CROSS-LINKING REACTIONS WITH BLOCKED CARBODIIMIDES

phenylene)-5-phenyl-1,2,3,5-thiaoxadiazole-1-oxide 1, a blocked bifunc tional carbodiimide, has been used as a crosslinker for carboxyl funct ional poly(meth)acrylates. The thermolysis (''deblocking'') reaction o f 1 has been analyzed by FTIR spectroscopy. The crosslinking reaction has been simulated by using monofunctional model compounds. Intermedia te compounds detected were thermally instable N-acylurea's decomposing into isocyanates and amides. Also some anhydride formation occurred. The final structure of the crosslinked product and the rates of crossl inking have been analyzed by FTIR and NMR spectroscopy. Modulus-M(c) r elations of networks based on carbodiimide compared with those based o n bisketeneimine indicate thermolysis of crosslinks in the former case .