THERMODYNAMICALLY REVERSIBLE AND IRREVERSIBLE CONTROL ON MORPHOLOGY OF MULTIPHASE SYSTEMS .1. RAYLEIGH-BRILLOUIN LASER-LIGHT SCATTERING STUDY ON MISCIBILITIES AND PHASE-DIAGRAMS OF RUBBER-MODIFIED EPOXIES

Morphology and properties of polymer alloys can be controlled by thermodynamically reversible (structure frozen-in) or irreversible (structure locked-in) processes by simultaneously manipulating miscibility, mechanisms of phase separation, glass transitions, and cure kinetics of polymer systems. A new method of using Rayleigh-Brillouin laser light scattering experiments for constructing phase diagrams consisting of the binodal and spinodal curves has been developed. The Brillouin spectra can also be used to study cure kinetics of thermosetting materials. The miscibility of an epoxy/carboxyl-terminated butadiene acrylonitrile copolymer (CTBN) rubber system has been studied by this new method. It was found that this system has an upper consolute temperature. An increase in the acrylonitrile content of the CTBN rubber improves the miscibility and depresses the consolute temperature of this polymer system. The miscibility gap (the consolute temperature) can be shifted up and down by the presence of different curing agents. The morphology of this epoxy/CTBN system can be controlled by simultaneously manipulating the kinetic processes of phase separation and curing reactions. © 1990 Chapman and Hall Ltd.