Synthesis Of Liquid Fluorosilicone Rubber

The equilibrium and product molecular weight control in the ring-opening polymerization of trimethylfluoropropylcyclotrisiloxane(DF3)were studied systematically.The factors affecting the synthesis of liquid fluorosilicone rubber(FLSR)were investigated.The influence of reaction temperature,reaction time,the type of promoter,the amount of promoter,the amount of modifier on the equilibrium process of DF3 copopolymer were investigated.Based on this,the effects of initiator type,polymerization time,polymerization temperature,Effect of Comonomer Proportion on Synthesis of DF3 and Octamethylcyclotetrasiloxane(D4)Copolymer.First,the reaction process was monitored by GPC,NMR and FTIR.Finally,the products were characterized by TG,DSC,Intrinsic viscosity of the product performance test for the liquid FLSR synthesis process provides a theoretical basis.The results showed that THF and DMSO promoted the reaction in the positive direction when the DF3 copopolymer was synthesized,but the promoting effect of THF was weak.However,no by-product ring was formed during the reaction.At the polymerization temperature Was 120?,the polymerization time was 5min,n(THF):n(NaOH)=0.5,the yield of polymer was 86.36%;while the promotion of DMSO was stronger and the polymerization reaction could be carried out at lower temperature,But there are by-products.Finally,DMSO and Hydroxyfluorosilicone oil(HFSO)will work together on the system,and the reaction at 90? for 20min will result in the yield of 86.70%of FLSR with terminal hydroxyl groups.Tetramethylammonium hydroxide(TMAH)is more conducive to the initiation of copolymerization.With TMAH as initiator and DMSO as accelerator,FLSR with different monomer ratios can be generated,and the proportion of DF3 is higher Which is conducive to the formation of copolymer.When n(DF3):n(D4)= 9:1,the yield of copolymer reached 89.24%.The obtained copolymer was tested for its properties.The test results showed that the obtained copolymer was a random copolymer.As the proportion of D4 increased,the thermal stability of the polymer was better.