PDMPV Preparation of Precursor Polymers, Fiber

PREPARATION OF PRECURSOR POLYMERS, FIBER SPINNING, DRAWING AND CONVERSION OF PTV AND PDMPV 

The arcing observed in the latter X-ray diffraction pattern is typical of moderately oriented crystalline material. For the PTV fibers, the orientation distribution of crystallites was about 18° (full width at half maximum) with respect to drawing direction for the PDMPV fibers, the full width at half maximum about 8°. A quantitative measure of the degree of orientation may be obtained from the angular half-width at half height of the intensity distribution. For PDMPV, the 8° angular spread corresponds to an orientation function 

The tensile strength of 0.5 GPa is identical to the value as reported for highly stretched PPV film prepared by a heated roll method [74] and comparable to the values obtained with stretched trans-polyacetylene films [75]. The modulus, however, was lower than the values reported for stretched PPV films [74] and for stretched polyacetylene [75] films. 

The many complex molecular processes that simultaneously occur in the drawing/conversion process need to be carefully optimized so that their time scales are in harmony. The critical parameters for process optimization are the degree of pre-conversion, deformation rate, process-temperature profile, conversion-catalyst concentration, and residence time. Obviously, in this initial study of PTV, we have not developed a fully balanced set of processing parameters. This is illustrated by the modest orientation indicated by the X-ray patterns. Nevertheless, the current materials have a Young s modulus of 7 GPa, a tenacity of 0.5 GPa and a conductivity of 2000 S/cm a combination of properties which are adequate for conductive textile applications. It should be clear that further optimization of the inter-related processing variables will undoubtedly result in materials of superior quality. 

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