Chemistry of Hydrogen-Octasilsesquioxane:  Preparation and Characterization of Octasilsesquioxane-Containing Polymers

Abstract

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 HT8 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 α−Ω 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.

Photodimerization of Coumarin‐Derived Pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane to Fabricate a Three‐Dimensional Organic–Inorganic Hybrid Material

“…The other peaks are thought to correspond to the cage dimension and the scale of one cage plus one linking molecule. [16] From TG±DTA (thermogravimetry±differ-ential thermal analysis) measurements of 5 (Fig. 9), the burning temperature of this organic substance was between about 300 C and 600 C. Approximately the same thermal stability was reported in materials obtained from pentacyclo [9.5.1.1 3,9 .1 5,15 .1 7,13 ]octasiloxanes.…”

“…This pattern resembles the reported examples obtained from the hydrosilylation of pentacyclo[9.5.1.1 3,9 .1 5,15 .1 7,13 ]octasiloxanes. [16] The peak at 23 was assigned to the Si±O±Si bond repeating unit, [16] which is commonly found in amorphous silica-based materials. The other peaks are thought to correspond to the cage dimension and the scale of one cage plus one linking molecule.…”

Characterization of low molecular weight components of [(ViMe2SiO1/2)x(PhSiO3/2)y(SiO4/2)z], [(ViMe2SiO1/2)x(SiO4/2)y], and [(SiO4/2)x(HO1/2)y(tBuO1/2)z] silsesquioxanes by electrospray ionization fourier transform mass spectrometry (ESI-FTMS)

“…Silsesquioxanes have been widely applied as electrically insulating coatings or protective coating against heat or abrasion [1,2]. Making new materials with low coefficient of thermal expansion (CTE), high glass transition temperature (Tg), controllable refractive index, and desirable mechanical (high toughness) and electrical properties (low dielectric constant k), has always been a major challenge for material scientists.…”

Characterization of a [(O3/2SiMe)x(OSi(OH)Me)y(OSiMe2)z] silsesquioxane copolymer resin by mass spectrometry

“…Silsesquioxanes, also termed three‐dimensional organosilicon resins, have a long history in the materials science community and continue to generate much interest due to their unique structures and physical properties 1–4. One particular structure type, methyl silsesquioxane nanotubes, is similar to carbon‐based fullerenes and nanotubes except that the silsesquioxane‐based resins form at room temperature by simple acid‐catalyzed hydrolysis and condensation chemistries.…”