engleski

Morphology, interfacial and mechanical properties study of silica reinforced iPP/SEBS(-g-MA) composites

The effects of different silica and elastomeric content on morphology, interfacial properties, and mechanical properties of polypropylene/silica 96/4 composites modified with 5, 10, 15, and 20 vol% of poly(styrene-b-ethylene-co-butylene-b-styrene) SEBS and SEBS grafted with maleic acid (SEBS-g-MA) were investigated. Four silica fillers differing in size (nano- vs. micro-) and in surface properties (untreated vs. treated) were chosen as fillers. Elastomers SEBS and SEBS-g-MA were added as impact modifier and compatibilizer at the same time. The morphology of binary blends and ternary polymer composites was studied by different microscopy techniques. While in binary iPP/SEBS(-g-MA) blends prevails typical two phase morphology with iPP as matrix, the ternary composites revealed the wide spectrum of morphologies rather than one exclusive, depended primarily on interfacial properties. [1, 2] Both iPP/silica/SEBS(-g-MA) composites preferred compartmentalized morphology (as the variety of core-shell m.) with hydrophilic silica while with hydrophobic silica there is a wide spectrum of different morphologies. The spherulitic morphology of polypropylene matrix in iPP/silica/SEBS(-g-MA) composites was abrupt with the addition of silica and the final morphology was a result of two competitive effects: nucleation effect of filler and solidification effect of elastomer. Tensile and impact strength properties were mainly influenced by combined competitive effects of stiff filler and tough SEBS(-g-MA) elastomer. Both elastomers showed great impact modifying properties

structure-propertiy relationships ; polypropylene composites

nije evidentirano