Silicone Compounds

Common Name: SIL, VMQ, Silicone
*Silicone is not to be confused with the chemical element silicon
Chemical Name: Polysiloxane
ASTM D1418 Designation: VMQ

General Characteristics

Hardness Range (Shore A): 30-90
Tensile Strength Range (psi): 200-1500
Elongation (Max %): 700
Compression Set: Good
Resilience-Rebound: Good
Abrasion Resistance: Fair to Poor
Tear Resistance: Poor
Solvent Resistance: Poor
Oil Resistance: Fair to Poor
Low Temperature: -60°F
High Temperature: 450°F
Aging, Weathering-Sunlight: Good

Advantages

  • Low compression set and good resilience.
  • Moderate solvent resistance, resistant to petroleum-based lubricants
  • Excellent heat resistance.
  • Good release characteristics.
  • Highly resistant to oxidation and ozone.

Disadvantages

  • Not recommended for most concentrated solvents, oils, concentrated acids and dilute sodium hydroxide.
  • Low Tensile Strength, abrasion and tear resistance.
  • Low resistance to gas permeability.

Silicone rubber (not to be confused with the chemical element Silicon) offer a high degree of resistance to ozone, heat, UV light, general weathering, ozone and compression set. However, Silicones have poor tensile strength, abrasion resistance and tear resistance and should not be used where gas tight seals are required or in dynamic applications.

Silicones are thermally stable which their physical properties stay consistent over a wide temperature range, typically from -65°F to over 450°F with some compounds reaching as  high as 600°F. Silicones can be formulated to be electrically conductive or insulative. They have low chemical reactivity, low toxicity and low thermo conductivity.

Some of the many uses for Silicone include, O-rings, gaskets, seals, hoses, wire and cable insulation, tubes. Many cooking products are made of silicone for their high heat resistance and low toxicity. Silicone is also used to make silicone grease, silicone oil, silicone resin and silicone caulk.

Silicone come in thermosetting rubbers that require heat to vulcanize and Room Temperature Vulcanizing (RTV) silicone rubber. Silicone O-rings, gaskets and seals are commonly made from thermosetting silicones. 2 part RTV silicones are used on Liquid Injection Molding (LIM). LIM is commonly used in the medical seal industry because the two part RTV silicone can go from tubs to molded parts without being touched.

Contact us to request more information: