Interphase between carbon fibre and thermotropic copolyester

摘要

This work is concerned with te interphase between carbon fibre and vectra liquid crystal copolyester. Two grades of vectra copolyester were used. An unfilled standard vectra A950 was used as a matrix for a carbon fibre reinforced vectra copolyester model composite material. And vectra A230, containing short carbon fibres, was used for the preparation of extruded composite material. Crystallization behaviour of vectra A950 and vectra A230 was ubvestugated bt a differential scanning microscopy, and the model composite materials were prepared and observed using a hot-stage polarizing microscopy. Photographs obtained with crossed polars show that molecules of vectra copolyester in a mesophase is the tendency to be aligned along the flow direction and to be disturbed by obstacles such as carbon fibre. The fracture surface of the extruded composite material after a tensile failure was observed in a scaning electron microscopy. It reveals that a layer of vectra copolyester adheres to the pull-out carbon fibre. The layer thickness of vectra coplyester adhering to the pull-out carbon fibre is about 0.2#mu#m. Transmission electron micrographs indicate that vectra copolyester is closely attached to the carbon fibre. Good adhesion between carbon fibre and vectra copolyester can be expected.