NEXT GENERATION GREEN BIO-ADHESIVES AS RENEWABLE ALTERNATIVES TO SYNTHETIC PETRO-ADHESIVES

Growing environmental concerns associated with petroleum-based synthetic adhesives, including toxicity, non-renewability, volatile organic compound emissions, and formaldehyde-related health risks, have accelerated the development of sustainable bio-based adhesive systems. This review summarizes recent advances in adhesives derived from renewable resources such as lignin, tannins, proteins, polysaccharides, and vegetable oils. Particular emphasis is placed on adhesion mechanisms, chemical and enzymatic modification, nanotechnology-assisted reinforcement, and self-bonding approaches that can improve mechanical strength, thermal stability, and water resistance. Recent progress in green crosslinking strategies and biodegradable adhesive technologies has expanded the potential application range of bio-based adhesives in wood composites, packaging, construction, furniture, automotive components, and selected biomedical uses. Life cycle assessment studies indicate that bio-based adhesives can reduce fossil resource use, toxicity, and greenhouse gas emissions compared with conventional petrochemical systems; however, these benefits strongly depend on feedstock selection, processing route, formulation, energy demand, and end-of-life scenario. Despite substantial progress, challenges related to outdoor durability, water resistance, cost, raw-material variability, and large-scale commercialization remain significant. Overall, development in green chemistry, material engineering, and biomass valorization suggests that bio-based adhesives are promising candidates for next-generation bonding technologies, provided that their performance and sustainability are evaluated for each specific application.