Interface modification and characterization in three-component polymer blends

The effect of interface characteristics on the properties of three-componen t polymer blends comprising PP/EVOH/mica and PP/EVOH/glass beads (GB) was i nvestigated (polypropylene-PP, ethylene-vinylalcohol-EVOH). The systems sel ected are based on the binary PP/EVOH immiscible blend representing a semi- crystalline apolar polymer (PP) and a semi-crystalline highly polar copolym er (EVOH), where PP serves as the matrix. A series of the binary and three- component blends with varying compositions was chosen to study the effect o f the molding procedure, i.e. compression versus injection molding. The str uctures observed by SEM analysis consisted of the filler particles engulfed by the EVOH phase, with some of the minor EVOH component dispersed within the PP matrix. The effects of silane treatment (GB/EVOH interface) and comp atibilization, using a maleated-PP compatibilizer (PP/EVOH interface), were studied in relation to the generated structures and properties. The compat ibilizer was added in a unique procedure by which the encapsulated GB/EVOH structures were preserved. The characterization methods used included morph ology by Scanning Electron Microscopy, thermal properties and crystallizati on behavior by Differential Scanning Calorimetry, mechanical properties by tensile testing, and dynamic characteristics by Dynamic Mechanical Thermal Analysis. The work has shown that structure-performance relationships in th e three-component blends can be varied and controlled.