Properties and structures of terephthalyl chloride (TPC) modified meta-aramid copolymers

The properties and structures of terephthalyl chloride (TPC) modified poly (m-phenylene isophthalamide) (PMIA) with TPC mole content in acylchloride from 5% - 15% were studied in this paper. The composition and structure of the copolymer were determined by H-1 NMR. The content of TPC moiety in the molecular chain was calculated. Thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) were used to analysis the thermal properties of TPC modified PMIA copolymer. The results show that by introducing TPC units in the PMIA molecular chain, PMIA copolymers with better thermal properties were prepared. With the increase of TPC content, the TPC modified PMIA exhibit increasing thermal stability. The pyrolysis process of the copolymer was detected by FTIR spectra. When the copolymers were pyrolyzed to 500 degrees C, an aryl nitrile band at 2230 cm(-1) appears in the FTIR spectrum. This means that at this temperature breakage of the amide bond occurred.