SYNTHESIS AND STUDIES ON SURFACE-ACTIVE WATER-SOLUBLE DERIVATIVES OF SILOXANE OLIGOMERS

We report the synthesis of cationic water-soluble siloxanes by reactin g aminosiloxanes with dimethyl, n-dodecyl 3-chloro-2-hydroxypropyl qua ternary ammonium iodide (DDCQA). Tetramethyl disiloxane on hydrosilati on with allyl amine in the presence of hexachloroplatinic acid/IPA gav e bis(3 -aminopropyl)octamethyltetrasiloxane. In addition, formation o f Si-H containing oligomeric siloxanes were detected during this react ion and the extent of formation of the oligomers was found to depend u pon the concentration of platinum. The oligomerization reaction was ex plained by dehydrogenative coupling of Si-H groups in the presence of platinum catalyst. A plausible mechanism for formation of aminosiloxan e and the Si-H oligomers were proposed. Alternatively, cyclic Si-H con taining siloxanes on polymerization using butyl lithium gave oligomeri c Si-H containing siloxanes, which were hydrosilated to give aminosilo xanes. The quaternary aminosiloxanes synthesized showed lowering in su rface tension of water to 26 mN/m.