MORPHOLOGY DEVELOPMENT THROUGH AN INTERFACIAL REACTION IN TERNARY IMMISCIBLE POLYMER BLENDS

We studied the morphology development of ternary immiscible blends thr ough an interfacial reaction between components. This phenomenon was o bserved in two ternary blend systems; one is composed of polyamide(6) (PA6), polycarbonate (PC), and poly[styrene-b-(ethylene-co-butylene)-b -styrene] (SEBS), and the other is composed of PA6, PC, and polystyren e (PS), where PA6 forms the continuous matrix in both blend systems. M aleinated SEES (SEBS-gMA) or maleinated PS (PS-gMA) is incorporated wi th its unmodified polymer (un-SEBS and un-PS, respectively) at various ratios into the blends of PA6/PC. The blends of PA6/PC/un-SEBS and PA 6/PC/un-PS show a similar phase formation in which the two dispersed p olymers are stuck together in a PA6 matrix. The use of the maleinated polymers instead of their unmodified polymers in the blends of PA6/PC changes the phase formation drastically. The maleinated polymers react with amine end groups of PA6 at the interface during the melt mixing. Through this interfacial reaction, the domains of the maleinated poly mers are dispersed in the PA6 matrix at about 100 nm in diameter, and at the same time the maleinated polymers encapsulate the PC domains. T his means that the interfacial reaction induces the change of the form ation of the domains composed of two dispersed phases. That is, the in terfacial reaction changes the formation from ''stack formation'', whe re the two dispersed polymers are stuck together, to ''capsule formati on'', where the PC domains are encapsulated by the other phase. Moreov er, when both the unmodified and its maleinated polymers are incorpora ted together in a variety of ratios, the encapsulation by SEES onto th e PC domains gradually becomes incomplete as the ratio of the unmodifi ed SEES increases, whereas the encapsulation by PS of the PC is comple te even when un-PS and PS-gMA are incorporated together. We discuss th is morphology development in terms of the change of interfacial tensio ns between PA6 and maleinated polymers through the interfacial reactio n. We assumed that the reduction of interfacial tension through the in terfacial reaction is the driving force for this morphology developmen t.