Comprehensive overview of wood polymer composite: Formulation and technology, properties, interphase modification, and characterization

Increasing global concerns regarding environmental sustainability and the responsible use of natural resources have led to global efforts to develop eco-friendly materials. These are driven by the desire to establish a circular and carbon-neutral economy and to reduce the environmental impact of non-renewable resources, particularly synthetic polymeric materials derived from finite petroleum fossil fuels. The adverse effects of the excessive use and waste accumulation of such materials have prompted the search for alternative routes for polymer production, emphasizing lower energy consumption and reduced emissions of pollutants such as greenhouse gases. Similarly, the growing population and negative environmental effects of conventional building materials demand more environmentally friendly building materials from sustainable untapped resources. Wood polymer composites (WPCs), which combine synthetic thermoplastic polymers as a matrix and lignocellulosic fibers as a dispersed phase, have been developed as alternative materials. This critical review provides a comprehensive overview of current WPC formulations, comparative advantages, and critical properties based on the matrix and filler compositions. Progress in various applications, interface functionalization, and modification of both hydrophilic lignocellulosic fibers and hydrophobic polymer matrices including WPC interphase characterization were considered. This review also investigates the recent developments and benchmarks in WPC formulations achieved through natural reinforcement and the use of recycled plastics as secondary resources. The effects of the polymeric matrix (from non-polar to polar) and reinforcement (from nano to micro) on mechanical performance were comprehensively reviewed to better understand the research trends, challenges, and unsolved problems of WPCs as promising a sustainable transition to green building materials. •Wood polymer composites (WPCs) combine thermoplastic polymers as a matrix and lignocellulosic fibers as a dispersed phase.•Comprehensive WPCs formulations, critical interphase modifications and characterization were discussed.•Recent benchmarks in WPC formulations using natural reinforcement and recycled plastics as secondary resources were discussed.•The effects of the polymeric matrix and reinforcement on WPC performance were comprehensively reviewed.