Hi Everyone,
I am performing free radical polymerization of MMA using AIBN as an initiator and DMF as a solvent (I NEED TO USE A SOLVENT AS IT IS REQUIRED OF THE PROJECT NEXT STEP).
I varied AIBN ,REACTION TIME AND TEMPERATURE FOR THE OPTIMIZATION OF PMMA Molecular weight. Does the amount of DMF as a solvent has any effect on the Molecualr weight of the PMMA? I am using 20ml dmf, 10ml of MMA and 60 mg of AIBN AND REACTION TIME IS 24 HOURS. WHAT IF I CHANGE DMF FROM 20ML TO 40 ML WILL THIS EFFECT MY POLYMER MW WHILE HAVING THE SAME CONDITION?
Hello. Actually, the Mw is proportionate to M/I0.5 for free radical polymerization in theory, while the M and I are concentration of monomer and initiator. So when you add more solvent to the reaction system, the Mw is likely to decrease.
Hi. The explanation of Zhen is correct. However, if you want to have the same MW, polymerize MMA with 20 ML solvent and dilute the resulting polymer solution after polymerization.
Dear all, DMF belongs to the family of reactive solvents, generally it has a high transfer constant to the solvent. If this occurs, than it is expected to have reduction in both MW and conversion. Check literature for the case of MMA. The following example is for the case of N-isopropylacrylamide. My Regards
https://doi.org/10.1002/pola.24612
Dear Ismail Khan, I just come to check your polymerization recipe. You are close to bulk polymerization, you are using high amount of MMA and low solvent one, it is not a true solution polymerization. These conditions favor the occurrence of both gel and cage effects. I think they are the reasons behind any anomaly in the final results. My Regards
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