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Natural Rubber (NR) has been used in dynamic applications for many years. NR has satisfactory resilience, vibration, and fatigue properties. Besides all these good properties, NR has quite poor aging resistance; also its service temperature is limited to about 90 °C. Improving aging characteristics of NR is a common problem for both rubber industry and academy. Nowadays, especially automotive industry has been focused on thermally resistant static and dynamic rubber based materials in new generation automobiles because of current strict emission regulations. There are a lot of attempts to improve service conditions of NR however; they are not comparable yet, with alternative saturated rubbers such as ethylene propylene diene monomer rubber (EPDM). In this study, a new grade EPDM, which had a high molecular weight, narrow molecular weight distribution, and tailor-made chain structure, has been studied in terms of rheological, mechanical, dynamic mechanical, aging, and low temperature properties for target dynamic applications. Especially possible service temperature and dynamic performance of EPDM were compared to that of NR based reference. It was concluded that, EPDM may be an assertive competitor to NR, if its chain structure is modified correctly. [ABSTRACT FROM AUTHOR]

Highlights • Comparing polyaniline with pentaerythritol as charring agent in flame retarded EPDM. • PANI compensated plasticizer-like effect of phosphorus flame retardants. • Improved mechanical properties. • PANI decreased effective heat of combustion and total heat evolved. • Passing glow-wire tests due to combining phosphorus flame retardants and PANI. Abstract Usually elastomers are loaded with high amounts of flame retardants to fulfill fire safety requirements. In this study the potential char precursor polyaniline (PANI) and the established fire retardant pentaerythritol (PER) were implemented in ethylene-propylene-diene monomer rubber (EPDM). PANI and PER were used in low loadings (7 phr) and combined with two phosphorous flame retardants, ammonium polyphosphate (APP) and a piperazine-pyrophosphate/phosphoric acid compound (FP), to boost their performance. A comprehensive study is presented, explaining the impact of PANI on curing and mechanical properties, including compensation for the plasticizer-like effect of APP in EPDM, and improved flame retardancy. In the cone calorimeter test, the combination of EPDM/FP/PANI reduced the effective heat of combustion by 20%. All nine EPDM rubber compounds were investigated with the LOI and UL 94 tests, cone calorimeter, FMVSS 302 and glow wire testing to quantify fire performance. The PANI-containing EPDM rubbers, EPDM/APP/PANI and EPDM/FP/PANI outperformed the corresponding PER containing, EPDM/APP/PER and EPDM/FP/PER rubbers in various tests. Moreover, the study investigated the impact of PANI and PER on the mode of action of the phosphorus species and showed that the addition of PANI increased the amount of phosphorus in the condensed phase. To receive a broader understanding of the flame retardant mode of action of PANI in combination with APP and FP, calculations were carried out to estimate the impact of PANI on the protective layer effect. [ABSTRACT FROM AUTHOR]

Ethylene-propylene-diene elastomer (EPDM) is employed as thermal insulation for rocket motors, as well as EPDM blends with ethylene vinyl acetate (EVA) have been used in the aerospace industry. The quantification of these blends is more common using Fourier Transform Infrared Spectrometry (FT-IR) by transmission mode, but without discussing sample preparation and methodology error. Considering this fact, a methodology was developed for determining EVA content in binary blend with EPDM samples, by Universal Attenuated Total Reflection (UATR) technique, associated to thermogravimetric analysis (TGA). This last one, it was applied to determine Vinyl Acetate (VA) content in EVA and to identify differences between EPDM/EVA blends. Samples of the analyzed blends showed two VA contents and five proportions of EPDM/EVA: 90/10, 70/30, 50/50, 30/70, and 10/90. The carbonyl stretching vibration band C=O at 1740 cm-1 was used as analytical band in FT-IR quantification. Finally, the results presented excellent accuracy with a good linear correlation coefficient (R > 0.940) and with relative error values lower than 2%, respecting the precision limits of the FT-IR spectrometer. [ABSTRACT FROM AUTHOR]

In recent years, bio-based polymers and fillers are attracting the attention of researchers due to strong concerns on environmental friendly production of rubbers. In this study, the waste walnut shell was used as an alternative filler for ethylene-propylene-diene monomer rubber (EPDM). The surface of the waste walnut shell was modified with bis[3-(triethoxysilyl)propyl] tetrasulfide to achieve a better interfacial interaction with EPDM matrix. Effect of different parameters on mechanical, thermal, and rheological properties of EPDM/waste walnut shell filler composite was investigated. It was seen that the increase of walnut shell content led the increase in tensile strength. Moving die rheometer tests have shown that the addition of walnut shell improved the torque value. In addition, the thermal tests were shown that using the waste walnut shell as filler results with no considerable difference in the thermal properties. Swelling test and cross-link density analyses showed that walnut shell addition has no negative effect on cross-link density. It was concluded that the waste walnut shell could be an effective filler with its advantages of bio-based and biodegradable. [ABSTRACT FROM AUTHOR]

• A novel EPDM ablation resistance composite was designed by integrating benzoxazine fine-tuned with octal (propyl glycidyl ether) polyhedral oligomeric silsesquioxane (BA-POSS) into the network structure of EPDM. • The EPDM/BAP18 composite in this study aims to strike a balance among these three key performance parameters (ablation rate, tensile strength, and elongation at break) of the insulation layer while maintaining a low density. • The structural evolution of EPDM composites during pyrolysis was studied through SEM, EDS, TG-IR and XPS, etc., in order to further understand the improvement of ablation resistance exhibited by EPDM composites. In order to meet the demands of the insulation layer in the swiftly advancing aerospace thermal protection system and enhance the ablation resistance of ethylene propylene diene rubber (EPDM) insulation layer, a novel EPDM ablation resistance composite was designed by integrating benzoxazine fine-tuned with octal (propyl glycidyl ether) polyhedral oligomeric silsesquioxane (BA-POSS) into the network structure of EPDM. The resulting composite exhibited a more densely cross-linked EPDM/BA-POSS network, consequently augmenting both the mechanical and ablation properties of the EPDM ablation resistance composite. The cross-linking density and tensile strength of EPDM/BA-POSS composite with 18 phr (parts per hundred rubber) BA-POSS increased by 78.4% and 30.7%, respectively, and the linear ablation rate significantly reduced by 47.7%, compared with EPDM composite without BA-POSS. Additionally, the ablation mechanism of EPDM/BA-POSS composites was elucidated through an investigation of the thermo-chemical transformation and analysis of the ablated carbon layer. This study contributes novel insights and methodologies for the future design of low-density rocket motor insulation compounds that offer cost efficiency, enhanced functionality, and wider applicability. [ABSTRACT FROM AUTHOR]

• The ceramizable insulation can be converted into SiC structure in situ. • VHPCS can effectively improve the interface performance between AF and EPDM. • VHPCS-coated aramid fibers can increase the content of SiC. As a type of filler with excellent performance, fibers can effectively enhance the mechanical properties and ablation resistance of the EPDM insulation layer inside a solid rocket motor. However, an excessive amount of short-cut fibers can reduce the mechanical performance of the insulation layer. Therefore, in this work, a novel EPDM insulation material was reinforced by aramid fiber (AF) coated with liquid hyperbranched polycarbosilane (VHPCS) to improve the mechanical properties and ablation resistance of obtained composites by enhancing the interfacial properties between EPDM and AF as well as protecting the AF framework by in-situ transformation into a ceramic structure during ablation. The test results demonstrated a significant improvement in the ablation performance of the AF insulation materials coated with VHPCS. The linear ablation rate and mass ablation rate decreased by 22.67 and 11.67%, respectively. Furthermore, compared with the composites without VHPCS, the elongation at break was improved while maintaining the original tensile strength (60.60%). XRD and XPS analysis confirmed the presence of SiC formation in the carbon layer during ablation. Thermal analysis indicated that VHPCS increased the mass residual rate of the EPDM composites. Coating AF with VHPCS-modified EPDM increased the content of SiC structures on the carbon layer surface, effectively protecting the carbon layer structure and enhancing the ablation performance of the ceramicizable insulation. [ABSTRACT FROM AUTHOR]

• The physical visco-hyperelastic constitutive model proposed by yuhai xiang can precisely represent static and dynamic mechanic behaviors of EPDM. • Mechanic behaviors of EPDM can be captured by using stress-strain curves of static and dynamic compression experiments to calibrate the physical visco-hyperelastic constitutive model. • An approximate physical visco-hyperelastic constitutive model for numerical calculation is developed. • Calculation efficiency and analysis accuracy of FEM model integrated with numerical algorithm of the approximate physical visco-hyperelastic constitutive model is verified. Multi-constitutive models integrated with microstructure parameters are suitable to capture different rubberlike material mechanical characteristics such as large deformation, hysteresis. However, the typical models are less often adopted to analyze realistic engineering problems due to difficult derivation of numerical algorithm which can be embedded into FEM models. Therefore, we take numerical algorithm derivation of physically visco -hyperelastic constitutive model proposed by Yuhai Xiang as an application example to analyze mechanic performance of EPDM (Ethylene Propylene Diene Monomer), which is widely utilized as cushion members of rail structure. After numerical algorithm is derived, static and dynamic compression tests are designed to calibrate mechanical parameters of EPDM. Finally, FEM models integrated with above numerical algorithm and calibration parameters are established to simulate mechanical response under different boundary conditions. In comparison of results between experiments and FEM simulations, accuracy and precision of numerical iteration formula and practicality can meet demands of engineering design and application when deformation and distortion of the FEM model mesh are not severe. We hope our work can supply some inspiration and be expanded to characterize, analyze, simulate and even predict performance of other similar rubberlike materials by applying suitable constitutive models in future. [ABSTRACT FROM AUTHOR]

Based on the analysis of aging behavior of ethylene propylene diene rubber(EPDM) and the mechanism of action of climate on EPDM,the aging data of EPDM exposed for 3 years in 11 typical material weathering test stations and the meteorological data there were studied to find out the relation between atmospheric environment and EPDM aging properties. By using the factor analysis and the technique for order preference by similarity to ideal solution(TOPSIS),the comprehensive values of aging properties were gained. With the grey correlation analysis,sever environmental parameters including irradiance,humidity,temperature were found to be the key climate factors which had a significant relation with the degradation of EPDM. Then a BP artificial neural network that connected the climate factors and EPDM aging properties was built. By inputting the meteorological data of cities,the comprehensive values of EPDM aging properties where weathering test had not been performed were predicted and a distribution map of these comprehensive values was draw out. The results show that the aging of EPDM in the south of Guangdong Province,Hainan Island,Taiwan Island,Tibet,and south of Xinjiang are the most serious.

The blends of EPDM and NR are immiscible in nature and incompatible. Introducing maleic anhydride as a compatibilizer into the blends was expected to produce compatible blends with balanced mechanical properties. The purpose of this research was to determine the effect of EPDM/NR ratio on the rheological, aging, thermal and swelling properties of the blends. The variation of EPDM/NR ratio were 100/0, 80/20, 70/30, 60/40, 50/50, and 40/60 phr. The blends were mixed using two roll mill. The results showed that the addition of NR affects the maximum torque, scorch time, and optimum vulcanization time. In the blends, EPDM plays an important role in improving aging, swelling, thermal properties.

EPDM (Ethylene propylene diene monomer) is one of synthetic rubber that widely used in automotive. It must be vulcanized and added by other materials before used. The aim of this study is to investigate the effect of vulcanization system and the addition of carbon black (CB) to the mechanical properties and swelling characteristic of EPDM. This research used three vulcanization system, conventional vulcanization (CV), efficient vulcanization (EV) and semi-efficient vulcanization (SEV) with the variation of carbon black 50, 60, 70 phr (per hundred resin). This research showed that EV system resulted faster vulcanization time and lower delta torque than SEV and CV systems. This system also performed the highest tensile strength, elongation, and tear strength, while SEV system resulted the highest hardness. Furthermore, the conventional vulcanization system resulted the lowest swelling index.

A novel mixing approach for achieving a good dispersion of multi-walled carbon nanotubes (MWCNTs) in ethylene- propylene diene monomer (EPDM) matrix has been investigated. In this approach EPDM was modified with vinyltrimethoxysilane (VTMS) during melt mixing. In addition the effect of MWCNT concentration on mechanical and rheological properties of modified EPDM has been studied. The formulated composites by this method exhibited significantly enhanced physical properties even at very low nanotube concentration. The grafting reaction was confirmed by Fourier transform infrared spectroscopy (FT-IR) peak at 1070 and 1250 cm-1according to Si-O and Si-C vibration. The state of dispersion of the fillers in the polymer matrix was evaluated through transmission electron microscopy (TEM) and scanning electron microscopy (SEM), In addition surface topology was studied with atomic force microscopy (AFM). The results showed that VTMS-grafted on the EPDM surface improved the dispersion of MWCNTs in the matrix. The rheological characteristics have been studied by rubber process analyzer (RPA). Some properties such as storage modulus (Ǵ) and complex viscosity (η^*) increased with increasing MWCNT content. It was found that at concentration of 2 wt.% MWCNT, the nanocomposites exhibited notably enhanced mechanical properties such as modulus and tensile strength.

Abstract The knowledge of the components that constitutes a rubber composition is important to justify the properties of the final device, particularly when it comes to elastomeric compositions used in the aerospace industry. The development of methodologies that can detect components, specially the smallest proportion of the rubbers composition is a constant challenge and an important gap in the studies of this nature. Therefore, methodologies by using standard techniques and/or of last generation are important in rubber industry and research laboratories, aiming application in related research. In this context, this study shows the coupling/association techniques (off-line) of thin layer chromatography and infrared spectroscopy (TLC/IR), being the IR spectra obtained by universal attenuated total reflection (UATR), applied to the analysis of additives in rubber compositions of ethylene-propylene-diene rubber (EPDM). Two EPDM compositions, a kind of eluent system and Gibbs' reagent, as developer, were used. Basically, all organic components were detected by this methodology, being possible to suggest that it can be applied for detecting additives of similar chemical structures, even though it's presents in small amounts in the composition.

This paper considers the problem of selecting the most appropriate ethylene propylene diene monomer (EPDM), which is a polyolefin with a variety of usages in different areas. The metallocene catalyst, bis(2-phenyl indenyl) zirconium dichloride ((2-PhInd)2ZrCl2) was synthesized by a modified method and applied to the terpolymerization of ethylene, propylene, and 5-ethylidiene-2-norbornene (ENB). The methylaluminoxane (MAO) was used as a cocatalyst. It showed an appropriate activity, a high incorporation ability of the comonomers, and good performance in terpolymerization. The compounded EPDM showed good thermal stability with time. Proper criteria were chosen for the selection of the best EPDM, and a hybrid of the analytical hierarchy process (AHP) and preference ranking organization method for enrichment evaluations (PROMETHEE) was used for prioritizing 15 different synthesized EPDM species. The sensitivity and Genetic Association Interaction Analysis (GAIA) analysis were also performed. Finally, one of the polymers, which had a very high quality and moderate yield, cost, and curing time was selected.

A grommet is a representative component that fixes the position of a cable. It is made from hyper-elastic materials (rubber), such as ethylene propylene diene monomer (EPDM). The grommet and cable are conventionally fixed through bonding; however, this method has numerous disadvantages that can be improved through relevant research. To apply a fixing method using the elastic force of EPDM rubber, this paper presents an empirical equation for approximating the bonding force of EPDM grommet parts with a hollow shaft geometry. First, tensile tests and the inverse method were used to approximate the basic mechanical properties. The physical properties were derived through basic tests; furthermore, bonding force tests and the inverse method were used on a grommet with a hollow shaft structure. In addition, the Box–Behnken design of experiments was used to predict the amount of change in the bonding force according to the geometry variables. Finally, this study was validated by comparing the approximation results derived through the design of experiments with the analysis and bonding force test results.

The present research investigates the effects of various concentrations of single-walled carbon nanotubes (SWCNTs) on the viscoelastic and thermomechanical characteristics of styrene-butadiene/ethylene propylene diene polymer (SBR/EPDM) blended polymeric matrices (60:40). Standard elastomeric methods are used to synthesise SWCNTs-reinforced EPDM/SBR nanocomposite blends. The results reveal that high SWCNTs concentrations offer remarkable thermal stability enhancement. SWCNTs reinforced with 0.6 mass% EPDM/SBR become 20% harder, with Tangent Delta values boosted by 70% with maximum cross-linking, elongation enhanced by 38% and tensile strength improved by 35%. With the 38% elongation enhancement, storage modulus is increased by 80%, whereas compressive strain is reduced by 20%. The planned hybrid nanocomposites exhibit viscoelastic characteristics against applied shock, in which the viscous component is associated with spongy structure, whereas the elastic component is associated with spring-like response.

Biofilms formed on rubber seals in dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health.

The vulcanization kinetics of Ethylene-propylene diene monomer (EPDM) rubber thermal insulation was studied by using rheometer under isothermal condition at different temperatures. The rheometry analysis was used to determining the cure kinetic parameters and predicting the cure time of EPDM thermal insulation. The experimental results revealed that the curing curves of EPDM thermal insulation were marching and the optimum curing time decreased with increasing the temperature. The kinetic parameters were determined from the autocatalytic model showed close fitting with the experimental results, indicating suitability of autocatalytic model in characterizing the cure kinetics. The activation energy was determined from the autocatalytic model is 46.3661 kJ mol-1. The cure time were predicted from autocatalytic model and the obtained kinetic parameter by using the relationship among degree of conversion, cure temperature, and cure time. The predictions of cure time provide information for the actual curing characteristic of EPDM thermal insulation. The mechanical properties of EPDM thermal insulation with different vulcanization temperatures showed the same hardness, tensile strength and modulus at 300%, except at temperature 70 °C, while the elongation at breaking point decreased with increasing temperature of vulcanization. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

AbstractThermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TG/FT-IR) is a very popular technique for rubbers characterization. It involves analyses of the base polymer and additives. Ethylene–propylene–diene (EPDM) rubbers are frequently investigated by TG/FT-IR; however, the focus has been the degradation temperature range of the polymer. In this study, unvulcanized and vulcanized EPDM rubber and its additives were investigated by TG/FT-IR, without solvent extraction, and in a wide temperature range. Initially, the additives were individually characterized. TG/FT-IR identified the characteristic groups of all the additives analyzed and distinguished them from each other. Afterwards, unvulcanized and vulcanized EPDM rubbers were investigated without prior extraction.TG/FT-IR detected absorptions due to the additives tetramethylthiuram monosulfide and 2-mercaptobenzothiazole. Both of these sulfur-containing additives were present in the EPDM formulation at concentrations of 0.7 phr (0.63 wt %). The TG/FT-IR technique had some limitations, because not all the additives in EPDM rubber were detected. Paraffin oil, stearic acid and 2,2,4-trimethyl-1,2-dihydroquinoline functional groups were not observed in either the unvulcanized or vulcanized EPDM. Nevertheless, in addition to the ability of this method to detect sulfur-containing groups, the lack of a pre-extraction reduces the time and effort required for additive analysis in rubbers.

Foi desenvolvida uma metodologia para a determinação do teor de 5-etilideno 2-norboneno (ENB) em amostras de borracha (elastômero puro), à base do copolímero de etileno-propileno-dieno (EPDM), por espectroscopia no infravermelho com transformada de Fourier (FT-IR) de transmissão, sendo as amostras analisadas, após pirólise controlada e em bico de Bunsen. Embora ambas as técnicas tenham apresentado boa precisão, a realizada por pirólise em bico de Bunsen, com uso de banda e concentração relativa, mostrou-se mais adequada à determinação e ao uso em cálculos complementares de teores de ET e P.

Abstract This work investigated the gamma-ray shielding, cure characteristics, physical, and mechanical properties of ethylene propylene diene monomer (EPDM) rubber composites with additions of metal oxides (either iron (II, III) oxide; Fe 3 O 4 , tungsten (III) oxide; W 2 O 3 or bismuth (III) oxide; Bi 2 O 3) for potential use as flexible, durable, and lead-free gamma-ray shielding materials. The results showed that increases in the metal oxide contents from 0 to 100, 300, and 500 phr (parts per hundred of rubber), respectively, improved the gamma-ray shielding properties of the EPDM rubber composites with the highest gamma attenuation in 500-phr Bi 2 O 3. The results also showed initial decreases in the cure times at a 100-phr metal oxide content but subsequently increased at higher contents (300 phr and 500 phr). Furthermore, while tensile modulus at 100% elongation and hardness (Shore A) kept increasing with increasing metal oxide contents, tensile strength and elongation at break behaved differently as they initially increased at 100 phr but later decreased at 300 phr and 500 phr. In addition, after the accelerated-weathering studies, the tensile modulus at 100% elongation and tensile strength of the EPDM rubber composites increased but the elongation at break and hardness (Shore A) decreased. In summary, the overall properties suggested that these developed metal oxide/EPDM rubber composites could be effectively used to replace lead-containing materials as durable gamma-ray shielding materials. Highlights • Metal oxide/EPDM rubber composites were developed as gamma-ray shielding materials. • Bi 2 O 3 /EPDM rubber composites had the highest gamma-ray shielding properties. • 500-phr Bi 2 O 3 /EPDM rubber composites had higher μ m than pure Pb sheets. • Bi 2 O 3 /EPDM composites could replace commercial lead-containing shielding materials. [ABSTRACT FROM AUTHOR]

Promising nanocomposites (EPDM-nRHP) were prepared from EPDM/ nanosized rice husk powder (nRHP) in the presence of HRH system as modifying dry bonding agent. HRH system comprised hydrated silica, resorcinol and hexamethylenetetramine. Different concentrations from nRHP were used for preparing such nanocomposites. The effect of nRHP was studied on the mechanical and dielectric properties of EPDM-nRHP nanocomposites whether in the presence or absence of HRH system. The presence of HRH modifying system enhanced the dispersion of nRHP in EPDM and consequently improved the mechanical and dielectric properties for the resulting EPDM-nRHP nanocomposites which may be used as electrical insulator. [ABSTRACT FROM AUTHOR]

Polypropylene (PP)–waste elastomer blends are particularly attractive as an economical way of producing sustainable materials, relieving the stress on the environment. Although PP is a commodity thermoplastic finding employment in various applications, its relatively low impact strength might be a significant factor limiting the variety of uses in many industries. Extensive consumption of thermoset elastomers has been a worldwide waste disposal problem. Here, we describe a facile, economical method for reuse of waste ethylene-propylene-diene monomer (EPDM) rubber to produce impact resistant blend materials with the PP via a high-shear thermokinetic mixer. In these blends, waste EPDM was used in various concentrations ranging from 20 to 80 wt%, as the remaining part, PP acts as a carrier matrix or a physical binder depending on the concentration in the blend. Briefly, fivefold increase was achieved in the impact resistance of PP by the addition of 60 wt% EPDM waste. The blend with 80 wt% waste EPDM shows characteristics similar to a thermoplastic elastomer. The conclusion of the study is that the blending method is quite effective to produce high-performance blend materials consisting of high concentrations of thermoset waste which addresses the worldwide disposal problem of waste thermoset rubbers. [ABSTRACT FROM AUTHOR]

Due to the severe impacts on the ecological environment and human life caused by oil leakage and organic solvent contamination of water bodies, a splendid absorption material is strongly demanded to remove the organic contaminants. In this research, we fabricated the superhydrophobic and superoleophilic absorption material of the ethylene-propylene diene monomer (EPDM) foam rubber modified with methyltrichlorosilane (MTCS) through a facile two-step approach including chemical coarsing and sol-gel process. The resultant foam rubber displayed favorable oil/water selectivity and strong repellence to water with contact angel of up to 159.3°. The prepared material displayed high absorption capacity for oils with a wider range of viscosity (from 0.3 to 400 mPa·s) and high oil/water separation efficiency of nearly 99.9%. More importantly, the as-obtained foam rubber exhibited an outstanding reusability and durability to both organic solvent and at least 100 cycles of mechanical compression, demonstrating its promising potential to serve as an absorbent in practical oil/water separation. [ABSTRACT FROM AUTHOR]

Abstract Cavitation is a damage process often observed during or after pressure release in polymers exposed to high-pressure diffusive gases. Only a few characterizations of the phenomenon have been reported in the literature, all of them being based on 2D pictures of the sample taken after removal from the pressure chamber or, more recently, inside the chamber during pressure release. This study displays the first time-resolved 3D imaging of decompression failure in high-pressure gas exposed polymers, obtained from in-situ X-ray computed tomography. New data were provided about the out-of-plane shape and volume distribution of cavities. It allowed rigorous estimation of a Morphological Representative Volume Element for the cavity field. The bias resulting from the former 2D-projection methods could be discussed. Highlights • Time-resolved 3D views of decompression failure in rubbers are reported for the first time. • An EPDM, exposed to high-pressure hydrogen, was tracked by in-situ computed tomography. • Novel and quantitative data were provided about the out-of-plane morphology and volume distribution of cavities. • Some bias, induced by 2D projection in the former visible light transmission methods, were discussed. • The experiment opens new routes for a better understanding and accurate quantification of decompression failure. [ABSTRACT FROM AUTHOR]

β-cyclodextrin with vinyl group (β-CD-MA) was synthesized from β-cyclodextrin (β-CD) and glycidyl methacrylate and identified by FT-IR and 1H-NMR spectroscopy analysis. A novel adsorption resin containing cyclodextrin cavity moieties was prepared by suspension polymerization technique with ethylene-propylene-diene (EPDM), styrene (St) and β-CD-MA as comonomers in this study. The adsorption resin was used as a solid skeleton for adsorption of phase change material such as polyethylene glycol (PEG) to prepare solid-solid phase change materials (SSPCMs). Structure and phase change behaviors of SSPCMs were studied by FT-IR and DSC, and the phase change process of the SSPCM was observed by using reflection mode of POM. The experimental results showed that the introduction of cyclodextrin cavity structure increased the adsorption capacity of PEG and improved the phase change latent heat of SSPCMs. Otherwise, during the whole process of phase change, the surface morphology of SSPCMs could be observed and appeared bright or dark change. During the transition, the whole PCMs remained in solid state. [ABSTRACT FROM AUTHOR]

Ethylene propylene diene polymethylene (EPDM) rubber is one of the fastest growing synthetic rubbers in the market. It is widely used in many fields due to its easy processing and high resistance against outdoor conditions compared to other rubber types. However, like all organic compounds, over time it is degraded under weathering conditions such as radiation, heat, ozone and chemical media, all of which can contribute to loss of bulk properties and reduce its service life. Cracks, discoloration, breakage, or staining can occur on the surface of visible automotive profiles due to the effect of UV light. These phenomena are definitely undesirable. In this study, five different EPDM rubber compounds (control and four different Flamestab® NOR 116 concentrations) were produced. The effects of the Flamestab NOR 116 were investigated by mechanical and rheological tests and ageing using the internationally recognised Florida artificial weathering test. The aged surfaces were visually scrutinised and surface morphological changes were examined via scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses. The results obtained showed that Flamestab® NOR 116 can be used as a UV stabiliser for EPDM rubber applications if it is added in amounts of between 1.25 and 2.0 phr. [ABSTRACT FROM AUTHOR]

In this study, the effect of bismuth (III) oxide addition on the mechanical, thermal, rheological and gamma ray attenuation capability of EPDM rubber was extensively investigated. In this context, surface modification with silane was carried out before bismuth oxide particles were incorporated into EPDM. In addition, EPDM samples including 10%, 20% and 30% (w/w) bismuth oxide were irradiated with doses of 25.6, 39 and 57 kGy up to irradiation period of 133 days using a gamma ray source with an initial dose rate of 18.3 Gy/h. Vulcanization parameters of EPDM with 30% bismuth oxide content were evaluated by using both of integral isoconversional method and Kamal-Sourour kinetic model. The activation energy, Ea, was determined as 86.3 kJ/mol. Mechanical tests result of non-irradiated and irradiated EPDM samples with 0 and 30% bismuth trioxide content show that bismuth trioxide content considerably affects the tensile properties. DSC and DMA analysis show that Tg increased with bismuth trioxide addition. The gel-content of the non-irradiated and irradiated EPDM compound was determined with Soxhlet extraction method and obtained result shown the gel-content was changed with the irradiation dose. Moreover, the effect of bismuth trioxide addition on radiation attenuation of EPDM composite was tested. Attenuation ratio from 68.6 to 94% were obtained for samples with different EPDM composite material thickness values. [ABSTRACT FROM AUTHOR]

The aim of this work was to study and develop a green process of plasticization and crosslinking of an EPDM matrix with a thiofuran based coupling agent. For this purpose, tung oil, composed of around 80 wt% of α-eleostearic acid, was used as both plasticizer and thermal crosslinker. Due to the low compatibility and weak interactions between vegetable oils and the EPDM matrix, the 2-furanmethanethiol (derived from the food industry) was used as a di-functional compatibilizing agent. The 2-furanmethanethiol was successfully grafted by a thiol–ene reaction onto both the tung oil and the EPDM matrix. The formulation was thermally treated in order to crosslink the EPDM matrix and the tung oil through expected Diels–Alder reaction. The reactions were evidenced by liquid 1 H NMR spectroscopy analysis. The crosslinked sample was characterized by different mechanical tests. The sample properties were also compared with the ones of an EPDM crosslinked by dicumyl peroxide (DCP) and plasticized by mineral oil. [ABSTRACT FROM AUTHOR]

The growing marine renewable energy sector has led to a demand for increasingly compliant mooring systems. In response, several innovative mooring tethers have been proposed demonstrating potential customisation to the stiffness profile and reduced peak mooring loads. Many of these novel systems utilise materials in a unique application within the challenging marine environment and their long term durability remains to be proven. This paper presents a multifaceted investigation into the durability of a novel polyester mooring tether with an elastomeric core. Laboratory based functionality tests are repeated on tether assemblies following a 6 month sea deployment. Results show a 45% average increase in dynamic axial stiffness. This is supported by high tension laboratory based fatigue endurance tests showing a peak increase in dynamic axial stiffness of 42%. Sub-component material tests on the core elastomer support the assembly tests, separately demonstrating that certain aspects of tether operation lead to increased material sample stiffness. The average increase in material radial compressive stiffness is 22% and 15% as a result of marine ageing and repeated mechanical compression respectively; these are the first results of this type to be published. The performance durability characterisation of the tether establishes the mooring design envelope for long-term deployment. This characterisation is crucial to ensure reliable and effective integration of novel mooring systems into offshore engineering projects. [ABSTRACT FROM AUTHOR]

Nowadays, amount of chrome tanned leather scraps (CTL) of leather industry is increasing rapidly due to decreasing interest on CTL utilization in related areas. These kind of wastes cause considerable negative environmental effects and therefore CTL producers should find new recycling and/or disposing routes for them. It is speculated that CTL may be a valuable additive in rubber based materials thanks to its similar bending properties. In this study, it is aimed to evaluate rheological, thermal, mechanical, morphological, and aging properties of CTL loaded EPDM based rubber compounds. CTL wastes are incorporated into EPDM in various ratios by using a banbury mixer and two roll mill, subsequently. Rheological measurements show that CTL incorporation does not cause considerable losses in compound properties. Higher glass transition temperatures of CTL containing composites are attributed to restricted chain mobility of EPDM in the composites. Cheap CTL incorporation significantly improves the tear resistance of EPDM before and after thermal aging due to fibrous nature of leather. [ABSTRACT FROM AUTHOR]

Butadiene–styrene/ethylene–propylene–diene monomer rubber blends were prepared with different blend ratios and modified with styrene–isoprene–styrene (SIS) and styrene–isobutylene–styrene (SiBS) triblock copolymers as compatibilizers. Influence of the triblock copolymers on the blend compatibility was examined utilizing scanning electron microscopy and differential scanning calorimetric analysis. Thermal stability of the prepared rubber blend vulcanizates, with and without incorporation of SIS and SiBS copolymers, was assessed by determining their physico-mechanical properties after exposure to thermal aging accelerated. Furthermore, the swelling behavior of the rubber blend vulcanizates under investigation was evaluated in organic solvent, oil, and in brake fluid. [ABSTRACT FROM AUTHOR]

The main aim is to investigate the effect of adding of 5% hydrolyzed poly (ethylene-co-vinyl acetate) (EVAOH), itaconic anhydride (naturally obtained during fermentation of sugars (It.anhydride)), and mercapto-modified ethylene-co-vinyl acetate (EVASH) as compatibilizers on the mechanical properties before and after thermal oxidative aging at 90°C for different time periods up to 7 days, electrical properties, and morphology of ethylene propylene diene monomer/ethylene vinyl acetate (EPDM/EVA) blends of different compositions (75/25, 60/40, 50/50, and 25/75, respectively). Stress at yield, tensile strength, and elongation at break of EPDM/EVA were improved markedly by the addition of 5% compatibilizers (EVAOH, It.anhydride, and EVASH). The micrographs of fractured surfaces obtained from the scanning electron microscope demonstrated further the enhancement of compatibility between EPDM and EVA by the addition of reactive compatibilizers. Further, the blends permittivity ε′ and dielectric loss ε″ have been measured at specific temperatures. The dielectric properties revealed that It.anhydride and EVASH/EPDM/EVA compositions are promising materials for insulation purposes. Finally, aging resistance was improved by the use of compatibilizers. [ABSTRACT FROM AUTHOR]

It is important to have a shielding material that is not easily breaking in order to have a robust product that guarantee the radiation protection of the patients and radiation workers especially during the medical exposure. In this study, nano sized lead oxide (PbO) particles were used, for the first time, to obtain an elastomeric composite material in which lead oxide nanoparticles, after the surface modification with silane binding agent, was used as functional material for radiation shielding. In addition, the composite material including 1%, 5%, 10%, 15% and 20% weight percent nano sized lead oxide was irradiated with doses of 81, 100 and 120 kGy up to an irradiation period of 248 days in a gamma ray source with an initial dose rate of 21.1 Gy/h. Mechanical, thermal properties of the irradiated materials were investigated using DSC, DMA, TGA and tensile testing and modifications in thermal and mechanical properties of the nano lead oxide containing composite material via gamma irradiation were reported. Moreover, effect of bismuth-III oxide addition on radiation attenuation of the composite material was investigated. Nano lead oxide and bismuth-III oxide particles were mixed with different weight ratios. Attenuation tests have been conducted to determine lead equivalent values for the developed composite material. Lead equivalent thickness values from 0.07 to 0.65 (2–6 mm sample thickness) were obtained. [ABSTRACT FROM AUTHOR]

Three types of bio-alkyd resins varies in their oil content and viscosity were added to EPDM rubber mix loaded by three bonding system consisting of Hexamethylenetetramine, Resorcinol and Hydrated silica (HRH). The mixes were charged by certain amount of thermal carbon black. Rubber dough was spread on polyester sheet fabric. The peel strength was used to measure the adhesion strength. The rubber-proofed fabric subjected to UV irradiation at different period of times. The dielectric constant, volume resistivity, thermal stability, water and air permeability of the various rubber coated fabric were examined. The addition of the bio-alkyd resin improved the various mechanical and physical properties of the rubber coated fabric materials. The suggested mechanism of bio-alkyd resin between EPDM and polyester fabric was also studied. [ABSTRACT FROM PUBLISHER]

Effects of mechanical stretching, produced after the expansion of cable accessories, on the electrical tree growth characteristics of EPDM (Ethylene Propylene Diene Monomer) are reported in the present work. FFV (fractional free volume) and CED (cohesion energy density), which were respectively related to free path of electrons and molecular chains splitting during electrical tree propagation process, were calculated through molecular dynamics simulations under different stretching ratios. A needle-plane electrode system with the stretching ratio ranging from 0 to 30% was used to investigate the electrical treeing characteristics in the experimental study. The simulation results show that the FFV becomes larger at higher stretching ratio, which enhances the collision between the hot electron and the molecular chain during the treeing process by extending the free path of the hot electron. While CED tends to become smaller at higher stretching ratio, reducing the cohesion strength for the tree channel crack to grow. Moreover, FFV and CED are investigated during the stretching recovery process, where FFV tends to decrease and CED turns to be larger. The experimental results indicate that mechanical stretching affects the electrical tree inception and propagation characteristics. The inception time of electrical tree becomes shorter as stretching ratio increases from 0 to 30%. Tree length and accumulated damage become larger with increasing the stretching ratio. Electrical tree propagation mechanism considering chemical and physical traps, which are generated under mechanical stretching, are also discussed and analyzed. [ABSTRACT FROM AUTHOR]

To ensure a certain interface electrical strength resistance, the cable accessories are densely coated onto the main cable insulation. Compressive stress is generated in the normal direction of high voltage cable by the spring clamp device or the banding force after the expansion of EPDM (Ethylene Propylene Diene Monomer) stress cone. This paper presented a compressive stress experimental study considering electrical treeing propagation in EPDM by employing a needle-plane electrode system. The results indicate that compressive stress affects the electrical tree inception and propagation characteristics. The inception time of electrical tree becomes longer as compressive rate increases from 0 to 30%. Tree length and accumulated damage become smaller with increasing the compressive rate. Electrical tree structure is also depended on compressive stress, and branch tree structure becomes the main electrical tree morphology at higher compressive rate. For better understanding the effects of compressive stress on electrical tree propagation characteristics, FFV (fractional free volume) and CED (cohesion energy density) were calculated and analyzed through molecular dynamics simulations under different compressive rates. Results show that the FFV becomes smaller at higher compressive rate, which shortens the free path of the hot electron and weakens the collision with the molecular chain during the treeing process. While CED tends to be lager under higher compressive rate, which improves the cohesion strength for the crack to grow in the tree channel tips and restrains the propagation of electrical tree. [ABSTRACT FROM AUTHOR]

In this paper the modifications induced in butyl rubbers (pristine, chlorinated and brominated sorts) by γ-irradiation are investigated by swelling, chemiluminescence and FT-IR. The susceptibility of butyl rubbers for the generation of radicals orders their stabilities in the following sequence: IIR > IIR—Cl > IIR—Br. The incorporation of butyl rubbers into ethylene-propylene terpolymer matrix brings about increased densities of radicals initiating modifications in the oxidation state in respect with recombination, which are intensified as the processing dose increases. Based on the variation of carbonyl and hydroxyl indices the favorable route for the recycling EPDM based formulations would be suggested in this study. The chemiluminescence spectra proving the formation of peroxyl radicals at about 100 °C prove their availability as reclaiming solutions. IIR—Br is the recommendable butyl rubber for the recovery procedure by association with EPDM. The suitability of IIRs for recycling purposes is analyzed by the variation in their crosslink densities, free volumes and swelling degrees. The crosslinking behavior of stabilized EPDM/IIR blends that runs to the improvement of durability is depicted by Charlesby–Pinner representation, which involves the different simultaneous contribution of scission and crosslinking processes. [ABSTRACT FROM AUTHOR]

Biofilms formed on rubber seals in dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic fourspecies bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health. [ABSTRACT FROM AUTHOR]

This work is dedicated to the mechanism underlying the influence of the oxidation on the dynamic and static characteristics of ethylene-propylene-diene monomer (EPDM) copolymer. A molecular dynamics simulation was employed to provide an insight into the effects of oxidation on the micro and macroscopic properties, such as the density and self-diffusion, free volume, glass transition, and chain transition dynamics. The carbonyl product, the chain scission, and the crosslinking in the EPDM were considered. Self-coefficients and radial distribution function were analyzed to achieve the diffusion and the structure of the systems using a 10 ns produce run at an equilibrium (298 K). The temperature dependence of glass transition and the autocorrelation function for internal torsional rotation have been discussed for understanding the chain dynamics and flexibility after aging, such as the relaxation time and the activation energy. It turns out that the introduction of more carbonyl groups suppresses the internal rotation and the conformational transition of the chains, resulting in the decrease of diffusion and less flexibility due to the strong polar interaction. A system associated with short chains after chain scission possesses a low activation energy, indicating a more flexibility of the chains. Furthermore, the crosslinked structure contributes to the weak chain transition of EPDM (higher T g ) and the high modulus (harden). The different molecular dynamics could be derived from the interaction energy and the structures, such as polar and nonbonded interaction. Some aspects of the details of chain rotation are discussed in this paper. [ABSTRACT FROM AUTHOR]

Polymer materials are used widely as sealing materials and liners in hydrogen storage and transportation infrastructure. During operating conditions, polymers are exposed to high pressure hydrogen gas periodically. When in contact, the hydrogen gas diffuses through the polymer material with ease due to its smaller sized molecules compared to the polymer molecules. In the event of rapid decompression of outside hydrogen gas, the hydrogen molecules within the polymer diffuse out. This process is known as the desorption of polymer and can cause blisters or cracking causing permanent damage to the polymer. Here, we used a combined experimental and modeling approach to investigate the desorption of the hydrogen gas in the polymer. Thermal desorption analysis (TDA) experiments were performed on the polymer sample exposed to the high-pressure hydrogen gas to measure the diffusion coefficient and equilibrium hydrogen concentration. Experiments also provided the quantity of hydrogen within the polymer during the desorption process which followed Fick's law. However, for higher pressurization values, some anomaly was observed in the quantity of hydrogen remaining in the polymer sample. A continuum mechanics based coupled diffusion–deformation-damage model was deployed to simulate the gas desorption process in the material using the finite element method to understand its effect on the material. It was found that the anomaly in TDA results were due to the blister formation on the polymer surface which resulted in longer hydrogen retention. Simulations also showed that blister formation can be affected by multiple parameters such as the addition of filler particles, and pre-existing cavity size. • Presents an experimental plus modeling approach to investigate the desorption of H 2. • Diffusivity of H 2 was obtained by thermal desorption analysis-gas chromatography. • A study was conducted for EPDM polymer and its two variants. • Addition of fillers was found to increase the coefficient of diffusion of the EPDM. • A coupled diffusion–deformation model was used to simulate the desorption process. [Display omitted] [ABSTRACT FROM AUTHOR]

During the COVID-19 pandemic, the use of face masks has been a worldwide primary protection measure to contain the spread of the virus. However, very little information is known about the possible inhalation of microplastics (MP) from wearing masks. This pilot study evaluates the presence of MP accumulated in nasal cavities through the nasal lavages technique. Six different commercial face masks were tested in 18 participants during five working days (8 h use/day). Eight different polymers (polystyrene, polyamide, poly(ethylene – propylene) diene monomer, polyester, polyethylene, polyvinylidene fluoride, polypropylene, and polyvinyl chloride) predominantly within the 20–300 µm size were detected in nasal lavages, with an average concentration of 28.3 ± 15.6 MP/5 mL nasal solution. Results demonstrate that MP in the nasal cavity are not associated to face mask use but rather to general exposure to airborne MP. We highlight the use of nasal lavages to evaluate human inhalation of MP and associate it to potential sources and risks. [ABSTRACT FROM AUTHOR]