MULTICOMPONENT LATEX IPN MATERIALS .1. MORPHOLOGY CONTROL

A series of novel structured latex particles with interpenetrating pol ymer network (IPN) cores and glassy SAN shells were developed in an at tempt to investigate the feasibility of these polymers as both toughen ing and damping agents in thermoplastics. The IPN cores were composed of one impact part (polybutadiene based) and one damping part (acrylic based, with T-g around +10 degrees C). The particle morphologies of t hese polymers were determined by TEM. The glass transitions and mechan ical behavior of the polymers were characterized from DMS. The effect of different components on the final core/shell particle morphologies and mechanical properties was studied. The mechanical behavior of core /shell particles with IPN cores was also compared with that of separat e core/shell and multilayered core/shell particles. In addition, norma l core/shell synthesis (rubbery part first then the glassy part) and i nverted core/shell synthesis (glassy part first then the rubbery part) were performed to provide another access for morphology control. It w as found that the core/shell latex particles with poly(butyl acrylate) based copolymers are more miscible than poly(ethylhexyl methacrylate) -based copolymers. The high grafting efficiency of poly(butyl acrylate ) plays an important role in governing phase miscibility. The latex pa rticles synthesized by the inverted core/shell mode showed higher misc ibility than the normal synthesized ones. (C) 1997 John Wiley & Sons, Inc.