S

Silicone rubber

IUPAC: poly(dimethylsiloxane)

(C2H6OSi)n Polymers & Plastics CAS 63394-02-5
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Quick Reference
Formula / Notation(C2H6OSi)n
CAS Number63394-02-5
Molecular WeightVariable (polymer)
Melting Point−55 °C (Tg)
Boiling PointDecomposes >450 °C
Density1.10–1.25 g/cm³
SolubilityInsoluble in water
Appearancewhite to translucent elastomeric solid
Also Known AsPDMS; silicone elastomer; dimethylsilicone
CategoryPolymers & Plastics

What is Silicone rubber?

Silicone rubber is an elastomeric polymer based on a silicon-oxygen backbone (–Si(CH₃)₂–O–)n, also known as polydimethylsiloxane (PDMS) in its simplest form. Unlike carbon-based rubbers, silicone rubber maintains its properties over an exceptionally wide temperature range (−55 to +300 °C) due to the high bond energy of Si–O bonds. It also exhibits excellent biocompatibility, electrical insulation, chemical resistance, and weatherability.

Formula & Notation

(C2H6OSi)n

IUPAC Name: poly(dimethylsiloxane)

Other Names / Synonyms: PDMS; silicone elastomer; dimethylsilicone

Properties & Characteristics

Appearance: white to translucent elastomeric solid or gum. Molecular formula: (C2H6OSi)n. Temperature range: −55 to +300 °C. Density: 1.10–1.25 g/cm³. Dielectric strength: 20–25 kV/mm. Solubility: insoluble in water; swells in chlorinated solvents and some hydrocarbons.

Physical Data

PropertyValue
Melting Point−55 °C (Tg)
Boiling PointDecomposes >450 °C
Density1.10–1.25 g/cm³
Molecular WeightVariable (polymer)
SolubilityInsoluble in water
Appearancewhite to translucent elastomeric solid

Uses & Applications

Medical implants and devices (catheters, prosthetics). Electrical insulation and connectors. Sealants and adhesives. Cooking utensils and bakeware. Baby bottle teats and pacifiers. Automotive gaskets and seals.

Safety Information

Biocompatible and generally non-toxic. Uncured silicone can cause skin irritation. Releases silicon dioxide and carbon oxides when burned. Avoid exposure to strong oxidising acids. Consult SDS before industrial processing.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Silicone rubber
Formula (C2H6OSi)n
CAS Number 63394-02-5
Molecular Weight Variable (polymer)
Synonyms PDMS; silicone elastomer; dimethylsilicone

Frequently Asked Questions

Silicone rubber is an elastomeric polymer based on a silicon-oxygen backbone (–Si(CH₃)₂–O–)n, also known as polydimethylsiloxane (PDMS) in its simplest form. Unlike carbon-based rubbers, silicone rubber maintains its properties over an exceptionally wide temperature range (−55 to +300 °C) due to the high bond energy of Si–O bonds. It also exhibits excellent biocompatibility, electrical insulation, chemical resistance, and weatherability.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.