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Abstract
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Styreneemethyl methacrylate (SteMMA) random copolymer in different compositions, polystyrene (PS)
and polymethyl methacrylate (PMMA) particles were synthesized by suspension polymerization. The
copolymer compositions were determined using nuclear magnetic resonance (H NMR) method as well as
their molecular weights were examined by gel permeation chromatography (GPC). The non-isothermal
degradation behavior of the synthesized copolymers was studied by thermal gravimetric analysis (TGA)
under nitrogen purge and the results were compared with corresponding homopolymers. In this study it
was tried to clarify the effect of SteMMA copolymer composition on the non-isothermal degradation
kinetics. It was found that with decreasing the MMA content in copolymer, the molecular weight was
decreased and degradation temperature in copolymer increased in all heating rates. The activation energy
was calculated by the FlynneWalleOzawa method. It was concluded that using the model fitting
methods couldn’t reveal the complexity of the thermal degradation process and the model-free methods
could be a reliable way to determine the kinetic parameters. Furthermore the iso-kinetic relationship
(IKR) was used to estimate a model independent pre-exponential factor (lnA) corresponding to a given
degree of conversion.
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