Exploring mechanical properties and failure mechanisms of aramid and PBO crystals through molecular dynamics simulations

Molecular dynamics simulations were used to analyze the mechanical properties and failure processes of poly(p-phenylene-terephthalamide) (PPTA), poly(p-phenylene-benzimidazole-terephthalamide) (PBIA), PBIA–PPTA (formed by 1:1 copolymerization of PPTA and PBIA), and poly(p-phenylene-benzobisoxazole)...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of chemical physics 2023-12, Vol.159 (22)
Main Authors: Yang, Hong-Li, Zhou, Ming, Li, Bing, Pei, Han-Wen, Sun, Yu-Wei, Lu, Zhong-Yuan, Sun, Zhao-Yan
Format: Article
Language:English
Subjects:
Copolymerization
Crystals
Failure mechanisms
Kinetic theory
Mechanical properties
Molecular chains
Molecular dynamics
Physics
Simulation
Strain rate
Stress-strain curves
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Molecular dynamics simulations were used to analyze the mechanical properties and failure processes of poly(p-phenylene-terephthalamide) (PPTA), poly(p-phenylene-benzimidazole-terephthalamide) (PBIA), PBIA–PPTA (formed by 1:1 copolymerization of PPTA and PBIA), and poly(p-phenylene-benzobisoxazole) (PBO) crystals at different strain rates and temperatures. The failure stress and strain were found to be linear with the temperature and logarithmic strain rate. Moreover, based on the kinetic theory of fracture and the comprehensive simulation results, we formulated a model that describes the failure stress of the aforementioned crystals under varying strain rates and temperatures. Through the analysis of the failure process, we found that in PPTA, PBIA, and PBIA–PPTA crystals, the bond failure probability is correlated with the strain rate and temperature. The examination of bond lengths and angles unveiled that bonds with larger initial aligning angles are more susceptible to failure during the strain process. Intriguingly, the stretching process induced a conformational change in the PBO molecular chain, leading to a deviation from the linear relation in its stress–strain curve.
ISSN:0021-9606
1089-7690
DOI:10.1063/5.0175010