The optimized synthesis method for producing high molecular weight polyacrylonitrile PAN from acrylonitrile AN monomer with minimal impurities and defects involves the following steps:1. Monomer purification: Start with high purity acrylonitrile monomer. Purify the monomer by distillation or other suitable methods to remove any impurities and stabilizers that may hinder the polymerization process or affect the final product quality.2. Polymerization process: Use a controlled radical polymerization technique, such as Atom Transfer Radical Polymerization ATRP or Reversible Addition-Fragmentation Chain Transfer RAFT polymerization. These methods allow for better control over molecular weight, molecular weight distribution, and polymer chain-end functionality, resulting in a high molecular weight PAN with minimal defects.3. Choice of initiator and catalyst: Select an appropriate initiator and catalyst system that is compatible with the chosen polymerization method and provides good control over the reaction. This will help ensure a high molecular weight PAN with minimal impurities and defects.4. Reaction conditions: Optimize the reaction conditions, such as temperature, pressure, and monomer-to-initiator ratio, to achieve the desired molecular weight and minimize side reactions that could lead to impurities and defects.5. Polymer isolation and purification: After the polymerization is complete, isolate the PAN polymer by precipitation or other suitable methods. Purify the polymer by washing with a suitable solvent to remove any residual monomer, initiator, catalyst, or other impurities.6. Drying and characterization: Dry the purified PAN polymer to remove any residual solvent and characterize the polymer using techniques such as Gel Permeation Chromatography GPC and Nuclear Magnetic Resonance NMR spectroscopy to confirm the molecular weight, molecular weight distribution, and chemical structure.By following these steps and optimizing each stage of the process, you can produce high molecular weight polyacrylonitrile with minimal impurities and defects.