Non-isothermal crystallization kinetics of organic montmorillonite/SiO₂ aerogel/PET composites

Abstract

Purpose Crystallization kinetics is a key factor that controls the crystallization process of polymers and influences the crystallinity and morphology of polymers. This study aims to explore the effects of functional filler SiO2 aerogel and co-modified filler organic montmorillonite (OMMT) on the crystallization process of polyester polyethylene terephthalate (PET). In this study, the nonisothermal crystallization kinetics of OMMT/SiO2 aerogel/PET composites were studied by Jeziorny method. Design/methodology/approach The catalyst (Sb2O3), OMMT and SiO2 aerogel were uniformly dispersed in ethylene glycol (EG). Then, the mixture and terephthalic acid (PTA) were put into a semicontinuous polyester synthesis reactor, and the SiO2 aerogel/PET composites were prepared by esterification and polycondensation. Findings Non-isothermal kinetic results showed that the high cooling rate hindered the movement of the molecular chain of the composites and made the crystallization peak move toward the low-temperature direction. With the increase of crystallization temperature (Tc), the melt crystallization rate decreases, but the cold crystallization rate increases. The introduction of OMMT and SiO2 aerogel condensation affected the nucleation and growth mode of crystals, lengthened the time with a relative crystallinity of 50% (t1/2) and decreased the crystallization rate. OMMT improved the crystallinity and Avrami index of the composites. Research limitations/implications Effects of thermal insulation functional filler SiO2 aerogel and co-modified filler OMMT on the crystallization process of PET were studied by non-isothermal crystallization kinetics, and the effects of SiO2 aerogel and OMMT on the nucleation mechanism of PET were clarified, which provided a theoretical reference for the preparation and performance optimization of PET matrix composites. Originality/value In this study, the OMMT/SiO2 aerogel/PET composites were prepared by in-situ polymerization, the crystallinity of PET matrix composites was improved, and the effects of OMMT and SiO2 aerogel on the crystallization process of PET were clarified.