Thermal degradation of copolymers of methyl methacrylate and n‐butyl acrylate. I. Thermal analysis

By means of thermal volatilisation analysis (TVA) the principal features of the thermal degradation of a series of copolymers of methyl methacrylate and n‐butyl acrylate covering the entire composition range have been revealed. The degradation which is initiated in poly(methyl methacrylate) at unsaturated chain terminal structures is progressively suppressed by increasing concentrations of copolymerised n‐butyl acrylate while the degradation initiated by random chain scission moves to higher temperatures. It is clear from the TVA thermograms that the products of degradation consist of a complex mixture of gases and liquids and a viscous oily fraction. Energies of activation have been derived from thermal gravimetric analysis thermograms by the method of COATS and REDFERN. The increase with increasing n‐butyl acrylate content of the copolymer has been associated with the greater heat of polymerisation of n‐butyl acrylate compared with methyl methacrylate.