Thermal degradation and flame retardance in copolymers of methyl methacrylate with diethyl(methacryloyloxymethyl)phosphonate

Ebdon, John R. ORCID: 0000-0003-4176-3912, Hunt, Barry J., Joseph, Paul, Konkel, Christopher S., Price, Dennis, Pyrah, Kelly, Hull, T. Richard, Milnes, G. John, Hill, Stephen B., Lindsay, Christopher I., McCluskey, John and Robinson, Ian (2000) Thermal degradation and flame retardance in copolymers of methyl methacrylate with diethyl(methacryloyloxymethyl)phosphonate. Polymer Degradation and Stability, 70 (3). pp. 425-436. ISSN 0141-3910

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Abstract

Methyl methacrylate (MMA) has been free radically copolymerized, both in bulk and in solution, with diethyl(methacryloyloxymethyl)phosphonate (DEMMP), to give polymers which are significantly flame retarded when compared with PMMA, as indicated by the results of limiting oxygen index (LOI) measurements, UL 94 tests, and the results of cone calorimetric experiments. The physical and mechanical properties of the copolymers are similar to those of PMMA, except that the bulk copolymers are slightly crosslinked, and are better than those of PMMA flame retarded to a similar extent by some phosphate and phosphonate additives. Examination of the some of the gaseous products of pyrolysis and combustion, and of chars produced on burning, show that flame retardation occurs in the copolymers by both a condensed-phase and a vapour-phase mechanism. The condensed-phase mechanism is shown to involve generation of phosphorus acid species followed by reaction of these with MMA units giving rise to methacrylic acid units. The methacrylic acid units subsequently form anhydride links, which probably impede depolymerization of the remaining MMA sequences, resulting in evolution of less MMA (the major fuel when MMA-based polymers burn). By undergoing decarboxylation, leading to interchain cyclisation and, eventually, to aromaticisation, the anhydride units are probably also the principal precursors to char.

Item Type: Article
Additional Information: Full-text of this article is not available in this repository. This article was originially published in Polymer degradation and stability, published by and copyright Elsevier.
Uncontrolled Keywords: Flame retardance, Cone calorimetry, diethyl(methacryloyloxymethyl)phosphonate, methyl methacrylate, Copolymer, Phosphorus Char, Limiting oxygen index, UL 94, mechanism
Divisions: University of Bolton Research Centres > Institute for Materials Research and Innovation
Depositing User: Scott Wilson
Date Deposited: 26 Nov 2013 12:52
Last Modified: 01 Mar 2018 16:02
Identification Number: 10.1016/S0141-3910(00)00138-5
URI: http://ubir.bolton.ac.uk/id/eprint/458

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