Low temperature cure of unsaturated polyester resins with thermoplastic additives II. Structure formation and shrinkage control mechanism

摘要

An important feature in the cure of unsaturated polyester (UP)/styrene/thermoplastics system is the formation of a two-phase structure. Its final morphology is primarily determined by the phase separation process and the gelation resulting from the polymerization. In was found that depending on the system miscibility and reaction kinetics, the formation of sample structure follows the same route, but may end at different stages with different types of structure. Two key factors-the volume fraction of the thermoplastic-rih phase and the phase separation period i.e. the time period between the onset of phase separation and the gelation-determine the final structure of the sample. Based on experimental results, a shrinkage control mechanism at low temperature cure was proposed.