A quantitative comparison of the pyrolysis and combustion behavior of plasticized and rigid poly(vinyl chloride) using two-dimensional modeling

A methodology to parameterize (or calibrate) comprehensive pyrolysis models is demonstrated on plasticized and rigid poly(vinyl chloride) specimens. Thermogravimetric analysis, differential scanning calorimetry and microscale combustion calorimetry were employed to characterize the kinetics and thermodynamics of thermal decomposition and heats of complete combustion of gaseous decomposition products. Controlled Atmosphere Pyrolysis Apparatus II gasification experiments were utilized to determine the thermal transport parameters within the undecomposed material and developing char. A numerical framework, ThermaKin2Ds, was employed to analyze and simulate all gasification experimental results. The two-dimensional (axisymmetric) models of plasticized and rigid poly(vinyl chloride) were shown to reproduce the gasification mass loss rates with mean errors of less than 19%. Idealistic, one-dimensional simulations of large burning panels in the presence of external radiant heat flux were subsequently conducted using the fully parameterized pyrolysis models. A quantitative comparison between the simulated plasticized and rigid poly(vinyl chloride) large-scale burning indicated that these materials have similar mass loss rate histories. However, significant differences become apparent when the mass fluxes of gaseous decomposition products are converted to heat release rate; the heat release rate of plasticized poly(vinyl chloride) was found to be approximately a factor of 2 greater than that of the rigid poly(vinyl chloride).