Synthesis and physical properties of the crosslinking poly(butyl acrylate)/polystyrene core-shell composite latex

Butyl acrylate and styrene were used as monomers in the first stage and second stage respectively, and potassium persulfate (K2S2Os), as the initiator to synthesize the polymer/polymer composite latex by two-stage soapless emulsion polymerization. In the first stage, the poly(butyl acrylate) with crosslinking structure (PBA(XL)) was synthesized to be the seed latex. In the second stage, the styrene was polymerized in the presence of PBA(XL) seeds to form the PBA(XL) / PS composite latex. The morphology of the composite latex was observed by transmission electron microscopy (TEM) and showed that composite latex particles were with core-shell structure. The particle size distribution of the composite latex was very uniform. The kinetics of reaction of the second stage polymerization were investigated. The results showed that the reaction rate would be influenced by the degree of crosslinking of the PBA(XL) seeds, initiator concentration and agitation speed. The components of the PBA(XL)/PS composite polymers were measured by thin-layer chromatographic (TLC) analysis. The results showed a thin layer of PBA-graft-PS copolymer between the core (PBA) and shell (PS) region. The morphology of the PBA(XL)/PS composite polymers, processed under heat and pressure, was observed by transmission electron microscope (TEM). The morphology may change gradually with increase of processing time. The mechanical properties and rheological properties of the composite polymers were investigated.