Influences of properties and heating characteristics on the thermal decomposition of polymer/carbon nanotube nanocomposites

• A transport model is developed of nanocomposite decomposition.
• PMMA, PP and PS nanocomposites with carbon nanotubes are simulated.
• Good agreement is obtained between predicted and measured mass loss rates.
• Flame retardance mechanisms are investigated by sensitivity/parametric analysis.

A comprehensive transport model (conductive, convective and radiative heat transfer, convective mass transport) is applied to simulate the thermal decomposition of thermoplastic polymer/carbon nanotube nanocomposites and corresponding neat polymers (poly(methylmethacrylatye), polypropylene, polystyrene). The flame retardant effectiveness of nanocomposites is confirmed and good quantitative agreement with measurements is shown. The effects of flame retardance are enhanced by increasing the intensity of the radiative heat flux and/or the sample thickness. Moreover, extensive parametric and sensitivity analyses, carried out by varying kinetic constants and polymer physical properties, indicate that activation energy, density, reaction heat and thermal conductivity exert the most significant role. Finally a crucial aspect in relation to the differences in the initial degradation behavior of neat polymers versus nanocomposites is played by the in-depth radiation absorption coefficient.