GROUP CONTRIBUTION ANALYSIS OF THE DAMPING BEHAVIOR OF HOMOPOLYMERS, STATISTICAL COPOLYMERS, AND INTERPENETRATING POLYMER NETWORKS BASED ON ACRYLIC, VINYL, AND STYRENIC MERS

The integral of loss modulus versus temperature plots in the vicinity of the glass transition temperature (loss area, LA) was characterized for various homopolymers, statistical copolymers, and interpenetrating polymer networks (IPNs), based on acrylics, vinyls, and styrenic mers. The quantity LA was found to be a molecular characteristic, governed by the structure of the individual mers. The LA of both IPNs and statistical copolymers obeys an additive relation of the component polymers. A group contribution analysis for LA was developed in which each moiety contributes a specific value to LA. A table derived via this group-contribution analysis permits the prediction of LA values. The results show that backbone motions and the moieties attached directly to the backbone contribute the most to the damping peak, and that long side chains act as diluents.