COMPOSITES .2. REINFORCEMENT OF POLY(EPSILON-CAPROLACTONE) VIA LYOTROPIC BLENDS OF RIGID-ROD POLYESTERS DERIVED FROM SUBSTITUTED TEREPHTHALIC ACIDS

摘要

Two aryloxyterephthalic acids and two 2,5-bis(alkoxy)terephthalic acids were synthesized and polycondensed with hydroquinone (HQ), methylhydroquinone (MeHQ), phenylhydroquinone (PhHQ), or 4,4'-dihydroxybiphenyl (DHBP). Eleven out of the possible 16 polyesters were selected for the preparation of blends with commercial poly(epsilon-caprolactone), PCL, as the matrix. The properties of blends containing 1, 2, 4, or 8 wt % of the rigid-rod polymer were studied. The optical microscopy revealed birefringence for the entire blend below the melting temperature (T-m) of the rigid-rod polymer. The lyotropic character vanished and phase separation took place above the T-m of the rigid-rod polymer. The lyotropic blends (PCL acting as a solvent) showed a significant mechanical reinforcement effect, when examined by melt rheology and stress-strain measurements. This effect depended largely on the aromatic character of the substituents. The most surprising and important finding is the formation of lyotropic blends from a rigid-rod polyester which is not liquid crystalline as a neat material. [References: 41]