bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and properties of poly(cis‐1,4‐dihydroxy‐2,3‐epoxybutane)
Authors: Vandenberg E. J. 
Published: May 2005

AbstractThe cyclic acetone ketal of 1,4‐dihydroxy‐2,3‐epoxybutane (DMTO) polymerizes with i‐Bu3Al‐0.7 H2O catalyst by a cationic mechanism at −78°C to a moderate molecular weight (ηinh up to 0.7), atactic (based on 13C‐NMR) polymer (PDMTO). At higher temperature and in bulk, up to 14% crosslinked polymer is obtained as a result of epoxide and ketal ring opening. Triethylaluminum is an effective catalyst at 0–50°C in bulk. Coordination catalysts were less effective but the results indicate that an effective one can be designed. PDMTO is readily hydrolyzed with aqueous HCl treatment to atactic, water‐soluble poly(1,4‐dihydroxy‐2,3‐epoxybutane) (PDHEB) with a Tg of 80°C. PDHEB is melt stable to 200°C and can be molded to give brittle, clear films that readily pick up 5–10% H2O from the atmosphere to give properties like those of plasticized poly(vinyl chloride). PDHEB is degraded by electron beam radiation but can be crosslinked with glyoxal plus toluene sulfonic acid/The bis(trimethylsilyl) ether of cis‐1,4‐dihydroxy‐2,3‐epoxybutane was polymerized cationically with the i‐Bu3Al‐0.7 H2O catalyst at −78°C to a fairly tactic, presumably racemic di‐isotactic, amorphous polymer, with ηinh of 0.16. A mechanism is proposed for this stereoregular polymerization based on a complexation of the Si side group of the last chain unit with the propagating oxonium on.
Structure and phase transitions in poly(diethylsiloxane)
Authors: Ya. Tsvankin D. , Papkov V. S. , Zhukov V. P. , Godovsky Yu. K. , Svistunov V. S. , Zhdanov A. A. 
Published: May 2005

AbstractThe structure changes accompanying phase transitions in poly(diethylsiloxane) (PDES) have been studied by WAXS and SAXS techniques using oriented and isotropic samples. PDES may exist in two low‐temperature modifications (the monoclinic α1‐form and presumably the “tetragonal” β1‐form) and two high‐temperature modifications (the monoclinic α2‐form and the “tetragonal” β2‐form). In linear PDES the crystal ‐ crystal transitions α1–α2 and β1–β2 occur near 214 and 206 K, respectively. At higher temperatures α2 (280 K) and β2 (290 K) forms transform into the mesomorphic phase αm that gradually melts at 280–300 K giving an amorphous phase. According to x‐ray and density data, αm phase is also characterized by monoclinic structure slightly different from hexagonal packing.
Atom transfer radical copolymerizationof acrylonitrile/n‐butyl acrylate: Microstructure determination by two‐dimensional nuclearmagnetic resonance spectroscopy
Authors: Brar A. S. , Saini Tripta 
Published: May 2005

AbstractAtom transfer radical polymerization conditions were optimized and standardized with different initiator and catalyst systems. Acrylonitrile/n‐butyl acrylate copolymers were synthesized with 2‐bromopropionitrile as the initiator and CuCl/Cu(0)/2,2′‐bipyridine as the catalyst system. Variations of the feed composition led to copolymers with different compositions. The number‐average molecular weight and the polydispersity index were determined by gel permeation chromatography. Quantitative 13C{1H} NMR was employed to determine the copolymer composition. The reactivity ratios calculated with a methodology based on the Mao–Huglin terminal model were rA = 1.30 and rB = 0.68 for acrylonitrile and n‐butyl acrylate, respectively. The reactivity ratios determined by the modified Kelen–Tudos method were rA = 1.29 ± 0.01 and rB = 0.67 ± 0.01. 13C{1H} NMR and distortionless enhancement by polarization transfer (DEPT‐45, 90, and 135) were used to distinguish methyl, methylene, methine, and quaternary carbon resonance signals. The overlapping and broad signals of the copolymers were assigned completely to various compositional and configurational sequences by the correlation of one‐dimensional (1H, 13C{1H}, and DEPT) and two‐dimensional (heteronuclear single quantum coherence, total correlation spectroscopy, and heteronuclear multibond correlation) NMR spectral data. The complete spectral assignments of carbonyl and nitrile carbons were performed with the help of heteronuclear multibond correlation spectra. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2810–2825, 2005
Environmentally responsive micelles from polystyrene–poly[bis(potassium carboxylatophenoxy)phosphazene] block copolymers
Authors: Chang Youngkyu , Powell Eric S. , Allcock Harry R. 
Published: May 2005

AbstractAmphiphilic diblock copolymers that contained hydrophilic poly[bis(potassium carboxylatophenoxy)phosphazene] segments and hydrophobic polystyrene sections were synthesized via the controlled cationic polymerization of Cl3PNSiMe3 with a polystyrenyl–phosphoranimine as a macromolecular terminator. These block copolymers self‐associated in aqueous media to form micellar structures which were investigated by fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. The size and shape of the micelles were not affected by the introduction of different monovalent cations (Li+, K+, Na+, and Cs+) into the stable micellar solutions. However, exposure to divalent cations induced intermicellar crosslinking through carboxylate groups, which caused precipitation of the ionically crosslinked aggregates from solution. This micelle‐coupling behavior was reversible: the subsequent addition of monovalent cations caused the redispersion of the polystyrene‐block‐poly[bis(potassium carboxylatophenoxy)phosphazene] (PS–KPCPP) block copolymers into a stable micellar solution. Aqueous micellar solutions of PS–KPCPP copolymers also showed pH‐dependent behavior. These attributes make PS–KPCPP block copolymers suitable for studies of guest retention and release in response to ion charge and pH. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2912–2920, 2005
Origin of the color of π‐conjugated columnar polymers: Poly(p‐n‐octylthiophenyl)acetylene prepared using a [Rh(norbornadiene)Cl]2 catalyst
Authors: Huang Kai , Tabata Masayoshi , Mawatari Yasuteru , Miyasaka Atsushi , Sato Eriko , Sadahiro Yoshikazu , Kashiwaya Yoshiaki , Ishii Kuniyoshi 
Published: May 2005

AbstractHighly stereospecific polymerization of a novel sulfur containing aromatic acetylenes, that is, (p‐n‐octylthiophenyl)acetylene (pOctSPA), was successfully performed using the Rh complex, [Rh(norbornadiene)Cl]2‐TEA, catalyst in the presence of various solvents under mild conditions. The resulting polymers were characterized in detail by 1H NMR, ESR, laser Raman, diffuse reflective UV‐Vis (DRUV‐Vis), and wide angle X‐ray diffraction methods. The data showed that the resulting polymers bear cis‐transoid form, which can induce the cis‐to‐trans isomerization when the cis polymers are subjected to pressure at room temperature under vacuum, breaking rotationally the cis CC bonds in the main‐chain giving two kinds of π‐radicals, the so‐called cis radical and trans radical as the origin of a polymer magnet like a novel spin glass material. Further, the resulting cis poly(acetylene)s were found to have a helical main‐chain, which is packed in pseudohexagonal crystal called π‐conjugated columnar or nano π‐conjugated columnar as a novel color controllable material. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2836–2850, 2005
Blue‐emitting poly(1,3‐phenylenevinylene) derivatives: Effect of substitution patterns on optical properties
Authors: Liao Liang , Ding Liming , Karasz Frank E. , Pang Yi 
Published: May 2005

AbstractBlue‐emitting poly{[5‐(diphenylamino)‐1,3‐phenylenevinylene]‐alt‐(2‐hexyloxy‐5‐methyl‐1,3‐phenylenevinylene)} (3), poly{[5‐bis‐(4‐butyl‐phenylamino)‐1,3‐phenylenevinylene]‐alt‐(1,3‐phenylene vinylene)} (4), and poly(2‐hexyloxy‐5‐methyl‐1,3‐phenylenevinylene) (5) were synthesized by the Wittig–Horner reaction. Although polymers 3–5 possess fluorescent quantum yields of only 13–34% in tetrahydrofuran solution, their films appear to be highly luminescent. Attachments of substituents tuned the emission color of thin films to the desirable blue region (λmax = 462–477 nm). Double‐layer light‐emitting‐diode devices with 3 and 5 as an emissive layer produced blue emission (λem = 474 and 477 nm) with turn‐on voltages of 8 and 11 V, respectively. The external quantum efficiencies were up to 0.13%. © 2005Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2800–2809, 2005
Fabrication of novel conjugated polymer nanostructure: Porphyrins and fullerenes conjugately linked to the polyacetylene backbone as pendant groups
Authors: Wang Ning , Li Yongjun , Lu Fushen , Liu Yang , He Xiaorong , Jiang Li , Zhuang Junpeng , Li Xiaofang , Li Yuliang , Wang Shu , Liu Huibiao , Zhu Daoben 
Published: May 2005

AbstractA new series of conjugated polyacetylenes with conjugately linked fullerene and porphyrin groups as pendant units were prepared by a copolymerization reaction catalyzed by chloronorbornadiene rhodium(I)dimer‐triethylamine ([Rh(nbd)Cl]2‐NEt3) in anhydrous CHCl3. These polymers were characterized with UV–vis spectroscopy, fluorescence spectroscopy, and voltammetry. Scanning electron microscopy indicated that the morphology of the copolymers consisted of uniform nanorods with a diameter of about 100 nm and a length of about 300 nm. Thin films of the copolymers produced steady and prompt photocurrent at an irradiation of 20.0 mW cm−2 of white light, which was higher than that of a mixture of poly[5‐(4‐Ethynyl‐phenyl)‐10,15,20‐tris(4‐carbomethoxyphenyl)porphyrin zinc] and C60. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2851–2861, 2005
Reversible addition–fragmentation chain transfer/miniemulsion polymerization of butyl methacrylate in the presence of β‐cyclodextrin
Authors: Zhang Feng , Ni Peihong , Xiong Qingfeng , Yu Zhangqing 
Published: May 2005

AbstractIn the presence of β‐cyclodextrin (β‐CD), reversible addition–fragmentation chain transfer (RAFT) polymerization has been successfully applied to control the molecular weight and polydispersity [weight‐average molecular weight/number‐average molecular weight (Mw/Mn)] in the miniemulsion polymerization of butyl methacrylate, with 2‐cyanoprop‐2‐yl dithiobenzoate as a chain‐transfer agent (or RAFT agent) and 2,2′‐azoisobutyronitrile (AIBN) as an initiator. β‐CD acted as both a stabilizer and a solubilizer, assisting the transportation of the water‐insoluble, low‐molecular‐weight RAFT agent into the polymerization loca (i.e., droplets or latex particles) and thereby ensuring that the RAFT agent was homogeneous in the polymerization loca. The polymers produced in the system of β‐CD exhibited narrower polydispersity (1.2 < Mw/Mn < 1.3) than those without β‐CD. Moreover, the number‐average molecular weight in the former case could be controlled by a definite amount of the RAFT agent. Significantly, β‐CD was proved to have a favorable effect on the stability of polymer latex, and no coagulum was observed. The effects of the concentrations of the RAFT agent and AIBN on the conversion, the molecular weight and its distribution, and the particle size of latices were investigated in detail. Furthermore, the influences of the variations of the surfactant (sodium dodecyl sulfate) and costabilizer (hexadecane) on the RAFT/miniemulsion polymerization were also studied. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2931–2940, 2005
Influence of alkyl chains of amphiphilic hyperbranched poly(ester amine)s on the phase‐transfer performances for acid dye and the aggregation behaviors at the interface
Authors: Tang Liming , Fang Yu , Tang Xianlai 
Published: May 2005

AbstractHyperbranched poly(ester amine) (HPEA) with terminal secondary amine groups was synthesized by the Michael addition reaction between piperazine and trimethylolpropanetriacrylate with a molar ratio of 13:6. It was further reacted with a series of aliphatic acid chlorides, including stearoyl chloride, dodecanoyl chloride, and octanoyl chloride, to yield three modified amphiphilic hyperbranched polymers, which were termed HPEA‐C18, HPEA‐C12, and HPEA‐C8, respectively. These polymers were characterized with Fourier transform infrared, 1H NMR, gel permeation chromatography, and differential scanning calorimetry measurements. Because of the existence of interior tertiary amine groups, the modified amphiphilic polymers were used as host molecules to extract the guest acid dye, methyl orange (MO), from the aqueous layer to the organic layer on the basis of the acid–base interaction. The influences of the pH of the aqueous layer and the length of the alkyl chains in the modified polymers on the phase‐transfer performances were investigated. The results indicated that more MO molecules could be extracted at a lower pH because of the formation of more quaternary ammonium ions within the host molecules. As the length of the alkyl chains in the modified polymers increased, both the transfer capability and the intermolecular aggregation at the interface were enhanced. The extracted MO could be reversibly released from the organic layer to the aqueous layer under basic conditions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2921–2930, 2005
Flame‐retardant epoxy resins with high glass‐transition temperatures from a novel trifunctional curing agent: Dopotriol
Authors: Cai Sheng Xiong , Lin Ching Hsuan 
Published: May 2005

AbstractA novel phosphorus‐containing trifunctional novolac (dopotriol) was synthesized through the addition reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide and rosolic acid. The structure of dopotriol was confirmed with NMR spectroscopy and elemental analyses. The dopotriol was blended with phenol novolac in the ratios of 10/0, 8/2, 6/4, 4/6, 2/8, and 0/10 to serve as a curing agent for diglycidyl ether of bisphenol A. Thermal properties, such as the glass‐transition temperature, thermal decomposition temperature, and flame retardancy, moisture absorption, and dielectric properties of the cured epoxy resins were evaluated. The activity and activation energy of curing were studied with the methods of Kissinger and Ozawa by dynamic differential scanning calorimetry scans. The glass‐transition temperatures of the cured epoxy resins were 138–159 °C, increasing with the phosphorus content. This is rarely seen in the literature after the addition of a flame‐retardant element. The flame retardancy increased with the phosphorus content, and a UL‐94 V‐0 grade was achieved with a phosphorus content of 1.87%. Similar dielectric properties and moisture absorption were observed for these phosphorus‐containing epoxy resins, and this implied that the addition of phosphorus to epoxy did not affect the dielectric properties and moisture absorption. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2862–2873, 2005
Preparation of polymer/silica composite nanoparticles bearing carboxyl groups on the surface via emulsifier‐free emulsion copolymerization
Authors: Zeng Zhong , Yu Jian , Guo Zhao‐Xia 
Published: May 2005

AbstractPolymer/silica organic/inorganic composite nanoparticles bearing carboxyl groups on the surface were prepared via the emulsifier‐free emulsion copolymerization of methyl methacrylate and sodium methacrylate (NaMA). Carboxyl groups were generated by the addition of hydrochloric acid at the end of the copolymerization. Two methods of NaMA addition were studied: batch and two‐stage procedures. The batch procedure allowed only a limited number of carboxyl groups to effectively bond to the composite nanoparticles. In contrast, the number of carboxyl groups could be altered over a wide range with the two‐stage procedure. Fourier transform infrared spectroscopy and chemical titration were independently used to quantify the number of carboxyl groups, giving values close to each other and to the feed. A kinetic study indicated that the copolymerization followed a mechanism different than that found earlier. The average size of the composite nanoparticles was approximately 40 nm, as measured by both transmission electron microscopy (TEM) and laser scattering, and their polydispersity index was close to 1, indicating a fairly narrow size distribution. TEM photographs of the composite nanoparticles showed a multilayered core–shell structure with one silica bead as the core and with poly(methacrylate acid) as the outmost shell. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2826–2835, 2005
Solution route to inorganic nanobelt‐conducting organic polymer core‐shell nanocomposites
Authors: Xu Jian , Li Xiaolin , Liu Junfeng , Wang Xun , Peng Qing , Li Yadong 
Published: May 2005

AbstractA facile and versatile solution‐based approach was developed to prepare semiconductor metal oxide nanobelt‐conducting organic polymer core‐shell nanocomposites. Well‐defined nanobelts of several types of oxide nanobelts were combined with conducting polymer [polypyrrole (PPy) and polyaniline (PANi)] via in situ polymerization in aqueous solution to obtain a new type of inorganic–organic composite nanostructure. Samples were characterized by using X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, electron energy loss spectra, high‐resolution transmission electron microscopy, and ultraviolet–visible techniques. Electron energy loss spectra revealed the existence of CC and CN bonds in coating layers to prove the encapsulation of PPy or PANi. The red‐shift of absorption band at high‐energy was observed for PPy‐encapsulated composites via ultraviolet–visible spectroscopy, and significant absorption band shifts were also encountered to PANi‐encapsulated composites, which suggest possibilities of band‐gap tuning of such metal oxide‐conducting polymer composites to be applied especially in solar cell devices. However, the sacrifice of nanobelts‐core led to hollow structures of PPy and PANi, which expands the synthetic strategies to prepare conducting polymer nanotubes. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2892–2900, 2005
2‐[(5‐methylisoxazol‐3‐yl)amino]‐2‐oxo‐ethyl methacrylate with glycidyl methacrylate copolymers: Synthesis, thermal properties, monomer reactivity ratios, and antimicrobial activity
Authors: Soykan Cengiz , Güven Şükran , Coşkun Ramazan 
Published: May 2005

AbstractWe report the monomer reactivity ratios for copolymers of glycidyl methacrylate (GMA) and a reactive monomer, 2‐[(5‐methylisoxazol‐3‐yl)amino]‐2‐oxo‐ethyl methacrylate (IAOEMA), using the Fineman–Ross method, the Kelen–Tüdös method, and a nonlinear error invariablemodel method with the computer program RREVM. Copolymers were obtained by radical polymerization initiated by α,α′‐azobisisobutyronitrile in a 1,4‐dioxane solution and were analyzed by Fourier transform infrared, 1H NMR, and gel permeation chromatography. Elemental analysis was used to determine the molar fractions of GMA and IAOEMA in the copolymers. The reactivity ratios indicated a tendency toward random copolymerization. The polydispersity indices of the polymers, determined with gel permeation chromatography, suggested a strong tendency for chain termination by disproportionation. The thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. The glass‐transition temperature of the copolymers increased with increasing IAOEMA content in the copolymers. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Setaram Labsys thermogravimetric analysis thermobalance. All the products showed moderate activity against different strains of bacteria and fungi. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2901–2911, 2005
Measurement of the Influence of Directed Particle motion on the turbulent particle deposition velocity by means of laser‐doppler anemometry
Authors: Holländer Werner , Pohlmann Gerhard 
Published: May 2005

AbstractThe dry deposition of particles from the atmosphere is not well understood for reasons of surface variabilities and mutual interactions between surface and particles. However, even relatively simple influences of physical parameters have so far resisted successful parameterization, although some progress has been achieved. There is no general way to determine the relative contributions of stochastic turbulent and Brownian diffusion and directed motions (i. e. sedimentation) to the total deposition velocity since they contribute in a nonlinear manner to the total deposition velocity. The directed motion is an unknown function of atmospheric turbulence, the particle diffusion coefficient Dp and the sum of all directed particle motions by thermophoresis, diffusiophoresis, photophoresis, electrophoresis, sedimentation etc. Practically nothing is known about the action of the first three forces and even the easily accessible electrophoresis has not been considered relevant for deposition of atmospheric particles. Because it is relatively easy to change an electric field with all other parameters kept constant and measure the absolute difference in total deposition velocity the following experimental Laser‐Doppler study was intended to show the feasibility of the field‐changing‐technique and the magnitude of the effects without quantitatively determining the electrical mobility distribution as a function of particle size.
High‐Temperature Evaporation Rates of Solid KBr and NH4Cl aerosol particles
Authors: Timmler JÜRgen , Roth Paul 
Published: May 2005

AbstractThe evaporation rates of particles of solid KBr or NH4Cl suspended in argon were studied under high‐temperature conditions behind incident shock waves. The mass‐transfer process during particle evaporation was observed by two optical techniques allowing the measurement of scattered light from a particle ensemble and also from individual particles. The scattered light flux signals were interpreted on the basis of the Mie theory, resulting in values for the time‐dependent particle size and for the refractive index of particle materials. The experiments were performed in the gas‐phase temperature ranges TG = 1070–1300K (KBr) and 525–650K (NH4Cl). The initial size of the suspended particles ranged between 0.6 and 1.0 μm. From the measured decrease in the particle size during the mass‐transfer process the evaporation coefficients of both materials were determined as a function of the gas‐phase temperature. They depend on the vapour pressure and the diffusion coefficient for vapour into gas. Typical parameters (àKBr, m) describing the diffusion coefficient of KBr vapour in argon and the vapour pressure of NH4Cl could be determined.
A Procedure for Blending and Mass Balancing fine particle size data
Authors: Mankosa Michael J. , Adel Greg T. 
Published: May 2005

AbstractAn increased interest in the development of new techniques for fine grinding has resulted in a growing concern over the accuracy of size distributions for extremely fine particles. Since most particle size analyzers have lower detection limits, care must be taken when comparing size distributions which have not been properly mass balanced.An automated technique has been developed in which a completely mass balanced size distribution can be obtained using an Elzone 80XY particle size analyzer. A computer program is used to blend the data from successively smaller orifice tubes, and to determine the weight percent of material finer than the lower detection limit of the analyzer. This result is then used to correct the distribution for the missing fine material. Experimental results indicate that size distributions obtained using this procedure are reproducible and compare favorably with those obtained using other size analysis techniques.