29Si NMR as a Tool for Studying Silicones

Abstract Compounds containing the Si—O—Si linkage are important both in geochemistry and for commercially produced materials. They occur in a wide range of physical states; it is particularly common to find them as “pseudo-solids,” i.e., as glasses, gels, rubbers, and resins. Unfortunately, it has not been easy to obtain detailed information about molecular structure and motion for silicones. This is partly due to the complexity of many of the systems—for instance, a typical commercially produced silicone fluid contains a range of species with various molecular weights. Effects of copolymerization, tacticity, cross-linking, and segmental motion may complicate matters.