Aqueously Soluble Semi-Aromatic Copolyamides With Dual-Functional Groups As Sizing Agent

A series of novel aqueously soluble semi-aromatic (co)polyamides, poly[(ethylenedioxy)bis(ethylene) terephthalamide]-ran-poly[(ethylenedioxy)bis(ethylene) (2,5-dihydroxy-3,6-diallyl)terephthalamide] (CRPAOT-x), were prepared via the solid-state Claisen rearrangement reaction of poly[(ethylenedioxy)bis(ethylene) terephthalamide]-ran-poly[(ethylenedioxy)bis(ethylene) 2,5-bis(allyloxy)terephthalamide] (APAOT-x), where x (= 0, 13, 25, 50, 75, and 100) represents the molar fraction of allyloxy containing unit. APAOT-x was obtained through the interfacial copolymerization of terephthaloyl chloride, 2,5-bis(allyloxy)terephthaloyl chloride, and 2,2-(ethylenedioxy)bis(ethylamine). The reaction conditions including reactant concentration, temperature, and solvent were optimized. The chemical structures of the target (co)polyamides and their precursors were characterized by proton nuclear magnetic resonance (H-1 NMR) and Fourier transform infrared spectroscopies. The incorporation of hydrophilic (ethylenedioxy)bis(ethylene) units greatly improved the polymer solubility. CRPAOT-x dissolved not only in polar organic solvents such as dimethylformamide, dimethyl sulfoxide, and N-methyl pyrrolidone but also in ammonia water. Due to the presence of hydroxyl groups and oxygen-rich aliphatic units, CRPAOT-x showed excellent affinity toward epoxy resins. The microbond test indicated that the aramid fibers sized by these dual-functional polymers exhibited remarkably enhanced interfacial shear strength in epoxy matrices. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47132.