Research on Synthesis and Crystallization Properties of Polyol‐Modified Copolyesters

Abstract

The slow crystallization rate of polyethylene terephthalate (PET) remains a major limitation for its processing and application. To address this challenge, a series of PET copolyesters were synthesized via melt polycondensation using multifunctional polyols as modifiers. Experimental findings indicate that among the selected polyols, pentaerythritol (PER) exhibits a uniquely superior nucleating ability, markedly enhancing the crystallization behavior compared to glycerol (GLY) and sorbitol (SOR). Both isothermal and non‐isothermal crystallization analyses revealed that the cold crystallization temperature of PET‐PER 0.5 decreased substantially from 146.3°C to 127.9°C, while the half‐crystallization time (t 1 / 2 ) was reduced to 0.7 min (approximately half that of PET) demonstrating a significant acceleration in crystallization kinetics. Furthermore, the incorporation of polyols concurrently improved the thermal stability of the copolyesters. This study confirms that PER serves as an effective crystallization modifier for PET, offering a viable strategy for the development of novel PET materials that combine rapid crystallization capability with enhanced thermal stability.