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A study on blends of liquid crystalline copolyesters with polycarbonate. I. Compatibility by transesterification
Author(s) -
Su KoeFu,
Wei KungHwa
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070560111
Subject(s) - transesterification , miscibility , materials science , differential scanning calorimetry , polycarbonate , scanning electron microscope , polymer blend , copolymer , compatibilization , diphenyl carbonate , chemical engineering , polymer chemistry , glass transition , nuclear chemistry , composite material , organic chemistry , polymer , chemistry , methanol , physics , engineering , thermodynamics
Blends of poly(bisphenol‐A carbonate) (PC) and synthesized liquid crystalline poly(oxybenzoate‐ co ‐ethylene terephthalate 40/60) (P46) were prepared through meltmixing in a Brabender mixer. The miscibility of the blends at different compositions and blending time was investigated with differential scanning calorimetry. The corresponding morphology of the blends was analyzed with scanning electron microscopy. It was found that for blends containing more than 20% P46 and mixed at 250°C or above the transesterification between PC and P46 took place. This transesterification was confirmed at a blend containing 40% P46 by nuclear magnetic resonance spectroscopy. The transesterification happened first between PC and the ester in the poly(ethylene terephthalate) (PET) block and then between PC and the ester in the polyoxybenzoate (POB) block. At 260°C and after 60 min' blending, the blend containing 30% P46 became an almost compatible system for appearing of a single glass transition temperature. This is also verified by the disappearing of P46 droplets in the PC matrix in the micrographs' observation. After 60 min' of blending, the compatibility of the system can be greatly improved even for the blend containing 40% P46 mixed at 260°C by the micrograph's observation. © 1995 John Wiley & Sons, Inc.