Sustainable polymer‐based composites for fused granular fabrication in large‐format additive manufacturing reinforced with lignocellulose derived from agroforestry and industrial waste: a critical review and technical outlook

Abstract Lignocellulosic‐reinforced polymers (LRPs) derived from agroforestry and industrial residues offer a promising route to reduce fossil‐polymer consumption and valorize residual biomass in fused granular fabrication (FGF) for large‐format additive manufacturing (LFAM). However, available knowledge remains fragmented across feedstock selection, composite formulation, interfacial modification, processing, performance evaluation, and industrial implementation. This review therefore critically examines the complete development chain of LRPs for FGF‐based LFAM, including lignocellulosic feedstocks and polymer matrices, pretreatment and surface‐modification strategies, compatibilization, compounding and fabrication conditions, and the resulting physical, mechanical, thermal, rheological, interfacial, and durability‐related properties. Particular attention is also given to application sectors, recyclability, environmental assessment, and technology readiness. The reviewed evidence shows that lignocellulosic reinforcements can reduce composite density, increase stiffness, and support the substitution of virgin polymer, but their moisture sensitivity, thermal instability, variable morphology, and limited matrix compatibility can impair extrusion stability, inter‐bead consolidation, dimensional accuracy, and long‐term performance. Surface modification and compatibilization improve interfacial adhesion, although their benefits depend strongly on the reinforcement–matrix–processing combination. Demonstrated applications include lighting products, furniture and interior‐design items, packaging, and decorative household products. The technology‐readiness assessment indicates that most academic studies are positioned at an estimated technology‐readiness level (TRLe) of 3–5, whereas the most advanced industrial initiatives assessed reach approximately TRLe 6–7, with scalability, durability validation, regulatory qualification, market integration, and life‐cycle assessment remaining the principal bottlenecks. Future progress requires standardized feedstock characterization, process monitoring, application‐specific qualification, circularity assessment, and coordinated academia–industry scale‐up.