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Copolymer Structure (copolymer + structure)
Selected AbstractsSynthesis of poly(N, N -dimethylacrylamide)- block -poly(ethylene oxide)- block -poly(N, N -dimethylacrylamide) and its application for separation of proteins by capillary zone electrophoresisELECTROPHORESIS, Issue 10 2010Jing Xu Abstract A series of well-defined triblock copolymers, poly(N, N -dimethylacrylamide)- block -poly(ethylene oxide)- block -poly(N, N -dimethylacrylamide) (PDMA- b -PEO- b -PDMA) synthesized by atom transfer radical polymerization, were used as physical coatings for protein separation. A comparative study of EOF showed that the triblock copolymer presented good capillary coating ability and EOF efficient suppression. The effects of the Mr of PDMA block in PDMA- b -PEO- b -PDMA triblock copolymer and buffer pH on the separation of basic protein for CE were investigated. Moreover, the influence of the copolymer structure on separation of basic protein was studied by comparing the performance of PDMA- b -PEO- b -PDMA triblock copolymer with PEO- b -PDMA diblock copolymer. Furthermore, the triblock copolymer coating showed higher separation efficiency and better migration time repeatability than fused-silica capillary when used in protein mixture separation and milk powder samples separation, respectively. The results demonstrated that the triblock copolymer coatings would have a wide application in the field of protein separation. [source] Copolymerization of carbon dioxide and propylene oxide with zinc glutarate as catalyst in the presence of compounds containing active hydrogenJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007L. J. Gao Abstract To enhance the catalytic copolymerization of CO2 and propylene oxide catalyzed by zinc glutarate, the influence of trace of water, ethanol, and propanal on the catalytic activity, the resulted copolymer structure, and the molecular weight and molecular weight distribution of the copolymer were investigated extensively. The experimental results showed that the catalytic activity decreased remarkably in the presence of either trace of ethanol or water, but increased in the presence of trace of propanal. Both 1H-NMR and 13C-NMR spectra suggested that the content of carbonate linkages of resulted copolymer was not effected obviously in the presence of above-mentioned impurities, giving completely alternating poly(propylene carbonate) (PPC). GPC results indicated that these impurities reduced the molecular weights but broadened the molecular weight distributions of resulted copolymers. Finally, the byproduct contents including both propylene carbonate determined by GC and polyether increased with the increase of three impurity concentrations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Zirconocene-catalyzed copolymerization of methyl methacrylate with other methacrylate monomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2004Giorgos Karanikolopoulos Abstract Statistical copolymers of methyl methacrylate (MMA) with n -butyl-, s -butyl, t -butyl-, n -hexyl-, decyl-, stearyl-, allyl-, trimethylsilyl- and trimethylsilyloxyethyl methacrylate were prepared by zirconocene-catalyzed copolymerization. The reactivity ratios of MMA copolymers with butyl-, hexyl-, and stearyl methacrylate were estimated using the Finemann,Ross, the inverted Finemann,Ross, and the Kelen,Tüdos graphical methods. Structural parameters of the copolymers were obtained from the calculated dyad sequences, derived by using the reactivity ratios. The effect of the nature of the methacrylate ester group and the catalytic system used on the copolymer structure is discussed. The glass-transition temperature (Tg) values of MMA copolymers with butyl- and hexyl methacrylate were measured and examined in the frame of several theoretical equations, allowing the prediction of these Tg values. The best fit was obtained using Barton and Johnston equations, taking the monomer sequence distribution of the copolymers into account. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3761,3774, 2004 [source] Novel pH- and Temperature-Responsive Methacrylamide Microgels,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13-14 2009Leyre Pérez-Álvarez Abstract A novel transition temperature in MeAM copolymer microgels is reported. Despite the fact that MeAM homopolymers do not show thermosensitive properties, a specific synthetic strategy leads to a thermo-responsive swelling behavior that could be potentially useful in medical and/or industrial applications. The pH and temperature-dependent swelling response of microgels of MeAM copolymerized with 2-aminomethylpyridine and ethylenediamine is reported. The changes in particle sizes, which depend on the nature of the surrounding environment, are recorded by QELS. The relation between copolymer structure and its novel behavior is analyzed by several techniques (1H NMR, TGA). [source] Copolymerization of cyclopentadiene with styrene by methylaluminoxane catalyst,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7-8 2006Junxian Hou Abstract Random copolymerization of cyclopentadiene (CPD) and styrene initiated by methylaluminoxane was investigated. The copolymer was analyzed using FT-IR, 1H-NMR and differential scanning calorimetry (DSC). The reactivity ratios of the monomers were rCPD,=,19.53, rstyrene,=,0.60. A single glass transition temperature is observed for each copolymer, which is in agreement with a random type copolymer structure. And a cationic initiation mechanism was speculated based on the polymerization results. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||