STUDIES ON POLYVINYL ALCOHOL FIBERS

Polyvinyl alcohol was heat-treated in powder form to a degree which will render it soluble in hot water but insoluble in cold water to permit purification with cold water. The heat-treated polyvinyl alcohol was then subjected to a formalization treatment in powder form. It was assumed that the reaction takes place mainly in the amorphous region of the polyvinyl alcohol molecule so that the formalized groups exist as selectively substituted groups and may be considered as a form of block copolymer.This polyvinyl alcohol was employed to study the rate of formalization, the degree of swelling of films and the physical properties of fibers prepared therefrom. Polyvinyl alcohol containing formal groups in the amount not more than 5% appeared to be selectively substituted. Fibers obtained from partially formalized polyvinyl alcohol were found to have improved mecnanical properties, especially improved elastic recovery under low strain.