bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of reactive mineral powders used for poly(sodium acrylate) composite superabsorbents
Authors: Lee Wen‐Fu , Chen Yung‐Chu 
Published: May 2005

AbstractReactive mineral powders were prepared with a vinyl monomer as an intercalating agent, which was grafted onto the surface of nanoclay layers, to offer crosslinking points between the nanoclay layers. According to IR characterization, the vinyl group of (3‐acrylamidopropyl)trimethylammonium chloride, grafted onto the clay, disappeared after polymerization was performed. This spectral evidence confirmed that the reaction occurred between the clay layers. Thermogravimetric curves showed that the weight percentage remaining at 750°C for the intercalated clay/sodium acrylate nanocomposites was about 5 wt % higher than that for organic poly(sodium acrylate). This indicated that the clay was not diminished in the polymerization, and this process produced intercalated mica with a quaternary ammonium content of approximately 38.8 mmol/100 g and intercalated montmorillonite with a quaternary ammonium content of approximately 45.36 mmol/100 g. We also investigated the effect of reactive clays on the crystalline morphology and water absorbency for these nanocomposite hydrogels. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 855–861, 2005
Crosslinking of cotton cellulose in presence of alkyl di‐allyl ammonium salts. III. Study on pore structure of treated fabrics from dyeing kinetics
Authors: Chen Jui‐Chin 
Published: May 2005

AbstractTwo kinds of alkyl di‐allyl ammonium salts (alkyl groups = methyl and propyl) as crosslinking agents are combined with dimethyloldihydroxyethyleneurea (DMDHEU) to study rate constants, structural diffusion resistance constants, and other parameters of dyeing. The dye absorptions for the various crosslinking agents are ranked DMDHEU–propyl di‐allyl ammonium salt > DMDHEU–methyl di‐allyl ammonium salt > DMDHEU, and the equilibrium absorption values are ranked DMDHEU–propyl di‐allyl ammonium salt > DMDHEU–methyl di‐allyl ammonium salt > DMDHEU. The dyeing rate constants and structural diffusion resistance constants of the finished fabrics are in the order DMDHEU–methyl di‐allyl ammonium salt > DMDHEU–propyl di‐allyl ammonium salt > DMDHEU; however, the activation energies are ranked inversely. The treated fabrics for DMDHEU–alkyl di‐allyl ammonium salts have a larger pore structure than those for DMDHEU. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 862–866, 2005
Synthesis and characterization of amphiphilic block copolymers of methyl methacrylate with poly(ethylene oxide) macroinitiators formed by atom transfer radical polymerization
Authors: Krishnan R. , Srinivasan K. S. V. 
Published: May 2005

AbstractAmphiphilic ABA triblock copolymers of poly(ethylene oxide) (PEO) with methyl methacrylate (MMA) were prepared by atom transfer radical polymerization in bulk and in various solvents with a difunctional PEO macroinitiator and a Cu(I)X/N,N,N′,N″,N″‐pentamethyldiethylenetriamine catalyst system at 85°C where X=Cl or Br. The polymerization proceeded via controlled/living process, and the molecular weights of the obtained block copolymers increased linearly with monomer conversion. In the process, the polydispersity decreased and finally reached a value of less than 1.3. The polymerization followed first‐order kinetics with respect to monomer concentration, and increases in the ethylene oxide repeating units or chain length in the macroinitiator decreased the rate of polymerization. The rate of polymerization of MMA with the PEO chloro macroinitiator and CuCl proceeded at approximately half the rate of bromo analogs. A faster rate of polymerization and controlled molecular weights with lower polydispersities were observed in bulk polymerization compared with polar and nonpolar solvent systems. In the bulk polymerization, the number‐average molecular weight by gel permeation chromatography (Mn,GPC) values were very close to the theoretical line, whereas lower than the theoretical line were observed in solution polymerizations. The macroinitiator and their block copolymers were characterized by Fourier transform infrared spectroscopy, 1H‐NMR, matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry, thermogravimetry (TG)/differential thermal analysis (DTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). TG/DTA studies of the homo and block copolymers showed two‐step and multistep decomposition patterns. The DSC thermograms exhibited two glass‐transition temperatures at −17.7 and 92°C for the PEO and poly(methyl methacrylate) (PMMA) blocks, respectively, which indicated that microphase separation between the PEO and PMMA domains. SEM studies indicated a fine dispersion of PEO in the PMMA matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 989–1000, 2005
Morphology determination of functional poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene]/poly[oxa‐1,4‐phenylene‐1,2‐(1‐cyanovinylene)‐2‐methoxy,5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylene‐1,2‐(2‐cyanovinylene)‐1,4‐phenylene] blends as used for all‐polymer solar cells
Authors: Loos Joachim , Yang Xiaoniu , Koetse Marc M. , Sweelssen Jörgen , Schoo Herman F. M. , Veenstra Sjoerd C. , Grogger Werner , Kothleitner Gerald , Hofer Ferdinand 
Published: May 2005

AbstractPoly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene] (MDMO‐PPV) blended with poly[oxa‐1,4‐phenylene‐1,2‐(1‐cyanovinylene)‐2‐methoxy,5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylene‐1,2‐(2‐cyanovinylene)‐1,4‐phenylene] (PCNEPV) has been used as the active layer for an all‐polymer photovoltaic cell. The photovoltaic performance of devices is improved by a thermal treatment, which alters the morphology of the active layer. The morphology of the MDMO‐PPV/PCNEPV blend has been studied with conventional transmission electron microscopy and energy‐filtered transmission electron microscopy based on electron energy loss spectroscopy. The nitrogen of the cyano group within the PCNEPV has been be detected, and two‐dimensional nitrogen distribution maps have been acquired. Nitrogen‐rich domains have a size of approximately 20–50 nm and are homogeneously distributed over the entire film. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1001–1007, 2005
Synthesis of pentavalent imidovanadium complexes and their catalyses for the polymerization of ethylene and propylene
Authors: Sato Yoshinori , Nakayama Yuushou , Yasuda Hajime 
Published: May 2005

AbstractImidovanadium complexes with cyclopentadienyl (Cp) ligands—(Cp)V(NC6H4Me‐4)Cl2 (1), (Cp)V(NtBu)Cl2 (2), and (tBuCp)V(NtBu)Cl2 (3; tBuCp = tert‐butylcyclopentadienyl)—were synthesized through the reaction of imidovanadium trichloride with (trimethylsilyl)cyclopentadiene derivatives. The molecular structure of 3 was determined by X‐ray crystallography. The monocyclopentadienyl complex 1 exhibited moderate activity in combination with methylaluminoxane [MAO; 10.3 kg of polyethylene (mol of V)−1 h−1 atm−1], whereas similar complexes with bulky tBu groups, 2 and 3, were less active. (2‐Methyl‐8‐quinolinolato)imidovanadium complexes, V(NR)(O ˆN)Cl2 (R = C6H3iPr2‐2,6 (4) or n‐hexyl (5), O ˆN = 2‐methyl‐8‐quinolinolato), were obtained from the reaction of imidovanadium trichloride with 2‐methyl‐8‐quinolinol. Upon activation with modified MAO, complex 4 showed moderate activities for the polymerization of ethylene at room temperature. The complex 5/MAO system also exhibited moderate activity at 0°C. The polyethylenes obtained by these complexes had considerably high melting points, which indicated the formation of linear polyethylene. Moreover, the 5/dried MAO system showed propylene polymerization activities and produced polymers with considerably high molecular weights and narrow molecular weight distributions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1008–1015, 2005
Photopolymerization kinetics of dimethacrylate‐based light‐cured dental resins
Authors: Davidenko N. , García O. , Sastre R. 
Published: May 2005

AbstractThe influence of certain factors [structure and concentration of tertiary amines as coinitiators, monomer composition, presence of inorganic pigments, and incident light intensity (I0)] on the polymerization rates (Rp), polymerization quantum yields, and conversions of bisphenol A–bis(glycidyl methacrylate) (Bis‐GMA)/triethylene glycol dimethacrylate based resins was studied. The initial rate of bulk polymerization increased and the final conversion decreased with the content of Bis‐GMA in the mixture. In contrast, it was established that, for all monomer compositions, the Rp grew when increasing the I0, the Rp being directly proportional to the square root of I0. Such behavior is in agreement with the well‐known kinetic expression for the ideal radical photoinitiated polymerization in solution of monofunctional monomers, in spite of the complexity of the dimethacrylate mixtures that were studied. Both the structure and the concentration of reducing amine affected the efficiency of the initiator system and therefore the kinetic behavior of polymerization of these formulations under irradiation. The rate of polymerization increased with the increase of coinitiator concentration over the interval of 0–1%, but later it diminished when increasing the amine content, suggesting that the excess coinitiator retards the polymerization process. The study of the photoreduction of camphorquinone in the presence of different amines showed that the efficiency of the coinitiator depends not only on its ability to photoreduce camphorquinone, forming amine‐derived radicals, but also on the reactivity of these radicals toward the initiation of acrylic monomer polymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1016–1023, 2005
Proper finishing treatments for sun‐protective cotton‐containing fabrics
Authors: Ibrahim N. A. , Refai R. , Youssef M. A. , Ahmed A. F. 
Published: May 2005

AbstractTo enhance both the performance and ultraviolet‐protection properties of cotton‐containing fabrics, attempts have been made to use poly(carboxylic acid)s as non‐formaldehyde durable‐press finishing agents alone or in combination with certain additives followed by posttreatment with metal salt solutions. Furthermore, simultaneous dyeing and resin finishing in the presence of triethanolamine hydrochloride (TEA · HCl) or citric acid (CA) as a reactive additive along with different anionic or cationic dyestuffs have been examined. The results reveal that the ester crosslinking of cotton‐containing fabrics in the absence or presence of chitosan (5 g/L), β‐cyclodextrin (20 g/L), or choline chloride (20 g/L) as an additive results in an improvement in the fabric resiliency as well as the ultraviolet‐protection properties. The extent of the improvement is determined by the type of poly(carboxylic acid), type of additive, type of substrate (i.e., cotton or cotton/polyester blend), and pretreatment history (i.e., grey, bleached, or bleached and mercerized). The posttreatment of easy‐care finished fabric samples with a copper acetate solution (5 g/L) results in a dramatic improvement in the ultraviolet‐protection factor, especially with bleached cotton, grey cotton/polyester blend, and bleached cotton/polyester fabric samples, regardless of the additive. Simultaneous dyeing and resin finishing with Reactive Black 5 and Direct Violet 31, in the presence of TEA · HCL as a reactive additive, or with Basilene Red PB, in the presence of CA as a reactive additive, result in a sharp increase in both the depth of shade and the ultraviolet‐protection values, regardless of the substrate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1024–1032, 2005
Swelling behavior of gelatin‐g‐poly(butyl acrylate) copolymers
Authors: Zheng Jun Ping , Wang Jian Xun , Gao Shan , Yao Kang De 
Published: May 2005

AbstractGelatin‐g‐poly (butyl acrylate) copolymers were prepared with gelatin and butyl acrylate. The effects of various reaction parameters, including the concentration of the monomer, the concentration of the initiator, the concentration of gelatin, the reaction time, and the temperature, on the swelling behavior were studied systematically. In addition, the effect of the intercalation of graft copolymers with montmorillonite on the swelling behavior was investigated. The results indicated that the graft copolymerization and intercalation with montmorillonite could greatly reduce the swelling degree of gelatin. The swelling process of the copolymers followed second‐order kinetics identical to those of the original gelatin. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1033–1037, 2005
Feasibility evaluation of chitosan coatings on polyethylene tubing for biliary stent applications
Authors: Lin Chih‐Hsiu , Lin Jui‐Che , Chen Chiung‐Yu , Cheng Chu‐Yuan , Lin Xi‐Zhang , Wu Jiunn‐Jong 
Published: May 2005

AbstractEndoscopic palliation for the obstructive jaundice caused by biliary or pancreatic malignant tumors is a commonly used medical treatment. However, plastic biliary stents are occluded by sludge deposition caused by bacterial adhesion in 3–5 months. Chitosan, which has both good biocompatibility and antimicrobial capability, was used to modify the inner surface of polyethylene (PE) tubing in this study. Chitosan was deposited onto the inner surface of oxidized PE tubing with the methanol precipitation technique. Attenuated total reflection/Fourier transform infrared and electron spectroscopy for chemical analysis indicated that the chitosan coating was feasible. Contact‐angle measurements revealed that the surface hydrophilicity of the PE tubing increased with the chitosan coating. Morphological analysis with scanning electron microscopy showed that the PE surface became rougher and exhibited micropores after the chitosan coating. The adhesion of living Escherichia coli to chitosan‐coated PE stents, characterized by the spreading plate method and scanning electron microscopy analysis, was more significant than that to unmodified stents after a 24‐h phosphate‐buffered saline or bile perfusion test. This finding may be attributed to the rougher and slightly positively charged surface of chitosan‐coated PE tubing and to the CH3 hydrophobic functional groups in the chitosan structure. Because of its good biocompatibility, chitosan coated on the surface of PE can still be used for biliary stent applications with further chemical modification, such as sulfonation and quaternization, to increase its antimicrobial ability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 893–902, 2005
Development of thermoregulating textile materials with microencapsulated phase change materials (PCM). IV. Performance properties and hand of fabrics treated with PCM microcapsules
Authors: Shin Younsook , Yoo Dong‐Il , Son Kyunghee 
Published: May 2005

AbstractPolyester knit fabrics were treated with phase‐change‐material microcapsules by a pad–dry–cure method with a polyurethane binder. The treated fabrics were evaluated in terms of the thermal properties, air permeability, moisture vapor permeability, moisture regain, low‐stress mechanical properties, and hand, with respect to the add‐on of microcapsules. The surface morphology of the treated fabrics was investigated with scanning electron microscopy. The low‐stress mechanical properties of the treated fabrics, including the tensile, shear, bending, surface, and compression properties, were measured with the Kawabata evaluation system for fabrics (KES‐FB). As the add‐on increased, the heat storage capacity of the treated fabrics increased. The treated fabric with 22.9% add‐on was capable of absorbing 4.44 J/g of heat. The air permeability and moisture vapor permeability decreased, whereas the moisture regain increased, with an increase in the add‐on. The tensile linearity and geographical roughness increased, whereas the resilience, bending, and shear properties decreased with an increase in the add‐on. The fabrics became stiffer, less smooth, and less full as the add‐on increased, and thus the total hand value decreased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 910–915, 2005
Particleboards from peanut‐shell flour
Authors: Batalla Leonel , Nuñez Adrián J. , Marcovich Norma E. 
Published: May 2005

AbstractPeanuts have been cultivated worldwide for hundreds, if not thousands, of years. However, most peanuts are sold without the shell, and so large quantities of peanut shells remain as byproducts in the field, not being used properly. In this work, the feasibility of making particleboard from milled peanut shells was studied. To obtain medium‐density panels, a low compaction pressure and a high fiber content were used. The physical and mechanical properties of the panels were similar to those reported for wood‐based particleboard when 80 wt % filler was used. The void content of the panels was experimentally determined and used in an attempt to predict the mechanical response of the panels. The stiffness of the particleboard could be greatly improved by a reduction of the porosity, but even a low void content had a critical effect on the strength of the composites. The stiffness of the composites could only be reasonably represented with simple theoretical models when the effect of the porosity was incorporated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 916–923, 2005
Characterization of 2‐(2‐methoxyethoxy)ethanol‐substituted phosphazene polymers using pervaporation, solubility parameters, and sorption studies
Authors: Orme Christopher J. , Klaehn John R. , Harrup Mason K. , Lash Robert P. , Stewart Frederick F. 
Published: May 2005

AbstractTwo linear phosphazene polymers were synthesized with differing amounts of hydrophilic 2‐(2‐methoxyethoxy)ethanol (MEE) and hydrophobic 4‐methoxyphenol (MEOP) substituted on the backbone. These high polymers were cast into membranes and their permeability to water, methanol, ethanol, and 2‐propanol was evaluated as a function of temperature. An additional polymer with a low content of MEE was studied for water permeation and was characterized by trace flux. At higher levels of MEE on the backbone, fluxes of all solvents increased. Solubility also was found to increase with increasing MEE content for all solvents except water. Unexpectedly, water was found to be less soluble in the higher MEE polymer, although higher membrane fluxes were observed. Diffusion coefficients showed the following trend: methanol ≫ 2‐propanol > ethanol ≫ water. Finally, the affinity of solvents and polymers was discussed in terms of Hansen solubility parameters. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 939–945, 2005
Tests for Differentiation in Gene Expression Using a Data‐Driven Order or Weights for Hypotheses
Authors: Hommel Gerhard , Kropf Siegfried 
Published: May 2005

AbstractIn the analysis of gene expression by microarrays there are usually few subjects, but high‐dimensional data. By means of techniques, such as the theory of spherical tests or with suitable permutation tests, it is possible to sort the endpoints or to give weights to them according to specific criteria determined by the data while controlling the multiple type I error rate. The procedures developed so far are based on a sequential analysis of weighted p ‐values (corresponding to the endpoints), including the most extreme situation of weighting leading to a complete order of p ‐values. When the data for the endpoints have approximately equal variances, these procedures show good power properties.In this paper, we consider an alternative procedure, which is based on completely sorting the endpoints, but smoothed in the sense that some perturbations in the sequence of the p ‐values are allowed. The procedure is relatively easy to perform, but has high power under the same restrictions as for the weight‐based procedures. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Peptide hairpins with strand segments containing α‐ and β‐amino acid residues: Cross‐strand aromatic interactions of facing Phe residues
Authors: Roy Rituparna S. , Gopi Hosahudya N. , Raghothama S. , Gilardi Richard D. , Karle Isabella L , Balaram Padmanabhan 
Published: May 2005

AbstractThe incporation of β‐amino acid residues into the strand segments of designed β‐hairpin leads to the formation of polar sheets, since in the case of β‐peptide strands, all adjacent carbonyl groups point in one direction and the amide groups orient in the opposite direction. The conformational analysis of two designed peptide hairpins composed of α/β‐hybrid segments are described: Boc–Leu–βPhe–Val–D‐Pro–Gly–Leu–βPhe–Val–OMe (1) and Boc–βLeu–Phe–βVal–D‐Pro–Gly–βLeu–Phe–βVal–OMe (2). A 500‐MHz 1H‐NMR (nuclear magnetic resonance) analysis in methanol supports a significant population of hairpin conformations in both peptides. Diagnostic nuclear Overhauser effects (NOEs) are observed in both cases. X‐ray diffraction studies on single crystals of peptide 1 reveal a β‐hairpin conformation in both the molecules, which constitute the crystallographic asymmetric unit. Three cross‐strand hydrogen bonds and a nucleating type II′ β‐turn at the D‐Pro–Gly segment are observed in the two independent molecules. In peptide 1, the βPhe residues at positions 2 and 7 occur at the nonhydrogen‐bonding position, with the benzyl side chains pointing on opposite faces of the β‐sheet. The observed aromatic centroid‐to‐centroid distances are 8.92 Å (molecule A) and 8.94 Å (molecule B). In peptide 2, the aromatic rings must occupy facing positions in antiparallel strands, in the NMR‐derived structure.Peptide 1 yields a normal “hairpin‐like” CD spectrum in methanol with a minimum at 224 nm. The CD spectrum of peptide 2 reveals a negative band at 234 nm and a positive band at 221 nm, suggestive of an exciton split doublet. Modeling of the facing Phe side chains at the hydrogen‐bonding position of a canonical β‐hairpin suggests that interring separation is ∼4.78 Å for the gauche+gauche− (g+g−) rotamer. A previously reported peptide β‐hairpin composed of only α‐amino acids, Boc–Leu–Phe–Val–D‐Pro–Gly–Leu–Phe–Val–OMe also exhibited an anomalous far‐UV (ultraviolet) CD (circular dichroism) spectrum, which was interpreted in terms of interactions between facing aromatic chromophores, Phe 2 and Phe 7 (C. Zhao, P. L. Polavarapu, C. Das, and P. Balaram, Journal of the American Chemical Society, 2000, Vol 122, pp. 8228–8231). © 2005 Wiley Periodicals, Inc. Biopoly 80: 787–799, 2005This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com