Bisphenol A-based co-polyarylates: synthesis, properties and thermal decomposition mechanism

A series of co-polyarylates containing m -aryl ether units were synthesized from bisphenol A, 1,3-bis(4′-formylchloridephenoxy)benzene and terephthaloyl chloride via interfacial polycondensation in order to improve the processability of the bisphenol A-based polyarylate (U-polymer). The structure and properties of the co-polyarylates were characterized using infrared spectra, differential scanning calorimety, thermogravimetric analyses, wide angle x-ray diffraction and solubility testing, etc. The results show that the introduction of the asymmetry and flexible m -aryl ether units could improve the solubility obviously, but the solubility parameter of the co-polyarylate almost keeps a constant with changing the content of m -aryl ether units. As the content of m -aryl ether unit increases, the crystallization ability of the polyarylate weakens, meanwhile, the melting temperature shifts to low temperature as expected and the melting enthalpy reduces. When the content of the m -aryl ether units is higher than 60 %, the co-polyarylates become amorphous polymers. Moreover, there is almost no reduction of the thermal stability with increasing the content of the m -aryl ether units. In addition, the stability of each chemical bond of the co-polyarylate to thermal decomposition was systematically studied by means of pyrolysis-gas chromatography/mass spectrometry, and the thermal decomposition mechanism of the co-polyarylate was obtained.