Improving the yield of polyacrylonitrile PAN during its synthesis process from acrylonitrile monomer can be achieved by optimizing various factors in the polymerization reaction. Here are some strategies to consider:1. Catalyst selection: Choose an appropriate catalyst that can effectively initiate the polymerization reaction and increase the rate of reaction. Commonly used catalysts for PAN synthesis are redox initiators, such as ammonium persulfate APS and sodium metabisulfite SMBS . The choice of catalyst can significantly impact the yield and properties of the resulting polymer.2. Reaction temperature: Optimize the reaction temperature to ensure that the polymerization process occurs at a rate that maximizes yield while minimizing side reactions and degradation. For PAN synthesis, a temperature range of 30-70C is typically used. The optimal temperature may vary depending on the specific catalyst and reaction conditions.3. Monomer concentration: Adjust the concentration of acrylonitrile monomer in the reaction mixture to achieve a balance between reaction rate and polymer chain growth. Higher monomer concentrations can lead to faster polymerization rates and higher molecular weight polymers, but may also increase the likelihood of side reactions and gel formation.4. Reaction time: Allow sufficient time for the polymerization reaction to proceed to completion or near completion. This will help to maximize the conversion of acrylonitrile monomer to PAN. However, excessively long reaction times may lead to degradation of the polymer and a decrease in yield.5. Solvent selection: Choose a suitable solvent that can dissolve both the monomer and the resulting polymer, and that does not interfere with the polymerization reaction. Common solvents for PAN synthesis include water, dimethyl sulfoxide DMSO , and dimethylformamide DMF . The choice of solvent can impact the reaction rate, yield, and properties of the resulting polymer.6. Inhibitor removal: Acrylonitrile monomer often contains inhibitors, such as hydroquinone, to prevent premature polymerization during storage. Prior to polymerization, these inhibitors should be removed or neutralized to ensure efficient conversion of the monomer to PAN.7. Copolymerization: Introducing comonomers, such as methyl acrylate or itaconic acid, can help to control the polymerization reaction and improve the yield of PAN. The choice of comonomer and its concentration should be carefully optimized to achieve the desired properties in the final polymer.8. Process control: Implementing advanced process control techniques, such as real-time monitoring and feedback control, can help to optimize the polymerization reaction and improve the yield of PAN.By optimizing these factors, it is possible to improve the yield of polyacrylonitrile during its synthesis process from acrylonitrile monomer.