Silikonpolymer

Silikonpolymer, commonly called silicone polymer, refers to a family of polymers with a backbone composed of alternating silicon and oxygen atoms (Si–O–Si). Organic substituents attached to silicon, such as methyl or phenyl groups, give a wide range of materials from liquids to rigid resins. The most widely used silicone polymers are polydimethylsiloxanes (PDMS).

Chemistry and synthesis: Polysiloxanes are formed by polymerization of siloxane units. The Si–O–Si backbone is flexible and contains strong bonds, contributing to a combination of stability and processability. Common routes include ring-opening polymerization of cyclic siloxanes and condensation of chlorosilanes. Crosslinking yields elastomers, resins, or gels, and curing can be addition-type (such as hydrosilylation) or condensation-type with removal of small molecules like water or alcohol.

Properties: Silicone polymers generally exhibit high thermal stability and broad operating temperature ranges, a low glass transition temperature, good electrical insulating properties, and resistance to weathering and many chemicals. They are typically flexible, have low surface energy, and can be optically transparent. Biocompatibility and low toxicity in many applications make them suitable for medical and consumer products, though specific formulations vary widely.

Applications: They are used in sealants and gasketing, adhesives, lubricants and lubricating oils, medical devices and implants, cosmetics and skincare products, cookware and bakeware (including food-grade silicones), electronics encapsulation and potting compounds, coatings, and mold-making materials.

Safety and environmental: Silicone polymers are generally inert and biocompatible, but some processing conditions can release trace cyclic siloxanes. Environmental concerns have been raised for certain cyclic siloxanes (often referred to as D4, D5), leading to regulatory scrutiny and regional disposal or usage guidelines. Handling and recycling practices vary by product and jurisdiction.