Synthesis and structure analysis of fluorosilicone copolymer raw rubber

1,3,5-tris（3,3,3-trifluoropyl）-1,3,5-trimethylcyclotrisiloxane （D3F） and hexamethylcyclotrisiloxane were used as raw materials to synthesize fluorosilicone copolymer with high molecular weight. The effects of reaction time and reaction temperature on molecular weight of the products and monomer ratio on chain segment content of the copolymers were studied. The structure of the copolymer was characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy, and its molecular weight was determined by Ubbelohde viscometer. The results showed that the proportion of chain segment content in fluorosilicone rubber was closer to that of feed when D3F amount was high. With increase of reaction temperature and time, molecular weight of the fluorosilicone copolymer first increased and then decreased. Molecular weight of fluorosilicone copolymer could be effectively increased by stopping heating at an approp-riate node in the reaction process. When the reaction temperature was 90 ℃, reaction time was 10