| abstract |
Silica nanopowders with biocidal properties, especially for polymer composites, are produced by sol-gel method. The silica sol is produced from the aqueous mixture containing tetraalkoxysilane, in which alkoxy group contains from C 1 to C 4 carbon atoms, an alcohol or the mixture of aliphatic alcohols from C 1 to C 4 , in the mole ratio of 1 : 5 to 1 : 35, in the presence of ammonium compound, used in an amount of from 0.001 to 0.05 mol per 1 mol of tetraalkoxysilane, with introducing, after thorough mixing of components, the silver salt in the form of aqueous solution in an amount from 0.02 to 1 mol per 1 mol of tetraalkoxysilane, and subsequently the aqueous solution of alkali metal hydroxide in an amount from 0.02 to 1 mol of hydroxide per 1 mol of tetraalkoxysilane. Silica nanopowders of the particle size of below 200 nm, contain silver nano- particles immobilized on silica, with stable physicochemical and biocidal properties. |