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

Over the past five years, there have been a number of studies that have con cerned themselves with controlling the structure of inorganic networks. Man y of these studies have been undertaken due to the need for more advanced o r structurally ordered materials in a variety of electrical and optical app lications. One of the approaches to create materials that are structurally ordered has been to assemble the higher molecular weight polymers and mater ials 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 bu ilding blocks for larger structural assemblies. In most cases materials mad e by employing these cages as the building blocks have afforded gels or ins oluble network materials due to the high degree of functionality (typically n) present in these building blocks. In this paper, we report the preparat ion of soluble resins that are T-H(8) cages linked together with divinyl sp ecies as links made by hydrosilation chemistry and their characterization a s it relates to previously reported studies. We have employed a range of li nking groups (L) from organics (divinyl benzene) and alpha-Omega functional siloxanes (from a degree of polymerization, DP, of 2-12). Interestingly, w e have also found it possible to make soluble network materials even when e mploying two linking groups (L) per cage. We have combined the characteriza tion of the high-molecular-weight polymers with detailed characterization o f small molecules made by these same hydrosilation reactions to provide ins ights into some relatively simple model Si-resin systems. The characterizat ion of these relatively simple systems helps provide insights into the stru cture <-> property relationships of silicone materials in general.