Chemistry of hydrogen-octasilsesquioxane: Preparation and characterization of octasilsesquioxane-containing polymers

Over the past five years, there have been a number of studies that have concerned themselves with controlling the structure of inorganic networks. Many of these studies have been undertaken due to the need for more advanced or structurally ordered materials in a variety of electrical and optical applications. One of the approaches to create materials that are structurally ordered has been to assemble the higher molecular weight polymers and materials not from monomeric precursors but from partially assembled oligomeric structural building blocks. In the silicone materials area, the well-known completely condensed cages T-n or Q(n)(n-) offer convenient higher order building blocks for larger structural assemblies. In most cases materials made by employing these cages as the building blocks have afforded gels or insoluble network materials due to the high degree of functionality (typically n) present in these building blocks. In this paper, we report the preparation of soluble resins that are T-H(8) cages linked together with divinyl species as links made by hydrosilation chemistry and their characterization as it relates to previously reported studies. We have employed a range of linking groups (L) from organics (divinyl benzene) and alpha-Omega functional siloxanes (from a degree of polymerization, DP, of 2-12). Interestingly, we have also found it possible to make soluble network materials even when employing two linking groups (L) per cage. We have combined the characterization of the high-molecular-weight polymers with detailed characterization of small molecules made by these same hydrosilation reactions to provide insights into some relatively simple model Si-resin systems. The characterization of these relatively simple systems helps provide insights into the structure <-> property relationships of silicone materials in general.