Peroxide-cured high-temperature vulcanized （HTV） silicone rubber was prepared by using allyl-capped carbosilane dendrimers, in which the core molecule is Si（CHaCH=CH2）4, as the cross-linker. It showed that this ki...Peroxide-cured high-temperature vulcanized （HTV） silicone rubber was prepared by using allyl-capped carbosilane dendrimers, in which the core molecule is Si（CHaCH=CH2）4, as the cross-linker. It showed that this kind of allyl-capped carbosilane dendrimer improved the mechanical properties of silicone rubber.展开更多
A series of fluorescent composites were prepared by blending silicone rubber with Eu(TTA )2(phen)(MA). The influence of mechanical blending temperature on fluorescent intensity of composites and dispersion of rare ear...A series of fluorescent composites were prepared by blending silicone rubber with Eu(TTA )2(phen)(MA). The influence of mechanical blending temperature on fluorescent intensity of composites and dispersion of rare earth complexes in the SiR matrix were investigated. As for the cured rubber, it is found that its fluorescent intensity is relatively low compared with that of uncured rubber. Low temperature is beneficial to dispersion of Eu(TTA )2(phen)(MA) homogeneously. When the amount of rare earth complexes is low, the fluorescent intensity of composites prepared by mechanical blending method above melting point of Eu(TTA )2(phen)(MA) is much higher than that of composites prepared below melting point.展开更多
SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a compreh...SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates,employing a combination of experimental,theoretical,and numerical analyses.Firstly,quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar(SHPB)apparatus.Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10^(−3) to 3065 s^(−1).The results indicated that the composite showed evident strain rate sensitivity,along with nonlinearity.Then,a nonlinear visco-hyperelastic constitutive model was developed,consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme.The model accurately characterized the dynamic mechanical response of SP-RSRC,effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models.Furthermore,the simplified rubber material(SRM)model,integrated within the LS-DYNA software,was chosen to depict the mechanical properties of SP-RSRC in numerical simulations.The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC,as predicted by the developed nonlinear visco-hyperelastic constitutive model.Finally,an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC.Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed,and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations.This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection.展开更多
Allyl terminated polyether was used to improve the hydrophilicity of addition-cured room temperature vulcanization silicone rubber. With the increasing of the polyether, both the hydrophilicity and water absorbed of t...Allyl terminated polyether was used to improve the hydrophilicity of addition-cured room temperature vulcanization silicone rubber. With the increasing of the polyether, both the hydrophilicity and water absorbed of the vulcanizates were increased. The mechanical properties were also improved by adding the polyether. The result showed that 1.5wt% of the polyether provided the silicone rubber with proper hydrophilicity.展开更多
One prominent method of modifying the properties of dielectric elastomers(DEs)is by adding suitable metal oxide fillers.However,almost all commercially available sili-cone elastomers are already heavily filled with si...One prominent method of modifying the properties of dielectric elastomers(DEs)is by adding suitable metal oxide fillers.However,almost all commercially available sili-cone elastomers are already heavily filled with silica to reinforce the otherwise rather weak silicone network and the resulting metal oxide filled elastomer may contain too much filler.We therefore explore the replacement of silica with titanium dioxide to ensure a relatively low concentration of filler.Liquid silicone rubber(LSR)has relatively low viscosity,which is favorable for loading inorganic fillers.In the present study,four commercial LSRs with varying loadings of silica and one benchmark room-temperature vulcanizable rubber(RTV)were investigated.The resulting elastomers were evaluated with respect to their dielectric permittivity,tear and tensile strengths,electrical breakdown,thermal stability and dynamic viscosity.Filled silicone elasto-mers with high loadings of nano-sized titanium dioxide(TiO_(2))particles were also studied.The best overall performing formulation had 35 wt.%TiO_(2) nanoparticles in the POWERSIL®XLR LSR,where the excellent ensemble of relative dielectric permittivity of 4.9 at 0.1 Hz,breakdown strength of 160 V µm^(−1),tear strength of 5.3 MPa,elongation at break of 190%,a Young’s modulus of 0.85 MPa and a 10% strain response(simple tension)in a 50 Vμm^(−1) electric field was obtained.展开更多
A reactive flame retardant cross-linker（SPTES） was successfully synthesized with dichloropentate and 3-triethoxysily-lpropylamine（APTES） in this research. Then it was further applied into the room temperature vulc...A reactive flame retardant cross-linker（SPTES） was successfully synthesized with dichloropentate and 3-triethoxysily-lpropylamine（APTES） in this research. Then it was further applied into the room temperature vulcanized（RTV） silicone rubber to prepare novel flame retarded RTV silicone rubbers containing phosphorus. The structure, thermal degradation stability, mechanical properties and flammability properties of the novel RTV silicone rubbers were tested and characterized. The results showed that the mechanical and flammability properties of the RTV silicone rubber simultaneously got better with the SPTES content increased. Compared with the sample prepared by APTES, the tensile strength of novel RTV silicone rubbers increased from 0.12 MPa to 0.38 MPa and the limit oxygen index increased from 19.8 to 23.5.展开更多
文摘Peroxide-cured high-temperature vulcanized （HTV） silicone rubber was prepared by using allyl-capped carbosilane dendrimers, in which the core molecule is Si（CHaCH=CH2）4, as the cross-linker. It showed that this kind of allyl-capped carbosilane dendrimer improved the mechanical properties of silicone rubber.
基金Project supported by the National Natural Science Foundation of China and the China Energy Conservation Investment Corporation (50173004 and 50503002)the Beijing New Star Project (2003A11)+1 种基金the National High-Tech Research Developing Foundation ("863", 2003AA324030) Beijing Municipal Commission of Education (JD100100403)
文摘A series of fluorescent composites were prepared by blending silicone rubber with Eu(TTA )2(phen)(MA). The influence of mechanical blending temperature on fluorescent intensity of composites and dispersion of rare earth complexes in the SiR matrix were investigated. As for the cured rubber, it is found that its fluorescent intensity is relatively low compared with that of uncured rubber. Low temperature is beneficial to dispersion of Eu(TTA )2(phen)(MA) homogeneously. When the amount of rare earth complexes is low, the fluorescent intensity of composites prepared by mechanical blending method above melting point of Eu(TTA )2(phen)(MA) is much higher than that of composites prepared below melting point.
文摘SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates,employing a combination of experimental,theoretical,and numerical analyses.Firstly,quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar(SHPB)apparatus.Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10^(−3) to 3065 s^(−1).The results indicated that the composite showed evident strain rate sensitivity,along with nonlinearity.Then,a nonlinear visco-hyperelastic constitutive model was developed,consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme.The model accurately characterized the dynamic mechanical response of SP-RSRC,effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models.Furthermore,the simplified rubber material(SRM)model,integrated within the LS-DYNA software,was chosen to depict the mechanical properties of SP-RSRC in numerical simulations.The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC,as predicted by the developed nonlinear visco-hyperelastic constitutive model.Finally,an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC.Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed,and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations.This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection.
文摘Allyl terminated polyether was used to improve the hydrophilicity of addition-cured room temperature vulcanization silicone rubber. With the increasing of the polyether, both the hydrophilicity and water absorbed of the vulcanizates were increased. The mechanical properties were also improved by adding the polyether. The result showed that 1.5wt% of the polyether provided the silicone rubber with proper hydrophilicity.
基金The authors gratefully acknowledge the financial support of InnovationsFonden.
文摘One prominent method of modifying the properties of dielectric elastomers(DEs)is by adding suitable metal oxide fillers.However,almost all commercially available sili-cone elastomers are already heavily filled with silica to reinforce the otherwise rather weak silicone network and the resulting metal oxide filled elastomer may contain too much filler.We therefore explore the replacement of silica with titanium dioxide to ensure a relatively low concentration of filler.Liquid silicone rubber(LSR)has relatively low viscosity,which is favorable for loading inorganic fillers.In the present study,four commercial LSRs with varying loadings of silica and one benchmark room-temperature vulcanizable rubber(RTV)were investigated.The resulting elastomers were evaluated with respect to their dielectric permittivity,tear and tensile strengths,electrical breakdown,thermal stability and dynamic viscosity.Filled silicone elasto-mers with high loadings of nano-sized titanium dioxide(TiO_(2))particles were also studied.The best overall performing formulation had 35 wt.%TiO_(2) nanoparticles in the POWERSIL®XLR LSR,where the excellent ensemble of relative dielectric permittivity of 4.9 at 0.1 Hz,breakdown strength of 160 V µm^(−1),tear strength of 5.3 MPa,elongation at break of 190%,a Young’s modulus of 0.85 MPa and a 10% strain response(simple tension)in a 50 Vμm^(−1) electric field was obtained.
基金Supported by the National Natural Science Foundation of China(51572201)the Project of the State Admimistration of Science,Technology and Industry for National Defense,PRC
文摘A reactive flame retardant cross-linker（SPTES） was successfully synthesized with dichloropentate and 3-triethoxysily-lpropylamine（APTES） in this research. Then it was further applied into the room temperature vulcanized（RTV） silicone rubber to prepare novel flame retarded RTV silicone rubbers containing phosphorus. The structure, thermal degradation stability, mechanical properties and flammability properties of the novel RTV silicone rubbers were tested and characterized. The results showed that the mechanical and flammability properties of the RTV silicone rubber simultaneously got better with the SPTES content increased. Compared with the sample prepared by APTES, the tensile strength of novel RTV silicone rubbers increased from 0.12 MPa to 0.38 MPa and the limit oxygen index increased from 19.8 to 23.5.
