Composites formed by interstitial polymerization of vinyl monomers in polyurethane elastomers: 1. Preparation and mechanical properties of methyl methacrylate based composites

• Published in: Polymer (Guilford) 1973-01, Vol.14 (12), p.597-603
• Main Authors: Allen, G., Bowden, M.J., Blundell, D.J., Hutchinson, F.G., Jeffs, G.M., Vyvoda, J.
• Format: Article
• Language: English
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/0032-3861(73)90033-5

High-impact cast sheets of poly(methyl methacrylate) (PMMA) were prepared by the interstitial polymerization of the monomer in a polyurethane (PU) gel which had been prepared in a state of dilution in the monomer. The physical and mechanical properties of the composites depended on: (i) initiator concentration; (ii) molar ratio of isocyanate to hydroxyl groups; (iii) the time interval between gelation and subsequent polymerization of the MMA; (iv) the theoretical network crosslink density of the PU; and (v) the overall ratio of PMMA to PU. For a typical 80:20 PMMA/PU composite, with the above parameters at optimum values, measurements of 12.5±1.0kJ/m 2 and 0.65±0.05GN/m 2 were obtained for notched impact strength and shear modulus respectively compared to 1.2±0.2kJ/m 2 and 1.47±0.03GN/m 2 in PMMA homopolymer. Optical transmission was similar for both materials, i.e. ⋍90%.