| Abstract: | Conclusions By treatment of undried polyphenyleneoxadiazole yarns with concentrated sulfuric acid under isometric conditions, it is possible to raise their strength by 20–30% and their elongation at break 40–50%.The improvement in physicomechanical properties of the yarns which have been treated with acid is caused by a reduction in internal stresses, an improvement in the interlayer packing of the macromolecules fragments, and an increase in the degree of orientation of the macromolecules.Translated from Khimicheskie Volokna, No. 6, pp. 33–35, November–December, 1985. |
