An Integrated Industrial Management Framework for Sustainable Wood–Plastic Composite Manufacturing and Waste Valorization

Abstract

Wood–plastic composites (WPCs) fall in between of those main three branches of polymer engineering, wood-residue valorization and circular manufacturing. However, typically and for centuries these various elements of the industrial practice have been handled as individual technical interventions (e.g., finding raw materials, drying, compounding the materials, putting them to use and handling the resulting scrap), rather than as part of a coherent and integrated socio-technical system. This paper proposes an Integrated Industrial Management Framework for WPC manufacturing (IIMF-WPC) to integrate the latest knowledge on recycled polymers, lignocellulosic raw materials, industrial extrusion, molding, repeated mechanical recycling, life-cycle assessment (LCA), environmental management and energy management and digital-twin for circular manufacturing. It structures the industrial decision-making process into 8 mutually dependent pillars: feedstock qualification, formulation and interphase design, process control, quality and compliance, closed-loop waste valorization, LCA and techno-economic control, digital traceability and predictive analytics, governance with continuous improvement. There is evidence showing that industrial circularity is technically possible and dependent. The moisture and contamination tolerances of wood flour are generally tightly controlled, thermal stability of lignocellulosic is a limiting constraint in the processing, the compatibilization is formulation-specific, and often clean post-industrial WPC can be reprocessed without significant deterioration of major mechanical properties. Conversely, if polymer families are not controlled for mixing, and/or the post-consumer material older than the target re-use time, weathers, additives and contaminants can compromise the re-use value and process stability. A multi-level KPI Hierarchy is then proposed to establish linkage between yield, energy intensity, recycled content, and scrap recirculation with mechanical-property retention, carbon intensity, cost, and customer quality and end-of-life recoverability. The paper also proposes research propositions and a validation protocol for plant scale studies. The main one is to change the WPC sustainability problem (whether it is a problem of material choice or not), into an integrated industrial-management problem, where the optimal combination of different factors of product quality, product circularity, resource effectiveness, and profitability are optimized simultaneously.