| 摘要 |
#CMT# #/CMT# A method for separating individual silicate platelets (I) from layered silicates (II) involves (a) adding (II)-containing starting material to alkaline medium so that the layers are expanded, (b) intensively mixing with latex (III) in a flow reactor, so that (III) penetrates into the interlayer space, (c) separating (I) from each other in the laminar flow and (d) precipitating (III)-encapsulated (I) using organic solvents and salts. #CMT# : #/CMT# A method for separating individual silicate platelets (I) from layered silicates (II) by alkali treatment involves (a) adding (II)-containing starting material, in which (I) are firmly chemically or electrically bonded, to an alkaline medium so that the layers are expanded, (b) intensively mixing with latex (III) in a flow reactor, so that (III) penetrates into the interlayer space, widens the layer spacings and loosens the bonds, (c) separating (I) from each other in the laminar flow in the reactor and (d) precipitating individual (III)-encapsulated (I) using organic solvents and salts. #CMT#USE : #/CMT# The silicate platelets (I) (derived from layered silicates (II) such as mica and typically having a thickness of 1-10 nm and a length of more than 100 nm) are impermeable to liquids and gases and show elastic properties, and are useful as diffusion inhibiting additives (e.g. in rubber) and for improving the flexural stress resistance of rubber products during milling. (I) are also useful as additives for thermoplastics, for damping water sound, increasing tensile strength, inhibiting widening of cracks, reducing solubility and swelling and increasing phase cohesion. (I) are obtained by the present process in the form of nanocomposites, which may also have further (unspecified) uses. #CMT#ADVANTAGE : #/CMT# A previously unattainable, very high level of disintegration of the agglomerates of (I) present in (II) is obtained. The procedure is simple and suitable for continuous operation, and has a low energy requirement. When (I) are added to rubber, the high level of disintegration improves the distribution and degree of dispersion of (I), improves phase cohesion and allows (I) to be used in smaller amounts. #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Process: The process is carried out in an expanding stream. The reactor used is a tube narrowing towards the end. The alkali is an alkali metal hydroxide. The precipitated material is washed and dried. #CMT#POLYMERS : #/CMT# Preferred Materials: The latex (III) is an alkali-stable latex, especially styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), chloroprene rubber (CR), carboxylated styrene-butadiene rubber (XSBR), carboxylated nitrile-butadiene rubber (XNBR) or epoxidized natural rubber latex. #CMT#EXAMPLE : #/CMT# No relevant example given. |
