Reactions of titanium alkoxide with SiH containing polymers as a route to titanium/siloxane hybrid materials with enhanced refractive index

Abstract

Reactions of titanium tetrabutoxide with polyhydromethylsiloxane (PHMS) and with some hydromethylsiloxane copolymers were used for synthesis of light transparent materials having enhanced refractive index. The FTIR, 1H NMR and 29Si NMR spectroscopies were used to study the reaction between PHMS and titanium tetrabutoxide in toluene. Reaction of SiH functional siloxane polymers with titanium tetrabutoxide results in a titanium‐containing heterosiloxane prepolymers that are stable under anhydrous anaerobic conditions. Exposure of the resulting materials to humid air transforms them into light transparent titanium/siloxane nanocomposites with enhanced refractive index. The films of these composites formed during the spin‐coating process were characterized by UV–Vis, ellipsometry, IR and 29Si NMR spectroscopies and transmission electron microscopy (TEM). Titanium/siloxane hybrid films obtained on the basis of poly(phenylmethylsiloxane‐co‐hydromethylsiloxane) copolymer are free of cracks and have a refractive index of up to 1.60.

Reactions of Zirconium (IV) n‐Propoxide with SiH‐Functional Polysiloxanes as a Route to Siloxane–Zirconium Hybrid Materials with Enhanced Refractive Index

“…In this process, hydrolytic condensation of reactive groups takes place, which can be catalyzed by zirconium species. [ 34 ] Contrary to the previously investigated siloxane‐titanium composites, [ 8 ] 1 mm thick siloxane–zirconium composites, especially with higher zirconium content, are much more brittle and crack easily during the hardening process (Figure S8, Supporting Information). This can be explained by the high content of alkoxy functional silanes and short oligomers in the reaction solution, which, when exposed to humid air, form a highly cross‐linked brittle network.…”

“…Our recent effort was focused on synthesis of polysiloxane‐titania composites. [ 8 ] Although our hybrids showed a reasonably high refractive index, their films did not show sufficient light transparency at wavelengths below 300 nm, which is required for LED encapsulation. The formation of UV absorbing species in polysiloxane‐titania hybrids is not well understood.…”

“…It was expected that the presence of phenyl groups in polysiloxane would increase the refractive index and the flexibility of the hybrid film. [ 8 ] Zirconium (IV) n ‐propoxide was used as the zirconium source. Commercial Zr(O n Pr) 4 contains about 30% of n ‐propanol, which may affect its reaction with organohydrosilanes.…”

“…Our recent effort was focused film. [8] Zirconium (IV) n-propoxide was used as the zirconium source. Commercial Zr(O n Pr) 4 contains about 30% of n-propanol, which may affect its reaction with organohydrosilanes.…”

Interaction of Polyphenylsilsesquioxane With Various β-diketonate Complexes of Titanium By Mechanochemical Activation

“…Titanesiloxanes can also be obtained by mixing titanium dioxide nanoparticles with a ready-made polymer matrix, as it was done by the authors of works [30][31][32][33], by sol-gel synthesis based on titanium alkoxides [34][35][36]. The processes of direct interaction of titanium alkoxides with hydromethylsiloxane, as well as cleavage of the siloxane bond in the copolymer hydromethylsiloxane-phenylmethylsiloxane under the action of tetrabutoxytitanium, have been studied [37].…”