Production of uniform polymethacrylimide foam blocks or panels, useful in aircraft construction, comprises copolymerization using at least three radical initiators with different half-lives

摘要

Process for producing polymethacrylimide foam blocks or panels comprises copolymerizing methacrylic acid and methacrylonitrile, cyclizing, and foaming the copolymer. The copolymerization is performed in the presence of at least three radical initiators with different half-lives. An Independent claim is also included for the foamed polymethacrylimide blocks or panels produced by process of the claim.