Modification of poly(vinyl alcohol) fibers with lithium bromide

The effect of lithium bromide (LiBr) on the structure and properties of poly (vinyl alcohol) (PVA) fibers obtained by wet-spinning was studied. The tensile modulus and strength of a PVA fiber were greatly enhanced irrespective of the post-spinning hot-stretching process. The high degree of molecular orientation arose from the reduction in the crystallinity and hydrogen bonding between PVA chains in the solution resulting from the addition of LiBr, which was revealed by the rheological properties of aqueous solutions. The LiBr was removed from the fiber during the spinning process in the coagulation bath, and during the washing process. This ensures strong hydrogen bonding in the fibers, and results in excellent mechanical properties.