Silicone gels – structure and properties

Structure

Silicone gels are essentially lightly crosslinked silicone fluids. Like silicone elastomers, they have a three-dimensional structure.

However, they have fewer reactive sites and higher molecular weight starting materials, which allows for more entanglement. Silicone gels do not contain fillers, and their network is easily swollen with silicone fluids.

The characteristics of the final gel are determined by the number of reactions that take place and the length of the polydimethylsiloxane (PDMS) chains. Low-molecular-weight PDMS and high reaction density will produce a stiff, almost solid gel. High-molecular-weight PDMS and low reaction density will create a softer, more flowable gel.

Properties of user-cured dielectric gels

• Low viscosity for easy and rapid dispensing
• A naturally tacky surface, which enables primerless adhesion to most surfaces
• Repairability
• Excellent dielectric properties
• Service range of -45 to 150°C (-49 to 302°F)
• Minimal shrinkage during cure
• The ability to cure in confinement
• Deep section cure capabilities
• No heat generated during cure
• No solvents or cure by-products
• Low toxicity

Properties of pre-cured formulating gels

• Loosely reacted cured gels with high silicone fluid content – very soft and flowable
• Sheer thinning (thixotropic), with the capability to impart this trait to the final product
• Non-toxic