Preparation and characterisation of novel random copoly(arylene ether–thioether ketone)s containing 2,2-bis(4-phenylene)propane units

This study investigates on the preparation and characterisation of new random copolymers containing the monomeric units of a poly(arylene ether ketone) (PEAEK) and a poly(arylene thioether ketone) (PTATK) previously synthesised by our group. The syntheses were performed using a one-pot polymerisation method starting from 4,4′-difluorobenzophenone, bis(N,N-dimethyl-S-carbamate) of 2,2-bis(4-mercaptophenyl)propane (MBTA) and bisphenol A (BPA). Different mole percentages of BPA with respect to MBTA, varying from 20% to 80%, were used. The copolymers, obtained in good yields, have molecular weights in the range from 19,000 to 32,000 as determined by GPC. The structural proof is provided by 1H NMR spectroscopy. The TGA analysis shows that the high stability of PEAEK is only slightly affected by the introduction of the PTATK co-units in the chain. Indeed, the presence of sulphur atoms induces an initial degradation process at temperatures slightly lower than that of PEAEK, but in a second stage tends to improve the formation of crosslinkings. Moreover, the copolymers with an amount of PEAEK equal to 40 and 20 mol% show a small crystallinity, due to the presence of PTATK units. The Tg values are not affected by the composition of copolymers. Therefore, the presence of sulphur atoms in the polymer backbone does not significantly modify the PEAEK characteristics, whereas can induce important new properties, such as better flame resistance or higher refractive index.