Structure And Property Of Additional Silicone Rubber Using Platinum Complex As Catalyst

The additional silicone rubbers had in general the following advantages:no by-produces while vulcanizing,minimal shrinkage,deep sulfide,besides excellent electric and mechanical properties,chemical stabilization,excellent resistance of water,ozone and weather,flame retarded and no harmful gas while vulcanizing.So the additional silicone rubber is widely used in scientific research and industry.The thesis is divided into six parts:In Chapter one the research development of additional silicone rubber was reviewed,the mechanism and the synthesized of catalyst of additional vulcanizing silicone rubber was discussed.The additional silicone rubber and the condensation-type silicone rubber were compared and the thesis briefly described the application of additional silicone rubber.Additionally the mechanism of complex pound of platinum catalyst was summed up in detail and the mechanism of other transition metals was described briefly.Last but not least the synthesis process of Pt catalyst was discussed.In Chapter two the equipments,experimental and measurement methods were described.The platinum complex with divinyl tetramethyl disiloxane and the platinum complex with divinyl tetramethyl disiloxane and 1,3,5,7-tetramethyl-tetravinyl disiloxane were prepared which were used as catalyst in synthesizing additional silicone rubber.The following characterization,i.e.viscosity, mechanical properties such as tensile and hardness,breakdown voltage and thermal property,crosslinking dense and exothermic enthalpy were measured and analyzed.In Chapter three the platinum complex with divinyl tetramethyl disiloxane was synthesized which was used to study on vulcanization process and properties of additional vulcanizing silicone rubber.The experimental results showed that the vulcanizing time of silicone rubber was shortened as the temperature raised and the amount of catalyst raised.The mechanical properties increased as the amount of catalyst raised but they would decrease as the catalyst was too much,and the crosslinking dense increased as the amount of catalyst raised but it would decrease as the catalyst was too much.The thermal properties of vulcanized silicone rubber which had excellent properties were independent upon the amount of catalyst.The volume resistivity of silicone rubber decreased as the filler amount increases,too much filler would block the cross linking,so that the mechanical properties of hardness decreased.In Chapter four the platinum complex with divinyl tetramethyl disiloxane and 1,3,5,7-tetramethyl-tetravinyl disiloxane was synthesized which was used to study on vulcanization process and properties of additional vulcanizing silicone rubber.The experimental results showed that the vulcanizing time of silicone rubber was shorten and the crosslinking dense of resulted silicone rubber inceased as the vulcanizing temperature raised.The thermal property of vulcanized silicone rubber was independent upon the vulcanizing temperature.The addition of different solvents had a certain impact on the vulcanization process of silicone rubber because of their changing the activity of catalyst system.The good mechanical properties of silicone rubber vulcanized at the temperature of Onset point was obtained.Besides the mechanical properties decreased as the amount of catalyst increased.In Chapter five the technical factors of breakdown voltage of addition silicone rubber was analyzed.The experimental results showed that the breakdown voltage of silicone rubber increased as the amount of catalyst increased too much,catalyst would block the cross linking,so that the breakdown voltage would decrease,and it was the same with maximum tensile property.The breakdown voltage of silicone rubber increased as the amount of hydrogen-containing silicone oil increased,but the breakdown voltage of silicone rubber would decrease as the amount was too much. The breakdown voltage would reach the maximum as the amount of silica was between 13%and 17%.The breakdown voltage of silicone rubber would increase, and then a little decrease,at last it would increase as the amount of Al₂O₃ and insulation thermal conductivity of powder increased.The crosslinking density increased and the mechanism properties increased as the amount of Al₂O₃ and insulation thermal conductivity of powder increased.The thermal property of vulcanized silicone rubber were excellent especially the insulation thermal conductivity of powder,the vulcanized silicone rubber only lost 5%of total weight at the temperature of 400℃and 15%at the temperature of 600℃.In Chapter six the research work of this thesis was summed up,and the conclusion was brought forward.