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<p>Polycarbosilane (PCS) is an ideal precursor for polymer-derived silicon carbide (SiC), which is an important engineering ceramic material with excellent thermal and mechanical properties. Nevertheless, facile preparation of high molecular weight PCS precursors with excellent processability remains a challenging task in both industrial and academic sectors. In this study, low molecular weight PCS is covalently linked with coupling agent containing alkenyl groups using hydrosilylation reaction, resulting in significant improvement on the PCS molecular weight. For instance, compared to the original PCS with a molecular weight of 1297&#xa0;g/mol (M<sub>n</sub>), the modified PCS shows a M<sub>n</sub> as high as 3441&#xa0;g/mol under optimized reaction conditions, suggesting that the molecular weight of the product increases up to almost three times. Moreover, the thermal decomposition temperature and ceramic yield of the product increases to 450&#xa0;°C and 81.3%, comparing to those of 350&#xa0;°C and 67% of unmodified PCS. This hydrosilylation can be conducted under mild reaction conditions, offering advantages over other methods that require high pressure or high temperature. The resulting products not only exhibit a desirable increase in ceramic yield but also contain vinyl or allyl groups on polymer chains that can be applicable for further functionalization of the ceramic precursors.</p> Graphical abstract <p></p>

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Facile and mild preparation of high molecular weight polycarbosilane with high ceramic yield and enhanced thermal stability

  • 期刊论文

  • 发表日期：

    2025年11月12日

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  • Hui Chen,
  • Yong Lu,
  • Yen-Nan Liang,
  • Xiao Matthew Hu

摘要

Polycarbosilane (PCS) is an ideal precursor for polymer-derived silicon carbide (SiC), which is an important engineering ceramic material with excellent thermal and mechanical properties. Nevertheless, facile preparation of high molecular weight PCS precursors with excellent processability remains a challenging task in both industrial and academic sectors. In this study, low molecular weight PCS is covalently linked with coupling agent containing alkenyl groups using hydrosilylation reaction, resulting in significant improvement on the PCS molecular weight. For instance, compared to the original PCS with a molecular weight of 1297 g/mol (Mn), the modified PCS shows a Mn as high as 3441 g/mol under optimized reaction conditions, suggesting that the molecular weight of the product increases up to almost three times. Moreover, the thermal decomposition temperature and ceramic yield of the product increases to 450 °C and 81.3%, comparing to those of 350 °C and 67% of unmodified PCS. This hydrosilylation can be conducted under mild reaction conditions, offering advantages over other methods that require high pressure or high temperature. The resulting products not only exhibit a desirable increase in ceramic yield but also contain vinyl or allyl groups on polymer chains that can be applicable for further functionalization of the ceramic precursors.

Graphical abstract