Abstract: This paper investigated the influence of PP-MAH on skin/core morphology and mechanical properties of injection molded polypropylene/hemp fiber composites. Without PP-MAH, highly oriented HFs along flowing direction was observed in both skin and core zone of the specimen. Moreover, the incorporation of HFs induced the formation of β-form crystal in skin zone. The skin zone showed ductile fracture while core zone brittle fracture. When 5 phr PP-MAH was introduced, only in the skin zone was highly oriented HFs observed, in the core zone but random ones. The relative content of β-form crystals in the skin zone was reduced. Impact strength of the composite decreased slightly. Brittle fracture behavior in both skin and core zone of the composite was observed. Additionally, the tensile and flexural strengths were significantly improved with the presence of PP-MAH.

Key words: Hemp fiber, Skin-Core Morphology, impact properties, polypropylene, mechanical properties