Nanodisperse metalloorganosiloksanovy fillers of polymers

Abstract

Synthesis of the highly dispersed hydrophobic metaloligomers that are compatible with polymers in order to obtain high performance homogeneous radiation protective polymer composites with the given properties is still of importance. The most perspective way is to use reactive organosiloxanes and to produce metal oligomers based on them. The method of synthesis of nanodispersed oligomer of lead polyalkylsiliconates by a chemical deposition of water solutions of lead ions according to zol-gel process that runs with participation of sodium alkylsiliconates has been developed. Interaction reaction between sodium ethylsiliconate and lead ions in aqueous solution proceeds as the mechanism of replacement of sodium ions in silanol group Si–ONa of sodium alkylsiliconate with lead ion. Finally there is a formation of ring structures, and cross-linking of oligomer molecules takes place while to the number of the siloxane ties is increasing. The microstructure of hydrophobic lead polyethylsiliconate that has amorphous and crystal nature with dense packaging of metal oligomer molecular chains is considered. There is a polyreaction between hydroxyl ОН-groups of metal oligomer and lead oxyhydroxide, i.e. lead oxyhydroxide serves as an adsorbent on which the metal oligomer is chemically absorbed thus giving hydrophobic properties to the product. An opportunity to carry out directional modification of an excipient in the course of collateral synthesis of metal oligomer and a lead excipient, i.e. to receive hydrophobic filled metaloligomer in the homogeneous environment is as a result reached. High deficiency of lead polyethylsilica is caused by steric effects because of the larger sizes of hydrocarbon ethyl (C2H5) radicals. The molecular mass of the unit of oligomer is about 600. Oligomer has a chain structure which siloxane chain may contain silanol groups (≡Si–OH). The partial structure and a molecular mass of the synthesized metal oligomer are given in the table. Bulk weight of lead polyethylsiliconate is 2250 kg/m3, and the maximal density at consolidation reaches 5950 kg/m3.

Keywords

• nano-disperse powders
• polialkilsilikanat of lead
• zol-gel technology
• receiving
• properties