End functionalization of styrene-butadiene rubber with poly(ethylene glycol)-poly(dimethylsiloxane) terminator

Abstract

A polar polydimethylsiloxane terminator was prepared and reacted with living copolymer anion of styrene and butadiene, to synthesize end-functionalized styrene-butadiene rubber (SBR). As a polar functional terminator, poly(ethylene glycol)-poly(dimethylsiloxane) block copolymer (PEG-PDMS) containing a chlorosilyl moiety at one chain end (1) was synthesized by two-step hydrosilylation. End capping of poly(styrene-butadiene) living anion with PEG-PDMS terminator (1) afforded polymers with polar poly(dimethylsiloxane) end groups. PEG-PDMS terminated SBR, SBR-1, showed higher interaction with silica particles by microscophy and chromatography. Dynamic-mechanical analysis on silica composites of SBR-1 strongly supports the assumption that the PEG-PDMS end groups behave as polar functional groups, showing increase of the glass transition temperature (Tg) and storage modulus in the composite of SBR-1 with silica particles. The SBR-1/silica composite showed lower tan δ at 60°C and higher tan δ at 0°C as compared to SBR-Sn/silica composite.