Synthesis And Application Study Of Epoxidized Silicone Rubber

A few advantages of silicone rubber are its ability to withstand both high and low temperatures,aging,electrical insulation,and biocompatibility.However,its limited applicability is mostly due to its poor tear strength.Enhancement of the tearing properties of methyl vinyl silicone rubber(MVQ)by the introduction of epoxidized silicone rubber to silica nanoparticles(silica).The addition of epoxidized silicone rubber improves the performance of ethylene propylene diene monomer rubber /methyl vinyl silicone rubber(EPDM/MVQ)systems.The main work of this paper is as follows:(1)Epoxidized silicone rubbers EMVQ10,EMVQ15 and EMVQ20 with epoxy group linkage content of 10%,15% and 20%,respectively,were prepared.It was found that the addition of EMVQ improved the dispersion of fumed silica in silicone rubber,and the dispersion of filler became better with the increase of EMVQ15 dosage after the addition of EMVQ15.The effects of the content of epoxy groups,the amount of EMVQ,the amount of crosslinker in the system and the size of EMVQ molecular weight on the tear resistance of silicone rubber were investigated.It was found that the tear strength of the composites increased from 19 k N/m to 63 k N/m,with an increase of tear strength by 332%,when 5 parts of EMVQ(EMVQ15),0.07 parts of vulcanizing agent and 40 parts of fumed silica were used.The orientation of the silicone rubber composites under different strains was characterized using nanomechanical atomic force microscopy and polarized infrared,and it was found that the topological entanglement of the multi-ring structure not only concentrated the stress during the stretching process,but also changed the direction of stress transfer,resulting in highly oriented molecular chains also perpendicular to the stretching direction.The tear strength of the composites increased from 19 k N/m to 63 k N/m,and the tearing resistance of the material was improved.(2)The effect of adding EMVQ15 on the performance of EPDM/MVQ combined system was investigated.The results of Mooney viscosity and RPA showed that the processing performance of the material was also improved and the silica was more uniformly dispersed in the material,which improved the problem that the two rubbers were difficult to process due to the large difference in viscosity.The vulcanization rate index(CRI)of the compound was reduced and decreased gradually with the increase of EMVQ15 to improve the consistency of the vulcanization rate of silicone rubber and EPDM rubber.The mechanical results showed that when 2.5 parts of EMVQ15 were added,the tensile strength of the material was increased from 12.5 MPa to16.1 MPa,and the performance was improved by 28.8 %.The elongation at break increased from 474 % to 565 %,an increase of 19.2 %.The thermal weight loss showed that the residual amount of the material increased significantly with the addition of a certain amount of EMVQ,from 34.9% to38.1%,and the thermal decomposition temperature increased from 375 °C to392 °C.