From Palm Triglycerides to Circular Polyurethane Engineering: Reaction Chemistry, Performance, Fire Safety and Industrial Readiness-A Critical Review

Abstract

Palm-derived polyols offer a renewable route to polyurethane materials, yet their sustainability and industrial performance cannot be inferred from biogenic carbon content alone. This critical qualitative literature review synthesises 2020–2026 evidence across triglyceride modification, polyol functionality, urethane reaction chemistry, rigid and flexible foams, elastomers, coatings, composite applications, fire safety, ageing, end-of-life recovery and industrial scale-up. A mechanism-informed thematic method distinguishes palm-specific findings from transferable studies of other vegetable oils and conventional polyurethanes. The synthesis shows that epoxidation–ring opening, transesterification, selective addition and residue liquefaction generate different hydroxyl distributions, viscosities and reactive architectures. These differences interact with the isocyanate index, gel–blow balance, phase morphology and filler interfaces, making product-specific optimization indispensable. Flame retardancy, smoke reduction and occupational safety require independent substantiation; renewable feedstocks do not make polymer networks inherently non combustible or recyclable. Recent advances in acidolysis, glycolysis, adaptive networks and enzymatic treatments create options but do not yet establish a universal closed loop. The paper proposes a seven-gate molecule-to-product framework and a staged industrial decision matrix connecting feedstock traceability, analytical control, service requirements, fire testing, recycled-output quality and functional-unit life-cycle assessment. Commercial translation should prioritize reproducibility and comparative evidence over nominal bio-based substitution percentages.