Synthesis of nylon 6-clay hybrid NCH

1 Clay organization and monomer swelling (Usuki, 1993a) 

If montmorillonite containing sodium ions between its layers is dispersed in water, its silicate layers swell uniformly. If an alkylammonium salt is added to this aqueous mixture, the alkylammonium ions are exchanged with the sodium ions. As a result of this exchange reaction, an organophilic clay forms, in which the alkylammonium ions are intercalated between the layers. Because the silicate layers in the clay are negatively charged, they form ionic bonds with the 

A novel compounding technique was developed to synthesize nylon 6 in a clay gallery by modifying the clay surface and intercalating monomers into the gallery. The organophilic material used in diis technique must satisfy the following three requirements  

It must have an ammonium ion at one end of the chain so that it can interact with clay through ionic bonding. 

It must have a carboxyUc acid group (-COOH) at die other end to react with e-caprolactam, a nylon 6 monomer, for ring opening and polymerization. It must possess intermediate polarity to enable e-caprolactam to intercalate among silicate layers. 

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