Mechanical properties of wollastonite-reinforced polypropylene composites modified with SEBS and SEBS-g-MA Elastomers

Mechanical properties of isotactic polypropylene/wollastonite/styrene rubber block copolymers (IPP/wollastonite/SRBC) composites were studied as a function of elastomeric poly(styrene-b-ethylene-co-butylene-b-styrene) triblock copolymer (SEBS) and SEBS grafted with maleic anhydride (SEBS-g-MA) content from 0 to 20 vol%. Microphase morphology was stronger influenced by SRBC elastomers than by different wollastonite types. Higher encapsulation ability of SEBS-g-MA than SEBS caused more expressive core-shell morphology and consequently higher notched impact strength as well as yield parameters, but lower Young's modulus. Higher ductility of the composites with SEBS than with SEBS-g-MA has been primarily caused by better miscibility of the polypropylene chains with SEBS molecules. Surface properties of components and adhesion parameters also indicated that adhesion at SEBS-g-MA/wollastonite interface, which was stronger than the one at the SEBS/wollastonite interface, influenced higher encapsulation of wollastonite particles by SEBS-g-MA.