Hyperbranched Polymers - Engineering Materials and Degradation Behavior

摘要

Hyperbranched polymers of unique compositions were studied for their mechanical properties and degradation behaviors. Highly branched polymeric architectures have been shown to exhibit properties that are unique to those of linear polymer materials. In the studies supported under this grant, hyperbranched polycarbonates were designed as analogs to common engineering polymers to investigate the effects of branching upon the chain-chain packing and cooperative motions. Remarkably, the local chain-chain interactions were quite similar for hyperbranched and linear polymer isomers. In another design, hyperbranched poly(silyl ester)s were studied as hydrolytically-degradable polymers to determine the effects of branching upon the degradation profile. The hyperbranched poly(silyl ester)s degraded by a two step degradation profile, whereas the analogous linear polymer gave smooth molecular weight loss with time. The result of these undertakings was the preparation of new materials and the acquisition of improved understanding of the structural conformation, three- dimensional solid-state packing, and physical and mechanical properties of highly-branched polymers.