High-strength,high-modulus fibers from hydrazide polymers and copolymers

A polyhydrazide was prepared from terephthaldihydrazide (TDH) and terephthaloyl chloride (TCl) and copolyhydrazides from oxalicdihydrazide (ODH) and from TCl with a 50:50 molar mixture of ODH and TDH. The 50:50 copolymer gave superior spinning performance and fiber properties and was studied extensively as a candidate for tire cords. The best yarn tensile properties were 21.6 gpd (grams/denier) tenacity, 6% elongation, and 443 gpd modulus. Temperature resistance and creep resistance were good, while the resistance to uv light was only fair. Stability in rubber and adhesion to rubber were good. In radial tires built with equal-strength belts, mileage from tires having the copolymer cord in the belts was equal to that of steel-belted tires.