Copolymerising methyl methacrylate with phosphonate monomers yields a polymer with very low flammability. Thermal depolymerisation releases phosphorus acid which reacts with the poly(methylmethacrylate), forming anhydrides that cross link the polymer chains. This reduces the fuel supply to the flame. The cross-linked chains further pyrolyse to form a char, insulating the polymer from the flame and reducing its air supply.
Polymer combustion
References
J.R. Ebdon, B.J. Hunt, P. Joseph, C.S. Konkel, D. Price, K. Pyrah, T.R. Hull, G.J. Milnes, S.B. Hill, C.I. Lindsay, J. McCluskey and I. Robinson Thermal degradation and flame retardance in copolymers of methyl methacrylate with diethyl(methacryloyloxymethyl)phosphonate Polymer Degradation and Stability 70 (2000) 425.
This feature is based on work carried out by Dr Barry Hunt and Prof John Ebdon, who have now retired from the Polymer Centre.
© The University of Sheffield Polymer Centre, 2008.
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