The synthesis of polyacrylonitrile PAN from acrylonitrile monomer is typically carried out through free radical polymerization. The reaction conditions, including temperature, pressure, and catalyst, play a crucial role in determining the yield and properties of the resulting PAN polymer.1. Temperature: The polymerization reaction of acrylonitrile is exothermic, meaning it releases heat. As the temperature increases, the reaction rate also increases, leading to a higher yield of PAN. However, if the temperature is too high, it can cause side reactions and degradation of the polymer, resulting in a lower molecular weight and poorer mechanical properties. Therefore, it is essential to maintain an optimal temperature usually around 40-70C to achieve a balance between reaction rate and polymer quality.2. Pressure: The effect of pressure on the polymerization of acrylonitrile is less significant compared to temperature and catalyst. However, higher pressure can lead to a higher concentration of monomers in the reaction mixture, which can increase the reaction rate and yield of PAN. On the other hand, very high pressure can cause safety concerns and increase the risk of side reactions.3. Catalyst: The choice of catalyst is critical in determining the yield and properties of PAN. Free radical initiators, such as azo compounds and peroxides, are commonly used as catalysts in the polymerization of acrylonitrile. The type and concentration of the catalyst can significantly affect the reaction rate, molecular weight, and polydispersity of the resulting PAN. For example, using a more efficient catalyst can lead to a higher reaction rate and yield, but it may also result in a broader molecular weight distribution, which can negatively impact the mechanical properties of the polymer.In summary, the reaction conditions, such as temperature, pressure, and catalyst, play a crucial role in determining the yield and properties of polyacrylonitrile synthesized from acrylonitrile monomer. By carefully controlling these parameters, it is possible to optimize the synthesis process and obtain PAN with desired properties for various applications.