Investigating glass transition in a PA6T/66 copolymer through molecular dynamics simulations.
basic_science · Level V
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- Record sourced from PubMed, PMID 40548391.
- Also identified by DOI 10.1039/d5sm00165j.
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Abstract
Tailoring copolymer composition is a key strategy for enhancing the thermal and mechanical performance of semi-aromatic polyamides. In this work, we investigate the thermal behavior of poly(hexamethylene terephthalamide-<i>co</i>-hexamethylene adipamide) (PA6T/66) copolymers by probing their glass transition temperature (<i>T</i><sub>g</sub>), a critical parameter governing material stability. Classical molecular dynamics simulations reveal <i>T</i><sub>g</sub> trends across PA6T/66 systems with varying molar ratios of poly(terephthaloyl hexylenediamine) (PA6T), in alignment with experimental data obtained from temperature-dependent density analysis. Increasing PA6T content promotes interchain hydrogen bond (HB) formation, which enhances thermal stability by restricting segmental mobility. However, beyond 55% PA6T content, <i>T</i><sub>g</sub> decreases due to steric hindrance from stacked benzene rings and a shift in the interchain/intrachain HB equilibrium, which disrupts cohesive interactions. These findings reveal the thermal properties at the atomic scale by which PA6T content modulates <i>T</i><sub>g</sub>, providing a molecular-level understanding that offers valuable guidelines for designing PA6T/66 copolymers with enhanced thermal performance.