Production of sustainable polymeric composites using grape pomace biomass

The incorporation of residues from a given crop into polymeric matrices is a valuable strategy to obtain multiple benefits, mostly environmental and economical, across the agricultural production chain. In this study, grape pomace residue from vineries were systematically combined with pinewood residues from sawmill to produce multi-component polymeric composites. A variety of composites were produced using polypropylene (PP) or high-density polyethylene (HDPE) matrices, with fixed polymer content at 50% and varied pine and grape pomace particle content. Mechanical and physical properties were investigated. The introduction of grape pomace into the composites led to reduced technical properties, but its composition with pinewood particles led to reasonably high mechanical performance. Although not suitable to be used as single component reinforcement for mechanical purposes, as in decks and handrails systems, grape pomace-based composites presented higher hydrophobicity. Such findings derive from (1) the non-fibrillar aspect of the residue, which usually leads to mechanical reinforcement in composites, and (2) due to the lipophilic nature of the chemical composition of such biomass. Grape pomace and wood particle utilization are a sustainable alternative to reduce petroleum-based plastics consumption in industries once the composites present 50% of plastic. This material is suitable in applications such as pallets, once the composites presented great behavior against water and good mechanical properties without no chemical treatment or coupling agents. Grape pomace opens a new possibility for extending service life for outdoor applications.