THE RELATIONSHIP BETWEEN MANUFACTURING CONDITIONS OF POLYVINYL ALCOHOL AND THE PROPERTIES POLYVINYL ALCOHOL FIBERS

Abstract

Vinyl acetate (VAc) was polymerized at temperature ranging from -30°C to +60°C in the presence of catalysts prepared from tri-n-butyl boron (BBu3) and a, a′-azo-bisisobutylonitrile (AIBN).In addition, polymerization of VAc was carried out at 30°C using BBu3 as catalyst in methanol (MeOH) and in methylacetate (MeOAc), and also carried out at 60°C in MeOH using three kinds of catalysts, (1) AIBN, (2) BBu3 and (3) AIBN-BBu3 mixtures.These polyvinyl acetates thus obtained were saponified to polyvinyl alcohol (PVA) and further deesterified.From the viewpoint of crystallinity and stereoregularity, the PVA prepared at the lower polymerization temperature has better qualities and the PVA (A) derived from polymerization in MeOH has much higher crystallinity and regularity than the PVA (B) derived from polymerization in MeOAc.Heat treated and not formalized PVA fibers derived from PVAc polymerized temperature below 10°C, neither dissolves nor shrinks in hot water up to 115°C. These fibers have very good resitance to hot water but their properties, such as tenacity, elongation and elastic recovery are not influenced by the polymerization temperature.Heat treated fibers prepared from PVA (A) have much better resistance to hot water at 110°C than those prepared from PVA (B), but other properties do not differ between (A) and (B).The properties of PVA and the fibers obtained from it are not influenced by the kinds of catalysts, when the polymerization temperature is same.