Organic/Inorganic Molecular Hybrid Materials From Cubic Silsesquioxanes

Abstract

Octafunctionalized silsesquioxanes [(RSiO!.5)8, cubes] offer potential as rigid, hard nanoplatforms to which a variety of organofunctional groups can be appended. Crosslinking these groups leads to novel organic/inorganic nanocomposites that consist primarily of interfacial interactions. These materials can be 100% interphase. We present efforts to develop nanocomposite materials that consist of both continuous and discontinuous organic/inorganic phases. We then discuss methods of probing the properties of these materials. INTRODUCTIONTwo general principles are often used to describe the origin of macroscopic properties in materials. The first is, "Intrinsic materials properties and processing taken together define microstructure." The second is,"Intrinsic materials properties and microstructure together define global properties."With the advent of chemical processing of materials, one can often replace the term microstructure with nanostructure.A less encompassing general principle is that "Control at the finest scales gives the highest homogeneity, thereby providing the highest reproducibility, predictability and ability to tailor properties." This principle is less encompassing because we often would like to prepare materials with "controlled heterogeneity," ie. composite materials. We may generally describe composites as materials that combine two (or more) materials and microstructures. In composite manufacture, the goal is usually to achieve properties that are more than the sum of the properties of the individual components; however, it is often possible to estimate the properties of typical composites using the rule of mixtures. The utility of the rule of mixtures in predicting properties is greatly diminished when applied to nanocomposites.

Solar Grade Silicon from Agricultural By-products

“…Mayaterials has long experience extracting SiO 2 from RHA as OA, the starting material for our core silica cage business, Scheme 1. [12][13][14] We have developed detailed methods of extracting most of the SiO 2 out of RHA at low temperatures (≈ 100°C) with short processing times, 5-7 h at 0.5-1 kg quantities. 2.…”

DEA and DSC study of cubic silsesquioxane epoxy resin nanocomposites

“…29 Si NMR: showed two peaks at -2.89 ppm (H-Si-CH 3 ) and -108.69 ppm (Si-O 4 ). Synthesis of 1,3,5,7,9,11,13,15-octa[dimethylsiloxypropylglycidylether] pentaciclo [9.5.1.1 3,9 .1 5,15 .1 7,13 ] octasilsesquioxane (ODPG) The synthesis of ODPG followed published procedures [19,20,28], as it is described below. A schematic representation of this reaction is showed in the Fig.…”

“…For instance, when DGEBA is cured with excess MDA the material changes from ductile to a brittle material, both tensile modulus and fracture toughness increase from φ ≈ 1.0 to φ ≈ 0.5, and, then, they drop significantly [19,20]. Therefore, while epoxy resin/hardener conventional systems become brittle with excess of curing agent (φ< 1.0), ODPG/MDA composites become rubbery.…”

“…The use of such nanosized epoxy resin in the preparation of an organic polymer by polymerization at one or more of the eight corner groups in the silsesquioxane epoxy resin macromer, can lead to nanocomposite materials. In these materials the cubes can be connected to one another by organic components with known architecture and lengths of the order of 3-5 nm, forming composites with completely defined interfacial component between organic and inorganic phase [19][20][21][22][23][24]. Nanocomposite materials can offer novel properties, such as significant improvements in tensile modulus, fracture toughness, thermal and oxidation resistance, and reduced flammability that can only be explained by extensive organic-inorganic interfacial interactions [10][11][12][13][14][19][20][21][22][23][24].…”

“…29 Si NMR: showed one peak at -99.4 ppm. 1,3,5,7,9,11,13,15-octa[hydridodimethylsiloxy]pentaciclo [9.5.1.1 3,9 .1 5,15 .1 7,13 [19,20,[25][26][27][28], as it is described below.…”