POLYANILINE/PPD-T FIBERS

Composite fiber of poly(paraphenylenediamine) (PPD)-terephthalic acid (T), the polymer for Kevlar(R)+ aramid, and emeraldine salt (ES) of polyaniline was prepared by mixing emeraldine base polymer in PPD-T/H2SO4 spin dope and extruding it into fibers. The typical fiber diameter is approximately 25 microns. The fibers contain 1.0 percent emeraldine polymer. They are green, reflecting the emeraldine salt state of the polyaniline component. The initial modules of the fibers is 62GPa with tensile strength at break of 2.8GPa. This compares with the 76 GPa and 3GPa, respectively, for PPD-T fiber alone. Temperature dependent electron spin resonance studies show that the emeraldine salt polymer within the PPD-T composite has a significant component in the polaron electronic structure with a temperature dependent localization comparable to what is observed in emeraldine hydrochloride for x = [Cl]/[N] less-than-or-equal-to 0.2. The localization observed is in accord with expectations for charge motion on isolated chains with an insignificant interchain transition rate.