Morphology and Mechanical Properties of Reactive Ternary Immiscible Polymer Blends

Morphology development of ternary immiscible polymer blends through an interfacial reaction between components is demonstrated. This phenomenon was observed in the two ternary blend systems, one of which is composed by polyamide6 (PA 6), polycarbonate(PC) and poly [styrene-b-(ethylene-co-butylene)-b-styrene](SEBS) and the other of which is composed by PA 6, PC and polystyrene (PS). Maleinated SEBS (SEBS-gMA) or maleinated PS (PS-gMA) is incorporated with their unmodified polymers (unSEBS and unPS respectively) at various ratios into the blends of PA 6/PC. The interfacial reaction between PA 6 and the maleinated polymer changes the phase formation from the 'stack formation', where the PC domains and SEBS or PS are stuck together, to 'capsule formation', where SEBS or PS encapsulates the PC domains. This morphology development is discussed in terms of the change of interfacial tension balance. It is speculated that the reduction of interfacial tension of the reactive interface is the driving force for this morphology development. Through this reaction induced phase formation, the compatibilization of the PA 6/PC blends can be achieved by the use of SEBS as a compatibilizer. Especially, when the both SEBSgMA and unSEBS are incorporated together and the encapsulation by SEBS on PC domains are moderately imperfect, the maxim mechanical properties have been obtained. The toughening mechanism was investigated by microscopic observation of the deformed speci-mens.