Xanthate mediated living polymerization of vinyl acetate: A systematic variation in MADIX/RAFT agent structure

Abstract

Eight xanthates were synthesized to induce living free radical polymerization of vinyl acetate. Four compounds, methyl (4-methoxyphenoxy)carbonothioylsulfanyl acetate, methyl (methoxycarbonothioyl)sulfanyl acetate, methyl (ethoxycarbonothioyl)sulfanyl acetate and methyl (isopropoxycarbonothioyl)sulfanyl acetate were identified as suitable MADIX/RAFT agents, yielding low polydispersity (PDI < 1.2) poly(vinyl acetate) of molecular weights exceeding 5 x 104 g·mol-1. All suitable MADIX/RAFT agents exhibited extended periods of inhibition (0.3 h < tinh < 10 h) andmoderate rate retardation. The abitity of these compounds to control vinyl acetate polymerization can be correlated with the electron density on the central carbon atom of the xanthate. Electrospray ionization mass spectrometric analysis was performed to complete the investigation on the new MADIX/RAFT agents.