What Is Polyacrylonitrile?
Polyacrylonitrile, or PAN, is a polymer derived from acrylonitrile (CH2=CHCN). It’s the foundation for acrylic fibers, a prominent industrial application. Thanks to its ease of copolymerization with other vinyl compounds, PAN features a wide range of physical properties.
Uses of Polyacrylonitrile
1. Acrylic Fiber
With a high softening point and exceptional fiber properties, polyacrylonitrile forms the basis of acrylic fibers. These fibers are noted for their heat resistance, gloss, light shielding, durability, and water repellency, making them ideal for clothing, bedding, carpets, and automobile interiors. Their superior dyeability and moisture retention also enable easy blending with natural fibers, enhancing their utility in various fabric products.
2. Raw Material for Carbon Fiber
As a crucial component in carbon fiber and carbon fiber reinforced plastic (CFRP) production, polyacrylonitrile contributes to materials that are lightweight, strong, heat, and chemical-resistant. These properties are invaluable in aerospace, high-end sports equipment, and military applications.
3. Pharmaceuticals and Biotechnology
In the pharmaceutical and biotechnology sectors, polyacrylonitrile-based separation membranes offer low protein adsorption and outstanding separation performance, underlining the polymer’s versatility and growing demand, particularly driven by China’s expanding carbon fiber and water treatment industries.
Properties of Polyacrylonitrile
This white or yellow solid decomposes above 300°C without melting, showcasing a high softening point. It’s insoluble in hydrocarbons, alcohols, and ethers but dissolves in specific solvents, demonstrating its chemical versatility. Upon heating with alkaline substances or at high temperatures, it undergoes structural changes, indicating its thermal sensitivity.
Other Information on Polyacrylonitrile
1. Production Method of Polyacrylonitrile
The polymer is synthesized through radical or ionic polymerization, employing either benzoyl peroxide or metallic sodium as catalysts. This process, adaptable to suspension or solution polymerization techniques, underscores its industrial scalability and flexibility.
2. Acrylic Fiber Production Method
For acrylic fiber production, polyacrylonitrile is copolymerized with other monomers and spun into fibers through solution spinning, highlighting the material’s adaptability and the precision required in its manufacturing.
3. Carbon Fiber Production Method
The transformation of PAN into high-strength, high-modulus carbon fiber involves a meticulous process of heating and carbonization, culminating in graphitization. This process exemplifies the material’s contribution to advanced materials science, particularly in fields demanding reliability and performance.