Polysiloxanes

What Does Polysiloxanes Mean?

Polysiloxanes, or polymerized siloxanes, are a polymer with a silicon-oxygen backbone. Its chemical formula is (R₂SiO)_{n ,} where R is usually methylsiloxanes (CH₃), although it can be H or alkyl or aryl group. Polysiloxane has shown greater resistance to the effects of UV radiation than organic polymers containing a carbon-carbon backbone. Polysiloxanes can be oils, greases, rubbers or plastics depending on molecular weight.

Polysiloxanes exhibit:

• Superb abrasion and corrosion resistance
• Strong chemical resistance
• Anti-graffiti properties
• Resilience to dirt pickup
• Low VOCs

Corrosionpedia Explains Polysiloxanes

Polysiloxanes refer to a wide range of fluids, resins, or elastomers, which are made from polymerizations of siloxanes. The siloxanes consist of alternating silicon and oxygen atoms.

Some useful properties of polysiloxanes include:

• Flexibility
• Chemical inertness
• Permeability to gases
• Resistance to water and oxidation
• Low glass transition temperature
• Low surface energy

These properties make polysiloxanes suitable for a wide range of commercial applications, such as:

• Electrical (e.g., insulation),
• Electronics (e.g., coatings),
• Household (e.g., sealants for cooking apparatus),
• Automobile (e.g., gaskets), airplane (e.g., seals),
• Textiles/paper (e.g., coatings)
• Lubricating greases

Polysiloxane coatings are very useful in industrial protective and maintenance coatings. They have excellent aesthetic weathering attributes. There are three key categories of polysiloxane coatings:

• Inorganic Polysiloxanes: Cured by hydrolytic polycondensation. These resist temperatures up to 1,400°F (760°C) and have excellent solvent resistance.
• Epoxy-Polysiloxane Hybrids: Cured by both hydrolytic polycondensation and conventional epoxy-amine mechanisms, these coatings create weather and corrosion-resistant hybrids. They provide superior resistance to weathering over other conventional epoxy coatings.
• Acrylic-Polysiloxane Hybrids: These produce a low VOC, highly weatherable topcoat.