MODEL STRUCTURES OF THERMOPLASTIC POLYESTERS HAVING REGULARLY ALTERNATED AROMATIC AND FLUORINATED SEGMENTS

Linear segmented polyesters containing soft perfluoropolyether (PFPE) and hard aromatic segments are obtained by an interfacial polycondensa tion reaction of an acyl chloride-ended fluorinated prepolymer with va rious aromatic diphenols in the presence of phase transfer catalysts ( PTC) as accelerators. Experimental conditions for reaching high molecu lar weights are discussed. The calorimetric analysis (DSC) of all the polyesters synthesized shows a typical biphasic morphology, where a ve ry low T-g (<-110 degrees C) corresponding to the segregated PFPE moie ty, is always accompanied by another T-g or a higher melting temperatu re, depending on the nature of the hard phase. Dynamic-mechanical anal ysis (DMA) has been carried out confirming the DSC results and suggest ing diversified mechanical behaviors at the various temperatures in li ne with the amorphous or semicrystalline nature of the polymer. Chemic al resistance was finally tested by dipping in several solvents and ch emicals. The new polyesters show high contact angles, a moderate swell ing in many organic solvents and excellent stability in aggressive hyd rolytic environments. (C) 1998 John Wiley & Sons, Inc.