Influence of the ion content of CaCl2-ionised polyamide-66 nucleator on the crystalline nucleation of poly(ethylene terephthalate) through ion-dipole interactions

Yuanfu Tian; Jinqiang Tan; Yixin Wu; Zhiyuan Song; Qian Tao; Xuan Zheng; Tao Hu; Xinghou Gong; Chonggang Wu

doi:10.1039/d0ra07024f

Influence of the ion content of CaCl₂-ionised polyamide-66 nucleator on the crystalline nucleation of poly(ethylene terephthalate) through ion-dipole interactions

RSC Adv. 2020 Sep 15;10(56):34177-34186. doi: 10.1039/d0ra07024f. eCollection 2020 Sep 10.

Authors

Yuanfu Tian¹, Jinqiang Tan¹, Yixin Wu¹, Zhiyuan Song¹, Qian Tao¹, Xuan Zheng¹, Tao Hu¹, Xinghou Gong¹, Chonggang Wu¹

Affiliation

¹ Hubei Provincial Key Laboratory of Green Materials for Light Industry, Collaborative Innovation Centre of Green Light-weight Materials and Processing and School of Materials and Chemical Engineering, Hubei University of Technology Wuhan Hubei 430068 P. R. China cgwu@mail.hbut.edu.cn.

Abstract

Polyamide (PA)-66 is successfully ionised with various weight fractions of CaCl₂ to prepare PA-66 ionenes bearing different ion contents (ICs). The PA-66 ionenes against PA-66 are incorporated as heterogeneous nucleators into poly(ethylene terephthalate) (PET) to effectively promote PET crystallisation. Compared to the PET/PA-66 (95/5 wt/wt), the PET/PA-66 ionenes (95/5) markedly improve the crystallisation rate and degree of crystallinity. Notably, as the IC of the PA-66 ionene rises from 0 to 11.4 mol%, the nucleation efficiency first increases and then decreases. This may be attributed to the introduction of strong ion-dipole interactions between the CaCl₂-coordinating amides of the PA-66 ionenes and the esters of the PET matrices as the IC increases, which gradually boosts the PET/PA-66 ionene interfacial compatibility to create finer nucleator crystals with a denser distribution, thereby steadily enhancing the nucleation efficiency. However, once the IC exceeds 6.5 mol%, the dramatically improved interfacial compatibility causes greatly more and thicker amorphous interphase, which inhibits PET crystallisation. The results indicate that the PA-66 ionene containing 6.5 mol% of Ca²⁺ is a promising nucleator to maximise the crystallisation acceleration of PET due to the moderate interfacial compatibility by medium-concentration ion-dipole interactions.