(513eb) Oxidative Treatment of Acid Activated Montmorillonite Clay Used in Production of Polydimethylsiloxane

Polydimethylsiloxane (PDMS) are generally produced by polymerizing a dimethyl siloxane such as hydroxyl endblocked dimethyl fluids, dimethyl cyclosiloxanes, and others in the presence of trimethylsilyl endblocker. Acid treated montmorillonite clays are an example of catalysts used for this reaction. Using a heterogeneous catalyst for this reaction allows for easy separation of catalyst after reaction removing the need for catalyst quenching typically required for homogeneous acid catalysts. However, there are certain disadvantages as well. Since the catalyst is a naturally occurring material, the impurities present in the catalyst can interact with PDMS to generating undesirable odor which needs to be mitigated before the PDMS can be used in odor sensitive end-application. The study presented will show that heat-treatment of the clay catalyst in air before its use in the reaction can lower the odor-generation potential of these catalysts during the PDMS reactions. Effect of heat-treatment temperature and residence time on catalyst properties and activity will also be discussed.