Modified Polysiloxanes with Tunable Thermal, Rheological and Adhesive Properties

Categories: “Chemistry“

Reference #: 2008-027

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Description

Polysiloxanes have a variety of applications including as adhesives, coatings, sealants and additives. The utility of a polysiloxane is determined by its physical properties, which are dependent upon the chemical functionality of the polysiloxane composition. By reacting polysiloxanes with carbon dioxide (CO2) and carbon disulfide (CS2), the chemical composition is modified via ionic and/or covalent crosslinking of the polysiloxane chains. This technique is an inexpensive method to make novel polysiloxane compositions that are tuned to have physical properties that enhance their utility for specific applications.

Applications

Modified crosslinked polysiloxane compositions have the potential to be novel materials for use as, for
example, adhesives, gels and packing materials for chromatography.

Advantages

• Novel crosslinked polysiloxanes may be formed with inexpensive CO2 and CS2 reactants
• Crosslinked polysiloxane products can be customized for specific applications
• Ammonium carbamate polysiloxanes resulting from CO2 reactions, can be reversed to produce original polysiloxane material

Stage of Development

Polysiloxanes with up to 15% amino content were allowed to react with CO2 and CS2, which resulted in ionic cross linked ammonium carbamate and dithiocarbamate polysiloxanes respectively. The formation of ammonium carbamate polysiloxanes was reversible upon heating in a stream of N2. Upon heating, dithiocarbamate polysiloxanes went on to form covalently cross-linked thiourea polysiloxane chains. The materials were then analyzed for properties including their viscoelastic properties, swelling and
adhesiveness.

Relevant Publications

“Reversibly Cross-Lining Amino-Polysiloxanes by Simple Triatomic Molecules. Facile Methods for
Tuning Thermal, Rheological and Adhesive Properties.” J. Phys Chem. C. 2009, ASAP online.

Inventor

Richard G. Weiss

Patent Status

Applications Pending