Enhancing the crystallinity and heat resistance of poly(ethylene terephthalate) using ZnCl2‐ionized polyamide‐66 as a heterogeneous nucleator

Abstract To achieve the maximal improvement in the crystallization rate and heat resistance of poly(ethylene terephthalate) (PET), 2.6 mol% of ZnCl 2 ionized polyamide (PA)‐66 (PA‐66–Zn), with a strong coordination ability, is prepared and used as PET nucleator. This study found that the PA‐66–Zn heterogeneously nucleates PET more effectively than the CaCl 2 ‐ionized PA‐66 and non‐ionized PA‐66 by differential scanning calorimetry, crystallization kinetics, X‐ray diffraction, and polarized optical microscopy. This is probably a result of the introduction of stronger ion–dipole interactions (IDIs) between the PET esters and the ionized‐PA‐66 ZnCl 2 ‐coordinating amides, which obviously heightens the PET/PA‐66–Zn interfacial compatibility. As shown by scanning electron microscopy, the compatibilization through an appropriate concentration of IDIs promotes the formation of smaller and denser PA‐66 crystals with immensely increased nucleator efficiency. Furthermore, the PET/PA‐66–Zn with significantly improved crystallinity displays a remarkable increase in heat‐resistant temperature, at 21.6 and 55.1°C higher than that of PET/PA‐66 and PET, respectively. The results demonstrate that the PA‐66–Zn can act as a superior nucleator and as an outstanding heat‐resistant agent for PET.