Higher Efficiency Process for Preparing Clays for Use in Nanocomposites
Polymer-clay nanocomposites are used in such applications as packaging films, containers, automobile trim and injection-molded components. Homostructured mixed ion clays used in such nanocomposites require a relatively slow and complicated process to be prepared. The existing process for preparing homoionic organoclays (a critical component of the above mixed ion clays) requires relatively long reaction times and significant amounts of solvents. An entire process to make the homoionic organoclay also has to be completed before it can be mixed with an inorganic clay to make a homostructured mixed ion clay.
Description of Technology
The new invention prepares the homostructured mixed ion clay through an acid-base reaction. A proton exchanged form clay is prepared by acid treatment or by thermal conversion of the ammonium-exchanged form of the mineral, and blended with a combined surfactant and hot proton clay suspension. As a result, the homostructured mixed ion clay is formed simultaneously. The entire process is more practical (solvent free or only a very small fraction of solvent used) and energy conservative (the homostructure is formed in a very short period of time compared with existing approaches).
- Energy conservative: The prepared clays are more quickly formed.
- Improved production efficiencies: Greatly reduced use of solvents during preparation of the clays.
The clays would have commercial applications in polymer-clay nanocomposites used in existing applications which require organoclays as reinforcing agents for the polymers, e.g., in packaging films, containers, automobile trim and injection-molded components.
US 6261640 (issued Jul 17, 2001)
Thomas Pinnavaia, Zhen Wang
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Michigan State University