Vigilancia Tecnológica

We synthesized vinyl?substituted hydridopolycarbosilane (VHPCS) by Grignard coupling method and found a new initiator system (TBPB/NIAA). This system increased the ceramic yield of VHPCS from 80.49% to 89.88%, and did not have adverse effects on the high?temperature oxidation?resistance of ceramified VHPCS. Utilizing this system can effectively enhance the performance of VHPCS.AbstractVinyl?substituted hydridopolycarbosilane (VHPCS) is widely studied for its low viscosity, abundance of active functional groups, rapid curing, and high ceramic yield. The curing reactions mainly involve the free radical polymerization of vinyl and hydrosilylation reactions, but these reactions typically require high temperatures such as 160–250°C. The curing behavior of VHPCS?17 with a tert?butyl peroxybenzoate/Nickel acetylacetonate (TBPB/NIAA) system is investigated using differential scanning calorimetry and in situ Fourier transform infrared. The properties of VHPCS?17 with different initiator systems and VHPCS with different vinyl contents (under TBPB/NIAA system) are studied using thermogravimetric analysis and x?ray diffraction. The results demonstrate that the TBPB/NIAA system can facilitate the free radical polymerization of vinyl; moreover, this system decreases the peak temperature of the curing reaction from 251 to 141°C and increases the ceramic yield from 80.49% to 89.88%. The ceramic yield of cured VHPCS increases gradually, reaching 89.88% when the vinyl content is 17%. The grain size of ??SiC decreases continuously with the increase in vinyl content, while the high?temperature oxidation?resistant properties of SiC ceramics obtained from different VHPCSs are not negatively affected.