High-energy multiple impact (HEMI) tests of wood–polypropylene composites: new insights in structural integrity

Abstract

ABSTRACT The structural integrity of wood–polymer composites (WPC) has not been fully investigated, which can be attributed to a lack of applicable test procedures. In this study, wood–polypropylene composites were assessed by High-Energy Multiple Impact (HEMI) testing. The acquired composites were based on wood particles from various sources and different wood fibre contents, respectively. With respect to wood fibre content, a clear relationship between resistance to impact milling (RIM) and unnotched impact bending strength (a cU) was obtained. The lower the fibre content of the WPC the more structural integrity was retained. In return, various wood sources had no effect on a cU, but a major impact on RIM values. RIM is suggested to be predominantly affected by structural features, such as fibre/particle content and characteristics, particle agglomerations, and spatial void distribution.