Abstract
Effects of pre-mixing method and saponification degree of poly(vinyl alcohol) on the morphology of poly(vinyl chloride) / poly(vinyl alcohol) blend was investigated. Two different pre-mixing methods were employed: powder method and aqueous solution method. In the powder method, the powders of both components were blended before melt kneading by a mixing roll. In the aqueous solution method, the poly(vinyl chloride) powder was added to as-prepared poly(vinyl alcohol) aqueous solution, followed by drying and then clashing before melt kneading. In the case of poly(vinyl alcohol) with saponification degree of 98mol%, the poly(vinyl alcohol) domains with sizes of several hundred μm were dispersed in the poly(vinyl chloride) matrix in the powder method system. Whereas the finer domains with sizes ranging from sub μm to several μm were observed in the aqueous solution method system. In the case of poly(vinyl alcohol) with saponification degree of 88mo1% and below, the domain size was about several ten μm for both powder and solution methods, which indicates that there was no influence of pre-mixing method on the domain size. When poly(methyl methacrylate) was added into the poly(vinyl chloride) / poly(vinyl alcohol) blend as the third component, smaller poly(vinyl alcohol) domains with sizes ranging from about 5 to 10 μm were observed in both powder and solution method systems. The viscoelastic properties showed the formation of specific interaction in poly(vinyl chloride) / poly(methyl methacrylate) and poly(methyl methacrylate) / poly(vinyl alcohol) blends.
