bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorescent polymer particles by emulsion and miniemulsion polymerization
Authors: Tronc Frédéric , Li Mei , Lu Jianping , Winnik Mitchell A. , Kaul Bansi Lal , Graciet Jean‐Christophe 
Published: February 2003

AbstractWe describe the synthesis and characterization of latex particles labeled with a brightly fluorescent yellow dye (HY) based on the benzothioxanthene ring structure. Three dye derivatives were synthesized with different spacers connecting the HY nucleus to a methacrylate group. For one of the dyes (HY2CMA, rA), we show that the reactivity ratios with styrene (rA = 0.71, rB = 0.25) and butyl methacrylate (rA = 0.87, rB = 0.14) should lead to random dye incorporation if the amount of dye in the feed is small. Seeded emulsion polymerization fails to lead to significant dye incorporation unless large amounts of nonionic surfactant are present. In contrast, miniemulsion polymerization worked well to yield latex particles of polystyrene, poly(butyl methacrylate), and poly(methyl methacrylate) with high monomer conversion and essentially quantitative dye incorporation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 766–778, 2003
Real‐time Fourier transform infrared study of the free‐radical ultraviolet‐induced polymerization of a hybrid sol–gel. II. The effect of physicochemical parameters on the photopolymerization kinetics
Authors: Soppera O. , Croutxé‐Barghorn C. 
Published: February 2003

AbstractFree‐radical photocurable hybrid sol–gel materials have gained special interest during the last decades. Compared to thermally processed materials, they present the advantages of fast curing, low energy consumption, and spatiotemporal control of the reaction. Although comprehension of the photochemical step is fundamental, little is known about the characteristic of photochemistry in this kind of material. Real‐time Fourier transform infrared spectroscopy was used to study the photopolymerization of a hybrid sol–gel upon ultraviolet irradiation. Various photoinitiator systems were tested for their efficiency in inducing the polymerization of pendant polymerizable moieties anchored on a partially condensed silicate network. The presence of O2 and the nature of the polymerizable function were shown to be crucial factors in the photoinduced process. The effects of the photoinitiator concentration and light intensity were also studied. These results were explained in terms of classical kinetic models developed for all‐organic photopolymers to point out the distinctive aspects related to the use of photoinitiated polymerization in hybrid sol–gel materials. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 831–840, 2003
Batch emulsion copolymerization of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose and butyl acrylate: Synthesis and properties of the sugar latices
Authors: Koch U. , Yaacoub E.‐J. 
Published: February 2003

AbstractTo obtain new polymer latices based on sugar derivative, batch emulsion copolymerizations of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG) and n‐butyl acrylate (BA) were carried out at 70 °C, with potassium persulfate as the initiator. 3‐MDG polymerizes faster than BA because of its higher reactivity ratio, r(3‐MDG) = 1.94 versus r(BA) = 0.54. The effect of the initial monomer composition on the polymerization rate and the thermal properties of the end copolymers was investigated. The overall rate of polymerization increases by enhancing the sugar content in the initial monomer composition. The glass‐transition temperature is linearly related to the sugar content in the copolymer. The influence of the type of surfactant showed that the particle size increases by changing from ionic to nonionic surfactant. Furthermore, the effect of the added acrylic acid (AA) on the rheological properties suggests that the sugar latices exhibit different non‐Newtonian flows depending on the pH of the latex and on the AA concentration on the particle surface. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 788–803, 2003
Samarium enolate on crosslinked polystyrene beads. II. An anionic initiator for the well‐defined synthesis of poly(allyl methacrylate) on a solid support
Authors: Tanaka Masayoshi , Sudo Atsushi , Sanda Fumio , Endo Takeshi 
Published: February 2003

AbstractA samarium enolate, supported on a crosslinked polystyrene resin, successfully initiated the living anionic polymerization of allyl methacrylate (AMA) to afford the corresponding poly(AMA) with well‐controlled molecular weights. Diblock, triblock, and tetrablock copolymerizations with methyl methacrylate (MMA) were also successfully performed. The formed polymers, supported on the resin by a benzyl ester linker, were quantitatively isolated from the resin by selective cleavage of the linker with trifluoroacetic acid (TFA). Allyl ester in the side chain was not affected by this isolation step. The allyl group of the immobilized poly(AMA‐b‐MMA) on the resin was transformed into a 2,3‐dihydroxypropyl group by osmium oxidation. The resulting copolymer was isolated by TFA treatment of the resin, and it showed amphiphilicity. In both the polymerization and side‐chain modification, the formed polymers were easily washed from excess reagents only by filtration, and this demonstrated the feasibility of the automated synthesis of functional polymers based on this solid‐supported polymerization technique. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 853–860, 2003
Sterically stabilized emulsion polymerization of styrene: Pseudo‐semicontinuous approach
Authors: Capek I. , Chudej J. , Janíčková S. 
Published: February 2003

AbstractThe sterically stabilized emulsion polymerization of styrene initiated by a water‐soluble initiator at different temperatures has been investigated. The rate of polymerization (Rp) versus conversion curve shows the two non‐stationary‐rate intervals typical for the polymerization proceeding under non‐stationary‐state conditions. The shape of the Rp versus conversion curve results from two opposite effects—the increased number of particles and the decreased monomer concentration at reaction loci as the polymerization advances. At elevated temperatures the monomer emulsion equilibrates to a two‐phase or three‐phase system. The upper phase is transparent (monomer), and the lower one is blue colored, typical for microemulsion. After stirring such a multiphase system and initiation of polymerization, the initial coarse polymer emulsion was formed. The average size of monomer/polymer particles strongly decreased up to about 40% conversion and then leveled off. The initial large particles are assumed to be highly monomer‐swollen particles formed by the heteroagglomeration of unstable polymer particles and monomer droplets. The size of the “highly monomer” swollen particles continuously decreases with conversion, and they merge with the growing particles at about 40–50% conversion. The monomer droplets and/or large highly monomer‐swollen polymer particles also serve as a reservoir of monomer and emulsifier. The continuous release of nonionic (hydrophobic) emulsifier from the monomer phase increases the colloidal stability of primary particles and the number of polymer particles, that is, the particle nucleation is shifted to the higher conversion region. Variations of the square and cube of the mean droplet radius with aging time indicate that neither the coalescence nor the Ostwald ripening is the main driving force for the droplet instability. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 804–820, 2003
Photosensitive fluorinated polyimides with a low dielectric constant based on reaction development patterning
Authors: Miyagawa Tomoko , Fukushima Takafumi , Oyama Toshiyuki , Iijima Takao , Tomoi Masao 
Published: February 2003

AbstractThe fluorinated polyimide PI(6FDA/HFBAPP) was prepared by the reaction of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (HFBAPP) in 1‐methyl‐2‐pyrrolidone/toluene. A multiblock copolyimide with both fluorinated and rigid‐rod segments, PI(6FDA/HFBAPP)(BPDA/2‐DMB), was prepared by the addition of a second dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), and a second diamine, 2,2′‐dimethylbenzidine (2‐DMB), to the polyimide main chain. The potential lithographic performance of photosensitive polyimides composed of nonphotosensitive fluorine‐containing polyimides and photosensitive diazonaphthoquinone (DNQ) was studied on the basis of a new imaging principle recently proposed by our laboratory, that is, reaction development patterning. Neat PI(6FDA/HFBAPP) showed a low dielectric constant (ϵ) of 2.41 and a low dissipation factor (tan δ) of 0.0027 at 20 GHz, and a 10‐μm resolution of the fluorinated polyimide/DNQ system was demonstrated with reactive development with a solution including ethanolamine after ultraviolet exposure. Although slight changes in the dielectric properties were observed in the presence of DNQ residues, these values (ϵ = 2.63 and tan δ = 0.0033 at 20 GHz) were low enough for use in microelectronic applications. However, PI(6FDA/HFBAPP)(BPDA/2‐DMB), having a lower coefficient of thermal expansion (CTE; 33 ppm/°C) than PI(6FDA/HFBAPP) (49 ppm/°C), exhibited good positive photosensitivity, whereas the relatively low‐CTE multiblock copolyimide displayed a much higher ϵ value (3.48 at 1 MHz) than the highly fluorinated polyimide (2.88 at 1 MHz). A film consisting of PI(6FDA/HFBAPP)(BPDA/2‐DMB) and the remaining DNQ derivatives showed a CTE value comparable to that of the neat polyimide film. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 861–871, 2003
Solution polycondensation of isophthalic acid/terephthalic acid and tetrachlorobisphenol A of low polymerizability with tosyl chloride/dimethylformamide/pyridine improved by the introduction of comonomers of smaller sizes
Authors: Higashi Fukuji , Moriya Miwako 
Published: February 2003

AbstractThe copolycondensations of a mixture of equal parts of isophthalic acid and terephthalic acid with tetrachlorobisphenol A (TC‐BPA) and various aromatic diol comonomers were performed with a tosyl chloride/dimethylformamide/pyridine condensing agent. The reaction with bisphenols containing nonpolar substituents yielded better results than the reaction with polar groups did. Dihydroxybenzenes smaller in size than bisphenols of two benzene rings, especially chlorohydroquinone and chlororesorcinol, were satisfactorily incorporated and yielded copolymers of high inherent viscosities and weight‐average molecular weights (by gel permeation chromatography). The results of the copolycondensations were examined with sequence distributions in the resultant copolymers by NMR and were well evaluated by the ratio of the length of comonomer unit segments to TC‐BPA unit segments. Homopolycondensation with TC‐BPA in the presence of dichlorobenzenes as additives was also promoted to some extent. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 821–830, 2003
Novel functional polymers: Poly(dimethyl siloxane)–polyamide multiblock copolymers. XI. The effects of sequence regularity on the thermal and mechanical properties
Authors: Kang Eui‐Chul , Kaneko Tatsuo , Shiino Daijiro , Akashi Mitsuru 
Published: February 2003

AbstractPoly(aramid silicone) (PAS) multiblock copolymers were synthesized by the low‐temperature solution polycondensation of isophthaloyl dichloride (IPC) and two diamines, diamino poly(dimethyl siloxane) (PDMS; number‐average molecular weight = 1680) and 3,4′‐diaminodiphenylether (3,4′‐DAPE), in tetrahydrofuran/dimethylacetamide (2/1 v/v). Two synthetic methods for the control of the PAS sequence were used: a one‐step synthesis that presumably gave PAS with a random sequence and the polymerization of 3,4′‐DAPE with a presynthesized dimer, IPC–PDMS–IPC (two‐step synthesis), that presumably gave PAS with an alternating sequence of 3,4′‐DAPE and PDMS segments. In a 1H NMR study of the amide protons of the 3,4′‐DAPE component in PAS, the relative length of the 3,4′‐DAPE segment of randomly sequenced PAS to that of ideally sequenced PAS could be estimated. The glass‐transition temperatures of the 3,4′‐DAPE and PDMS segments of random PAS were 152–234 and −104 to −117 °C, respectively, whereas the alternating PAS sequences showed no glass transition for the 3,4′‐DAPE segments. A tensile test indicated that randomly sequenced PAS behaved like a rubber‐toughened material at lower PDMS contents and like a thermoplastic elastomer at higher PDMS contents, whereas the alternately sequenced PAS behaved like a very soft rubber, showing a high value of elongation at the breaking point. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 841–852, 2003
Negative expiratory pressure: A new tool for evaluating lung function in children?
Authors: Tauber Erich , Fazekas Tamas , Eichler Irmgard , Eichstill Christina , Gartner Christian , Koller Dieter Y. , Frischer Thomas 
Published: February 2003

AbstractThe negative expiratory pressure technique (NEP) has been applied in adults with chronic obstructive pulmonary disease (COPD), demonstrating flow limitation in many of these patients. Because this technique does not require patient cooperation, it is of potential interest for application in the pediatric population. This study was performed to test the feasibility of NEP in children, and to further investigate it in children with asthma and cystic fibrosis (CF). We performed NEP (0.3–0.7 kPa) measurements in 14 healthy children (13.3 years, ± 2.4), in 12 children with asthma (11.7 years, ± 3.0), and in 17 children with CF (13.3 years, ± 2.7). NEP‐derived flow‐volume loops were visually analyzed for flow limitation at tidal breathing. In addition, expiratory flow at 50% of tidal volume (TEF50) was measured. In healthy children, the intraclass coefficient of correlation was 77%, and intraindividual short‐ and long‐term variability was 5.8% and 10.8%, respectively. In asthmatics, TEF50 was lower compared with controls, and increased after inhalation of salbutamol. However, appropriate size‐correction has still to be established. Measurement of TEF50 using NEP is feasible in children. Despite good reproducibility in individual patients, the high intersubject variability may limit its usefulness as a clinical tool. In addition, the lack of flow limitation using NEP even in severely obstructed patients with CF warrants further investigation. Pediatr Pulmonol. 2003; 35:162–168. © 2003 Wiley‐Liss, Inc.
Influence of particle size on lung deposition and pharmacokinetics of beclomethasone dipropionate in children
Authors: Agertoft L. , Laulund L.W. , Harrison L.I. , Pedersen S. 
Published: February 2003

AbstractWe set out to evaluate lung deposition, systemic availability, and basic pharmacokinetic parameters of beclomethasone dipropionate (BDP) in children with chronic asthma. Plasma levels of BDP, 17 and 21 beclomethasone monopropionate (17‐BMP and 21‐BMP), and beclomethasone were measured after an intravenous infusion of 60 μg BDP and after inhalation of A) 100 μg HFA‐BDP, B) 200 μg HFA‐BDP, C) 200 μg HFA‐BDP after ingestion of charcoal to block gastrointestinal (GI) absorption of drug, and D) 400 μg CFC‐BDP. A breath‐actuated pMDI (Autohaler™) was used for HFA inhalations, and a pMDI with a large volume spacer (Volumatic™) for CFC inhalations. Treatments A–D were given in a randomized, cross‐over design. Fourteen patients aged 10–14 years completed all 5 study days. The mean systemic bioavailabilities in percent of dose leaving the canister valve (ex‐valve) were 70% (100 HFA), 74% (200 HFA), 60% (200 HFA + charcoal), and 27% (400 μg CFC). After HFA treatment, 82% of the systemically available dose was absorbed through the lungs, and 18% from the gastrointestinal tract. The estimated bioavailability of BDP from the GI tract was 68%. BDP was metabolized to 17‐BMP within minutes. Mean steady‐state volume of distribution of 17‐BMP was 84 L, and the mean terminal half‐life (T½) after the four inhalations was 2.7 hr (range, 2.2–3.7 hr). Mean T½ and clearance after i.v. administration were 1.7 hr and 0.9 L/min, respectively. The HFA Autohaler delivers approximately three times as much BDP to the intrapulmonary airways as a CFC‐pMDI with a large volume spacer. Pediatr Pulmonol. 2003; 35:192–199. © 2003 Wiley‐Liss, Inc.
Airway and tissue mechanics in anesthetized paralyzed children
Authors: Peták Ferenc , Babik Barna , Asztalos Tibor , Hall Graham L. , Deák Zoltán I. , Sly Peter D. , Hantos Zoltán 
Published: February 2003

AbstractTo estimate the mechanical properties of the airways and respiratory tissues, respiratory system impedance (Zrs) was measured with low‐frequency forced oscillations in 26 anesthetized, paralyzed children (aged 3 months–10 years) undergoing surgical correction of congenital heart diseases. Zrs was determined from the signals of tracheal flow and pressure between 0.4–12 Hz before surgery at zero mean transrespiratory pressure. The pulmonary (ZL) and chest wall (ZW) components of Zrs were also determined in 5 children by measuring esophageal pressure. A model containing frequency‐independent resistance (R) and inertance (I), and coefficients of tissue‐damping (G) and elastance (H), was fitted to the Zrs, ZL, and ZW spectra. The total respiratory parameters normalized to body weights were 82.2 ± 8.5 (SE) hPa · sec · l−1 · kg, 0.152 ± 0.05 hPa · sec2 · l−1 · kg, 293.8 ± 20.0 hPa · l−1 · kg, and 1,583 ± 65.5 hPa · l−1 · kg, for R, I, G, and H, respectively. The measurements of ZL and ZW revealed the dominance of the lungs in R (91 ± 4.3%) and I (109 ± 16%), and the major contribution of the lung parenchyma to G (61 ± 7.3%) and H (66 ± 7.4%) of the total respiratory system. It is concluded that anesthesia‐paralysis provides an ideal condition for the measurement of low‐frequency forced oscillatory impedance and its partitioning into airway and tissue components in mechanically ventilated children. The separation of pulmonary and chest wall mechanics demonstrates that airway properties can be estimated appropriately from Zrs data, while the chest wall may damp the changes in parenchymal properties. Pediatr Pulmonol. 2003; 35:169–176. ©2003 Wiley‐Liss, Inc.
Case of congenital bronchial atresia detected by fetal ultrasound
Authors: Kamata Shinkichi , Sawai Toshio , Usui Noriaki , Nose Keisuke , Kitayama Yasuhiro , Iiboshi Yasuhiko , Okada Akira , Kanzaki Tohru 
Published: February 2003

AbstractCongenital bronchial atresia is an anomaly characterized by a mucocele associated with a blindly terminating segmental or lobar bronchus. We report on a case of congenital atresia of the left superior segmental bronchus (B6) followed by fetal ultrasonography, which showed a large simple cyst with a surrounding small echogenic area. A large cyst and persistent lung fluid in the affected segment were noted in the early neonatal period. Pediatr Pulmonol. 2003; 35:227–229. © 2003 Wiley‐Liss, Inc.
Determining the amount of Si–Si bonding in CVD oxynitrides
Authors: Tompkins Harland G. , Smith Steven , Convey Diana , Gregory R. B. , Kottke M. L. , Collins David 
Published: January 2003

AbstractIn this work we propose a method of determining the amount of excess Si in chemical vapor deposited (CVD) oxynitrides that is due to silicon bonded to other silicon (the amount of excess Si due to more‐than‐normal Si–H bonds can be determined by Fourier transform infrared spectroscopy and has been dealt with adequately in the literature). The amount of Si–Si bonding in CVD oxynitride usually represents a small fraction of the total silicon (<5%) and we show that, in this case, the subtractive method of determination is inadequate due to the uncertainty in the values obtained from typical elemental analysis (with Rutherford backscattering spectroscopy or other methods). By choosing atypical samples made specifically such that the amount of Si–Si bonding represents a significant fraction of the total silicon (mostly >50%), we use the subtractive method to provide a relationship between the extinction coefficient k at a particular wavelength (250 nm) that can be used for typical samples. Copyright © 2003 John Wiley & Sons, Ltd.
Electropolishing of aluminium: processing and assessment of visual appearance
Authors: Van Gils S. , Holten S. , Stijns E. , Vancaldenhoven M. , Terryn H. , Mattsson L. 
Published: January 2003

AbstractThe process of electropolishing aluminium and its influence on the visual appearance are studied. Angle‐resolved scattering (ARS) and total integrated scattering (TIS) are used to investigate the influence of electropolishing on surface roughness. The ARS apparatus is built similar to the ASTM E430‐97A standard. This standard test method is used for measurement of distinctness of image and haze by goniophotometry. These visual appearance parameters, together with TIS, reflect the changes in surface roughness. Total reflectance is correlated to the composition of the aluminium as well as the composition and thickness of the layer formed on the aluminium. Copyright © 2003 John Wiley & Sons, Ltd.
AFM analysis of organic silane thin films for bioMEMS applications
Authors: Popat Ketul C. , Sharma Sadhana , Johnson Robert W. , Desai Tejal A. 
Published: January 2003

AbstractDesigning surfaces that elicit the desirable response is essential for bioMEMS (biological microelectromechanical systems) applications. To this end, we have developed two different types of silane film—hydrophobic and hydrophilic—using vinyltrichlorosilane and poly(ethylene glycol) silane, respectively. As the surface topography plays a very important role in governing protein or cell interactions, these films were characterized extensively using atomic force microscopy. All the films developed were found to have a very low root‐mean‐square roughness value (<1.3 nm). Furthermore, the topography of protein‐adsorbed silane‐modified surfaces was investigated because cell adhesion is mediated primarily by proteins. Three‐dimensional and section plots were able to differentiate the way in which protein interacts with hydrophobic and hydrophilic surfaces. Copyright © 2003 John Wiley & Sons, Ltd.
Surface characterization of Co,K/La2O3 catalysts used for the catalytic combustion of diesel soot
Authors: Moggia J. M. , Milt V. G. , Ulla M. A. , Cornaglia L. M. 
Published: January 2003

AbstractCatalysts of Co,K/La2O3 have been prepared by wet impregnation. The samples have been calcined at 400°C and 700°C and have been characterized for phase composition using x‐ray diffraction and Fourier transform infrared spectroscopy. The XPS analysis of the samples has been obtained by examination of the O 1s, K 2p, C 1s and La 3d spectral regions. The XPS data are discussed with respect to the calcination temperatures and the soot combustion performed in the spectrometer reaction chamber. Analysis of the XPS data indicates considerable carbonation of the surfaces of all samples, even after burning the soot. The K/La2O3 solid presents the highest content of surface carbonated species, showing the highest catalytic activity for soot combustion. Interaction of the catalysts with CO2 is studied by temperature‐programmed desorption and microbalance experiments. Kinetic studies and surface characterization of the potassium‐containing samples suggest that an appropriate surface potassium concentration is necessary for a synergetic action between potassium and lanthanum. In the cobalt‐containing catalysts calcined at 700°C, an increase is observed in the concentration of the outer‐layer perovskite species when the potassium content increases, following the same tendency observed in the bulk. Such LaCoO3 species would limit the reaction of lanthanum with CO2. Copyright © 2003 John Wiley & Sons, Ltd.