Controlled/'living' radical polymerization of methyl methacrylate with p-TsCl/CuBr/BPY initiating system under microwave irradiation

摘要

Atom-transfer radical polymerization of methyl methacrylate under microwave irradiation (MI) using p-TsCl/CuBr/BPY as the initiating system was successfully carried out. The polymerization of methyl methacrylate under MI shows linear first-order rate plots, a linear increase in the number-average molecular weight with conversion and low polydispersities, 1.1 < M_w/M_n < 1.3. The influence of polymerization time, temperature and monomer/initiator ratio on the conversion, molecular weight and polymer distribution were studied using the MI process, and compared with that obtained by the corresponding conventional heating (CH) process. The MI process not only increases the rate of polymerization, but also narrows the polydispersity index of polymers. The apparent rate constant, k_p~(app), under MI is 6-8 times higher than that under CH with an identical initiating system and polymerization temperature. The effect of MI on the stereoregularity and T_g of PMMA were investigated by ~(13)C NMR spectroscopy and DSC, respectively.