Crystallization of Aromatic Oligoester from Bisphenol A and Diphenyl Terephthalate/lsophthalate Mixtures

Abstract

We succeeded in the crystallization of the title oligomeric ester, which was denoted hereafter as polyarylate, and was sythesized by the melt condensation polymerization of bisphenol A and diphenyl terephthalate/isophthalate (mole ratio 1/0.5/0.5) contacting with the proper solvent. Oligomeric polyarylate could be crystallized in a solvent whose solubility parameter was from 8 to 10. This oligomeric polyarylate had a heat of fusion from 2 to 20 J/g, and the melting temperature was changed from 140 to 220°C depending upon the crystallizing solvent and the reduced viscosity of the oligomer used. When the same oligomer was used for the crystallization, the melting point increased with the increase in the heat of fusion. However, with the increase in the reduced viscosity of the oligomer, the heat of fusion decreased, while the melting point and glass transition of the polymer increased with the increase in the reduced viscosity of the oligomer used, and finally, both reached inthe saturated points with the in crease in the reduced viscosity of the oligomer used. The X-ray analysis for this solvent-induced crystallized oligomeric polymer showed partially crystalline nature. A spherulite structure was observed using a photomicroscope, and a detailed structure of the crystallized structure was also discussed using a scanning electron microscope.