Abstract:

Grafting of methyl methacrylate(MMA) onto chloroprene latex was carried out by emulsion polymerization. FTIR and 1H NMR confirmed that the grafted polymer was formed. Effects of the reaction temperature, the emulsifier concentration, the initiator concentration and the monomer concentration on the apparent polymerization rates were investigated. The results showed that the monomer conversion and the grafting efficiency could reach 99.1%, 54.9%, respectively, under the conditions where the reaction temperature was 50 ℃, the dosage of initiator tert-butyl hydroperoxide/tetraethylenepentamine(t-BHP/TEPA) was 0.5%(based on the mass of dry chlorene rubber latex(CRL)), mass ratio of monomer to polymer was 3∶5, and the amount of emulsifier sodium dodecylbenzenesulfonate(DSB) was 1%(based on the mass of monomer). The kinetics equation Rp=Kc(E)0.15c(I)0.30c(MMA)1.41, where K is a constant, was obtained. The overall activation energy for the polymerization process was 60.2 kJ/mol within 40~55 ℃. The graft-copolymerization reaction follows the free radical mechanism generally.

Key words: chloroprene latex, emulsion graft polymerization, kinetics, methyl methacrylate, grafting mechanism