Preparation And Properties Of Thiol-ene Crosslinked Silicone Rubber

In this paper,one kind of thiol-containing cross-linking agent andthe silicone rubber with thiol-ene networks were prepared and characterized,and the influence of the flame retardant and ablative fillers on properties of thiol-ene crosslinking silicone rubber were studied.First of all,on the basis of the synthesis of poly（methyl mercaptoprpopyl）siloxane crosslinking agent,using methyl vinyl silicone rubber as the substrate,nano gas phase SiO₂ as reinforcing filler,benzoin dimethyl ether（DMPA）as initiator,the siloxane compound films were prepared by double roller mixing and platform pressing,then cured under the ultraviolet lamp.This paper studied the effects of SiO₂ dosage,amount of curing agent,the content of DMPA,and UV light curing time on the performance of the silicone rubber composites.Silicone rubber has the best properties when the amount of SiO₂ is 35phr,the DMPA photoinitiator is 0.05phr,the curing agent content is 0.5phr,and the curing time against each other 5min.Secondly,aluminium two ethyl phosphonic acid（ADP）,aluminum hydroxide（ATH）,mica,glass powder,eight phenyl silsesquioxane（OPS）and eight vinyl silsesquioxane（OVP）were filled into the thiol-ene crosslinked silicone rubber,and the effects of these fillers on the properties of silicone rubber were studied.The results showed that mechanical properties of 10 phr ADP silicone rubber were better,the tensile strength was 3.05MPa,the elongation at break was 855%.ATH-containing silicone rubber has a high limit oxygen index of 28.6%,but its mechanical properties decrease obviously.The properties of silicone rubber with 15phr mica were outstanding with tensile strength of 4.31MPa,elongation of 1061%,linear ablation rate of 0.482mm/s,the limit oxygen index of 27.7%.Adding 15 phr of glass powder,the back temperature,in the 1800s did not reach 300 degrees.With 10 phr OPS,the silicone rubber has good mechanical properties with tensile strength of 3.25MPa,elongation of 985%.The limit oxygen index of the silicone rubber with 15 phr OPS was 28.8%.The line ablation rate of 15 phr OVP silicone rubber was only 0.121mm/s,which was 84.8%lower than that of pure silicone rubber,which was 0.796mm/s.Finally,mica,glass powder,ADP and OPS were used as fillers to explore the influences of fillers compounding on the properties of silicone rubber.Silicone rubber containing 10 phr OPS and 15 phr ADP has better thermal stability,ablation properties and flame retardant properties compared to silicone rubber containing 25phr ADP.In the silicone rubber with fixed OPS and ADP content,the addition of the ceramic filler will increase the limit oxygen index of silicone rubber.When the ceramic filler（mica,glass powder）loading was fixed,increasing the content of OPS and decreasing the content of ADP,the peak heat release rate of silicone rubber composites decreased.