The best reaction conditions for synthesizing polystyrene from styrene monomer with a high yield and molecular weight using free radical polymerization are as follows:1. Temperature: The reaction temperature should be maintained between 60-120C. Higher temperatures can lead to faster reaction rates and shorter polymerization times, but may also result in increased side reactions and lower molecular weights. A moderate temperature, such as 80-100C, is often optimal for achieving a balance between reaction rate and molecular weight.2. Initiator: A suitable initiator, such as benzoyl peroxide BPO or azobisisobutyronitrile AIBN , should be used to generate free radicals for initiating the polymerization. The initiator concentration should be optimized to achieve a high yield and molecular weight. Typically, a concentration of 0.1-1 wt% relative to the styrene monomer is used.3. Solvent: Although bulk polymerization without solvent can be performed, using a solvent can help control the reaction rate and molecular weight. Common solvents for styrene polymerization include toluene, xylene, and ethylbenzene. The solvent should be used in a sufficient amount to dissolve the styrene monomer and maintain a homogeneous reaction mixture.4. Inert atmosphere: The reaction should be carried out under an inert atmosphere, such as nitrogen or argon, to prevent oxygen from inhibiting the polymerization and to minimize side reactions.5. Chain transfer agent: To control the molecular weight and polydispersity of the resulting polystyrene, a chain transfer agent CTA can be added to the reaction mixture. Common CTAs include thiols, such as dodecyl mercaptan, and can be used at concentrations of 0.1-1 wt% relative to the styrene monomer.By optimizing these reaction conditions, it is possible to synthesize polystyrene from styrene monomer with a high yield and molecular weight using free radical polymerization.