Investigating glass transition in a PA6T/66 copolymer through molecular dynamics simulations

Area of Science:

• Materials Science
• Polymer Chemistry
• Computational Materials Science

Background:

• Semi-aromatic polyamides are crucial engineering materials.
• Tailoring copolymer composition is vital for optimizing thermal and mechanical properties.
• Glass transition temperature (Tg) is a key indicator of material thermal stability.

Purpose of the Study:

• To investigate the thermal behavior of poly(hexamethylene terephthalamide-co-hexamethylene adipamide) (PA6T/66) copolymers.
• To understand how varying molar ratios of poly(terephthaloyl hexylenediamine) (PA6T) affect the glass transition temperature (Tg).
• To provide molecular-level insights into the design of PA6T/66 copolymers with improved thermal performance.

Main Methods:

• Classical molecular dynamics simulations were employed to study PA6T/66 copolymers.
• Temperature-dependent density analysis was used for experimental validation of Tg trends.
• Analysis focused on interchain hydrogen bonding and segmental mobility.

Main Results:

• Simulated Tg trends across different PA6T/66 compositions aligned with experimental data.
• Increasing PA6T content initially enhanced Tg by promoting interchain hydrogen bonds and restricting mobility.
• Beyond 55% PA6T, Tg decreased due to steric hindrance and altered hydrogen bond equilibrium.

Conclusions:

• PA6T content critically modulates the Tg of PA6T/66 copolymers.
• Molecular dynamics simulations offer atomic-scale understanding of thermal property variations.
• Findings provide guidelines for designing PA6T/66 copolymers with tailored thermal stability.