Structure evolution and kinetics steps of the melting process of thermoreversible polymer gels

Abstract

Helical junction-helix-wormlike transformation of syndiotactic polystyrene (sPS) conformations in a sPS/chloroform gel was investigated during melting process. The gel melting process involved a reversible dissociation of the network structure at low temperature and a reversible transformation process from helix to wormlike conformation at high temperature. The reaction order for the normal melting process adopted was 1. The quantitative description of the phase transformation kinetics for the melting process of sPS/chloroform gel was performed by resonance light scattering technique (RLS). Only the dissociation of the three helical junctions existed when the temperature was lower than 57 °C. As the rate-determining step, the transition from helix to wormlike conformation was identified when the temperature was higher than 57 °C. RLS proved to be an effective means for characterization of kinetic processes in polymer gels.