Estimation of the drawing efficiency of hot spinning of co-polyester fibres in producing high degrees of preferred orientation

A range of liquid crystalline polyester fibres varying in diameter from 65 to 440m were produced by spinning from a hot melt. These were analysed for preferred orientation by flatplate X-ray diffraction to produce equatorial azimuthal densitometry scans/() which were processed to produce the corresponding planar orientation profiles/() corresponding to a Bragg separation of 0.448nm. A further mathematical analysis was applied to these to produce the respective molecular orientation profiles/() which may be more directly related to fibre mechanical properties,/() profiles from this analysis were matched against theoretical/() calculated by assuming an idealized mechanism of affine deformation with no orientation losses due to thermal perturbations. The theoretical draws ratios corresponding to the experimentally observed cos² were matched against experimentally observed draw ratios to produce ratios which indicate drawing efficiencies. Although preferred orientation increased with increasing draw ratios, the drawing efficiency diminished with draw ratio.