Definition - 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.
- 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:
- 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.