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Benoit Lessard Edwin Jee Yang Ling Marie Sylvianne Thérèse Morin Milan Marić 《Journal of polymer science. Part A, Polymer chemistry》2011,49(4):1033-1045
The controlled nitroxide‐mediated homopolymerization of 9‐(4‐vinylbenzyl)‐9H‐carbazole (VBK) and the copolymerization of methyl methacrylate (MMA) with varying amounts of VBK were accomplished by using 10 mol % {tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino} nitroxide relative to 2‐({tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino}oxy)‐2‐methylpropionic acid (BlocBuilder?) in dimethylformamide at temperatures from 80 to 125 °C. As little as 1 mol % of VBK in the feed was required to obtain a controlled copolymerization of an MMA/VBK mixture, resulting in a linear increase in molecular weight versus conversion with a narrow molecular weight distribution (Mw /Mn ≈ 1.3). Preferential incorporation of VBK into the copolymer was indicated by the MMA/VBK reactivity ratios determined: rVBK = 2.7 ± 1.5 and rMMA = 0.24 ± 0.14. The copolymers were found significantly “living” by performing subsequent chain extensions with a fresh batch of VBK and by 31P NMR spectroscopy analysis. VBK was found to be an effective controlling comonomer for NMP of MMA, and such low levels of VBK comonomer ensured transparency in the final copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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A series of linear tetrapeptides containing two histidyl residues in positions 2 and 4 with different chirality: DHGH, DHG(d-His), KHGH, KHG(d-His), Ac-DHGH-NH2, Ac-DHG(d-His)-NH2, Ac-KHGH-NH2, and Ac-KHG(d-His)-NH2 were synthesized, characterized and their binding properties towards Ni2+ were investigated. To establish the stoichiometry and the stability of the resulting Ni2+ complexes, potentiometric titrations were carried out. The coordination mode of the complexes formed was investigated by performing extensive spectroscopic analyses (UV–Vis, CD) in strict correlation with the potentiometric results. The effects of the nature of the first amino acid (Lys versus Asp) and of the N-terminal amino group acetylation were determined. A careful comparison of the Ni2+ coordination abilities of the linear peptides provides a specific insight into the impact of the chirality of the C-terminal histidine residue (His4) on the metal binding properties. 相似文献
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As Editors of Reviews in Macromolecular Chemistry, we often wonder how useful our journal is to the polymer community. Apparently other people have the same sort of thoughts. 相似文献
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Xiaoshan Fan Guowei Wang Zhen Zhang Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2011,49(19):4146-4153
The amphiphilic heterograft copolymers poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate)‐graft‐(poly(acrylic acid)/polystyrene) (P(MMA‐co‐BIEM)‐g‐(PAA/PS)) were synthesized successfully by the combination of single electron transfer‐living radical polymerization (SET‐LRP), single electron transfer‐nitroxide radical coupling (SET‐NRC), atom transfer radical polymerization (ATRP), and nitroxide‐mediated polymerization (NMP) via the “grafting from” approach. First, the linear polymer backbones poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate) (P(MMA‐co‐BIEM)) were prepared by ATRP of methyl methacrylate (MMA) and 2‐hydroxyethyl methacrylate (HEMA) and subsequent esterification of the hydroxyl groups of the HEMA units with 2‐bromoisobutyryl bromide. Then the graft copolymers poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate)‐graft‐poly(t‐butyl acrylate) (P(MMA‐co‐BIEM)‐g‐PtBA) were prepared by SET‐LRP of t‐butyl acrylate (tBA) at room temperature in the presence of 2,2,6,6‐tetramethylpiperidin‐1‐yloxyl (TEMPO), where the capping efficiency of TEMPO was so high that nearly every TEMPO trapped one polymer radicals formed by SET. Finally, the formed alkoxyamines via SET‐NRC in the main chain were used to initiate NMP of styrene and following selectively cleavage of t‐butyl esters of the PtBA side chains afforded the amphiphilic heterograft copolymers poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate)‐graft‐(poly(t‐butyl acrylate)/polystyrene) (P(MMA‐co–BIEM)‐g‐(PtBA/PS)). The self‐assembly behaviors of the amphiphilic heterograft copolymers P(MMA‐co–BIEM)‐g‐(PAA/PS) in aqueous solution were investigated by AFM and DLS, and the results demonstrated that the morphologies of the formed micelles were dependent on the grafting density. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Xeniya Savelyeva Milan Marić 《Journal of polymer science. Part A, Polymer chemistry》2014,52(14):2011-2024
Nitroxide‐mediated polymerization (NMP) of N‐(2‐methacryloyloxyethyl) pyrrolidone (MAEPYR) with 2‐([tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino]oxy)‐2‐methylpropanoic acid (BlocBuilder) initiator and N‐tert‐butyl‐N‐[1‐diethylphosphono‐(2,2‐dimethylpropyl)] (SG1) nitroxide permitted controlled synthesis of poly(N‐(2‐methacryloyloxyethyl)‐pyrrolidone‐stat‐9‐(4‐vinylbenzyl)‐9H‐carbazole) (poly(MAEPYR‐stat‐VBK)) statistical copolymers. With at least 5 mol % VBK, the dispersity ? of the copolymers was below 1.4 at conversions less than 50%. At conversions higher than 50%, and at lower VBK feed content, there was a significant amount of termination reactions, which broadened the molecular weight distribution of the final polymers (? = 1.4–2.3). The MAEPYR‐rich statistical copolymers were subsequently tested for thermoresponsive behavior in aqueous media. The cloud point temperatures (CPTs) in aqueous solution were tuned by changing the VBK composition, solution concentration, and heating rate, and the transitions were thermally reversible with partial loss of reversibility at higher heating rates. The CPT decreased from 59.0 to 49.7 °C with addition of only 1 mol % of VBK in the copolymer, and at more than 6 mol % VBK, the copolymer was water insoluble. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2011–2024 相似文献
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Surface‐initiated nitroxide‐mediated polymerization of sodium 4‐styrene sulfonate from latex particles
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Claude St Thomas Judith Nazareth Cabello‐Romero Omar Garcia‐Valdez Enrique Javier Jiménez‐Regalado Hortensia Maldonado‐Textle Ramiro Guerrero‐Santos 《Journal of polymer science. Part A, Polymer chemistry》2017,55(3):437-444
In this study, we report the use of a double‐headed dialkoxyamine trithiocarbonate ( I ) capable of acting as chain transfer agent via reversible addition‐fragmentation chain transfer polymerization or as initiator via nitroxide‐mediated polymerization. It is worth mentioning that I was revealed as an effective dual chain transfer agent in the synthesis of multiblock copolymers via bulk and emulsion processes. In this article, we report the employing of I in dispersed systems to obtain amphiphilic multiblock copolymers and latexes. In this case, a water soluble macroagent of PAA previously synthetized was used in disperse media using a mixture of methanol/water (70:30, w/w). Stable latexes were obtained via polymerization‐induced self‐assembly and surface‐initiated polymerization of SSNa from alkoxyamine‐functionalized latex PAA‐b‐PS‐b‐PAA was also obtained © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 437–444 相似文献