Rheological and thermal behaviours of a hyperbranched polycarbosilane: Monitoring the shaping ability of a hyperbranched polycarbosilane

A hyperbranched polymer, a precursor of silicon carbide (SiC), was successfully synthesized using a hydrosilylation reaction with Karstedt's catalyst. This reaction was optimized with the use of a rheometer coupled with an infrared spectrometer. The polymeric precursor was characterized using NMR and Fourier transform infrared spectroscopies, and dynamic theology. The polymerization reaction was followed in situ by combined rheological and infrared measurements, indicating a gel-like behaviour for alkene conversions higher than 0.55. Overall second-order kinetics was determined for the hydrosilylation reaction. Pyrolysis at 1400 degrees C led to porous materials with beta-SiC and free carbon.