Premium
Preparation of High Strength and Toughness Aramid Fiber by Introducing Flexible Asymmetric Monomer to Construct Misplaced‐Nunchaku Structure
Author(s) -
Xu Ruopei,
Qiu Yue,
Tang Siyi,
Yang Cheng,
Dai Yu,
Zhang Dajie,
Gao Yue,
Gao Kexiong,
Luo Longbo,
Liu Xiangyang
Publication year - 2021
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.202000814
Subject(s) - aramid , materials science , ultimate tensile strength , toughness , composite material , elongation , fiber , diamine , monomer , ether , polymer , polymer chemistry , chemistry , organic chemistry
High performance fibers with high strength and toughness have great potential in composites, but contradiction between tensile strength and elongation at break makes the preparation to become a current challenge. Herein, an asymmetric structure of more flexible diamine, 3,4′‐diaminodiphenyl ether (3,4′‐ODA), is introduced into heterocyclic aramid (PBIA) fibers to replace rigid symmetric p‐phenylenediamine (PDA). By studying the properties of copolymer (mPEBA) fibers with different ratios of diamine, it is found that the mPEBA fiber reached the optimal mechanical properties with the 30% content of 3,4′‐ODA. Compared with homopolymerized heterocyclic aramid fibers, the tensile strength and elongation at break of mPEBA fiber are improved by 26.2% and 38.7%, respectively. Results of X‐ray diffraction show that the introduction of 3,4′‐ODA structure can increase stretchability of mPEBA fibers, improving the orientation degree during hot‐drawing. Molecular dynamics simulations confirm that 3,4′‐ODA structure undergoes a conformation transformation to form a straightened chain during hot‐drawing, while symmetrical 4,4′‐diaminodiphenyl ether (4,4′‐ODA) cannot form the same conformation. The misplaced‐nunchaku structure is formed based on the special meta‐para position of 3,4′‐ODA, achieving the synergy of high strength and high toughness.