RUI: Phase Separation Behavior of Polymer Blends Modified by Copolymer Additives

Pacific Lutheran University, Tacoma WA

Investigators

Abstract

This RUI award focuses on equilibrium thermodynamics and kinetics of phase separation in binary polymer blends with additives of various copolymer structures and concentrations. The goal of this work is to better understand how copolymers can influence phase evolution and thermodynamic boundaries. Expanding on previous research, scattering and simulation techniques will be employed. The copolymers to be studied include random, block, multi-block, and graft copolymers. The monomer composition of the copolymer will also include both symmetric and asymmetric compositions for some of the copolymers. The specific experimental ternary system is a blend of polybutadiene, polystyrene, and various copolymers of butadiene and styrene. The molecular weights of the homopolymers will be in two classes, a low molecular weight blend and a blend with molecular weight greater than the entanglement molecular weight. These systems will be studied experimentally using temperature jump wide-angle light scattering as well as small angle neutron scattering (SANS) techniques when appropriate. Lastly, Monte Carlo computer simulation techniques will be employed to model the experimental polymer systems. %%% The development of new polymer-based materials with tailored properties is often attempted through the mixing of currently existing materials. Successful mixing has often been challenging to accomplish and to aid in the mixing an additive is commonly introduced as a compatibilizer. In this work, the effects various compatibilizers have on the mixing of polymer materials will be studied with the goal being to better understand the fundamental processes involved. As these effects are better understood, the knowledge can be applied to industrial systems with the aim of improving the processing and performance of polymer-based materials.