Home About us Contact
|
Home About us Contact | ||
|
|
||
Polymer Consisting (polymer + consisting)
Selected AbstractsA Study of the Determination of Cu(II) by Anodic Stripping Voltammetry on a Novel Nylon/Carbon Fiber ElectrodeELECTROANALYSIS, Issue 7 2004A. Mylonakis Abstract In this work we report a new electrode material formed by injection-moulding of a conducting polymer consisting of carbon fibers in a Nylon matrix. This material is highly conductive, inexpensive, easy to mould in different shapes and requires minimal pretreatment. The electrode was tested as a mercury-free sensor for the trace determination of Cu(II) by anodic stripping voltammetry (ASV). The deposition and stripping behavior of copper on the conducting material was initially studied by cyclic voltammetry and the chemical and instrumental parameters of the determination were investigated. The electrode has been shown to be suitable for the determination of Cu(II) in the range 8,,g L,1 to 30,mg,L,1 (with deposition times ranging from 30,s to 10,min) with a relative standard deviation of 2.2% (at the 0.5,mg,L,1 level) and a limit of detection of 8,,g L,1 Cu(II) for 10,min of accumulation (at a S/N ratio of 5). The electrode was, finally, applied to the determination of copper in tap-water, pharmaceutical tablets and bovine serum with recoveries of 97.4, 94.9 and 93.4%, respectively [source] NMR Studies of Proton Transport in Anhydrous Polymer Electrolytes for High Temperature Fuel Cells,FUEL CELLS, Issue 3-4 2008H. A. Every Abstract This paper presents an NMR study of the dynamic processes related to proton transport in a new polymer consisting of two blocks , poly(2,6-diphenylphenol) (P3O) and an imidazole functionalised poly(2,6-dimethylphenol) (imi-PPE) , and subsequently doped with polyphosphoric acid (PPA). From 1H and 31P NMR relaxation and diffusion measurements of the individual homopolymers and block copolymer, it was observed that addition of PPA significantly enhanced the mobility of imi-PPE and the imi-block copolymer, but not of P3O. The similarity in 1H T2 values between imi-PPE and the imi-block copolymer suggests that the relaxation behaviour in the block copolymer is dominated by the imi-PPE phase. 1H diffusion in P3O and the imi-block copolymer were comparable to pure PPA, suggesting that the proton diffusion is similar in each case. For imi-PPE, the diffusion coefficients were several orders of magnitude lower, reflecting a restricted diffusion process that is not indicative of the proton mobility. For all three polymers, the 31P T2 relaxation behaviour and inability to measure 31P diffusion coefficients imply hindered translational motion of the phosphonate groups. From these results, it can be concluded that hydrogen bonds between the phosphoric acid and the polymer form a network that facilitates proton transport via a hopping mechanism. [source] Compounds from rose (Rosa rugosa) flowers with human immunodeficiency virus type 1 reverse transcriptase inhibitory activityJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2006M. Fu The aqueous extracts and ethanol precipitates of aqueous extracts of 18 medicinal herbs traditionally used in China were screened for their ability to inhibit human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) in-vitro. Among the samples screened at a concentration of 500 ,g mL,1, dried rose (Rosa rugosa) flowers showed the strongest inhibition. The ethanol precipitate of the aqueous extract of R. rugosa was processed and two components (P1 and P2) were obtained after ion exchange chromatography on DEAE-cellulose. Then, P1-a (Mr 150 kDa) and P1-b (Mr 8 kDa) were isolated from P1 by gel filtration on Sephadex G-200. They inhibited the activity of HIV-1 RT with an IC50 of 158 nm and 148.16 ,g mL,1 (18.5 ,m), respectively. Further structural analyses revealed that P1-a was a polysaccharide-peptide complex, and P1-b was a polymer consisting of acteoside and acteoside derivatives identified by Fourier transform infrared spectroscopy, nuclear magnetic resonance, assays of carbohydrate and protein contents and high-performance liquid chromatography electrospray ionization mass spectrometry. [source] Synthesis and chiroptical properties of ,-conjugated polymer consisting of dihydropentahelicene units with axial chiralityJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2010Masahiro Abe Poly(dihydropentahelicene) or poly(1,1,-naphthalene- 4,4,-diyl) with axial chirality was prepared. The polymer showed a large circular dichroism of 1.8 degrees/,m in a cast film. [source] Synthesis of well-defined AB20 -type star polymers with cyclodextrin-core by combination of NMP and ATRPJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2005Yutaka Miura Abstract The synthesis of an AB20 -type heteroarm star polymer consisting of a polystyrene arm and 20-arms of poly(methyl methacrylate) or poly(tert -butyl acrylate) was carried out using the combination of nitroxide-mediated polymerization (NMP) and atom transfer radical polymerization (ATRP). The NMP of styrene was carried out using mono-6-[4-(1,-(2,,2,,6,,6,-tetramethyl-1,-piperidinyloxy)-ethyl)benzamido]-,-cyclodextrin peracetate (1) to afford end-functionalized polystyrene with an acetylated ,-cyclodextrin (,-CyD) unit (prepolymer 2) with a number-average molecular weight (Mn) of 11700 and a polydispersity (Mw/Mn) of 1.17. After deacetylation of prepolymer 2, the resulting polymer was reacted with 2-bromoisobutyric anhydride to give end-functionalized polystyrene with 20(2-bromoisobutyrol)s ,-CyD, macroinitiator 4. The copper (I)-mediated ATRP of methyl methacrylate (MMA) and tert -butyl acrylate (tBA) was carried out using macroinitiator 4. The resulting polymers were isolated by SEC fractionation to produce AB20 -type star polymers with a ,-CyD-core, 5. The well-defined structure of 5 with weight-average molecular weight (Mw)s of 13,500,65,300 and Mw/Mn's of 1.26,1.28 was demonstrated by SEC and light scattering measurements. The arm polymers were separated from 5 by destruction with 28 wt % sodium methoxide in order to analyze the details of their characteristic structure. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4271,4279, 2005 [source] Synthesis of ,-conjugated polymers via regioregular organometallic polymers 2.APPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2010Transformation of titanacyclopentadiene- containing polymer into poly(p -phenylene) derivative Abstract The transformation of a regioregular organometallic polymer possessing titanacyclopentadiene-2,5-diyl units into a poly(p -phenylene) derivative by means of a novel polymer reaction method is described. The organotitianium polymer was prepared by the polymerization of 1,4-diethynyl-2,5-dioctyloxybenzene and a low-valent titanium complex, generated in situ from titanium(IV) isopropoxide and isopropylmagnesium chloride, and was subjected to the reaction with 3-bromo-1-propyne followed by the protonation. Consequently, a polymer consisting of the substituted phenylene-1,4-diyl units could be produced in a high yield, which is soluble in organic solvents such as chloroform. The number-average molecular weight and the molecular weight distribution of the polymer were estimated as 4800 and 1.8, respectively (GPC, polystyrene). The UV,vis absorption spectrum of the polymer exhibited the absorption maximum (,max) at 329 nm, which was bathochromically shifted by 53 nm compared with that of a model compound, 1,4-bis(2-methoxyphenyl)-2-methylbenzene (,max = 276 nm). Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||