Research On Silicone Rubber Compounding Technology And Modification Technology

Silicone rubber has excellent high and low temperature resistance,good chemical stability and high elasticity,is a rubber material that can be applied in many fields,with the continuous expansion of the use of silicone rubber,the basic research of silicone rubber materials is more and more worthy of attention,such as silicone rubber in the storage process is prone to harden "structured" problems,defense and aviation field to silicone rubber to put forward a higher standard of high temperature resistance.In this paper,methyl vinyl silicone rubber is the main body,the structural phenomenon and solution of silicone rubber are studied in depth,and the high temperature aging resistance of silicone rubber is continuously improved in the study of the basic formula of silicone rubber.This article first discusses the role of vinyl content on the properties of silicone rubber.When the vinyl content increases,more crosslinking points are generated,which in turn increases its crosslinking density.However,this also results in a decrease in tensile strength,compression set,and tear capacity.In the study of silica reinforced silicone rubber,it is found that with the increase of the amount of fumed silica,the tensile strength,elongation at break and tear strength of silicone rubber will first rise and then fall back,in contrast,the use of precipitation silica silicone rubber are on the rise,fumed silica reinforcing effect and higher high temperature resistance characteristics are better than precipitation silica.Since the end hydroxyl group of silica is easy to combine with silicone rubber to form hydrogen bonds,resulting in structural phenomenon,it is necessary to add structural control agents to eliminate excess end hydroxyl groups,and continue to study the effects of structural control agents such as hydroxyl silicone oil,methoxy silicone oil and dimethyldiethoxysilicone oil on the structural and mechanical properties of silicone rubber.After high temperature accelerated structuring,the degree of structure is studied by studying the number of rubber refining times and observing the state of different stages of repression,and the change of storage modulus with the extension of parking time is studied by rubber processing analyzer.The results show that the structural control agent reduces the crosslinking degree,tensile strength,tensile strength and resilience of silicone rubber,improves the elongation at break and improves the compression set performance.The use of hydroxyl silicone oil,methoxy silicone oil and dimethyldiethoxysilicone oil can improve the structural phenomenon of silicone rubber,reduce the storage modulus,and extend the parking time,among which the improved structural performance of hydroxy silicone oil is the best,and the dosage can reach a better state when it reaches 6 parts,and the number of structuring times is the least.Finally,the effect of vulcanization system on the properties of silicone rubber was studied,and the type and dosage of vulcanizing agent were changed,and it was found that the degree of crosslinking of peroxide-type vulcanized silicone rubber was higher than that of platinum vulcanized silicone rubber,and the hardness,tensile strength,fixed tensile strength and elongation at break of the former were higher than those of the latter,and the thermal stability of platinum vulcanized silicone rubber was better.Increase the dosage of double 25,increase the degree of vulcanization,reduce the vulcanization time,increase the hardness,increase the tensile strength,tear strength and elongation at break,and increase the resilience and compression set rate.According to the above experiments,the factors that have a greater influence on thermal stability were screened,and the crosslinking density and mechanical properties of silicone rubber with different reinforcing systems and vulcanization systems after aging were tested and analyzed after thermal oxygen aging experiments,and the influence of different reinforcing systems and vulcanization systems on the aging performance of silicone rubber was compared and studied.The results show that the effect of the reinforcing system on the thermal oxygen aging performance of silicone rubber is more significant.With the extension of aging time,the crosslinking density of silicone rubber shows a gradual increase trend,the hardness increases,the tensile strength first increases and then decreases,and the elongation at break decreases.However,the silicone rubber using precipitation silica showed different property changes,the crosslinking density decreased first and then increased,and the hardness,tensile strength and elongation at break all showed a downward trend.The performance of silicone rubber using different vulcanization systems before thermal oxygen aging is basically the same,after thermal oxygen aging,the silicone rubber using platinum vulcanization system is slightly lower crosslinking density,hardness,high elongation at break,and the law presented in the hot oxygen aging process is basically the same as that of the filling system.Finally,the effect of adding different metal oxides on the thermal aging resistance of silicone rubber was studied,and it was found that the mechanical properties of silicone rubber with antimony trioxide,iron oxide and cerium oxide were better than those of the blank group,and after thermal oxygen aging,ferric oxide and cerium oxide had the best retention rate of mechanical properties of silicone rubber,and the silicone rubber with cerium oxide had the best thermal stability.Increase the amount of cerium oxide,and find that the heat resistance of silicone rubber can be further improved.