CAS number 68083-19-2 identifies Poly(dimethylsiloxane), vinyl terminated, a highly versatile silicone polymer.
Understanding CAS Number 68083-19-2
A Chemical Abstracts Service (CAS) Registry Number is a unique numerical identifier assigned to every chemical substance described in the scientific literature. It is used globally to provide an unambiguous way to identify chemical substances, regardless of their various names, synonyms, or structural representations. CAS number 68083-19-2 precisely refers to a specific type of silicone: Poly(dimethylsiloxane) with vinyl functional groups at its termini (ends).
Here's a quick overview:
| Feature | Description |
|---|---|
| CAS Number | 68083-19-2 |
| Substance Name | Poly(dimethylsiloxane), vinyl terminated |
| Common Abbreviation | Vinyl-terminated PDMS (VT-PDMS) or V-PDMS |
| Chemical Class | Organosilicon Polymer, Silicone Elastomer Precursor |
What is Poly(dimethylsiloxane), Vinyl Terminated?
Poly(dimethylsiloxane), commonly known as PDMS, is a silicone polymer characterized by its flexible silicon-oxygen backbone and methyl groups attached to the silicon atoms. It is widely recognized for its unique properties, including high thermal stability, excellent flexibility, water repellency, and low toxicity.
The "vinyl terminated" aspect means that the ends of the PDMS polymer chains are capped with vinyl groups (—CH=CH₂). These vinyl groups are highly reactive, which is crucial for the polymer's utility in various applications. They enable the PDMS chains to undergo crosslinking reactions, typically with a hydride-functional siloxane (containing Si-H bonds) in the presence of a platinum catalyst. This reaction allows the liquid PDMS to cure into a solid, elastic material, often referred to as a silicone elastomer.
Key Characteristics and Uses
Poly(dimethylsiloxane), vinyl terminated, is a foundational material in many industries due to its controllable curing process and resulting material properties.
Key Characteristics:
- Reactivity: The vinyl groups allow for precise crosslinking, leading to tunable mechanical properties (e.g., hardness, elasticity).
- Flexibility: Remains flexible over a wide range of temperatures, from very low to high.
- Thermal Stability: Excellent resistance to high temperatures and thermal degradation.
- Biocompatibility: Generally non-toxic and inert, making it suitable for biomedical applications.
- Hydrophobicity: Repels water, making it useful in water-resistant coatings and sealants.
- Electrical Insulation: Good dielectric properties.
Common Applications:
The versatility of vinyl-terminated PDMS makes it invaluable in a diverse range of fields:
- Elastomer Manufacturing: It serves as a primary component in two-part addition-cure silicone systems. These are used to produce:
- Molds: For casting various materials like resins, waxes, and concrete.
- Sealants and Adhesives: In construction, automotive, and electronics industries.
- Encapsulants: For protecting delicate electronic components.
- Biomedical Devices: Its biocompatibility leads to applications in:
- Medical Implants: Such as catheters, prosthetics, and drug delivery systems.
- Microfluidic Devices: For lab-on-a-chip applications due to its ease of molding and optical clarity.
- Tissue Engineering Scaffolds: Providing a flexible and inert substrate for cell growth.
- Coatings and Textiles: Used to impart water repellency, softness, and durability to surfaces:
- Textile Finishing: To create wrinkle-resistant and soft fabrics.
- Release Coatings: On papers and films to prevent sticking.
- Protective Coatings: For electronic components and consumer goods.
- Specialty Chemicals:
- Defoamers: In industrial processes and food production.
- Personal Care Products: As a conditioning agent in shampoos and lotions, contributing to a smooth feel.
Poly(dimethylsiloxane), vinyl terminated, is a testament to the power of polymer chemistry, allowing for the creation of materials with tailored properties essential for modern technology and everyday products.
