Mechanism of Poly(Methyl Methacrylate) Fire Retardation by Wilkinson's Salt
Journal of Applied Polymer Science
The reaction of Wilkinson's salt, CIRh(PP3)3, and poly(methyl methacrylate) (PMMA) has been studied. Char formation is observed, and some 30% of the reaction product is nonvolatile at 600°C. In order to understand the pathway of this reaction, the reaction of dimethylglutarate (DMG) and CIRh(PP3)3 has been studied. A pathway is proposed in which the initial step is the oxidative addition of the rhodium species into a carbon—oxygen bond of the DMG molecule. Six different products have been isolated from this reaction and can be seen to result from the oxidative insertion. This pathway also seems to apply to the PMMA reaction and leads to an interpretation of the results of this reaction and permits one to understand the role of this, and similar, compounds as flame retardants.