Preparation And Characterization Of DMC/MVQ Insulating Composite Materials

Recently, many researches have focused on the polymer materials with multiple functions.The composites based on fiber strengthen rubber exhibit superior properties. At the same time,rubber is of excellet insulating properties. However, Methyl vinyl silicone rubber is of the bestheat resistant and outstanding insulating property. But, its mechanical property is very bad. Tosolve this problem, DMC/MVQ insulating composite materials is prepared, in which MVQ(Methyl vinyl silicone rubber) is used as matrix, dough moulding compound (DMC) asreinforcement phase and SBR as compatilizer agent. The effects of silica, DMC and SBR(Butadiene styrene rubber) contents on the properties of MVQ are investigated by testingtensile strength, elongation at break, oxygen index (OI) and volume resistivity. The effects ofmixed modes and cure conditions on the properties of composite materials are studied too.The optimum cure conditions of composite materials are determined by testing mechanicalproperties and oxygen index of vulcanized rubber. The insulating property of compositematerials is researched by testing volume resistivity. The results show that the properties ofMVQ with silica and DMC are better than that with silica. The blending rubber properties ofMVQ with SBR are superior to another. The best mass ratio is DMC60phr, SBR25phr andMVQ75phr. The best mixed mode is that MVQ and SBR are mixed respectively, then, addedcuring agent and accelerating agent to obtain the mixed rubber. The proper cure conditions areat180℃under1.2MPa for15min. The insulating property of composite materials are goodabove1.5×1012m. The compatibility and cross-linking structure of the composites arestudied by SEM, DMA, PLM and IR, and separately proved that the compatibility ofDMC/MVQ composites is better than that without DMC, a small number of unsaturatedpolyester (UP) in the DMC could bond SBR and MVQ to form-CO-and-C-O-C-bonds onthe surfaces of the rubbers. The physical entanglement between fiber and rubber are formed,the fiber plays framework and reinforcement roles, and a small quatity of UP and rubbercross-link to form the matrix of the composites. DMC improves the compatibility ofDMC/MVQ composites. The property of DMC/MVQ insulating composite materials isimproved, which could be attributed to larger interface and more interfacial interactionbetween DMC and MVQ matrix.