Preparation of polydimethylsiloxane nanolatices by emulsion polymerization in a water-amino ethanol system

摘要

Stable and translucent polydimethylsiloxane nanolatices in a water-aminoethanol (AE) system were prepared by the emulsion polymerization of octamethylcyclotetrasiloxane (D-4) with nonionic polyoxyethylene alcohol ethers and polyoxyethylene aryl ether as surfactants and with KOH as an initiator. The effects of the AE concentration on the emulsion polymerization rate (R-p) of D, and the physical properties of the resultant nanolatices were investigated. Increasing the AE concentration in the reaction mixture dramatically increased the emulsion R-P value of D-4 and the kinetics of the D-4 emulsion polymerization in this system were consistent with the Morgan-Kaler theory of micro-emulsion polymerization. When the AE concentration in the emulsion increased, the transparency value of the resultant emulsion increased, and the size of the droplets in the resultant nanolatices decreased. In addition, the molecular weight of the polysiloxane in the resultant emulsion also increased with the increase in the AE concentration in the reaction mixture. A nanolatex prepared by the emulsion polymerization of 0.98M D-4 with 185 g/L AE had a transparency value of 80.9 % and a mean diameter of 59.5 nm. The morphology of polysiloxane nanolatices cured with (N,N-diethylaminomethyl)-triethoxysilane was observed with transmission electron microscopy, and the size of the globular particles was consistent with that obtained by dynamic light scattering. (c) 2005 Wiley Periodicals, Inc.