Thermal stability and degradation kinetics of poly(methyl methacrylate)/layered copper hydroxy methacrylate composites

Poly(methyl methacrylate) (PMMA)/copper hydroxy methacrylate (CHM) composites were prepared via solution blending and bulk polymerization. Addition of 3% by weight of the CHM additive using solution blending resulted in a significant increment (similar to 45 degrees C) in thermogravimetric analysis (TGA) T-50, the temperature at which 50% of the original polymeric mass is lost. The value T-50 increased by 30 degrees C for a PMMA composite with 4% CHM, synthesized via bulk polymerization. Activation energies, E-a, were calculated as a function of conversion fractions (TGA decomposition profile) for the polymeric materials. Analysis of multiple heating rate data using the Flynn-Wall-Ozawa method resulted in E-a values that were 50 kJ mol(-1) higher for conversions above 0.5 in the solution blended composite compared to a reference sample of pure PMMA recrystallized from the same solvent. Similar results were obtained for bulk polymerization process with differences in E-a values > 30 kJ mol(-1) relative to pure PMMA. However, in contrast to previous studies of bulk polymerized samples, the solution-blended composite exhibited no improvement in cone calorimetry determination of total heat release as compared with the reference PMMA sample. Copyright (C) 2006 John Wiley & Sons, Ltd.