Synthesis and characterization of polycarbodiimides by MALDI-TOF MS and NMR spectroscopy: kinetic and mechanism study

Matrix-assisted laser desorption/ionization time of flight mass spectrometry and nuclear magnetic resonance spectrometry techniques have been used to characterize carbodiimide oligomers and to identify the reaction intermediate that demonstrates the original synthetic route. The isomerization of the catalyst during the kinetic mechanism of the reaction has been also studied. The number of different isomerization species of the catalysts and the dose of catalysts added during the reaction are responsible for the final molecular weight and structure of the oligomer (linear and branched structures). The study shows that controlling the correct catalyst isomerization reaction can decrease the reaction time by up to 5 h and control the synthesis of linear or branched oligomer structures.