Controlled Radical Photopolymerization Of N-Butyl Methacrylate Mediated By Nitroxide

In this paper, Controlled radical polymerization of n-butyl methacrylate(n-BMA) was carried out using photo-induced polymerization method, and the composition and the microstructure of n-BMA/MPMP copolymers were measured with ¹H-NMR method. The complex kinetic performance of n-BMA in the photopolymerization was opened out by further studying on the mechanism and kinetic rule of controlled free radical photopolymerization of n-BMA. Obtained conclusions were of high academic and reference value to how to come true controlled/"living" radical polymerization of (meth) acrylate monomers. The following are main conclusions of our work:1. After selecting experiment conditions, the kinetic influence of the bulk photopolymerization of n-BMA of three systems, included HTEMPO,PMP and PMP/HTEMPO controlled systems, was studied using Irgacure651 as an initiator at ambient temperature. And controlled operation of these systems was discussed respectively. The results were shown that obtained the n-BMA homopolymers exhibited narrow polydispersities (PDI = 1.20～1.35), which was characterized by GPC, even until the conversion up to 85%. Plots of number-average molecular weight vs. conversion and Ln([M₀]/[M]) vs. time were liner respectively, indicating that was a controlled photopolymerization. This showed that HTEMPO combined with PMP used as mediators was evidently available. When the molar ratio of PMP/HTEMPO was 2.0, the photopolymerization of n-BMA was controlled, and the smallest value of polydispersity index (PDI) was 1.23. It was found that when HTEMPO was only used as mediator, the same results with the PMP/HTEMPO system were obtained. The number average molecular weight (M|-_n) of the n-BMA homopolymers increased linearly with conversion , however, PDI was higher over 1.4, indicating that PMP/HTEMPO system was superior with HTEMPO system. But the system with PMP used as a mediator was not controlled, in which the number average molecular weight without disciplinarian and the polydispersity were higher.2. The photopolymerization of n-BMA in benzene solution was performed at ambient temperature. It was found that obtained plots of conversion vs. time and ln([M ]₀/[M ]) vs. time were liner respectively in the photo-induced solution polymerization of n-BMA with HTEMPO or PMP used as a mediator. However, the number average molecular weight did...