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. POLYM. ENG. SCI., 47:1873–1880, 2007.