Thermal Degradation of Poly(methyl methacrylate) in the Presence of Tin (IV) Chloride and Tetraphenyltin
Polymer Degradation and Stability
The thermal degradation of poly(methyl methacrylate) in the presence of tin(IV) chloride and tetraphenyltin has been studied and the mechanistic pathways of the reactions are provided. In the case of SnCl4, the interaction begins with the coordination of the carbonyl oxygen of the polymer with SnCl4 followed by the loss of methyl chloride from the complex. When the amount of SnCl4 is increased, the formation of monomeric methyl methacrylate is drastically reduced whereas the amounts of methacrylic acid and isobutyric acid are increased. Ph4Sn accelerates the degradation of PMMA via the loss of phenyl radicals to form elemental tin. This interaction is facilitated by homolytic bimolecular substitution reactions. The phenyl radicals will interact with PMMA to produce benzene, methyl methacrylate, and cross-linked char as major degradation products.