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NMP
Selected AbstractsAgglomeration of NTO on the surface of HMX particles in water-NMP solventCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2008Kwang-Joo Kim Abstract A sensitive explosive was coated with a less sensitive explosive in order to improve stability while maintaining explosion performance. Agglomeration of 3-nitro-1,2,4-triazole-5-one (NTO) on the surface of cyclotetramethylene tetranitramine (HMX) crystals in water- N -methyl-2-pyrrolidone (NMP) solvent was performed by cooling crystallization. Phenomena for coating by crystallization and agglomeration were studied by in-situ measurement. The agglomeration kinetic for the coating of NTO on HMX crystals was correlated with the 3rd power of the solution supersaturation and the 2nd power of the number of the suspended particles. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Palladium(II) Chloride and a (Dipyridin-2-ylmethyl)amine-Derived Palladium(II) Chloride Complex as Highly Efficient Catalysts for the Synthesis of Alkynes in Water or in NMP and of Diynes in the Absence of ReoxidantEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2005Juan Gil-Moltó Abstract The (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 and PdCl2 are efficient catalysts for cross-coupling reactions between terminal alkynes and aryl iodides or bromides under modified Sonogashira,Cassar,Heck conditions. The alkynylation can be performed under copper-free conditions in water at reflux or at room temperature under air with pyrrolidine as base and tetra- n -butylammonium bromide (TBAB) as additive, with TONs of up to 7,×,104 and TOFs(h,1) of up to 6666. Terminal alkynes can be arylated in NMP as well under copper- and amine-free conditions at 110 °C or room temperature, with tetra- n -butylammonium acetate (TBAA) acting as base with TONs up to 2,×,105 and TOFs (h,1) up to 66,666. In general, complex 1 displays a slightly higher efficiency than PdCl2 as catalyst and maintains the same activity after five consecutive runs. Alternatively, these alkynylation processes can be carried out under microwave heating conditions. The homocoupling of terminal alkynes to the corresponding 1,3-diynes proceeds under phosphane-free conditions with the (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 or with PdCl2 as catalysts and with CuI as cocatalyst in NMP with use of either TBAA or pyrrolidine as bases. This Glaser-type reaction can be performed at 110 °C or at room temp. in the presence of air without the use of a reoxidant. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Towards Efficient Dispersion of Carbon Nanotubes in Thermotropic Liquid CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Stefan Schymura Abstract Motivated by numerous recent reports indicating attractive properties of composite materials of carbon nanotubes (CNTs) and liquid crystals (LCs) and a lack of research aimed at optimizing such composites, the process of dispersing CNTs in thermotropic LCs is systematically studied. LC hosts can perform comparably or even better than the best known organic solvents for CNTs such as N -methyl pyrrolidone (NMP), provided that the dispersion process and choice of LC material are optimized. The chemical structure of the molecules in the LC is very important; variations in core as well as in terminal alkyl chain influence the result. Several observations moreover indicate that the anisotropic nematic phase, aligning the nanotubes in the matrix, per se stabilizes the dispersion compared to a host that is isotropic and thus yields random tube orientation. The chemical and physical phenomena governing the preparation of the dispersion and its stability are identified, taking into account enthalpic, entropic, as well as kinetic factors. This allows a guideline on how to best design and prepare CNT,LC composites to be sketched, following which tailored development of new LCs may take the advanced functional material that CNT,LC composites comprise to the stage of commercial application. [source] One-Pot Suzuki/Heck Sequence for the Synthesis of (E)-Stilbenes Featuring a Recyclable Silica-Supported Palladium Catalyst via a Multi-Component Reaction in 1,3-PropanediolADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Lionel Joucla Abstract The synthesis of (E)-stilbenes was performed following a one-pot Suzuki/Heck sequence through the use of potassium vinyltrifluoroborate. The combination of heterogeneous palladium/silica (Pd/SiO2) catalyst with potassium phosphate monohydrate (K3PO4,H2O) as base resulted in useful to good isolated yields regardless of the ortho- , meta- or para- substitution of the aryl halides employed. In a sustainable approach, we found that bio-sourced 1,3-propanediol could advantageously replace N -methylpyrrolidone (NMP) as similar yields were obtained. Moreover, the reactivity gap between aryl iodides and bromides resulting from the use of 1,3-propanediol allowed an efficient multi-component approach toward the synthesis of (E)-stilbenes. Furthermore, this heterogeneous catalyst was found to be extremely robust despite the use of aerobic conditions and was successfully re-used over several cycles. [source] Survey of quantitative feedback theory (QFT),INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 10 2001Isaac Horowitz QFT is an engineering design theory devoted to the practical design of feedback control systems. The foundation of QFT is that feedback is needed in control only when plant (P), parameter and/or disturbance (D) uncertainties (sets ,,={P}, ,,={D}) exceed the acceptable (A) system performance uncertainty (set ,,={A}). The principal properties of QFT are as follows. (1) The amount of feedback needed is tuned to the (,,, ,,, ,,) sets. If ,, ,exceeds' (,,, ,,), feedback is not needed at all. (2) The simplest modelling is used: (a) command, disturbance and sensor noise inputs, and (b) the available sensing points and the defined outputs. No special controllability test is needed in either linear or non-linear plants. It is inherent in the design procedure. There is no observability problem because uncertainty is included. The number of independent sensors determines the number of independent loop transmissions (Li), the functions which provide the benefits of feedback. (3) The simplest mathematical tools have been found most use ful,primarily frequency response. The uncertainties are expressed as sets in the complex plane. The need for the larger ,,, ,, sets to be squeezed into the smaller ,, set results in bounds on the Li(j,) in the complex plane. In the more complex systems a key problem is the division of the ,feedback burden' among the available Li(j,). Point-by-point frequency synthesis tremendously simplifies this problem. This is also true for highly uncertain non-linear and time-varying plants which are converted into rigorously equivalent linear time invariant plant sets and/or disturbance sets with respect to the acceptable output set ,,. Fixed point theory justifies the equivalence. (4) Design trade-offs are highly transparent in the frequency domain: between design complexity and cost of feedback (primarily bandwidth), sensor noise levels, plant saturation levels, number of sensors needed, relative sizes of ,,, ,, and cost of feedback. The designer sees the trade-offs between these factors as he proceeds and can decide according to their relative importance in his particular situation. QFT design techniques with these properties have been developed step by step for: (i) highly uncertain linear time invariant (LTI) SISO single- and multiple-loop systems, MIMO single-loop matrix and multiple-loop matrix systems; and (ii) non-linear and time-varying SISO and MIMO plants, and to a more limited extent for plants with distributed control inputs and sensors. QFT has also been developed for single- and multiple-loop dithered non-linear (adaptive) systems with LTI plants, and for a special class (FORE) of non-linear compensation. New techniques have been found for handling non-minimum-phase (NMP) MIMO plants, plants with both zeros and poles in the right half-plane and LTI plants with incidental hard non-linearities such as saturation. [source] Effects of ethyl benzoate on performance, morphology, and erosion of PLGA implants formed in situADVANCES IN POLYMER TECHNOLOGY, Issue 1 2008R. Astaneh Abstract An in situ forming implant (ISFI) is a novel drug delivery system used for protein and peptide delivery, especially for cancer treatment. An ISFI based on 33% (w/w) poly(D,L -lactide- co -glycolide)(PLGA; 50:50)/3% (w/w) leuprolide acetate (LA)/64% (w/w) N -methyl-2-pyrrolidone (NMP) was prepared for this study. After injection of the final formulation, which is a viscous liquid to an aqueous medium, it deforms to become a semisolid or solid matrix. The performance of this matrix was investigated on the basis of peptide release from it. Erosion and morphology of ISFI were also studied. The effects of adding 12.8% (w/w) ethyl benzoate (EB) as a rate-modifying agent on performance, erosion, and morphology of ISFI were assessed. The implant containing EB showed very low burst release (5.53% ± 0.82%) and the morphology turns to closed pore-like structures. After adding EB, the morphology turns to closed pore-like structures. This type of morphology has very close relation to the performance of the implant as well. Finally, the effect of EB on performance, erosion, and morphology is explained by means of solvent,nonsolvent affinity, water permeation, and the rate of phase inversion. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 27:17,26, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20114 [source] Comparison of poly(o -anisidine) and poly(o -anisidine- co -aniline) copolymer synthesized by chemical oxidative methodJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010J. Longun Abstract In this study, poly(o -anisidine) [POA], poly(o -anisidine- co -aniline) [POA- co -A], and polyaniline [PANi] were chemically synthesized using a single polymerization process with aniline and o -anisidine as the respective monomers. During the polymerization process, p -toluene sulfonic acid monohydrate was used as a dopant while ammonium persulfate was used as an oxidant. N -methyl-pyrolidone (NMP) was used as a solvent. We observed that the ATR spectra of POA- co -A showed features similar to those of PANi and POA as well as additional ones. POA- co -A also achieved broader and more extended UV,vis absorption than POA but less than PANi. The chemical and electronic structure of the product of polymerization was studied using Attenuated Total Reflectance spectroscopy (ATR) and UV,visible spectroscopy (UV,vis). The transition temperature of the homopolymers and copolymers was studied using differential scanning calorimetry and the viscosity average molecular weight was studied by using dilute solution viscometry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of new soluble polyamides from an unsymmetrical diamine bearing a bulky triaryl pyridine pendent groupJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Mousa Ghaemy Abstract New unsymmetrical diamine monomer containing triaryl pyridine pendent group, 2,4-diaminophenyl [4-(2, 6-diphenyl-4-pyridyl) phenyl]ether, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-(2,6-diphenyl-4-pyridyl) phenol, followed by Pd/C-catalyzed hydrazine reduction. Five Polyamides (PA) were prepared by the phosphorylation polycondensation of different dicarboxylic diacids with the diamine. Inherent viscosities of PAs were in the range 0.51,0.59 g/dL indicating formation of medium molecular weight polymers. The weight and number average molecular weights of a PA, (PA-d), determined by GPC were 6944 g/mol and 17,369 g/mol, respectively. PAs exhibited glass-transition temperatures (Tg) in the range 140,235°C. These polymers, essentially amorphous, were soluble in polar aprotic solvents such as DMF, NMP, DMAc, DMSO, pyridine, m -cresol, and THF. The initial decomposition temperatures (Ti) of PAs, determined by TGA in air, were in the range 300,380°C indicating their good thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of novel polyimide/SiO2 nanocomposite materials containing phenylphosphine oxide via sol-gel techniqueJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Canan Kizilkaya Abstract In this article, a series of novel polyimide/silica (PI/SiO2) nanocomposite coating materials were prepared from tetraethoxysilane (TEOS), ,-glycidyloxypropyltrimethoxysilane (GOTMS), and polyamic acid (PAA) via sol-gel technique. PAA was prepared by the reaction of 3,3,,4,4,-benzophenone tetracarboxylic dianhydride (BTDA) and bis (3-aminophenyl) phenyphosphine oxide (BAPPO) in N -methyl-2- pyrrolidone (NMP). BAPPO was synthesized hydrogenation of bis (3-nitrophenyl) phenyphosphine oxide (BNPPO) in the presence of Pd/C. The silica content in the hybrid coating materials was varied from 0 to 20 wt %. The molecular structures of the composite materials were analyzed by means of FT-IR and 29Si-NMR spectroscopy techniques. The physical and mechanical properties of the nanocomposites were evaluated by various techniques such as, hardness, contact angle, and optical transmission and tensile tests. These measurements revealed that all the properties of the nanocomposite coatings were improved noticeable, by the addition of sol-gel precursor into the coating formulation. Thermogravimetric analysis showed that the incorporation of sol-gel precursor into the polyimide matrix leads to an enhancement in the thermal stability and also flame resistance properties of the coating material. The surface morphology of the hybrid coating was characterized by scanning electron microscopy (SEM). SEM studies indicated that nanometer-scaled inorganic particles were homogenously dispersed throughout the polyimide matrix © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of novel poly(arylene ether)s based on 9,10-bis-(4-fluoro-3-trifluoromethylphenyl) anthracene and 2,7-bis-(4-fluoro-3-trifluoromethylphenyl) fluoreneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Arun K. Salunke Abstract Two new bisfluoro monomers 9,10-bis-(4-fluoro-3-trifluoromethylphenyl) anthracene and 2,7-bis-(4-fluoro-3-trifluoromethylphenyl) fluorene have been synthesized by the cross-coupling reaction of 2-fluoro-3-trifluoromethyl phenyl boronic acid with 9,10-dibromo anthracene and 2,7-dibromo fluorine, respectively. These two bisfluoro compounds were used to prepare several poly(arylene ether)s by aromatic nucleophilic displacement of fluorine with various bisphenols; such as bisphenol-A, bisphenol-6F, bishydroxy biphenyl, and 9,9-bis-(4-hydroxyphenyl)-fluorene. The products obtained by displacement of the fluorine atoms exhibits weight-average molar masses up to 1.5 ×105 g mol,1 and number average molecular weight up to 6.8 × 104 g mol,1 in GPC. These poly(arylene ether)s show very high thermal stability even up to 490°C for 5% weight loss occurring at this temperature in TGA in synthetic air and showed glass transition temperature observed up to 310°C. All the polymers are soluble in a wide range of organic solvents, e.g., CHCl3, THF, NMP, and DMF. Films cast from DMF solution are brittle in nature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] ,O -Acyl isopeptide method' for peptide synthesis: Solvent effects in the synthesis of A,1,42 isopeptide using ,O -acyl isodipeptide unit'JOURNAL OF PEPTIDE SCIENCE, Issue 12 2007Atsuhiko Taniguchi Abstract ,O -Acyl isopeptide method' is an efficient synthetic method for peptides. We designed ,O -acyl isodipeptide units', Boc-Ser/Thr(Fmoc-Xaa)-OH, as important building blocks to enable routine use of the O -acyl isopeptide method. In the synthesis of an A,1,42 isopeptide using O -acyl isodipeptide unit Boc,Ser(Fmoc,Gly),OH, a side reaction, resulting in the deletion of Ser26 in the O -acyl isopeptide structure, was noticed during coupling of the unit. We observed that the side reaction occurred during the activation step and was solvent-dependent. In DMF or NMP, an intramolecular side reaction, originating from the activated species of the unit, occurred during the activation step. In non-polar solvents such as CHCl3 or CH2Cl2, the side reaction was less likely to occur. Using CH2Cl2 as solvent in coupling the unit, the target A,1,42 isopeptide was synthesized with almost no major side reaction. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] Experimental and theoretical investigation of a new rapid switching near-infrared electrochromic conjugated polymerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2010Han-Yu Wu Abstract A new rapid switching near-IR electrochromic conjugated propeller-shape polymer (PBTPAFL) with lower oxidation potential containing a di-triarylamine group was synthesized via Suzuki coupling approach. The observed UV-vis-NIR absorption changes in the PBTPAFL film at various potentials are fully reversible and associated with strong color changes from the original light green to dark green and then to a Prussian blue. Excellent continuous cyclic stability of the electrochromic characteristics with a rapid color switching time 2.58 s and bleaching time 1.76 s was found as well. Compared with P1 and P2, the introduction of more electron-donating propyl phenyl group in the para position of PBTPAFL lowered the oxidative potential and prevented coupling reaction during the electrochromic procedure. The high molecular weight conjugated polymer having high thermal stability with Td10 more than 450 °C has excellent solubility in common organic solvents such as NMP, THF, chloroform, toluene, xylene, and benzene at room temperature (25 °C) due to the propeller-shape structure and long alkyl chain on fluorene. Herein, from the combination of the experimental and computational study, we proposed a mechanism on the basis of the molecular orbital theory to explain the electrochromic oxidation behavior. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3913,3923, 2010. [source] Cyclic alkoxyamine-initiator tethered by azide/alkyne-"click"-chemistry enabling ring-expansion vinyl polymerization providing macrocyclic polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2010Atsushi Narumi Abstract A cyclic initiator for the nitroxide-mediated controlled radical polymerization (NMP) is a powerful tool for the preparation of macrocyclic polymers via a ring-expansion vinyl polymerization mechanism. For this purpose, we prepared a Hawker-type NMP-initiator that includes an azide and a terminal alkyne as an acyclic precursor, which is subsequently tethered via an intramolecular azide/alkyne-"click"-reaction, producing the final cyclic NMP-initiator. The polymerization reactions of styrene with cyclic initiator were demonstrated and the resultant polymers were characterized by the gel permeation chromatography (GPC) and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). These results prove that the ring-expansion polymerization of styrene occurred together with the radical ring-crossover reactions originating from the exchange of the inherent nitroxides generating macrocyclic polystyrenes with higher expanded rings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3402,3416, 2010 [source] Free radical and nitroxide mediated polymerization of hydroxy,functional acrylates prepared via lipase,catalyzed transacylation reactionsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2010Dragos Popescu Abstract 3-Hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-methyl-3-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, neopentyl glycol acrylate, glyceryl acrylate, and dihydroxyhexyl acrylate were prepared via transacylation reaction of methyl acrylate with diols and triols catalyzed by Candida antarctica lipase B. After removal of the enzyme by filtration and the methyl acrylate by distillation, the monomers were polymerized via free radical polymerization (FRP) with azobisisobutyronitrile as initiator and nitroxide mediated polymerization (NMP) employing BlocbuilderÔ alkoxyamine initiator and SG-1 free nitroxide resulting in hydroxy functional poly(acrylates). The NMP kinetics are discussed in detail. In addition, the polymers obtained by FRP and NMP are compared and the results are related to the amount of bisacrylates that are present in the initial monomer mixtures resulting from the transacylation reactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2610,2621, 2010 [source] Controlled/living heterogeneous radical polymerization in supercritical carbon dioxideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2009Per B. Zetterlund Abstract Supercritical carbon dioxide (scCO2) is an inexpensive and environmentally friendly medium for radical polymerizations. ScCO2 is suited for heterogeneous controlled/living radical polymerizations (CLRPs), since the monomer, initiator, and control reagents (nitroxide, etc.) are soluble, but the polymer formed is insoluble beyond a critical degree of polymerization (Jcrit). The precipitated polymer can continue growing in (only) the particle phase giving living polymer of controlled well-defined microstructure. The addition of a colloidal stabilizer gives a dispersion polymerization with well-defined colloidal particles being formed. In recent years, nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition fragmentation chain transfer (RAFT) polymerization have all been conducted as heterogeneous polymerizations in scCO2. This Highlight reviews this recent body of work, and describes the unique characteristics of scCO2 that allows composite particle formation of unique morphology to be achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3711,3728, 2009 [source] Highly stable electrochromic polyamides based on N,N -bis(4-aminophenyl)- N,,N,-bis(4- tert -butylphenyl)-1,4-phenylenediamineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2009Sheng-Huei Hsiao Abstract A new triphenylamine-containing aromatic diamine monomer, N,N -bis(4-aminophenyl)- N,,N,-bis(4- tert -butylphenyl)-1,4-phenylenediamine, was synthesized by an established synthetic procedure from readily available reagents. A novel family of electroactive polyamides with di- tert -butyl-substituted N,N,N,,N,-tetraphenyl-1,4-phenylenediamine units were prepared via the phosphorylation polyamidation reactions of the newly synthesized diamine monomer with various aromatic or aliphatic dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, such as N -methyl-2-pyrrolidinone (NMP) and N,N -dimethylacetamide, and could be solution-cast into tough and flexible polymer films. The polyamides derived from aromatic dicarboxylic acids had useful levels of thermal stability, with glass-transition temperatures of 269,296 °C, 10% weight-loss temperatures in excess of 544 °C, and char yields at 800 °C in nitrogen higher than 62%. The dilute solutions of these polyamides in NMP exhibited strong absorption bands centered at 316,342 nm and photoluminescence maxima around 362,465 nm in the violet-blue region. The polyamides derived from aliphatic dicarboxylic acids were optically transparent in the visible region and fluoresced with a higher quantum yield compared with those derived from aromatic dicarboxylic acids. The hole-transporting and electrochromic properties were examined by electrochemical and spectro-electrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium-tin oxide-coated glass substrate exhibited two reversible oxidation redox couples at 0.57,0.60 V and 0.95,0.98 V versus Ag/AgCl in acetonitrile solution. The polyamide films revealed excellent elcterochemical and electrochromic stability, with a color change from a colorless or pale yellowish neutral form to green and blue oxidized forms at applied potentials ranging from 0.0 to 1.2 V. These anodically coloring polymeric materials showed interesting electrochromic properties, such as high coloration efficiency (CE = 216 cm2/C for the green coloring) and high contrast ratio of optical transmittance change (,T%) up to 64% at 424 nm and 59% at 983 nm for the green coloration, and 90% at 778 nm for the blue coloration. The electroactivity of the polymer remains intact even after cycling 500 times between its neutral and fully oxidized states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2330,2343, 2009 [source] Optical properties of a novel fluorene-based thermally stable conjugated polymer containing pyridine and unsymmetric carbazole groupsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2009Der-Jang Liaw Abstract A new diiodo monomer containing heterocyclic pyridine and carbazole groups was synthesized via Chichibabin reaction and used in the preparation of a conjugated polymer via Suzuki coupling approach. The conjugated polymer was highly soluble in common organic solvents such as NMP, THF, dichloromethane, chloroform, toluene, xylene, and benzene at room temperature. The polymer had high glass transition temperature at 191 °C and Td10 at 434 °C in nitrogen atmosphere. The pristine polymer exhibited the UV,vis maximum absorption at 355 nm and shifted to 420 nm after protonation. The emission of the polymer in THF solution changed from the blue region with maximum peak at 400 nm to the yellow region with maximum peak at 540 nm after protonated by HCl, and the intensity of emission depended on the concentration of acid. The polymer also showed electrochromic behavior under applied voltage. The emission color of the polymer film changed from blue (435 nm) to yellow (570 nm) when 2.5 V bias voltage was applied. The polymer also exhibited write-once and read-many-times (WORM) polymer memory effect with tristable states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 991,1002, 2009 [source] ROMP-NMP-ATRP combination for the preparation of 3-miktoarm star terpolymer via click chemistryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2009Aziz Gozgen Abstract A combination of ring opening metathesis polymerization (ROMP) and click chemistry approach is first time utilized in the preparation of 3-miktoarm star terpolymer. The bromide end-functionality of monotelechelic poly(N -butyl oxanorbornene imide) (PNBONI-Br) is first transformed to azide and then reacted with polystyrene- b -poly(methyl methacrylate) copolymer with alkyne at the junction point (PS- b -PMMA-alkyne) via click chemistry strategy, producing PS-PMMA-PNBONI 3-miktoarm star terpolymer. PNBONI-Br was prepared by ROMP of N -butyl oxanorbornene imide (NBONI) 1 in the presence of (Z)-but-2-ene-1,4-diyl bis(2-bromopropanoate) 2 as terminating agent. PS- b -PMMA-alkyne copolymer was prepared successively via nitroxide-mediated radical polymerization (NMP) of St and atom transfer radical polymerization (ATRP) of MMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 497,504, 2009 [source] Synthesis of well-defined polymeric activated estersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2008Patrick Theato Abstract Monomers bearing an activated ester group can be polymerized under various controlled polymerization techniques, such as ATRP, NMP, RAFT polymerization, or ROMP. Combining the functionalization of polymers via polymeric activated esters with these controlled polymerization techniques generate possibilities to realize highly functionalized polymer architectures. Within this highlight two different research areas of activated esters in polymer science will be discussed: (i) the preparation of defined reactive polymer architectures by controlled polymerization techniques and (ii) the preparation of defined reactive thin films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6677,6687, 2008 [source] Heterograft copolymers via double click reactions using one-pot techniqueJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2008Aydan Dag Abstract The double click reactions (Cu catalyzed Huisgen and Diels,Alder reactions) were used as a new strategy for the preparation of well-defined heterograft copolymers in one-pot technique. The synthetic strategy to the various stages of this work is outlined: (i) preparing random copolymers of styrene (St) and p -chloromethylstyrene (CMS) (which is a functionalizable monomer) via nitroxide mediated radical polymerization (NMP); (ii) attachment of anthracene functionality to the preformed copolymer by the o -etherification procedure and then conversion of the remaining CH2Cl into azide functionality; (iii) by using double click reactions in one-pot technique, maleimide end-functionalized poly(methyl methacrylate) (PMMA-MI) via atom transfer radical polymerization (ATRP) of MMA and alkyne end-functionalized poly (ethylene glycol) (PEG-alkyne) were introduced onto the copolymer bearing pendant anthryl and azide moieties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6969,6977, 2008 [source] Dendrimer-like miktoarm star terpolymers: A3 -(B-C)3 via click reaction strategyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2008Ozcan Altintas Abstract Two samples of dendrimer-like miktoarm star terpolymers: (poly(tert -butyl acrylate))3 -(polystyrene-poly(,-caprolactone))3 (PtBA)3 -(PS-PCL)3, and (PS)3 -(PtBA-poly(ethylene glycol)3 were prepared using efficient Cu catalyzed Huisgen cycloaddition (click reaction). As a first step, azido-terminated 3-arm star polymers PtBA and PS as core (A) were synthesized by atom transfer radical polymerization (ATRP) of tBA and St, respectively, followed by the conversion of bromide end group to azide. Secondly, PS-PCL and PtBA-PEG block copolymers with alkyne group at the junction as peripheral arms (B-C) were obtained via multiple living polymerization mechanisms such as nitroxide mediated radical polymerization (NMP) of St, ring opening polymerization (ROP) of ,-CL, ATRP of tBA. Thus obtained core and peripheral arms were linked via click reaction to give target (A)3 -(B-C)3 dendrimer-like miktoarm star terpolymers. (PtBA)3 -(PS-PCL)3 and (PS)3 -(PEG-PtBA)3 have been characterized by GPC, DSC, AFM, and SAXS measurements. (PtBA)3 -(PS-PCL)3 did not show any self-organization with annealing due to the miscibility of the peripheral arm segments. In contrast, the micro-phase separation of the peripheral arm segments in (PS)3 -(PtBA-PEG)3 resulted in self-organized phase-separated morphology with a long period of , 13 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5916,5928, 2008 [source] One-pot preparation of 3-miktoarm star terpolymers via click [3 + 2] reactionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2007Ozcan Altintas Abstract The preparation of 3-miktoarm star terpolymers using nitroxide mediated radical polymerization (NMP), ring opening polymerization (ROP), and click reaction [3 + 2] are carried out by applying two types of one-pot technique. In the first one-pot technique, NMP of styrene (St), ROP of ,-caprolactone (,-CL), and [3 + 2] click reaction (between azide end-functionalized poly(ethylene glycol) (PEG-N3)/or azide end-functionalized poly(methyl methacrylate) (PMMA-N3) and alkyne) are carried out in the presence of 2-(hydroxymethyl)-2-methyl-3-oxo-3-(2-phenyl-2-(2,2,6,6-tetramethylpiperidin-1-yloxy)ethoxy) propyl pent-4-ynoate, 2, as an initiator for 48 h at 125 °C (one-pot/one-step). As a second technique, NMP of St and ROP of ,-CL were conducted using 2 as an initiator for 20 h at 125 °C, and subsequently PEG-N3 or azide end-functionalized poly(tert -butyl acrylate (PtBA-N3) was added to the polymerization mixture, followed by a click reaction [3 + 2] for 24 h at room temperature (one-pot/two-step). The 3-miktoarm star terpolymers, PEG-poly(,-caprolactone)(PCL)-PS, PtBA-PCL-PS and PMMA-PCL-PS, were recovered by a simple precipitation in methanol without further purification. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3588,3598, 2007 [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] Novel thermally stable poly(amine hydrazide)s and poly(amine-1,3,4-oxadiazole)s for luminescent and electrochromic materialsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2005Guey-Sheng Liou Abstract We describe the preparation, characterization, and luminescence of four novel electrochromic aromatic poly(amine hydrazide)s containing main-chain triphenylamine units with or without a para-substituted N,N -diphenylamino group on the pendent phenyl ring. These polymers were prepared from either 4,4,-dicarboxy-4,- N,N -diphenylaminotriphenylamine or 4,4,-dicarboxytriphenylamine and the respective aromatic dihydrazide monomers via a direct phosphorylation polycondensation reaction. All the poly(amine hydrazide)s were amorphous and readily soluble in many common organic solvents and could be solution-cast into transparent and flexible films with good mechanical properties. These poly(amine hydrazide)s exhibited strong ultraviolet,visible absorption bands at 346,348 nm in N -methyl-2-pyrrolidone (NMP) solutions. Their photoluminescence spectra in NMP solutions or as cast films showed maximum bands around 508,544 and 448,487 nm in the green and blue region for the two series of polymers. The hole-transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. All obtained poly(amine hydrazide)s and poly(amine-1,3,4-oxadiazole)s exhibited two reversible oxidation redox couples at 0.8 and 1.24 V vs. Ag/AgCl in acetonitrile solution and revealed excellent stability of electrochromic characteristics, changing color from original pale yellow to green and then to blue at electrode potentials of 0.87 and 1.24 V, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3245,3256, 2005 [source] Synthesis of polyesters by the polyaddition of bis(oxetane)s with active di(ester)sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2004Hiroto Kudo Abstract The polyaddition of bis(oxetane)s 1,4-bis[(3-ethyl-3-oxetanylmethoxymethyl)]benzene (BEOB), 4,4,-bis[(3-ethyl-3-oxetanyl)methoxy]benzene (4,4,-BEOBP), 1,4-bis[(3-ethy-3-oxetanyl)methoxy] -benzene (1,4-BEOMB), 1,2-bis[(3-ethyl-3-oxetanyl)methoxy]benzene (1,2-BEOMB), 4,4-bis[(3-ethyl-3-oxetanyl)methoxy]biphenyl (4,4,-BEOMB), 3,3,,5,5,-tetramethyl-[4,4,-bis(3-ethyl-3-oxetanyl)methoxy]biphenyl (TM-BEOBP) with active diesters di- s -phenylthioterephthalate (PTTP), di- s -phenylthioisoterephthalate (PTIP), 4,4,-di(p -nitrophenyl)terephthalate (NPTP), 4,4,-di(p -nitrophenyl)isoterephthalate (NPIP) were carried out in the presence of tetraphenylphosphonium chloride (TPPC) as a catalyst in NMP for 24 h, affording corresponding polyesters with Mn's in the range 2200,18,200 in 41,98% yields. The obtained polymers would soluble in common organic solvents and had high thermal stabilities. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1528,1536, 2004 [source] Synthesis of new photoresponsive polyesters containing norbornadiene residues by the polyaddition of donor,acceptor norbornadiene dicarboxylic acid diglycidyl ester with dicarboxylic acids and their photochemical propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2001Yousuke Konno Abstract A donor,acceptor norbornadiene derivative, 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-2,5-norbornadiene-2,3-dicarboxylic acid diglycidyl ester (D,A NDGE), was synthesized by the reaction of the cesium salt of 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-2,5-norbornadiene-2,3-dicarboxylic acid with epibromohydrin in N -methyl- pyrrolidone (NMP). The polyaddition reactions of D,A NDGE with certain dicarboxylic acids were carried out with tetrabutylammonium bromide as a catalyst in NMP, producing corresponding polyesters containing D,A norbornadiene (NBD) residues in the main chain in fair to good yields. The photoisomerization of the D,A NBD residues in the polyesters proceeded very smoothly, forming the corresponding quadricyclane groups. The photoreactivities of the D,A NBD residues in the polymer were 50 times higher than those of the NBD residues in the film state and 60 times higher than those in a tetrahydrofuran solution. The stored energy in the quadricyclane groups of the polymers was about 45,55 kJ/mol according to differential scanning calorimetry analysis of the irradiated polymer films. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2683,2690, 2001 [source] Synthesis of Polystyrene- block -Poly(methyl methacrylate) with Fluorene at the Junction: Sequential Anionic and Controlled Radical Polymerization from a Single CarbonMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 24 2009Nathan D. Contrella Abstract Polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA) has been synthesized by sequential anionic and reverse atom transfer radical polymerization (ATRP) or a variation of nitroxide mediated polymerization (NMP) from a single initiating site, specifically the 9-carbon on 2,7-dibromofluorene or fluorene. The addition of the second arm (PS) relied on thermal decomposition of 2,2,-azoisobutyronitrile (AIBN) to generate radicals, abstracting the 9-H on the polymer-bound fluorene species to form the initiating radical. Styrene was not present in the reaction mixture when AIBN was decomposed, preventing competition between addition across the monomeric alkene and hydrogen abstraction from the fluorene. After 1,h, styrene was introduced and mediation of the subsequent radical polymerization was achieved by the presence of CuCl2/ligand or TEMPO. Characterization of the diblock copolymers by gel permeation chromatography (GPC) revealed substantial shifts in number average molecular weight () values compared to the anionically prepared PMMA macroinitiator, while polydispersity indices (PDI's) remained relatively low (typically,<,1.5). Characterization by UV detection with GPC (at 310,nm) verified that the diblock polymer is chromophore-bound, which was further verified by UV-vis spectroscopy of the isolated diblock. [source] Novel Amphiphilic Styrene-Based Block Copolymers for Induced Surface ReconstructionMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 1 2008Lutz Funk Abstract This paper describes the synthesis of amphiphilic block copolymers by living radical polymerization (NMP) of new styrene-like monomers. The polar monomers (ethylene oxide side chains and free hydroxyl- or amino-groups after deprotection) were polymerized in a "protected form" to adjust the solubility of the monomers. In this way high molar mass polymers with a narrow polydispersity (around or below 1.2) were accessible. In the bulk state hydrophobic and hydrophilic domains demix. By exposing thin films of these polymers to vacuum (air) or alternatively to water or a hydrophilic surface it becomes possible to switch the surface polarity reversibly between contact angles of about 105° and 83° as a result of surface reconstruction. Through side chains of different length and with different functionalities, it was possible to adjust the glass transition temperatures to values between ,2,°C to 140,°C for the hydrophilic blocks and ,30,°C to 100,°C for the hydrophobic block. The wide range of the glass temperatures allowed it to find a block copolymer system with a slow kinetic concerning the surface reconstruction process, so that a mechanistic examination of the process by AFM was possible. It got, thereby, possible to detect the break-up of the hydrophobic surface lamella and the upfold of the hydrophilic lamella in contact with water. [source] Physical and Electrochemical Properties of PVdF-HFP/SiO2 -Based Polymer Electrolytes Prepared Using Dimethyl Acetamide Solvent and Water Non-SolventMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2007Kwang Man Kim Abstract Poly[(vinylidene fluoride)- co -hexafluoropropylene]/SiO2 polymer electrolytes were prepared by a phase inversion technique using DMAc solvent and water non-solvent. Cast film electrolytes filled with the same amount of SiO2 using DMAc were also made to compare physical and electrochemical properties. DMAc had a higher solubility to PVdF-based polymers than NMP, and DMAc produced highly porous structures with bigger cavities and influenced the reduction of crystallinity. Due to the highly porous nature of phase inversion membranes, the uptake of electrolyte solution reached more than 400% and room-temperature ionic conductivity was more than 10,3 S,·,cm,1. All of the liquid absorbed, however, did not necessarily contribute to increases in ionic conductivity. This was due to the different conduction modes of lithium cations in a complicated porous structure. Comprehensively optimizing all the properties measured, the phase inversion membrane electrolytes with 10,30 wt.-% SiO2 were the best candidates for use as the polymer electrolyte of lithium rechargeable batteries. [source] Lyotropic Liquid Crystalline Polyamides Containing Aromatic, Heterocyclic Structures: Preparation and PropertiesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 17 2006Pengtao Liu Abstract Summary: A series of novel lyotropic liquid crystalline polyamides derived from 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-(aminophenoxyl)phenyl)]-phthalazinone (DHPZ-DA), p -phenylene diamine (PPD) and terephthaloyl dichloride (TPC) have been successfully synthesized by the low temperature solution polycondensation method. The copolymers obtained with inherent viscosity of ,1.21 to 3.29 dl,·,g,1, determined in NMP (1 wt.-% LiCl) or concentrated H2SO4 at 25,°C, were confirmed to be amorphous by WAXD and differential scanning calorimetry (DSC). Their solubility was improved by the introduction of non-coplanar, twisted phthalazinone moieties and ether linkages into the main chain with the result that they can be soluble in some polar solvents containing a small amount of LiCl. Their Tgs were all above 310,°C and 10% weight loss temperatures in nitrogen above 500,°C. Most of these polyamides can form an anisotropic phase in concentrated H2SO4, NMP (1 wt.-% LiCl) and DMAc (1 wt.-% LiCl) solutions, observed on a polarizing light microscope. Optical micrograph (×40) of polyamide P-4060 at 10 wt.-% in NMP/LiCl (1% w/v) solution at room temperature. [source] | ||||||||||||||||||||||