Synthesis and characterization of novel semiaromatic copolyamides bearing both polar hydroxyl and unsaturated allyl substituents

Abstract

A series of novel semiaromatic (co)polyamides, poly(octylene terephthalamide)‐ran‐poly[octylene 2,5‐bis(allyloxy)terephthalamide] (APA8T‐x, x represents the molar fraction of allyloxy containing structure unit), were prepared via the interfacial polymerization of 1,8‐diaminooctane, terephthaloyl chloride, and 2,5‐bis(allyloxy)terephthaloyl chloride. The polymerization conditions were optimized in terms of the yields and the molecular weights of the resultant polymers. These polymers were converted to the target macromolecules, poly(octylene terephthalamide)‐ran‐poly[octylene (2,5‐dihydroxy‐3,6‐diallyl)terephthalamide] (CRPA8T‐x), through solid state Claisen rearrangement reaction, as characterized by 1H NMR and FT‐IR spectroscopies. While APA8T‐x was only soluble in very limited solvents, the solubility of CRPA8T‐x in polar solvents improved remarkably, especially for those with high counit content. Due to the polarity of hydroxyl group, CRPA8T‐x showed an improved hydrophilicity than APA8T‐x. The treatment of aramid fibers with CRPA8T‐x, as sizing agents, enhanced obviously their interfacial adhesion toward epoxy resin. The fibers sized with 0.5 wt% CRPA8T‐75 solution in the mixture of 1,1,2,2‐tetrachloroethane and phenol (40:60, w/w) exhibited a maximum increase of 60% in interfacial shear strength than the naked fibers. The easy preparation and the facility for the further modification through the dual functional substituents may greatly widen the application of semiaromatic polyamides. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 690–698

Aqueously soluble semi‐aromatic copolyamides with dual‐functional groups as sizing agent

“…As shown in Figure , exothermic peaks were observed for the polyamides containing allyloxyl substituents on the first scanning curves. The starting temperature of CR reaction was lower than that of APA8T‐x, suggesting that CR reaction could occur under a milder condition in the present system. Increasing the co‐unit content made the exothermic peak more remarkable.…”

“…The solubilities of APAOT‐x and CRPAOT‐x polymers were evaluated in various solvents. As listed in Table , these polymers were more soluble in organic solvents compared with our previous reported semi‐aromatic and wholly aromatic polyamide system . All APAOT‐x and CRPAOT‐x polymers could be dissolved in formic acid, TFA, and m‐Cresol.…”

“…E‐51 epoxy resin was purchased from Shenzhen JiTian Co. Ltd (Shenzhen, China) at a resin to hardener ratio of 30: 10.5 in weight. 2,5‐Bis(allyloxy)terephthaloyl chloride (ATPC) was synthesized according to the previously reported procedures . Terephthaloyl chloride (TPC, AR, Aladdin, Shanghai, China) was sublimated twice under vacuum.…”

“…In a subsequent work, semi‐aromatic polyamides with dual‐functional groups were prepared using 1,8‐diaminooctane to replace p‐phenylenediamine. Their solubilities in organic solvent were improved . The interface affinity between epoxy resins and the aramid fibers treated with the solutions of these polymers was even more significantly enhanced, as estimated by single‐fiber pull‐out and microbond tests.…”

“…Second, 1,8‐diamino‐3,6‐dioxaoctane was expected to endow the polymer with solubility in water. Compared with the previously reported systems, the CR reaction of APAOT‐x could be carried out at a milder temperature with less side reaction. The resultant CRPAOT‐x showed much improved solubility and excellent performance as sizing agent.…”