Process for the formation of polyhedral oligomeric silsesquioxanes

Abstract

Three methods for the preparation of polyhedral oligomeric silsesquioxanes (POSS) using the action of bases capable of attacking silicon atoms or any other compounds capable of reacting with protic solvents (such as ROH, H2O, etc.) and producing hydroxides[ OH]-, alkoxide [RO]- and other compounds. The first method utilizes these bases to effectively redistribute the silicon-oxygen framework in polymerized silsesquioxane [RSiO1.5]∞ into POSS nanostructures, that is, the formula [(RSiO1.5)n]∑ The homoleptic segment shown in #, the functionalized homoleptic segment shown in [(RXSiO1.5)n]∑#, the heterogeneous segment shown in [(RSiO1.5)m(R'SiO1.5)n]∑# Segment (heteroleptic) and {(RSiO1.5)m(RXSiO1.0)n}∑ #shown as a functionalized heterosegment nanostructure, where ∞=1-1,000,000 or higher. The second method uses a base to help form POSS nanostructures from silane RSiX3 and linear or cyclic silsesquioxanes of the formula RX2Si-(OSiRX)m-OSiRX2, that is, the formula [(RSiO1.5)n ]∑#, the homogeneous segment shown in [(RSiO1.5)m(R'SiO1.5)n]∑# and the miscellaneous segment shown in [(RSiO1.5)m(RXSiO1.0)n]∑# Functionalized heterosegment nanostructures, where m=0-10, X=OH, Cl, Br, I, alkoxide OR, acetate OOCR, peroxide OOR, amine NR2, isocyanate NCO and R. The third method utilizes bases to selectively open silicon-oxygen-silicon (Si-O-Si) bonds in the POSS structure to form POSS species with incompletely condensed nanostructures. These methods also provide control over the stereochemistry of X. The three methods can generate new POSS species, which can be finally transformed into POSS species suitable for polymerization, grafting or other desired chemical reactions after additional chemical control.

Description

Background of the invention [0001] The present invention describes methods that enable selective control of the silicon-oxygen backbone structure in polyhedral oligomeric silsesquioxane (POSS) cage molecules. It is desirable to be able to selectively control the framework structure of POSS as they serve as chemical species that can be further converted or incorporated into a wide variety of chemical feedstocks for the preparation of catalyst supports, monomers, polymers, And as a solubilized form of silica to replace fumed and precipitated silica or for biological applications and surface modification. POSS, when incorporated into polymeric materials, can provide new and improved thermal, mechanical and physical properties to common polymeric materials. [0002] A wide variety of POSS framework structures can be synthesized in useful quantities by hydrolytic condensation of alkyl- or aryl-trichlorosilanes. However, in most cases, hydrolytic condensation reactions of trifunct...

AI Technical Summary

Problems solved by technology

Thus POSS compositions and methods associated with the type of system desired for POSS monomer/polymer technology are unforeseen by the prior art

Additionally, the prior