Core–shell encapsulation of PMHS@EPDM onto BF surface for strengthening and toughening of BF/HDPE composites

Abstract

Bamboo flour/high-density polyethylene (BF/HDPE) composite was strengthened and toughened simultaneously by the surface encapsulation of BF with poly(methylhydrogen)siloxane (PMHS) and Ethylene Propylene Diene Monomer (EPDM). A elastic PMHS@EPDM shell was fabricated on BF surface by successively spraying PMHS/hexane and EPDM/hexane solutions onto BF, based on the dehydrogenation and addition reaction of PMHS with BF and EPDM. It was found that surface encapsulation of wood at high PMHS content would simultaneously increase the strength and toughness of BF@PMHS/HDPE composite. The tensile strength and impact strength were increased by 54.2% and 9.9%, respectively as PMHS content was 3.3%. Furthermore, an encapsulation of BF@PMHS with EPDM further increased the strength and toughness by 5.1% and 14.7%. Compared with the pristine BF/plastic composites (BPC), the tensile, flexural and impact strength of modified BPC increased by 62.1%, 28.0% and 26.1%. The changes in the microstructure of the interface between BF and HDPE as a function of encapsulation of PMHS and EPDM and the relationship between chemical structure, microstructure and mechanical properties were discussed in detail. This work gave a novel MAH-free method for strengthening and toughening BF/HDPE or wood flour/high-density polyethylene (WF/HDPE) composites.