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This study investigates the feasibility of fabricating a dynamic foot prosthesis for lower knee amputees using a composite material composed of polypropylene (PP), fresh cow bone powder (FCBP), and silicon rubber (Si). Nine samples with variable compositions of these components were prepared and subjected to mechanical testing to evaluate their compression strength, elongation, factor of safety, impact energy, and energy storage efficiency. The results demonstrated that the innovative composite made up of 68% PP, 18% FCBP, and 14% Si has exhibited the highest foot energy storage efficiency of 67.83%, which is within the standards of 63–100%. Furthermore, the synthesised dynamic foot has obtained excellent mechanical properties and a maximum factor of safety of 2.71. Accordingly, this study proposes that the developed composite material has the potential to be utilised for the fabrication of dynamic foot prostheses, as it offers a set of improved mechanical properties and potentially enhances the mobility and quality of life for lower knee amputees. [ABSTRACT FROM AUTHOR]

Constructing a synergistic effect with different structural fillers is an important strategy for improving the comprehensive properties of polymeric composites. To improve the comprehensive properties of two-component additive liquid silicon rubber (SR) materials used in electronics packaging, the synergistic effect of granular aluminum nitride (AlN) and tubular carbon nanotube (CNT)-reinforced SR nanocomposites was investigated. AlN/CNT/SR composites with different AlN/CNT ratios were fabricated with two-component additive liquid SR via the thermal curing technique, and the influence of AlN/CNT hybrid fillers on the hardness, strength, elongation at break, surface resistivity, thermal conductivity, and thermal decomposition was investigated in detail. With the incorporation of AlN/CNT hybrid fillers, the comprehensive properties of the obtained AlN/CNT/SR composites are better than those of the AlN/SR and CNT/SR composites. The synergistic thermal conductive mechanism of AlN/CNT hybrid fillers was proposed and demonstrated with the fractural surface morphology of the obtained composites. The obtained AlN/CNT/SR composites show promising applications in electronic packaging, where necessary mechanical strength, electrical insulating, thermal conductivity, and thermal stable materials are needed. [ABSTRACT FROM AUTHOR]

Flame retardant rubber composites have attracted a great attention during the past decades owing to their irreplaceable roles in complex industrial systems. Large amounts of efforts have been made to improve the flame retardant ability, developing high efficiency flame retardant systems which can reduce the release of heat, smoke and toxic gases while not deteriorate overall properties is becoming more and more important. This review briefly outlines the recent developments of flame retardant natural rubbers, silicon rubbers, some kinds of artificial rubbers and polyurethane elastomer composites, focuses on the design, development, mechanism and applications of advanced high-performance flame-retardant methods. Finally, outlooks the future tendency including more environmental-friendly strategies, higher flame-retardant efficiency and development of multifunctional flame-retardant rubber composites are proposed.

Constructing a synergistic effect with different structural fillers is an important strategy for improving the comprehensive properties of polymeric composites. To improve the comprehensive properties of two-component additive liquid silicon rubber (SR) materials used in electronics packaging, the synergistic effect of granular aluminum nitride (AlN) and tubular carbon nanotube (CNT)-reinforced SR nanocomposites was investigated. AlN/CNT/SR composites with different AlN/CNT ratios were fabricated with two-component additive liquid SR via the thermal curing technique, and the influence of AlN/CNT hybrid fillers on the hardness, strength, elongation at break, surface resistivity, thermal conductivity, and thermal decomposition was investigated in detail. With the incorporation of AlN/CNT hybrid fillers, the comprehensive properties of the obtained AlN/CNT/SR composites are better than those of the AlN/SR and CNT/SR composites. The synergistic thermal conductive mechanism of AlN/CNT hybrid fillers was proposed and demonstrated with the fractural surface morphology of the obtained composites. The obtained AlN/CNT/SR composites show promising applications in electronic packaging, where necessary mechanical strength, electrical insulating, thermal conductivity, and thermal stable materials are needed.

Entangled metallic wire material–silicone rubber (EMWM–SR) composites with a three-dimensional interpenetrating network structure were manufactured through the vacuum infiltration method with the matrix of entangled metallic wire material (EMWM) and reinforcing element of silicone rubber (SR). Quasistatic compression tests and low-velocity impact tests of the proposed composites were performed, and the deformation model and damage characteristics of the tested EMWM–SR composites were investigated by performing computerized tomography scans and indentation depths. Experimental results show that the stiffness and energy consumption of the EMWM–SR composites are more than twice the sum of those of the individual EMWM and SR in the displacement range of 1.5–4.0 mm. With the increase of loading displacement, the stiffness of EMWM–SR composites increases steadily and the energy consumption increases sharply. Compared with EMWM and SR, the maximum displacement and peak force of the composite materials are decreasing significantly in the low-velocity impact tests. With increasing density, the impact resistance of the composites increases, while the energy absorption decreases. In other words, EMWM–SR 2.6 has better impact resistance but lower energy absorption capacity. The maximum displacement and the peak force increase synchronously with the increase in impact velocity. Interestingly, the composites maintain a high energy absorption capacity at different impact speeds. Furthermore, the energy absorption characteristics of the EMWM–SR composites under low-velocity impact are described in terms of the deformation mechanism of the wires.

The research progress in dynamically vulcanized polyurethane/silicone rubber thermoplastic elastomer was summarized from the aspects of raw material selection, processing technology and compatibilizer with 20 references.

Abstract Marine biofouling will bring a series of environmental and social problems, which restrict the development and utilisation of marine resources. Therefore, how to prevent biofouling has become a global issue. With the exploration of antifouling methods, bionic antifouling technology with environmentally friendly, broad‐spectrum, and long‐term advantages has gradually attracted people's attention. Inspired by the antifouling strategy of soft coral (Sarcophyton trocheliophorum), the silicone rubber (RTV‐2) with similar elasticity to coral skin was selected as the substrate. The composite structure of the upper transparent layer and the lower porous layer was prepared by simulating the structure of soft coral as the structural factors of the bionic antifouling coatings. Meanwhile, several organic antifouling components with high content contained in soft coral were added to the transparent layer and porous layer, respectively, as the component factors of biomimetic coatings. The bionic antifouling coatings, which are highly consistent with the coral structure, obtained the best antifouling performance under static and dynamic conditions. The above results provide new ideas for the synthesis of environmentally friendly bionic antifouling coatings.

In this work, boron nitride nano sheets (BNNSs) were prepared by exfoliation of h-BNs using mono ethylene glycol (MEG) as a novel exfoliating agent. For comparison, isopropyl alcohol (IPA)/water mixture was also used for exfoliation of h-BNs. It was found that using MEG caused preparing nano layers with higher yield and lower thickness compared to the IPA/water mixture. Thereafter, silicon rubber nanocomposites contained 3 and 5 wt% of pure and exfoliated BNNSs were prepared and evaluated for thermal and electrical performances. It was found that h-BNs and exfoliated-BNs drastically enhanced thermal conduction of SR. The silicon rubber contained 5 wt% of the h-BN and exfoliated-BNs illustrated around 20 times higher thermal conductivities compared to pure SR. Exfoliation of h-BNs had negligible effect on improvement of thermal properties, however, it caused 5.7 and 2.3 times enhancement in the electrical volume resistivity compared to the pristine SR and pure h-BN containing nanocomposite, respectively. Both of the BNNSs caused improvement in the heat dissipation performances of SR matrix, however, the exfoliated one with MEG showed better performances. Based on the results, it was claimed that mono ethylene glycol could improve exfoliation of h-BNs and enhance the performances of silicon rubber.

Silicone rubber (SR)/vinyl-graphene oxide (vinyl-GO) nanocomposites were prepared through the hydrosilylation reaction of silicon hydrogen polydimethylsiloxane (H-PDMS) with vinyl polydimethylsiloxane (vinyl-PDMS), in which vinyl-GO was used as a nano filler. The thermally conductive and antistatic properties of the nanocomposites, and their tensile strength and thermal stability were evaluated. The thermally conductive and antistatic properties increased naturally when the nanocomposites had eight to nine parts of vinyl-GO. The addition of 9 parts of vinyl-GO increased the thermal conductivity to 0.44 from 0.17 W/m−1·K−1 of neat SR and the surface resistance value to 108 from 1014 Ω of neat SR. Vinyl-GO is effective in improving the tensile strength and toughness of the nanocomposites. The tensile strength and elongation at break of the nanocomposites were much higher than that of neat SR, especially for 10 parts of vinyl-GO in the nanocomposite, and the tensile strength was 1.84 MPa and the elongation at break was 314.1%. Additionally, compared with neat SR, the nanocomposites had a much higher thermal stability. For eight parts of vinyl-GO in the nanocomposites, H-PDMS with the selected silicon hydrogen content and vinyl-PDMS with the selected vinyl content could offer an appropriate cross-linking degree that suits the character of GO. When the nanocomposite had eight parts of vinyl-GO, its scanning electron microscope exhibited a monolayer GO with folded, twisted, and local surface folds. However, there was a certain amount of multilayer aggregation of GO for 10 parts of vinyl-GO in the nanocomposite. [ABSTRACT FROM AUTHOR]

Marine biofouling will bring a series of environmental and social problems, which restrict the development and utilisation of marine resources. Therefore, how to prevent biofouling has become a global issue. With the exploration of antifouling methods, bionic antifouling technology with environmentally friendly, broad‐spectrum, and long‐term advantages has gradually attracted people's attention. Inspired by the antifouling strategy of soft coral (Sarcophyton trocheliophorum), the silicone rubber (RTV‐2) with similar elasticity to coral skin was selected as the substrate. The composite structure of the upper transparent layer and the lower porous layer was prepared by simulating the structure of soft coral as the structural factors of the bionic antifouling coatings. Meanwhile, several organic antifouling components with high content contained in soft coral were added to the transparent layer and porous layer, respectively, as the component factors of biomimetic coatings. The bionic antifouling coatings, which are highly consistent with the coral structure, obtained the best antifouling performance under static and dynamic conditions. The above results provide new ideas for the synthesis of environmentally friendly bionic antifouling coatings. [ABSTRACT FROM AUTHOR]

A new nanocomposite superhydrophobic of the RTV (room temperature vulcanized) silicon rubber reinforced with a different percentage of nanosilica was prepared by a two-stage sol-gel route to obtain a superhydrophobic surface coating on high voltage glass insulator, preventing the dust-water droplet from adhering to its surface. The cold spraying technique was utilized to build up a thin nanocomposite superhydrophobic layer on the glass insulator containing different percentages of the nanosilica particles, such as 23 wt %, 33 wt %, and 44 wt % with RTV silicon substrate. The synthesized nanocomposite was analyzed using the contact angle, roughness, adhesion, hardness, and dielectric strength tests. Moreover, the prepared RTV silicon rubber/nanosilica superhydrophobic nanocomposite layer was characterized using the field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and the particle size analysis test. Based on the results, the nanosilica particles were well-incorporated into the RTV silicon rubber, obtaining an excellent homogenous distribution thin layer on its surface, supporting its capability to be a superior superhydrophobic surface. The results reveal that the RTV silicon rubber/33wt % nanosilica was the best as a superhydrophobic behavior with a contact angle reaching higher than 158°± 3; also, a significant change in the dielectric strength was obtained to be 25.5 kV (using a speed voltage of 5.0 kV/s). Importantly, the flashover test was also conducted, and it was found that there was a significant change in the leak current between the coated and uncoated samples. The leak current of the coated sample with a superhydrophobic nanocomposite was reduced to 2.5 mA, while the uncoated sample became 3.2 mA using a voltage load value of 60 kV. The results presented here may improve the nanocomposite material as an antiweathering superhydrophobic thin layer supported by the prepared nano-SiO2 particles against the dust-water droplets which may be adhesive to the high voltage glass insulator. [ABSTRACT FROM AUTHOR]

The problem of the research conceder Inefficiency of the floors of open or closed sports fields in weather conditions such as heat and rain. also, the floors of sports fields are affected by constant pressure on them, which exposes them to damage and shredding. Most of these floors are imported from abroad and there is no Egyptian technology to produce them. The research aims to providing local qualities for sports stadium floors produced with Egyptian technology and using reinforced fillers of banana and glass fibers. In this research, a hybrid superposed material based on polymeric basis was prepared using the hand lay-up method. - 4 silicon rubber samples were produced : The first sample : 50 grams banana fiber whiskers, 1 kg silicon rubber.The second sample: 100 grams banana fibers whiskers, 1 kg silicon rubber.The third sample : 100 grams of fiberglass (1) woven layer, 1 kg of silicon paper.The fourth sample: 200 grams of fiberglass (2) woven layer, 1 kg of silicon paper. The third sample is the ideal sample for the work of the sports stadiums appropriate for the track or field for small sports, due to the increase in the strength by an appropriate amount while maintaining the highest amount of elongation, as it is one of the least samples losing weight and land resistance. These are very suitable qualities for the track and field halls and gymnasium floors, which allows a significant decrease in the percentage of sports athletes injured, and not affected by conditions of weather conditions such as high temperature, cold and rain. The important economic aspect in producing this type of stadium flooring in a simple way and in a pure Egyptian style, as the material of banana fibers was used instead of burning or disposing in a way that achieves an important environmental aspect. The glass fibers are used for reinforcement, which gives a large part of the continuity of the floor with some maintenance. As for the silicon material, it is less expensive than other materials used to cover sports fields.

In this paper, factors affecting the mechanical properties of polymeric granite artificial stone have been investigated. Epoxy resin and three types of additives called Poly ether ether ketone, Silicon rubber, and Nanoclay have been used to make the artificial stone. Unlike previous research on resin alone, this study has been conducted on artificial stone and samples made using these materials. These samples are compared with the control sample and the sample with optimal mechanical characteristics. The method of making artificial stone is that crushed stone blend with resin, and is molded into molds that are defined according to the American Association of Materials and Testing. Samples were made with two percentages of 7.5 and 15 percent to determine the optimum amount of additive. After curing, the sample is subjected to testing. The results obtained from these experiments for artificial stone show that the addition of polyether ether ketone to epoxy resin compressive strength by more than 30%. 7.5wt% of Nanoclay increases more than 6% in compressive strength in epoxy resin. Therefore, the amount of 7.5% by weight of the additive has been selected as the optimum percentage and only this percent is considered in the manufacture of flexural and tensile strength samples. Adding Silicon rubber to the epoxy resin, increases the flexural strength by 7%. Contrary to expectation, Nanoclay reduces flexural strength significantly. By examining the results of the tensile test, it was determined that the addition of silicon to the epoxy resin increased the resistance to 46% . It is concluded that the addition of silicon rubber has been effective in increasing the compressive strength and in increasing the flexural and tensile strength and adding polyether ether ketone.

Development of stretchable wearable devices requires essential materials with high level of mechanical and electrical properties as well as scalability. Recently, silicone rubber-based elastic polymers with incorporated conductive fillers (metal particles, carbon nanomaterials, etc.) have been shown to the most promising materials for enabling both high electrical performance and stretchability, but the technology to make materials in scalable fabrication is still lacking. Here, we propose a facile method for fabricating a wearable device by directly coating essential electrical material on fabrics. The optimized material is implemented by the noncovalent association of multiwalled carbon nanotube (MWCNT), carbon black (CB), and silicon rubber (SR). The e-textile sensor has the highest gauge factor (GF) up to 34.38 when subjected to 40% strain for 5,000 cycles, without any degradation. In particular, the fabric sensor is fully operational even after being immersed in water for 10 days or stirred at room temperature for 8 hours. Our study provides a general platform for incorporating other stretchable elastic materials, enabling the future development of the smart clothing manufacturing.

Rubber magnet merupakan material maju yang dapat dipolarisasi secara magnetis yang tertanam dalam matriks karet lunak. Rubber magnet diaplikasikan sebagai komponen pada pintu atau jendela sebagai pengunci dan sealer, atau sebagai material perekat antara dua komponen, serta sebagai komponen motor listrik DC yang kecil. Penelitian ini dilakukan untuk mengetahui pengaruh komposisi silicon rubber terhadap sifat fisis, mekanik (kuat tarik) dan sifat kemagnetannya atau kekuatan magnet. Rubber magnet dibuat dengan menggunakan partikel magnet Ba-Ferrite (BaFe12O) dan silicon rubber (SR) sebagai perekat dengan komposisi 5%, 10%, 20% dan 30% berat SR. Kedua bahan baku tersebut dicampur hingga homogen, kemudian dibentuk dengan metode tuang. Selanjutnya sampel yang telah dibentuk dalam bentuk lembaran dikeringkan pada suhu kamar selama 2 jam. Karakterisasi sampel yang dilakukan meliputi pengukuran densitas, pengujian kuat tarik, dan kuat medan magnet menggunakan Gauss meter. Berdasarkan hasil karakterisasi bahwa dengan meningkatnya komposisi SR nilai densitas cenderung menurun, namun nilai kuat tarik dan elongasi cenderung meningkat hingga komposisi 20% SR, kemudian menurun pada komposisi 30% SR. Artinya semakin banyak kandungan SR maka fleksibilitasnya cenderung meningkat. Berdasarkan pengukuran kuat magnet menunjukkan bahwa sampel dengan komposisi SR yang semakin meningkat maka nilai kuat medan magnet cenderung menurun. Rubber magnets are advanced, magnetically polarized materials embedded in a soft rubber matrix. They are applied as components in doors or windows as locks and sealers, or as an adhesive material between two components, and as a component of a small DC electric motor. This research was conducted to determine the effect of the composition of silicon rubber on its physical, mechanical (tensile strength) and magnetic properties or magnetic strength. Rubber magnets are made by using magnetic particles Ba-Ferrite (BaFe12O) and silicon rubber (SR) as an adhesive with a composition of 5%, 10%, 20% and 30% by weight of the SR. The two raw materials are mixed until homogeneous and then formed by the casting method. Furthermore, the samples that had been formed in sheet form were dried at room temperature for 2 hours. The sample characterization includes measurement of density, tensile strength test, and magnetic field strength using a Gauss meter. Based on the characterization results, with the increase in the SR composition the density value tended to decrease, but the tensile strength and elongation values tended to increase up to the composition of 20% SR, then decreased at the composition of 30% SR. This means that the more SR content, the flexibility tends to increase. Based on the measurement of magnetic strength using a Gauss meter, it shows that samples with an increasing SR composition, the value of the magnetic field strength tends to decrease.

Surface tracking and erosion is an irreversible degradation occurring on the insulator surface, and this can ultimately lead to failure of the insulator. Polymeric materials such as silicone rubber have many advantages; including a superior hydrophobic surface. However, polymers are exposed to ageing and degradation resulting from electrical and environmental stresses. The rotating wheel dip test is adopted to conduct a comparative study of surface conduction on the two insulators. A conventional design has been selected and compared with insulators having textured surface. Monitoring of the shed surface and insulator trunk using an IR camera were carried out to assess the temperature distribution along insulator profiles. A spatial analysis was also performed to identify key features of the two designs. Localised surface conductance measurements are proposed in this study. This helps to understand and distinguish the trends of conductance and its distribution on each surface, helping to predict the future surface degradation associated to each design.

Objective The present study investigated the clinical effects of a single complete denture using two ⁃ step fine impression during the restoration of mandibular alveolar ridge atrophy. Methods A back ⁃end window tray that was personalized and adjusted was used to obtain the original impression for a mandibular alveolar ridge case. The individual trays were made with the conception of mandibular occlusal denture, and the final impression was obtained after active edge shaping using different viscous silicones. Results A case of single complete denture with mandibular alveolar ridge atrophy restoration was accomplished using a single complete denture and two⁃step fine impression. The denture was well fixed and functioned well, and the patient was satisfied. Conclusion The application of fine impres⁃ sion into a single complete denture is helpful for the restoration of mandibular alveolar ridge atrophy.

The aim of this article is to improve the interfacial adhesion between silicone rubber (SR) and Rayon fiber by the help of functional hybrid POSS nanoparticles. Two POSS types were compared, octavinyl‐POSS (O‐POSS) and methacryl‐POSS (M‐POSS), having reactive CC double bonds that can impart in peroxide crosslinking. O‐POSS is nonpolar, whereas M‐POSS is polar and is able to make H‐bond with Rayon fibers. POSS type and their concentrations were examined as the experimental parameters. H‐adhesion tests indicated that both POSS types enhanced the adhesion of SR composites to Rayon fibers compared with control recipe. Specifically, slightly higher values were obtained with the use of M‐POSS. It was observed that both O‐POSS and M‐POSS slowed down the curing rate but increased the degree of crosslinking. The cure extent of O‐POSS containing composites was found to be higher than that of M‐POSS containing ones. Thermal gravimetric analyses revealed that thermal stability of SR composites was significantly improved by the addition of POSS particles. Higher char yield and degradation temperatures were obtained with O‐POSS at higher loadings with respect to M‐POSS. The POSS distribution at lower loading levels was found to be homogenous for both POSS types as observed from scanning electron microscope and transmission electron microscope. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a new pneumatic actuation method inspired from a soft robot, which could drive the multi-stable carbon fiber-reinforced polymer (CFRP) structure transition among five stable configurations under air pressure. Multi-stable structure was manufactured by the carbon fiber prepreg laid in asymmetrical and anti-symmetric layup methods and stacked at the joint during the preparation process according to the designed scheme. In experiments, multi-stable structures with two different fibers layups were prepared to study the snap-through behaviors. The snap-through process of two kinds of multi-stable structures was investigated by experiment. The parameters used to characterize efficiency of the pneumatic actuator actuating the multi-stable structures, including air pressure and snap time, were measured. The influence of the pneumatic actuator on the curvature of multi-stable structures was discussed by comparing the shape characteristic of multi-stable structures with or without pneumatic actuation, and it showed pneumatic actuator has little effect to the structure. The results demonstrated that the proposed pneumatic actuation could be used to drive multi-stable morphing structure flexibly. The combination of multi-stable laminates develops the function of multiple point bending and shape retention of pneumatic actuation. [ABSTRACT FROM AUTHOR]

Robust superhydrophobic surfaces with periodic array structures composed of circular silica islands on silicone rubber substrates were fabricated using a combination of multi-laser exposure and chemical modification. Abrasion tests with sandpaper demonstrate that hard silica regions on the surface can protect the silicone rubber region from external damage, resulting in long-lasting superhydrophobicity. Moreover, with an increase in area fraction and a decrease in array hole radius, the wear of the filled superhydrophobic silica is slowed while the protection for the silicone rubber region is enhanced. Particularly, the optimum surface geometry had an area fraction of 35 % and array hole radius of 100 μm retaining its hydrophobicity up to 63 times of abrasion, eight times more than that of the superhydrophobic surface processed by lasers alone. The results of a sand impact test confirmed the resulting surface's resilience in an aeolian sand environment. This research demonstrated the feasibility of producing robust, superhydrophobic surfaces on flexible silicone rubber substrates and providing a foundation for improving and innovating related products. [Display omitted] • Superhydrophobic silicone rubber surface was fabricated by laser processing and silica filling. • The periodic array structures provide surface protection and maintain flexibility. • Circular silica islands in surface periodic array structures exhibit a self-similar property. • Rubost surfaces demonstrate long-lasting superhydrophobicity during abrasion. [ABSTRACT FROM AUTHOR]

Nanocomposite made by blending nano-montmorillonite (MMT) and Silicon Rubber (SR) for mechanical and tribological performance is explored in this work. Different configurations of MMT/SR nanocomposite, with 0, 0.5, 2 and 5 wt % of MMT are manufactured by two roll mixing methods. Noticeable improvement in the mechanical and tribological performance is observed, which is also justified by a morphological study of fractured and wear surfaces through SEM. Two percent of MMT loading is found to be the optimum content that shows excellent performance compared to other compositions. The performance improvement can be linked to the good interfacial interaction between the MMT and SR. Statistical modeling through ANOVA is carried out for tribological performance, which reveals the influence of load on the coefficient of friction (COF) and the influence of sliding distance on the wear rate.

Benzoxazine resin is a new generation of anti-ablation resin with high char yield and high-temperature oxidation resistance. Using high temperature vulcanized silicon rubber as ablation resistance matrix and 2,2'-(3-methyl-4-dihydro-1,3,2-benzoxazine)propane as anti-ablation resin, silicon rubber/polybenzoxazine anti-ablation composite was prepared by blending method. The mechanical properties were tested,and the ablation structure and the composition of the composite were investigated by DSC,SEM,FT-IR and Raman.Experimental results show that the polybenzoxazine resin can improve the ablation resistance property of silicone rubber composite. The composite has good ablation resistance and mechanical property when the addition of polybenzoxazine resin reaches 20 phr. After ablated by oxygen acetylene flame,the ablation layer is divided into three obvious layers as surface ceramic layer,pyrolysis carbonization layer and base layer. The surface ceramic layer formed in the progress of ablation plays a positive role in the ablation property of the composite material.

[Display omitted] • The mechanical properties of composites at low temperature were studied. • The effect of the ratio of ZnO to LDH on the properties of rubber was studied. • Composite fillers improve the tensile properties of rubber. • Composite filler reduces glass transition temperature of rubber. • Construction of cross-linked network of ZnO and LDH in rubber. Low-temperature conditions can degrade various properties of rubber, impacting the application of rubber products in such conditions. In this study, we incorporated zinc oxide (ZnO) and magnesium aluminum layered double hydroxide (LDH) into silicone rubber (SR) to produce x-ZnO/LDH/SR composites, where X represents the addition ratio of ZnO to LDH. The results indicated that, at −40 °C, the tensile strength and elongation at break for 1/2-ZnO/LDH/SR were 10.6 % and 5.0 % greater than the original silicone rubber, respectively. In addition, after aging at −40 °C for 3 days, the compression set of the composites decreased by 48.6 %. This improvement was attribute to ZnO and LDH forming a physical cross-linking network within the rubber. This not only enhanced the mechanical properties of silicone rubber at low temperatures but also offers a straightforward and viable approached to producing high-performance, low-temperature-resistant sealing products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cyclosiloxane with single C=C bond was synthesized by hydrocondensation and was further copolymerized with octamethyl cyclotetrasiloxane to prepare silicone rubber with well-distributed crosslinking groups. • The effect of vulcanization groups type on vulcanization rate was investigated. • The well distribution vulcanization groups enhanced the mechanical properties of SR. • The matched vulcanization rate of SR with EPDM improved the mechanical properties and breakdown strength of SR/EPDM blends. Due to the low intermolecular force, silicone rubber (SR) processes weak mechanical properties and it's difficult to blend with other conventional rubbers, which limits its application. Herein, a series of novel SRs with evenly distributed and different types of crosslinking groups were synthesized and cured to SR blends. The novel SRs promote the uniform distribution of crosslinking points during vulcanization, which contributes to the increase in both tensile strength and elongation at break. Besides, the introduction of different types of crosslinking groups decreases vulcanization speed as well as increases the flexibility of the bridge between two crosslinked polymer chains, resulting in the elongation at break as high as 1143%, which is twice higher than commercial SR. The novel SRs were subsequently blended with ethylene-propylene-diene rubber (EPDM) to prepare high-performance blends. Compared with the commercial SR/EPDM blend, the matching vulcanization resulted in an increase in the tensile stress and elongation at break by 27.6% and 35.3%, respectively. In addition, dielectric strength increases from 34.2 to 40.8 kV/mm for SEP-VCH. Our work provides a new strategy to prepare SR with high mechanical properties and improve the properties of SR/EPDM blend without the addition of a compatibilizer, thus extending the application of SR. [ABSTRACT FROM AUTHOR]

Loss of the lower limb can cause loss of mobility.At all places and at all times, efforts have always been made to make up for such a loss.In this work polymer composite materialshad been used to manufacture prosthetic foot. Polymer composite materialsPMMA:SR/PURreinforced by carbon fibers (CF) were prepared as suitable material for prosthetic foot then, tensile characteristics were measured and determined. Numerical work included Finite element method (ANSYS-15) was used to analyze and evaluate deformation, stress and strain characteristics of a new designed prosthetic foot, which was treated as three-dimensional structure composite polymer material. The experimental and theoretical results were improvedthat polymer composite material can be used for this application

Shock wave properties of porous specimens made on the basis of matrices composed of inert and chemically active media (silicon rubber and emulsion, which is an aqueous solution of ammonium nitrate with mineral oil and emulsifier) are studied. The porosity of the specimens is generated by using a filler composed of glass microspheres. The wave velocity profiles are measured by a VISAR laser Doppler interferometer. It is shown that the shock compressibility of porous silicon rubber at pressures below 0.1 GPa displays an anomalous behavior, resulting in smearing of the compression pulse front propagating over the specimen. In the emulsion matrices without microspheres, there are no noticeable chemical transformations up to the pressure of 15 GPa. Addition of microspheres drastically decreases the threshold of chemical reaction initiation and leads to the formation of a steady detonation wave. [ABSTRACT FROM AUTHOR]

The objective of this study is the investigation of dielectric barrier discharges (DBDs) with the solid plates and the flexible polymer films. A high capacitance with a high dielectric constant and a small thickness is responsible for the discharge of a high plasma current with a low operation voltage; here, the thin flexible polyimide film ensured a high capacitance, and is comparable to the thick solid-plate alumina. In the long-duration test of the dielectric-surface plasma erosion, the solid plates show a high resistance against the plasma erosions, while the polymer films are vulnerable to the etching by the plasma-species chemical reaction. The polymer-film surface, however, was reinforced remarkably against the plasma erosion by the silicone-paste coating. [ABSTRACT FROM AUTHOR]

The use of medium voltage cable joints is mandatory when dealing with power cable faults and the installation of new lines. However, such an accessory is among the top causes of faults among the grid. To this purpose, one of the quantities monitored to understand the causes of such faults is the interfacial pressure between the insulating layers of the cable joint. In this work, the interfacial pressure between Cross-linked polyethylene (XLPE) and silicon rubber has been evaluated when the cable joint experiences thermal cycles. From the results, the pressure variation caused by the thermal cycles is demonstrated. Such a phenomenon may be connected to the generation of voids and weak spots that accelerate cable joint ageing. Therefore, proper comments and conclusions are drawn.

This work combines experiments and finite element simulations to study the effect of pre-imposed cyclic loading on surface instability of silicon rubber under compression. We first fabricate cuboid blocks of silicon rubber and pinch them cyclicly a few times. Then, an in-house apparatus is set to apply uniaxial compression on the silicon rubber under exact plane strain conditions. Surprisingly, we find multiple creases on the surface of silicone rubber, significantly different from what have been observed on the samples without the cyclic pinching. To reveal the underlying physics for these experimentally observed multiple creases, we perform detailed nanoindentation experiments to measure the material properties at different locations of the silicon rubber. The modulus is found to be nonuniform and varies along the thickness direction after the cyclic pinching. According to these experimental results, three-layer and multilayer finite element models are built with different materials properties informed by experiments. The three-layer finite element model can excellently explain the nucleation and pattern of multiple surface creases on the surface of compressed silicone rubber, in good agreement with experiments. Counterintuitively, the multilayer model with gradient modulus cannot be used to explain the multiple creases observed in our experiments. According to these simulations, the experimentally observed multiple creases should be attributed to a thin and stiff layer formed on the surface of silicon rubber after the pre-imposed cyclic loading. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hexagonal boron nitride (h-BN) nano sheets were prepared from nanoparticles by a novel/effective exfoliating agent (i.e. mono ethylene glycol). • Exfoliation of h-BN was performed much better in mono ethylene glycol as replacing solvent for water/isopropyl alcohol. • Silicon rubber (SR) nanocomposites were prepared using pure and exfoliated h-BNs and evaluated for thermal and electrical properties. • The exfoliated h-BNs caused considerable improvement in the thermal conductivity and electrical resistance of SR compared to pure h-BNs. In this work, boron nitride nano sheets (BNNSs) were prepared by exfoliation of h-BNs using mono ethylene glycol (MEG) as a novel exfoliating agent. For comparison, isopropyl alcohol (IPA)/water mixture was also used for exfoliation of h-BNs. It was found that using MEG caused preparing nano layers with higher yield and lower thickness compared to the IPA/water mixture. Thereafter, silicon rubber nanocomposites contained 3 and 5 wt% of pure and exfoliated BNNSs were prepared and evaluated for thermal and electrical performances. It was found that h-BNs and exfoliated-BNs drastically enhanced thermal conduction of SR. The silicon rubber contained 5 wt% of the h-BN and exfoliated-BNs illustrated around 20 times higher thermal conductivities compared to pure SR. Exfoliation of h-BNs had negligible effect on improvement of thermal properties, however, it caused 5.7 and 2.3 times enhancement in the electrical volume resistivity compared to the pristine SR and pure h-BN containing nanocomposite, respectively. Both of the BNNSs caused improvement in the heat dissipation performances of SR matrix, however, the exfoliated one with MEG showed better performances. Based on the results, it was claimed that mono ethylene glycol could improve exfoliation of h-BNs and enhance the performances of silicon rubber. [ABSTRACT FROM AUTHOR]

The objective of this study is the investigation of dielectric barrier discharges (DBDs) with the solid plates and the flexible polymer films. A high capacitance with a high dielectric constant and a small thickness is responsible for the discharge of a high plasma current with a low operation voltage; here, the thin flexible polyimide film ensured a high capacitance, and is comparable to the thick solid-plate alumina. In the long-duration test of the dielectric-surface plasma erosion, the solid plates show a high resistance against the plasma erosions, while the polymer films are vulnerable to the etching by the plasma-species chemical reaction. The polymer-film surface, however, was reinforced remarkably against the plasma erosion by the silicone-paste coating.

Graphite powder was mixed to polyurethane, silicon rubber and Araldite® (epoxy) in order to prepare composite materials to be used in the preparation of electrodes. Results showed that voltammetric response could be obtained when at least 50% of graphite (w.w-1) is present in the material. SEM and thermogravimetry were also used in the characterization of the composites.

cis- and trans-Isomers of the platinum(II) nitrile complexes [PtCl2(NCR)2] (R = NMe2, N(C5H10), Ph, CH2Ph) were examined as catalysts for hydrosilylation cross-linking of vinyl-terminated polydimethylsiloxane and trimethylsilyl-terminated poly(dimethylsiloxane-co-ethylhydrosiloxane) producing high quality silicone rubbers. Among the tested platinum species the cis-complexes are much more active catalysts than their trans-congeners and for all studied platinum complexes cis-[PtCl2(NCCH2Ph)2] exhibits the best catalytic activity (room temperature, c = 1.0 × 10–4 mol/L, τpot-life 60 min, τcuring 6 h). Although cis-[PtCl2(NCCH2Ph)2] is less active than the widely used Karstedt’s catalyst, its application for the cross-linking can be performed not only at room temperature (c = 1.0 × 10–4 mol/L), but also, more efficiently, at 80 °C (c = 1.0 × 10–4–1.0 × 10–5 mol/L) and it prevents adherence of the formed silicone rubbers to equipment. The usage of the cis- and trans-[PtCl2(NCR)2] complexes as the hydrosilylation catalysts do not require any inhibitors and, moreover, the complexes and their mixtures with vinyl- and trimethylsilyl terminated polysiloxanes are shelf-stable in air. Tested catalysts do not form colloid platinum particles after the cross-linking. [ABSTRACT FROM AUTHOR]

Finite element method simulations were implemented to understand how the strain energy is distributed in a disk-like sample during a punch shear test. Material's Young modulus can be estimated from this test; however, there is not enough available information about the distribution of the strain energy inside the sample during the deformation process. The proposed methodology seeks to give insight into the deformation process. Experimental results for a cured silicon rubber sample were used to validate the simulation results. It was found that the estimation of the Young modulus with the punch shear test depends on the ratio between the span-to-punch diameters. This conclusion applies to the simulated results, following Timoshenko's theory for the deformation of thin plates. Understanding how energy is accumulated during a punch shear test is an important and useful characteristic in terms of the design of armor systems. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the effect of trabecular filtration surgery combined with scleral interlayer filled with silicon rubber for refractory glaucoma and its complications.METHODS: A total of 32 cases(32 eyes)of refractory glaucoma underwent trabecular filtration surgery combined with sclera interlayer filled silicone piece, namely trabeculectomy combined silicon rubber filled in sclera between layers was as experimental group. Twenty-one cases(21 eyes)treated by simple trabecular filtration surgery were as control group. Reducing effect of intraocular pressure(IOP)and complications of two groups were observed after operation.RESULTS: Postoperative follow-up was 6-24 months. The mean IOP was 14.36±5.2mmHg(1mmHg=0.133kPa)in experimental group and 23.36±9.3mmHg in control group after operation. IOP of three eyes(9.4%)in experimental group and 5 eyes(23.8%)in control group was over 30mmHg. There was no serious complications and rejection correlated with silicone piece during the follow-up period.CONCLUSION:Silicone piece filled between sclera layer is an effective method for refractory glaucoma, and can effectively reduce IOP. Due to its economic, convenient, especially can replace expensive imported drainage plant figure treatment of refractory glaucoma in our country the grass-roots hospital, it should be widely applied.

An innovative bioinspired method is presented for the preparation of surface-modified nanodiamonds (ND) particles by poly(dopamine) (PDA). The process was aimed at improving the thermal conductivity and maintaining the insulating capability of silicone rubber (SiR). ND was successfully and effectively modified by dopamine in different hours, which was confirmed by HR-TEM, TGA, FTIR, and XRD. The poly(dopamine) coating on ND particles improved its interfacial interaction with silicon rubber and promoted the uniform dispersion of fillers, resulting in the ND-18/SiR composite that acquired a higher thermal conductivity (0.295 W/(m·K)) at the loading of 6 wt%, 81 % higher than that of pure silicone rubber (0.163 W/(m·K)). In addition, the composite materials still displayed an excellent insulating property with a resistance of ≈1011 Ω·cm, which was a big advantage for thermal management. [Display omitted] • The agglomeration problem of ND nanoparticles was reduced by using dopamine. • ND-X particles exhibit excellent dispersibility and compatibility with SiR. • ND-X particles enhance thermal conductivity and maintain electrical insulation of nanocomposites. [ABSTRACT FROM AUTHOR]