Thermal Degradation of Poly(methyl methacrylate): Condensed-phase Kinetic Model and Experimental Investigation

Studying the thermal degradation of polymeric materials is a key step towards a sustainable chemical industry and to improve fire safety. This work proposes a condensed-phase semi-detailed kinetic model in CHEMKIN format for poly(methyl methacrylate) (PMMA) pyrolysis, based on a consolidated functional groups approach. The reaction network is built following previous studies on PMMA and analogous small gas-phase methyl esters. The elementary kinetic parameters are obtained from high-accuracy gas-phase kinetic data, polymerization studies, and by comparison with other vinyl polymers. A dedicated experimental campaign is conducted to assess the role of the defects in the polymer microstructure on the degradation behaviour. The model is validated by comparison with the new experimental data and a comprehensive set of literature data in terms of characteristic degradation times and product yields, proving able to describe and predict the underlying physico-chemical phenomena with reasonable accuracy. This work lays the basis for deriving reduced models and assessing secondary gas-phase reactions, extending the CRECK polymer degradation framework. It represents an initial step toward designing recycling reactors and advancing fire simulation studies.