Xu, Ruopei;Qiu, Yue;Tang, Siyi;Yang, Cheng;Dai, Yu;Zhang, Dajie;Gao, Yue;Gao, Kexiong;Luo, Longbo;Liu, Xiangyang published 《Preparation of High Strength and Toughness Aramid Fiber by Introducing Flexible Asymmetric Monomer to Construct Misplaced-Nunchaku Structure》 in 2021. The article was appeared in 《Macromolecular Materials and Engineering》. They have made some progress in their research.Safety of 3-(4-Aminophenoxy)aniline The article mentions the following:
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 asym. structure of more flexible diamine, 3,4′-diaminodiphenyl ether (3,4′-ODA), is introduced into heterocyclic aramid (PBIA) fibers to replace rigid sym. 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 mech. 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%, resp. 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. Mol. dynamics simulations confirm that 3,4′-ODA structure undergoes a conformation transformation to form a straightened chain during hot-drawing, while sym. 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. To complete the study, the researchers used 3-(4-Aminophenoxy)aniline (cas: 2657-87-6) .
3-(4-Aminophenoxy)aniline is one of ethers-buliding-blocks. Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. Safety of 3-(4-Aminophenoxy)aniline The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.
Reference:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem