Synthesis and properties of poly(ether sulfone)-poly(tetrahydrofuran) multiblock copolymers

Multiblock copolymers consisting of poly(ether sulfone) and poly(tetrahydrofuran) (PTHF) as hard and soft segments, respectively, were synthesized by post-polymerization of poly(ether sulfone) and PTHF oligomers via the Williamson ether synthesis. Hydroxy-terminated polysulfone oligomers composed of 4,40-dihydroxydiphenyl ether or 4,4'-dihydroxybiphenyl and 4,4'-dichlorodiphenyl sulfone were prepared as thermally stable hard segments. Bromo-terminated PTHF oligomers were prepared by ring-opening polymerization of tetrahydrofuran (THF) initiated by trifluoromethanesulfonic anhydride and terminated by lithium bromide. The high-molecular-weight multiblock copolymers (M-w > 10(5) g mol(-1)) were obtained by post-polymerization. Both the multiblock copolymers showed good thermal stability and high transition temperatures from elastic film to viscous liquid. Flexible films of the multiblock copolymers showed much larger elongation at break than the corresponding poly(ether sulfone). Microphase separation of hard and soft domains was observed for the resulting multiblock copolymer films. The results suggest that these multiblock copolymers are promising candidates for novel, thermally stable thermoplastic elastomers.