Preparation of vinyl-containing perfluoropolyether-b-polysiloxane and its properties in silicone rubber

Poor solvent resistance is one of the important factors restricting the development and application of silicone rubber, and fluorine modification is one of the effective means to solve this problem. Vinyl-containing polysiloxane (Vi-PSi) was prepared by potassium tert-butanol induced cyclosiloxane anionic ring-opening, and Vinyl-containing perfluoropolyether-b-polysiloxane block copolymer (PFPE-b-PMVS) was grafted with perfluoroether siloxane. Its structure was determined by FT IR and ¹H NMR. The effects of PFPE-b-PMVS on mechanical properties, vulcanization properties, solvent resistance and thermal stability of methyl vinyl silicone rubber (MVQ) were studied. The results show that with the increase of PFPE-b-PMVS content, the tensile strength of modified MVQ increases first and then decreases after high temperature vulcanization crosslinking. When the addition of PFPE-b-PMVS is 2%, the tensile strength and elongation at break can reach 11.38 MPa and 396%. The coke time (t₁₀) and positive vulcanization time (t₉₀) decreased with the increase of PFPE-b-PMVS. The solvent resistance decreased with the increase of PFPE-b-PMVS. When the PFPE-b-PMVS added amount was 20%, the adsorption solvent in p-xylene solvent was 83.22% lower than that in unmodified MVQ. The 10% thermogravimetric temperature decreased with the increase of the dosage of PFPE-b-PMVS.