Facile preparation of fluoroalkyl end-capped vinyltrimethoxysilane oligomer/α, ω-dihydroxy-terminated poly(dimethylsiloxane) composite rubber: application to effective removal of fluorinated aromatic compound from aqueous methanol solution by fluoroalkylated silicone composite rubber

Abstract Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [$ R_{F} $–($ CH_{2} $CHSiOMe)3)n–$ R_{F} $; n = 2, 3; $ R_{F} $ = CF($ CF_{3} $)$ OC_{3} %$ F_{7} $: $ R_{F} $–(VM)n–$ R_{F} $] undergoes the sol–gel reactions in the presence of α, ω-dihydroxy-terminated poly(dimethylsiloxane) [HO–($ S...
Ausführliche Beschreibung

Abstract Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [$ R_{F} $–($ CH_{2} $CHSiOMe)3)n–$ R_{F} $; n = 2, 3; $ R_{F} $ = CF($ CF_{3} $)$ OC_{3} %$ F_{7} $: $ R_{F} $–(VM)n–$ R_{F} $] undergoes the sol–gel reactions in the presence of α, ω-dihydroxy-terminated poly(dimethylsiloxane) [HO–($ SiMe_{2} $O)nH: HPDMS] under non-catalytic conditions to provide the crosslinked $ R_{F} $–(VM)n–$ R_{F} $/HPDMS composite rubber in quantitative isolated yields. Especially, we can isolate the expected composite rubber through the sol–gel reactions, in which the contents of the $ R_{F} $–(VM)n–$ R_{F} $ oligomer based on employed oligomer and HPDMS are greater than 0.16%. In contrast, traditional silane coupling agents such as tetraethoxysilane, methyltrimethoxysilane and triethoxy-1H, 1H, 2H, 2H-tridecafluoro-n-octylsilane were unable to afford the expected composite rubber through the sol–gel reactions with HPDMS under similar conditions. The fluoroalkylated silicone composite rubber thus obtained gave no swelling behavior toward water, dimethyl sulfoxide and methanol; however, the composite rubber was found to display the higher swelling characteristic for toluene, hexane and tetrahydrofuran, especially for fluorinated aliphatic solvents. Interestingly, it was demonstrated that the fluoroalkylated silicone composite rubber swollen with hexane can adsorb a variety of aromatic compounds in aqueous methanol solutions. More interestingly, we found that the fluoroalkylated silicone composite rubber can exhibit an excellent adsorption ability toward the fluorinated aromatic compounds such as 2′, 3′, 4′, 5′, 6′-pentafluoroacetophenone, compared to that of the corresponding non-fluorinated one. Graphic abstract Ausführliche Beschreibung