Experimental Study and a Short Kinetic Model for High-Temperature Oxidation of Methyl Methacrylate

ABSTRACT

Synthetic and natural polymeric esters find applications in transport and construction sectors, where fire safety is an important concern. One polymer that is widely used is poly (methyl methacrylate) (PMMA), which almost completely undergoes thermal decomposition into methyl methacrylate (its monomer) $\mathrm{C}{\mathrm{H}}_2=\mathrm{C}(\mathrm{C}{\mathrm{H}}_3)-\mathrm{C}(=\mathrm{O})-\mathrm{O}-\mathrm{C}{\mathrm{H}}_3$ (MMA) at $\sim 250$–${300}^{\circ }$C. In order to analyze the high-temperature gas-phase oxidation of PMMA, and thereby predict its fire behavior (such as burning rate, temperature of the material, and heat fluxes) with less computational effort, a compact kinetic model for the oxidation of its primary decomposition product, MMA, is most essential. This is accomplished in the present work by obtaining a reduced mechanism for MMA oxidation from a detailed mechanism from the Lawrence Livermore National Laboratories group.

To extend the available data base for model validation and present validation data at atmospheric pressure conditions, for the first time, (i) detailed measurements of species profiles have been performed in stoichiometric laminar flat flames using flame sampling molecular beam mass spectrometry (MBMS) technique and (ii) laminar burning velocities have been obtained using the heat flux method for various unburnt mixture temperatures. Evaluating the model against these data sets point to the need to revise the kinetic model, which is achieved by adopting rate constants of key reactions among analogous molecules from recent literature. The updated compact kinetic model is able to predict the major species in the flat flame as well as the burning velocity of MMA satisfactorily. The final “short MMA mechanism” consists of 88 species and 1084 reactions.

KEYWORDS:

• methylmethacrylate
• kinetics
• laminar flat flame
• laminar burning velocity
• short model

Acknowledgments

The authors like to thank Bin Yang from Tsinghua University, for sharing the mechanism files for MMA oxidation. The first and the last author would like to thank Dr. Perrine Pepiot at Cornell University for sharing the source code for DRGEP technique and the mechanism combination tool.

Supplemental data

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by joint RSF/DST under Grant No. 16-49-02017; and Centre for Combustion Science and Technology (CECOST), Sweden.