Carbazole‐based poly(aryl ether ketone) containing crosslinkable allyl groups on the side chains: synthesis, characterization and properties

Abstract

AbstractThis paper presents a feasible method for introducing crosslinkable groups into a polymer to achieve excellent chemical resistance and improved thermal stability. Here, 3,6‐bi(4‐fluorobenzenzoyl)‐N‐allylcarbazole, a novel allyl‐containing difluoroketone monomer, is synthesized and characterized. The resulting monomer is polymerized with phenolphthalein through the aromatic nucleophilic substitution reaction at 160 °C to provide the soluble poly(aryl ether ketone) (PAEK) with a pendant allyl group. The obtained PAEK is characterized using Fourier transform infrared spectroscopy, NMR and gel permeation chromatography. The crosslinking reaction of the polymer occurs at 270 °C, and it imparts excellent solvent resistance. DSC analysis shows that the glass transition temperature (Tg) of the cured polymer increases to 262–306 °C when the curing temperature is elevated or when the curing time is extended within certain limits. The rate of increase of Tg and the rate of the crosslinking reaction decrease as the curing time is extended under all of the investigated curing temperatures. The cured PAEKs possess good thermal stability with 5% weight loss temperatures up to 450 °C. The tensile strength and Young's modulus of the polymer film cured at 300 °C for 2 h are 65 MPa and 1.4 GPa, respectively. In addition, the polymer films before and after curing exhibit similar UV−visible absorption and blue light emission. © 2014 Society of Chemical Industry