Acrylate Emulsion Polymerization In The Study

Water-soluble surfactant-free Emulsion Polymerization is the newest hotspot of research. It has great potential in the adhesives and paint. On the base of former research works and update products investigation , a new soap-free P(2-EHA/BA/Vac)emulsion was prepared in the presence of the sodium salt of poly(butylacrylate/arrylic acid)(abbreviated as P(BA/AANa))oligomer. The results show that the emulsion is very stable. The properties of such emulsion coating are superior to that of the ordinary one. The kinetics of soap-free emulsion polymerization of acrylates were studied.1. Soap-free emulsion were prepared by using BA . 2-EHA and VAc as monomers, AA and HEMA as reformer, KSP as initator. Pre-emulsion technology was adopted. First, oligomer were prepared by using BA and AA as momoners, KSP as initator. Oligomer had super emulsified property at the optimized reaction condition: amount of DDM 0.5%, amount of AA 50%, amount of KPS 1.2%, reaction time 1.5h. Second, soap-free emulsion were prepared when this oligomer were used emulsifier. Temperature-keeping time on soap-free emulsion polymerization were studied. Four reaction conditions were optimized by orthogonal experiment as monomer conversion reached 97.4%. The optimized reaction condition: amount of oligomer 3%, polymerization temperatue 80 C, amount of KPS 0.8%, reaction time 3h. The property of emulsion was fine when the amount of functional monomer was 15%.2. On the base of soap-free emulsion polymerization, we studied its kinetics. The reaction speed of polymerization initial stage was invariable when all stages were studied. Study on kinetics soap-free emulsion polymerization was carried out by changing only one of reaction conditions. The reaction followed the mechanism of free radical copolymerization and the activation energy of reaction was about 142KJ mol-1 . Kinetic equation was represented as: Rp = k [KPS]2.0[BA] 1.46[2-EHA]2..68 [VAc]2.0.