New fluorinated thermoplastic elastomers, 4a -: Synthesis and characterization of alternating fluorinated polyimide-polyhybridsiloxane block copolymers prepared via polycondensation

The synthesis of fluorinated polyimide-polyhy-bridsiloxane block copolymers (FPI-HPHSX) was performed by polycondensation of alpha,omega-dichlorosilane fluorinated polyimides (SiCI-FPI) and alpha,omega-disilanol-polyhybridsiloxanes (SiOH-HPHSX). The alpha,omega-disilanol polyhybridsiloxanes were synthesized by polyhydrosilylation between 1,7octadiene and hexamethyltrisiloxane (HMTS). The resulting siloxanes exhibit a glass transition temperature close to -98degreesC. The alpha,omega-dichlorosilane fluorinated polyimide was prepared by hydrosilylation of alpha,omega-diallyl fluorinated polyimide and dimethylchlorosilane in the presence of Karstedt's catalyst. Then a series of four FPI-HPHSX was synthesized by polycondensation and, with tuning of the number average molecular weight (M-n) of the soft polyhybridsiloxane and the hard polyimide groups, they were characterized. The influence of the segment lengths on the behavior (surface tension and thermal stability) of the thermoplastic elastomer (TPE) material was studied. The FPI-HPHSX block copolymers' thermomechanical properties are also reported and discussed.