On the behaviour of solid materials and biomaterials for the chemical industry under extreme thermal conditions

The transition toward safer and more sustainable materials requires a deep understanding of their response under extreme thermal and oxidative conditions, during both production and use. As research explores innovative and bio-derived substances to replace conventional systems, elucidating their combustion and oxidation mechanisms becomes essential for scientific and safety insight. This dissertation investigates the reactive behaviour of diverse material systems, including polymers, biopolymers, liquids, polymer–solvent mixtures, and metallic powders, focusing on how structure, composition, and morphology govern decomposition pathways, heat generation, and overall fire response. Using an integrated approach combining calorimetric analysis, gas-phase diagnostics, and morphological characterisation, a unified framework was developed to interpret transformations from thermal degradation to combustion and oxidation. This methodology enables comparison across organic and inorganic systems, revealing common reactive principles emerging under similar energetic conditions. The study demonstrates the multistep nature of thermal oxidation, where overlapping physical and chemical processes control ignition and flame propagation. Bio-based polymers and green solvents appear as safer alternatives, exhibiting moderated heat release and lower emissions of toxic species, while metallic powders show how particle size and surface morphology dictate oxidation kinetics and exothermicity. Across all systems, structure–property relationships determine both stability and the transition between safe and hazardous regimes. Beyond mechanistic insights, the dissertation introduces a framework for quantitatively assessing ignition propensity and combustion intensity, supporting consistent hazard classification across material families. The methodology was applied to a manufacturing context, the production of carbon membranes from bio-derived polymeric precursors, demonstrating its capacity to evaluate thermal reactivity and safety under process-relevant conditions and guide the optimisation of sustainable production involving thermally active materials. Overall, this work highlights that understanding the chemistry of thermal reactivity is key to advancing innovation in material science and sustainability, where performance, safety, and environmental responsibility emerge as interconnected outcomes of the same inquiry.