Nonmigratory Poly(vinyl chloride)-block-polycaprolactone Plasticizers and Compatibilizers Prepared by Sequential RAFT and Ring-Opening Polymerization (RAFT-T̵-ROP)

Abstract

Well-defined nonmigrating polymeric plasticizers, poly(vinyl chloride)-block-polycaprolactone (PVC-b-PCL), were synthesized by sequential reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP) with 2-hydroxyethyl 2-(ethoxycarbonothioylthio)propanoate (HECP) as RAFT agent and incipient initiator for ROP of e-caprolactone (CL, oxepan-2-one). Kinetic experiments demonstrated that HECP provided good control in RAFT polymerization of vinyl chloride (VC) with dispersity (Đ) ∼ 1.2 for 3400 < Mn < 11000. Chain extension experiments with VC and vinyl acetate proved the high end-group fidelity of the macroRAFT agent formed. The hydroxy end-group of the PVC macroRAFT agent allowed its use as a ROP initiator in forming a series of PVC-b-PCL with different PCL block lengths by RAFT-T-ROP. Characterization by wide-angle X-ray diffraction (WAXD), polarized light microscopy (PLM), and differential scanning calorimetry (DSC) indicates that there is enhanced chain enta...