-field sensitivity closely relates to the response time for changing the viscoelastic properties of magnetic elastomers. Here, the magnetic-field sensitivity is defined by the increment in the storage modulus against the magnetic field at low magnetic fields. The value of magnetic-field sensitivity distributes widely depending on the kind of magnetic elastomers. It can be considered that the magnetic-field sensitivity mainly depends on the mobility of magnetic particles within a cross-linked network. Moreover, the mobility of magnetic particles would be affected by the diameter of magnetic particle size, small magnetic particles can be easily move in the network and easily make a chain structure under magnetic fields. The vis

Here, we used atomic force microscopy (AFM) nanomechanics, along with a specially designed holder, to visualize the nanoscale stress distribution of carbon black (CB)-reinforced isoprene rubber (IR) vulcanizate at various elongation ratios., We could quantitatively assess its volume fraction for the first time. The stress concentration having fibrillar structures (stress chains) formed around the CB fillers were successfully observed, which help us to understand the relationship between the local nanoscale stress distribution and macroscopic tensile properties., Here, we used atomic force microscopy (AFM) nanomechanics, along with a specially designed holder, to visualize the nanoscale stress distribution of carbon black (CB)-reinforced isoprene rubber (IR) vulcanizate at various elongation ratios., We could quantitatively assess its volume fraction for the first time. The stress concentration having fibrillar structures (stress chains) formed around the CB fillers were successfully observed, which help us to understand the relationship between the local nanoscale stress distribution and macroscopic tensile properties.

In this study, we measured stress and small angle X-ray scattering simultaneously under oscillatory one-axis elongation to investigate the relationship between mechanical property and the filler dispersion in rubber. The results show that the aggregates deform by one-axis elongation. In addition, we discuss the relationship between stress and structure., In this study, we measured stress and small angle X-ray scattering simultaneously under oscillatory one-axis elongation to investigate the relationship between mechanical property and the filler dispersion in rubber. The results show that the aggregates deform by one-axis elongation. In addition, we discuss the relationship between stress and structure.

The efficiency of an extrusion line also includes the quality of the extrudate, besides the typical parameters such as line speed, energy consumption and the amount of work. If this would not comply with the demands, the remaining features could be clearly above the average; nevertheless, the acceptance of the extrudate would remain moderate. The quality of the extrudate is again the sum of countless quantities that are defined, affected and controlled by a variety of participants. Which are, besides the rubber compound and their quality in terms of homogeneity and flow behavior, specific process parameters, head design, tools, stability of take-away conveyor, specific features of the extruder and also the rubber compound feed interacting with the feed roll., The efficiency of an extrusion line also includes the quality of the extrudate, besides the typical parameters such as line speed, energy consumption and the amount of work. If this would not comply with the demands, the remaining features could be clearly above the average; nevertheless, the acceptance of the extrudate would remain moderate. The quality of the extrudate is again the sum of countless quantities that are defined, affected and controlled by a variety of participants. Which are, besides the rubber compound and their quality in terms of homogeneity and flow behavior, specific process parameters, head design, tools, stability of take-away conveyor, specific features of the extruder and also the rubber compound feed interacting with the feed roll.

With the development of rubber industry, the preparation of new additives with high efficiency, multifunction and “green” has become a new research area. The tea polyphenols (TP) is a kind of natural compound, with a large number of phenolic hydroxyl groups in its molecular structure, and can be easily modified to prepare derivatives. In this paper, based on the Mannich reaction, TP was reacted with 2-mercaptobenzothiazole (accelerator M) and formaldehyde to prepare a new kind of TP based rubber additive (TPM). Its effects on the processing and mechanical properties of rubber compounds were investigated., With the development of rubber industry, the preparation of new additives with high efficiency, multifunction and “green” has become a new research area. The tea polyphenols (TP) is a kind of natural compound, with a large number of phenolic hydroxyl groups in its molecular structure, and can be easily modified to prepare derivatives. In this paper, based on the Mannich reaction, TP was reacted with 2-mercaptobenzothiazole (accelerator M) and formaldehyde to prepare a new kind of TP based rubber additive (TPM). Its effects on the processing and mechanical properties of rubber compounds were investigated.

Differential scanning calorimetry (DSC) measures the thermal flux differential between sample and reference during programmed temperature variations, to characterize physical and chemical changes related with heat effect. This paper studied the role of the typical zinc oxide/stearic acid activator system and its difference from zinc stearate in the vulcanization of natural rubber by DSC using squalene as analogue of natural rubber, and particularly studied the role of several aids launched in recent years that have vulcanization crosslinking capabilities in the processes of rubber vulcanization and anti-reversion. The examples include bismaleimides, biscitraconimides and acrylates, Differential scanning calorimetry (DSC) measures the thermal flux differential between sample and reference during programmed temperature variations, to characterize physical and chemical changes related with heat effect. This paper studied the role of the typical zinc oxide/stearic acid activator system and its difference from zinc stearate in the vulcanization of natural rubber by DSC using squalene as analogue of natural rubber, and particularly studied the role of several aids launched in recent years that have vulcanization crosslinking capabilities in the processes of rubber vulcanization and anti-reversion. The examples include bismaleimides, biscitraconimides and acrylates

A new international agreement on climate change as global warming was adopted in COP 21 on December 2015. We have to follow the guidelines for production activity. Especially, the hydrogen energy system was focused on the solution to global energy issues, but a lot of specialized problems are still left. High reliability and safety are required in hydrogen energy system. High-pressure hydrogen gas is difficult to seal by rubber materials due to blister fracture which the rapid gas decompression sometimes causes. The fracture failure of rubber seal often deteriorates sealing performance. In addition, the hydrogen properties such as physical deterioration, chemical change, permeability behavior and so on are not evaluated enough. High-pressure hydrogen seal durability, seal criteria standard and reliability improvement ways are not recognized sufficiently yet. In this study, we investigated sealing properties of high-pressure hydrogen gas in particular. Information about the technical issues regarding hydrogen energy system and seal material for high-pressure hydrogen devices were gathered. The accumulation of such information becomes more and more important for seal technology in the near future., A new international agreement on climate change as global warming was adopted in COP 21 on December 2015. We have to follow the guidelines for production activity. Especially, the hydrogen energy system was focused on the solution to global energy issues, but a lot of specialized problems are still left. High reliability and safety are required in hydrogen energy system. High-pressure hydrogen gas is difficult to seal by rubber materials due to blister fracture which the rapid gas decompression sometimes causes. The fracture failure of rubber seal often deteriorates sealing performance. In addition, the hydrogen properties such as physical deterioration, chemical change, permeability behavior and so on are not evaluated enough. High-pressure hydrogen seal durability, seal criteria standard and reliability improvement ways are not recognized sufficiently yet. In this study, we investigated sealing properties of high-pressure hydrogen gas in particular. Information about the technical issues regarding hydrogen energy system and seal material for high-pressure hydrogen devices were gathered. The accumulation of such information becomes more and more important for seal technology in the near future.

The contact area between hard road and bias tyre can be well described by ellipse, especially the tyre has large deformation. When the deformation is relatively small, the contact area may be described by a circle. The ellipses were also used to describe the contact areas of tractor tyres, aircraft tyres, and plate tests. In general, the contact area between radial tyre and ground is not an ellipse apparently, a rectangle with rounded ends was used to describe it, and half circles were used as the rounded ends usually. Because of using multiple curves to describe the contact area is not convenient, super ellipse was used to replace the curves; it can be a circle, ellipse or rectangle if the exponent is appropriately changed, and it was used to describe the contact area of agricultural tyres. Most simple contact areas can be described by the curves introduced above, however, the contact shape of tire with a slip angle and a steer angle cannot be well described by the equations mentioned above. In this paper, a new described model is developed to describe the contact shapes, and some examples are used to verify the equations., The contact area between hard road and bias tyre can be well described by ellipse, especially the tyre has large deformation. When the deformation is relatively small, the contact area may be described by a circle. The ellipses were also used to describe the contact areas of tractor tyres, aircraft tyres, and plate tests. In general, the contact area between radial tyre and ground is not an ellipse apparently, a rectangle with rounded ends was used to describe it, and half circles were used as the rounded ends usually. Because of using multiple curves to describe the contact area is not convenient, super ellipse was used to replace the curves; it can be a circle, ellipse or rectangle if the exponent is appropriately changed, and it was used to describe the contact area of agricultural tyres. Most simple contact areas can be described by the curves introduced above, however, the contact shape of tire with a slip angle and a steer angle cannot be well described by the equations mentioned above. In this paper, a new described model is developed to describe the contact shapes, and some examples are used to verify the equations.

This investigation concerns the study of the cohesion and adhesion forces in peroxide cured 1, 4-cis polyisoprene when different grades of carbon black compounded into the rubber formulation. The measured lap shears between the vulcanized rubber and the metal substrate have been correlated with the microstructural changes associated with the rubber in the cure process, detected by spectroscopy. These results could have a significant bearing on the mechanism of carbon black reinforcement as well as the strength development in adhesion forces of rubber to metal bonding with the objective of producing a uniform, high quality product that is free from failure. The results are discussed in the light of polymer conformation and carbon black aggregate structures, This investigation concerns the study of the cohesion and adhesion forces in peroxide cured 1, 4-cis polyisoprene when different grades of carbon black compounded into the rubber formulation. The measured lap shears between the vulcanized rubber and the metal substrate have been correlated with the microstructural changes associated with the rubber in the cure process, detected by spectroscopy. These results could have a significant bearing on the mechanism of carbon black reinforcement as well as the strength development in adhesion forces of rubber to metal bonding with the objective of producing a uniform, high quality product that is free from failure. The results are discussed in the light of polymer conformation and carbon black aggregate structures

High-resolution photoelectron spectroscopy is used to study the chemical composition at the rubber-brass adhesive interface and to elucidate mechanisms of strong adhesion and adhesion-degradation processes. A layer composed of CuxS (x ≈ 2) and CuS is formed as an adhesive agent. The CuxS/CuS ratio is higher at the bonding front than in the bulk of the adhesive layer. Thermal aging leads to the reduction of the CuxS/CuS ratio and the adhesion force. These results suggest the important role that CuxS (x ≈ 2) plays in adhesion, High-resolution photoelectron spectroscopy is used to study the chemical composition at the rubber-brass adhesive interface and to elucidate mechanisms of strong adhesion and adhesion-degradation processes. A layer composed of CuxS (x ≈ 2) and CuS is formed as an adhesive agent. The CuxS/CuS ratio is higher at the bonding front than in the bulk of the adhesive layer. Thermal aging leads to the reduction of the CuxS/CuS ratio and the adhesion force. These results suggest the important role that CuxS (x ≈ 2) plays in adhesion

In this study, several kinds of bismaleimides, including N,N'-4,4'-diphenylmethane bismaleimide (BMI), polymethene polyphenyl polymaleimide (PAPI-BMI) and etc, were studied in the natural rubber and styrene-butadiene rubber for tire applications. Their reactivitywith thenatural rubber, butadiene rubber andstyrene-butadiene rubber was studied throughthemodel compounds. The static and dynamic properties of the vulcanized compounds before and after aging were investigated. It was found that the tear resistance improved significantly for the bismaleimide containing compounds. These bismaleimide containing natural rubber compounds also showed better steel cord adhesion comparing to the blank reference. And the crack propagation speed after thermal aging was measured at different imposed energy in order to evaluate the effects of bismaleimides on the endurance performance of the rubber compounds, In this study, several kinds of bismaleimides, including N,N'-4,4'-diphenylmethane bismaleimide (BMI), polymethene polyphenyl polymaleimide (PAPI-BMI) and etc, were studied in the natural rubber and styrene-butadiene rubber for tire applications. Their reactivitywith thenatural rubber, butadiene rubber andstyrene-butadiene rubber was studied throughthemodel compounds. The static and dynamic properties of the vulcanized compounds before and after aging were investigated. It was found that the tear resistance improved significantly for the bismaleimide containing compounds. These bismaleimide containing natural rubber compounds also showed better steel cord adhesion comparing to the blank reference. And the crack propagation speed after thermal aging was measured at different imposed energy in order to evaluate the effects of bismaleimides on the endurance performance of the rubber compounds

Prevulcanization of isoprene rubber (IR) latex was investigated by latex-state 13C-NMR spectroscopy. The prevulcanization was carried out at 50 to 90 °C with vulcanizing agents. The signal at 44 ppm was assigned to secondary carbons adjacent to carbons linking to S atoms, whereas the signal at 58 ppm was assigned to tertiary and quaternary carbons linking to S atoms. The time evolution of the small signals at 44 and 58 ppm was investigated at various temperatures, and kinetic constants were determined at each temperature. The activation energy was estimated from the kinetic constants to be about 80 kJ/mol., Prevulcanization of isoprene rubber (IR) latex was investigated by latex-state 13C-NMR spectroscopy. The prevulcanization was carried out at 50 to 90 °C with vulcanizing agents. The signal at 44 ppm was assigned to secondary carbons adjacent to carbons linking to S atoms, whereas the signal at 58 ppm was assigned to tertiary and quaternary carbons linking to S atoms. The time evolution of the small signals at 44 and 58 ppm was investigated at various temperatures, and kinetic constants were determined at each temperature. The activation energy was estimated from the kinetic constants to be about 80 kJ/mol.

3-D printers and the 3-D Scanners, which can collect the 3D data from scanning a real object, cause much attention from around 2012 in Japan. These 3-D technologies provide us more opportunities to touch soft materials because the soft materials such as a rubber, plastic and gels are being usually used in many fields. For these reasons, it will be more important to investigate the physical properties of soft materials. However, theoretically there are no 3-D scanners that collect the data of the internal density distribution strongly related the physical properties. It means that a new system for scanning the internal structure and visualizing it are needed now. In this study, we have tried to develop the new 2-D/3-D system applying scanning microscopic light scattering (SMILS) system and to observe the internal fluctuation of transparent gels with our system. The SMILS based on the techniques of dynamic light scattering (DLS) and numerical analysis provides us the density distribution of crosslinking points to solve the frozen inhomogeneities in gel media. This system might be not only the fundamental device for analysis of gels and but also novel 3-D scanners that collect the inner structure of gel samples, 3-D printers and the 3-D Scanners, which can collect the 3D data from scanning a real object, cause much attention from around 2012 in Japan. These 3-D technologies provide us more opportunities to touch soft materials because the soft materials such as a rubber, plastic and gels are being usually used in many fields. For these reasons, it will be more important to investigate the physical properties of soft materials. However, theoretically there are no 3-D scanners that collect the data of the internal density distribution strongly related the physical properties. It means that a new system for scanning the internal structure and visualizing it are needed now. In this study, we have tried to develop the new 2-D/3-D system applying scanning microscopic light scattering (SMILS) system and to observe the internal fluctuation of transparent gels with our system. The SMILS based on the techniques of dynamic light scattering (DLS) and numerical analysis provides us the density distribution of crosslinking points to solve the frozen inhomogeneities in gel media. This system might be not only the fundamental device for analysis of gels and but also novel 3-D scanners that collect the inner structure of gel samples

Inflation pressure loss rates (IPLR) were measured for >300 passenger car tyres manufactured worldwide. Rolling resistance forces were measured and coefficients (RRC) calculated for 83 models. RRC was also measured upon decreasing inflation pressure in order to calculate the change in vehicle fuel economy with pressure loss. Current and projected data from the Exxon Mobil 2014 Energy Outlook is used for total light vehicles worldwide, and in selected countries in Asia Pacific. Using the average distances that vehicles are driven yearly and the average number of liters consumed to drive 100 kilometers, the total fuel consumed each year can be calculated. The potential fuel saved can then be calculated as a function of air loss using tyre IPLR and tyre reinflation at 3-month intervals. Corresponding savings in CO2 emissions are estimated., Inflation pressure loss rates (IPLR) were measured for >300 passenger car tyres manufactured worldwide. Rolling resistance forces were measured and coefficients (RRC) calculated for 83 models. RRC was also measured upon decreasing inflation pressure in order to calculate the change in vehicle fuel economy with pressure loss. Current and projected data from the Exxon Mobil 2014 Energy Outlook is used for total light vehicles worldwide, and in selected countries in Asia Pacific. Using the average distances that vehicles are driven yearly and the average number of liters consumed to drive 100 kilometers, the total fuel consumed each year can be calculated. The potential fuel saved can then be calculated as a function of air loss using tyre IPLR and tyre reinflation at 3-month intervals. Corresponding savings in CO2 emissions are estimated.

The spin-trapping method using ESR measurement was applied to a reaction analysis of mechanical degradation of styrene butadiene rubber (SBR) on milling at 77 K. As a result, some radical intermediates in the powder part of milled SBR were successfully trapped by the spin-trapping reagent which was dispersed in the SBR before, and the isotropic ESR spectrum of the spin adducts was able to be observed even after swelling the sample by benzene. The molecular structures of some radical intermediates produced by main chain scission of SBR were assigned. It was revealed that the mechanical degradation of SBR occurs homolytically in both trans-butadiene part and styrene part., The spin-trapping method using ESR measurement was applied to a reaction analysis of mechanical degradation of styrene butadiene rubber (SBR) on milling at 77 K. As a result, some radical intermediates in the powder part of milled SBR were successfully trapped by the spin-trapping reagent which was dispersed in the SBR before, and the isotropic ESR spectrum of the spin adducts was able to be observed even after swelling the sample by benzene. The molecular structures of some radical intermediates produced by main chain scission of SBR were assigned. It was revealed that the mechanical degradation of SBR occurs homolytically in both trans-butadiene part and styrene part.