| Nitroxide mediated photo-polymerization (NMPP) has attracted considerable interest because of its reaction conditions are mild and as a living procedure in which control over molecular weight and macromolecular architecture can be achieved. In the paper, controlled/living photopolymerization of methyl methacrylate (MMA) in anionic reverse microemulsions, n-butyl methacrylate (n-BMA) and i-butyl methacrylate (i-BMA) in anionic normal microemulsions mediated by2,2,6,6-tetramethyl-l-piperidine-l-oxyl (TEMPO)/2,2,6,6-tetramethyl-4-piperidinol (TMP) have been performed. In the end, preparing PMMA-b-PS, Poly(n-BMA)-b-PS and Poly(i-BMA)-b-PS via ATRP technique which use the macroinitiator such as PMMA-Br, Poly(n-BMA)-Br and Poly(i-BMA)-Br.The main work and conclusions as following:1. A noval bifunctional initiator (HMPP-Br) was synthesized by the condensation of2-bromoisbutyryl bromide (BSB) with Darocur1173(2-hydroxy-2-methyl-propiophenone, HMPP) in methylene dichloride (CH2Cl2), with pyridine as a catalyst. The structure and reactivity of the product has been characterized by FTIR,1H NMR and UV-Vis spectroscopy. Especially, the results show that the wavelength of the absorption peak of HMPP-Br is almost as same as Darocur1173, which was important to the photopolymerization in the next step.2. After selecting excellent experimental conditions, NMPP of MMA, n-BMA and i-BMA mediated by TEMPO/TMP have been carried out in anionic microemulsion, using HMPP-Br as an initiator. The results show that polymers exhibited narrow molecular weight distribution. The polymers were characterized by GPC, DSC, TGA, FTIR and1H NMR.3. PMMA-b-PS, Poly(n-BMA)-b-PS and Poly(i-BMA)-b-PS diblock copolymers was prepared by atom-transfer radical polymerization (ATRP) technique, with the macroinitiator PMMA-Br, Poly(n-BMA)-Br and Poly(i-BMA)-Br as initiator, CuBr/2,2’-bipyridine as a catalyst. The symmetric unimodal elution peak was found from the GPC trace, which was a powerful evidence for the homogeneous products. The absorption peak or signal ascribed to the homopolymer segment and PS segment could be seen in the1H NMR,13C NMR and FTIR spectra respectively. There were two decomposition peaks in the TGA and DSC curve of the polymers, thus supporting the polymer (PMMA-b-PS, Poly(n-BMA)-b-PS and Poly(i-BMA)-b-PS) was indeed a single two-block copolymer structure. |
