Monitoring a polycycloaddition by the combination of dynamic rheology and FTIR spectroscopy

Abstract : A rheometer coupled with a FTIR spectrometer under controlled atmosphere was successfully used to monitor in situ the synthesis of a preceramic polycarbosilane starting from two suitable monomers. This original hyper-branched polymer was obtained using the azide-alkyne cycloaddition activated by temperature. The device allowed for the following of the polymerization reaction by monitoring the intensity of several characteristic vibrational bands corresponding to the reagents (e.g. eN 3 , CeH alkyne) and the products (e.g. CeH triazole). The impact of the surrounding atmosphere and the kinetic aspects of the reaction were investigated for the three studied temperatures, and an apparent activation energy of 73.3 kJ mol À1 was calculated for the 1,3-dipolar polycycloaddition.