Synthesis and NMR Studies of Linear Polycarbosilanes-CeramicPrecursors and Novel Polymeric Materials

在这个由Interrante和Apple化学部特别项目办公室资助的项目中，将研究一系列独特的聚碳硅烷的合成、结构和热解，这些聚碳硅烷来自聚（硅乙烯）（PSE），这是生产化学计量碳化硅的前体。 开环聚合（ROP）工艺将被研究和发展成为一种有效的聚碳硅烷的通用路线。 溶液和固态NMR光谱将提供有关PSE和其他甲硅烷基聚合物的分子和晶体结构以及它们的一些陶瓷和陶瓷热解产物的信息。 这项研究将使系统的研究一类新兴的无机/有机聚合物，有效地桥梁之间的差距差距的全碳链聚合物，如聚乙烯，和基于硅的无机聚合物，如聚硅烷和聚硅氧烷。 %碳化硅是一种具有高强度和模量的材料，能够在实际应用中（如燃气涡轮机发动机）的高工作温度下工作。 碳氧化硅也是一种目标陶瓷材料，它可能是陶瓷复合材料中的纤维和基质材料。 然而，在这两种情况下，由有机硅前体分解产生的过量碳影响最终产物的机械性能和氧化稳定性。 本研究探讨了生产这些最终产品的路线，而没有麻烦的过量碳，从而产生具有上级材料性能的陶瓷。

In this project funded in the Special Projects Office of the Chemistry Division Interrante and Apple will investigate the synthesis, structures, and pyrolysis of a unique series of polycarbosilanes derived from poly(silaethylene) (PSE), which is a precursor to the production of stoichiometric silicon carbide. Ring-opening polymerization (ROP) processes will be investigated and developed into an effective general route to polycarbosilanes. Both solution and solid-state NMR spectroscopy will provide information about the molecular and crystal structures of PSE and other silyl polymers as well as some of their preceramic and ceramic pyrolysis products. This study will enable the systematic study of an emerging class of inorganic/organic polymers which effectively bridge the gap between the all-carbon chain polymers, such as polyethylene, and the inorganic polymers based on silicon, such as polysilanes ald polysiloxanes. %%% Silicon carbide is a material with high strength and modulus capable of performing at high working temperatures in practical applications such as a gas turbine engine. Silicon oxycarbide is also a target ceramic material which is potentially a fiber and matrix material in ceramic composites. However, in both cases excess carbon, which results from decomposition of the organosilicon precursors, affects both the mechanical properties and oxidative stability of the end products. This research investigates routes to producing these end products without the troublesome excess carbon, resulting in ceramics with superior material properties.