Novel trifluoromethyl-containing poly(amide-imide)s: Organosolubility, optical behavior, thermostability, and crystallinity

Abstract

A new dicarboxylic acid monomer, 2,6-bis(1,3-dioxo-5-carboxyisoindolin-2-yl)-4,4′-bis(trifluoromethyl)-1,1′-diphenyl ether (IFDPE), bearing two preformed imide rings was synthesized via a three-step manner from 4-(trifluoromethyl)phenol and 4-chloro-3,5-dinitrobenzotrifluoride. The monomer IFDPE was then used to prepare a series of novel trifluoromethyl-containing poly(amide–imide)s via a direct phosphorylation polycondensation with various aromatic diamines. The intrinsic viscosities of the polymers were found to be in the range 0.86–1.02 d/g. The weight- and number-average molecular weights of the resulting polymers were determined with gel permeation chromatography. The polymeric samples were readily soluble in a variety of organic solvents and formed low-color, flexible thin films via solution casting. The values of the absorption edge wavelength were determined by ultraviolet–visible spectroscopy, and all of the resulting poly (amide–imide)s films exhibited high optical transparency. The resulting polymers showed moderately high glass-transition temperatures in the range 295–324°C and had 10% weight loss temperatures in excess of 524°C in nitrogen. The crystallinity extents were qualitatively investigated with wide-angle X-ray diffraction measurements. Scanning electron microscopy images revealed an agglomerated bulk with nonuniformity on the surface. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012