Synthesis of poly[arylene ether sulfone-b-vinylidene fluoride] block copolymers

A series of alpha,omega-dihydroxy polyarylene sulfones (PAES) were synthesized comprising bisphenol A (PAES1, M-n = 1800, 4900, and 9500 daltons), 4,4'-biphenol (PAES2, M-n = 4100 daltons), and hexafluorobisphenol A (PAES3, M-n = 3300 daltons). These were reacted with alpha,omega-dibromo poly(vinylidene fluoride) (PVDF, M-n = 1200 daltons) prepared by telomerization, to yield block copolymers possessing rigid and flexible segments. Block copolymers were characterized by FTIR, NMR, GPC, DSC, TGA and TEM. In several cases the block copolymers exhibited distinct thermal transitions, i.e. T-m and T-g for PVDF and PAES segments, respectively. Where observable, T-g of PAES domains in the block copolymers occurred at a temperature lower than the corresponding PAES homopolymer due to the flexible nature of the surrounding PVDF domains. Block copolymers exhibited a similar thermal stability to the corresponding PAES homopolymers but higher stability than the PVDF homopolymer, and much higher still than alpha,omega-dibromo PVDF. TEM analyses indicate that phase separation of PAES and PVDF domains occurs on the nanometer scale. (C) 2003 Elsevier Ltd. All rights reserved.