Development of a poly(methyl methacrylate‐<i>co</i>‐<i>n</i>‐butyl methacrylate) copolymer binder system

Abstract

Abstract Low molecular weight poly(methylmethacrylate) and poly(methylmethacrylate‐co‐ n ‐butylmethacrylate) emulsion‐based polymers are developed for use as fugitive binders of high temperature powders to be used with the rapid prototyping method known as selective laser sintering. Kinetics of the homopolymerization of methylmethacrylate and n ‐butyl‐methacrylate are found to deviate from Smith‐Ewart Type II predictions. Reactivity ratios for the monomer pair are determined and indicate the pair to yield random copolymers. Molecular weight was controlled by the addition of chain transfer agents. Several transfer agents were studied and one, iso ‐octyl‐3‐mercaptopropionate, was selected for use with emulsion polymerizations. Glass transition temperatures of the homopolymers and copolymers were studied. © 1994 John Wiley &amp; Sons, Inc.