BLOCK-COPOLYMERS OF POLY(ETHER-ETHER-SULFONES) WITH LIQUID-CRYSTALLINE NON-LIQUID-CRYSTALLINE POLYESTERS

The synthesis of telechelics of poly(ether-ether-sulfones) (PEES) is c ontrolled by high-resolution gel-permeation chromatography to optimize for low content of side products. Under optimum conditions the bifunc tional polymer-homologous series is formed to 99,9%. These telechelics were used to synthesize block copolymers with aromatic polyesters. Th e polyesters (PE) contain phenylhydroquinone and terephthatic acid (se micrystalline liquid-crystalline (LC) polyester), phenylterephthalic a cid (amorphous LC polyester) or isophthalic acid (amorphous non-LC pol yester). Block copolymers with amorphous polyesters show one glass tra nsition temperature depending on the composition but blends of corresp onding homopolymers are biphasic. Block copolymers with semicrystallin e LC polyesters are phase-separated. Incorporation of semicrystalline LC polyester segments into PEES increases their solvent resistance. Th e storage modulus of the block copolymer with 50 wt.% of the semicryst alline polyester shows the same temperature dependence as PEES. Homoge neous block copolymers show anisotropy only if the weight function of polyester is larger than 0,5 whereas phase-separated systems show anis otropy at smaller fractions of polyester.