Research On Preparation And Properties Of Low Density And Flame Retardant Silicone Rubber Foam

Silicone rubber foam is a kind of new material which integrates the advantages of both silicone rubber and foam materials,which have used widely.However,there are still many problems exiting in the processing of the silicone rubber foam Therefore,attention has been focused on the influence of foaming method,and formula composition on properties of silicone rubber foams,hoping to get silicone rubber foam with more excellent comprehensive properties.This paper focuses on three parts: firstly,we probed effect of processing factors and formula composition on properties of moulded silicone rubber foams,afterwards,we researched on activation mechanism and blend of foaming agent and its application in silicone rubber foams.In the research of process conditions,the curing conditions were further studied by using the combination of the single variable and the orthogonal experiment design method.It turned out that two-step vulcanization was superior to one-step vulcanization.Besides,when the mold filling coefficient was close to 100%,the density of silicone rubber foams was lower and the mechanical properties of silicone rubber foams were better.In the next section,which the curing temperature and time of two stages were researched.Our results showed that the curing temperature of one-step had the more influence of the silicone rubber foams,and It was relatively appropriate when we adopted the curing temperature of one-step was about 110?,the vulcanization time was about 9min;the curing temperature of two-step was about 165?and the vulcanization time was about 30 min.In addition,through the formulation optimization,the following conclusions: to begin with,using Q20 as matrix materials,texture soft silicone rubber foams can be obtained which possessed better comprehensive performance.However,compression permanent deformation was bigger and this remains to be further improved.In the second place,when the dosage of the vulcanizing agent BIPB = 0.5phr,BPO=0.5phr,foaming agent H =4.0 phr,the silicone rubber foam had a relatively low density,and the tensile,compression and tearing resistance performance was better.In addition to the above,aluminium hydroxide(ATH)which is as a kind of flame retardant,when added 40 phr,its dispersion in the silicone rubber,flame retardant property,thermostability was relatively better and comprehensive performance close to the goals.And in the last part,we used TGA and DSC method,according to the results of the thermal analysis and practical comprehensive performance of foaming materials,it was concluded that when the proportion of blowing agent H :urea = 4:1(mass ratio),more effective play to the role of blowing agent H and lower the decomposition temperature of H.At this point,the silicone rubber foam' density can reach 0.513 g/cm3 and the various aspects of performance were excellent.Furthermore,using blowing agent H/AC did not produce obvious synergy effect and foaming result was bad,however,it improved the degree of cure.The last point is that using blowing agent H/OBSH did not produce obvious synergy effect also and foaming result was bad,however,it suppressed the degree of cure.