bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical properties of ethyl‐cyanoethyl cellulose/poly(acrylic acid) cholesteric liquid crystalline composite films
Authors: Wang Linge , Wang Xiaohua , Huang Yong 
Published: February 2004

AbstractEthyl‐cyanoethyl cellulose [(E–CE)C]/poly(acrylic acid) (PAA) composite films were prepared by photopolymerizing acrylic acid (AA) in (E–CE)C/AA cholesteric liquid crystalline solutions. With the selection of suitable concentrations, (E–CE)C/PAA composite films showed vivid colors due to the selective reflection property of the cholesteric phase. It was found that the wavelength of reflection was a function of the concentration of (E‐CE)C, and the reflectivity was increased with increasing thickness of the film. The selective reflection of the composite holds well upon heating at temperatures below 160°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 213–217, 2004
Photopolymerization of an expanding monomer with an aromatic dioxirane
Authors: Smith Robert E. , Pinzino Charles S. , Chappelow Cecil C. , Holder Andrew J. , Kostoryz Elisabet L. , Guthrie Jill R. , Miller Matthew , Yourtee David M. , Eick J. David 
Published: February 2004

AbstractThe objective was to study the photocationic polymerization of an expanding monomer, 1,5,7,11‐tetraoxaspiro[5.5]undecane (TOSU), and an aromatic dioxirane, bisphenol A diglycidyl ether (BADGE). Both homopolymerizations and binary polymerizations were conducted. The homopolymer, poly(TOSU), was found to be a linear poly(carbonate), which was soluble in acetone. Poly(BADGE) products contained ether linkages in addition to primary and secondary alcohol functionalities. Binary polymerization products varied depending on the irradiation time and length of dark cure. 13C‐NMR analysis of binary polymerizate products revealed peaks not seen in homopolymer spectra consistent with the formation of copolymer linkages. Mass spectrometry data revealed peaks consistent with oligomers that contained both TOSU and BADGE mer units. The structures of key reaction products were proposed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 62–71, 2004
Miscibility and properties of blend materials from waterborne polyurethane and carboxymethyl konjac glucomannan
Authors: Yang Guang , Huang Qilin , Zhang Lina , Zhou Jinping , Gao Shanjun 
Published: February 2004

AbstractWe prepared composite materials by blending waterborne polyurethane (WPU) and carboxymethyl konjac glucomannan (CMKGM) with CMKGM content from 15 to 80 wt % in an aqueous system. The structures and properties of the blend materials were characterized by FTIR, dynamic mechanical analysis, ultraviolet spectroscopy, scanning electron microscopy, wide‐angle X‐ray diffraction, thermogravimetric analysis, and tensile testing. The results indicated that the blend sheet with 80 wt % CMKGM exhibited good miscibility and higher tensile strength (89.1 MPa) than that of both WPU (3.2 MPa) and CMKGM (56.4 MPa) sheets. Moreover, with an increase of CMKGM content, the tensile strength, Young's modulus, and thermal stability increased significantly, attributed to intermolecular hydrogen bonding between CMKGM and WPU. Based on the experimental results, the blend materials have good, or a certain degree of, miscibility over the whole range of composition ratio of WPU to CMKGM. In addition, the blend materials exhibited organic solvent resistance. This work not only provided a simple method to prepare environmentally friendly materials, but also expanded the application of CMKGM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 77–83, 2004
Modifying adhesion of linear low‐density polyethylene to polypropylene by blending with a homogeneous ethylene copolymer
Authors: Poon B. C. , Chum S. P. , Hiltner A. , Baer E. 
Published: February 2004

AbstractAdhesion of a Ziegler–Natta catalyzed ethylene copolymer (ZNPE) to polypropylene (PP) was studied by measuring the delamination toughness G of coextruded microlayers by using the T‐peel test. Low values of G compared to a homogeneous copolymer with approximately the same short chain branch (SCB) content were attributed to an amorphous interfacial layer of low molecular weight, highly branched ZNPE fractions. Blending ZNPE with a homogeneous metallocene catalyzed copolymer (mPE) increased G. In this regard, mPE with higher SCB content was more effective than mPE with slightly lower SCB content. The ZNPE interface was mimicked by microlayering ZNPE and ZNPE blends with polystyrene from which the ZNPE layers were easily separated without damage to the surface. Examination with atomic force microscopy revealed a soft coating about 8 nm thick on the surface of the ZNPE layer. Blending with mPE reduced or eliminated the amorphous interfacial layer. It was proposed that mPE increased miscibility of low molecular weight, highly branched fractions of ZNPE and prevented their segregation at the interface. After blending with mPE eliminated the interfacial layer, G increased to a value comparable to that of a homogeneous copolymer with about the same SCB content as ZNPE bulk chains. The increase in G was attributed to epitaxial crystallization of the ethylene copolymer in the absence of an amorphous interfacial layer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 109–115, 2004
Formation of thermosensitive water‐soluble copolymers with phosphinic acid groups and the thermosensitivity of the copolymers and copolymer/metal complexes
Authors: Nonaka Takamasa , Hanada Yukiko , Watanabe Tsutomu , Ogata Tomonari , Kurihara Seiji 
Published: February 2004

AbstractThermosensitive and water‐soluble copolymers were prepared through the copolymerization of acryloyloxypropyl phosphinic acid (APPA) and N‐isopropyl acrylamide (NIPAAm). The thermosensitivity of the copolymers and copolymer/metal complexes was studied. The APPA–NIPAAm copolymers with less than 11 mol % APPA moiety had a lower critical solution temperature (LCST) of approximately 45°C, but the APPA–NIPAAm copolymers with greater than 21 mol % APPA moiety had no LCST from 25 to 55°C. The APPA–NIPAAm copolymers had a higher adsorption capacity for Sm3+, Nd3+, and La3+ than for Cu2+, Ni2+ and Co2+. The APPA–NIPAAm (10:90) copolymer/metal (Sm3+, Nd3+, or La3+) complexes became water‐insoluble above 45°C at pH 6–7, but the APPA–NIPAAm (10:90) copolymer/metal (Cu2+,Ni2+, or Co2+) complexes were water‐soluble from 25 to 55°C at pH 6–7. The temperature at which both the APPA–NIPAAm copolymers and the copolymer/metal complexes became water‐insoluble increased as the pH values of the solutions increased. The APPA–NIPAAm copolymers were able to separate metal ions from their mixed solutions when the temperature of the solutions was changed; this was followed by centrifugation of the copolymer/metal complexes after the copolymers were added to the metal solutions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 116–125, 2004
Mechanical and fracture behavior of an artificially ultraviolet‐irradiated poly(ethylene‐carbon monoxide) copolymer
Authors: Abanto‐Bueno J. , Lambros J. 
Published: February 2004

AbstractIn this work, 1 wt % carbon monoxide (CO) poly(ethylene‐carbon monoxide) (ECO) copolymer sheets were artificially exposed to ultraviolet (UV) light with a power density of 3 mW/cm2 for up to 130 h. A thorough mechanical characterization of the irradiated material was conducted, in which both the stress–strain data and the values of the quasistatic crack initiation and growth toughness were measured and correlated with companion uniaxial tensile tests and single‐edge‐notched fracture tests. Average values of the elastic modulus, failure strain, and failure stress were determined from the tensile tests. The full‐field optical technique of digital image correlation was used to quantify in‐plane deformation (displacements and displacement gradients) during the fracture experiments and to extract values of the crack initiation and growth fracture toughness. The elastic modulus increased monotonically with UV irradiation for the exposure times used in this investigation. In addition, for low irradiation times of less than 5 h, both the failure strain and failure stress of ECO decreased, and this caused a corresponding decrease in the crack initiation and growth toughness. However, for longer irradiation times, the failure strain remained almost invariable, whereas the failure stress increased by about 25% over that of unirradiated ECO. As a result, for longer irradiation times (>5 h), 1 wt % CO ECO became not only stiffer but also stronger and tougher, as quantified by companion fracture experiments. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 139–148, 2004
Design and synthesis of new photoresist materials for ArF lithography
Authors: Seo Hwang‐Un , Jin Sung‐Ho , Choi Sang‐Jun , Gal Yeong‐Soon , Lim Kwon Taek 
Published: February 2004

AbstractA new class of photoresist matrix polymers based on vinyl ether–maleic anhydride (VEMA) alternating copolymers was developed for ArF single‐layer lithography. These polymers were synthesized by copolymerization of alkyl vinyl ether and maleic anhydride alternating copolymers with acrylate derivatives containing bulky alicyclic acid‐labile protecting groups. The resulting polymers showed good control of polymerization and high transmittance. Also, these resists exhibited good adhesion to the substrate, high dry‐etching resistance against CF4 mixture gas (1.02 times the etching rate of deep UV resist), and high selectivity to silicon oxide etching. Using an ArF excimer laser exposure system with 0.6 NA, 120‐nm L/S patterns were resolved under conventional illumination. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 165–170, 2004
Fumaryl chloride and maleic anhydride–derived crosslinked functional polymers for nonlinear optical waveguide applications
Authors: Maaref Shahin , Roz Zeina , Sun Sam‐Shajing , Seo Kang , Winston Kizzy , Bonner Carl E. 
Published: February 2004

AbstractThe synthesis, processing, and characterization of new crosslinked functional polymer thin films derived from fumaryl chloride and maleic anhydride is presented. Experimental data demonstrated that this is a versatile, convenient, and cost‐effective method of fabricating ultrastructure crosslinked and functional polymer thin films for potential nonlinear optical (NLO) or other applications where molecular orientation is required. The unsaturated and processable polyester thin films are capable of crosslinking in air to form a hardened lattice under a variety of conditions, including both thermal and photoinitiated crosslinking. The thermal stability of the second harmonic (SHG) signal for a crosslinked NLO thin film was stable at temperatures up to 150°C, which is in contrast to uncrosslinked polymers whose SHG signals typically decreased over 50% below 100°C. Because of the lack of NH/OH groups and their vibrational overtones in the polymer, these crosslinked polyester systems have a great potential for low optical loss applications at 1550 nm communication wavelength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 317–322, 2004
Engineering the friction‐and‐wear behavior of polyelectrolyte multilayer nanoassemblies through block copolymer surface capping, metallic nanoparticles, and multiwall carbon nanotubes
Authors: Pavoor Prem V. , Gearing Brian P. , Gorga Russell E. , Bellare Anuj , Cohen Robert E. 
Published: February 2004

AbstractIn previous work, it was demonstrated that coating a surface with polyelectrolyte multilayers (PEMs) composed of polyallylamine hydrochloride (PAH) and poly(acrylic acid) (PAA) resulted in increased friction forces at low normal loads. At stress levels sufficient to cause system wear, however, PAH/PAA PEMs provided significant wear protection for the underlying substrate. This report evaluates three strategies for reducing the coefficients of friction associated with PEMs at low normal stress, while retaining their wear‐retarding properties at high normal loads. Anchoring polystyrene‐block‐poly(acrylic acid) to the PAH surface of a multilayer film, less than 10 nm thick, enhanced the hardness, and hence the load‐bearing capacity of these structures. The effect of surface capping was most pronounced at high normal stresses, where substantial wear prevention was observed, accompanied by low friction forces. These films are well suited for systems where wear particle generation hinders smooth operation. The second strategy used the in situ synthesis of silver nanoparticles in the PEM matrix for friction reduction. Optimum levels of silver clusters are required at the surface to reduce the friction forces. Finally, multilayer composites were constructed using PAH and multiwall carbon nanotubes. These assemblies exhibited the lowest values of friction among the strategies studied, at all levels of stress; in addition, substrate wear prevention was also achieved. The tribological behavior of the PEM‐modification strategies was correlated with the mechanical properties of the films, elicited by nanoindentation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 439–448, 2004
On line measurement of crystallinity of nylon 6 nanocomposites by laser Raman spectroscopy and neural networks
Authors: Ergungor Z. , Batur C. , Cakmak M. 
Published: February 2004

AbstractA neural network is trained to estimate the unknown crystallinity and temperature of Nylon 6 and its nanocomposites while the material is undergoing cooling at a fixed rate. The innovation of the work is that the full spectrum captured by the laser Raman spectroscope is used to train a neural network for estimation of crystallinity and temperature. The small‐angle light scattering (SALS) and differential scanning calorimetry (DSC) data were used to provide the training examples for the neural network. Results indicate that the neural network can provide reliable estimates of the crystallinity and temperature provided that there is a sufficient number of training data available. Neural network methodology is also efficient in establishing the crystallization–temperature relationship as a function of cooling rate and demonstrates the heterogeneous nucleation effect of nanoclay in the nylon 6 matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 474–483, 2004
Weathering studies of epoxidized and hydroxy‐fluoroester pendent guayule rubber in powder coatings
Authors: Gupta Sandhya , Mendon Sharathkumar K. , Thames Shelby F. 
Published: February 2004

AbstractAlthough numerous coatings have been synthesized from guayule rubber derivatives, there have been no studies detailing the weatherability of such coatings. We report herein the results of accelerated weathering tests on powder coatings synthesized from epoxidized guayule rubber (EGR) and hydroxy‐fluoroester pendent guayule rubber (FGR) derivatives. Our studies indicate that EGR and FGR powder coatings exposed to alternating cycles of fluorescent UVA light and water condensation for 400 h exhibit reduced yellowing and a high degree of gloss retention. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 493–497, 2004
Vitamin A microencapsulation within poly(methyl methacrylate)‐g‐polyethylenimine microspheres: Localized proton buffering effect on vitamin A stability
Authors: Lee Jong Suk , Nam Yoon Sung , Kang Byung‐Young , Han Sang‐Hoon , Chang Ih‐Seop 
Published: February 2004

AbstractTo stabilize vitamin A in a cosmetic/dermatological formulation, we present here a new encapsulation method based on polymer microspheres having a localized “proton‐buffering” capacity. Poly(methyl methacrylate)‐g‐polyethylenimine (PMMA‐g‐PEI) was prepared by direct condensation grafting of PEI onto poly(methyl methacrylate‐co‐methyl acrylic acid). The reaction was confirmed by FT‐IR analysis showing the amide vibration at 1,550 cm−1. Elemental analysis indicated that the weight content of the grafted PEI was 1.6% (w/w). Vitamin A was encapsulated into PMMA‐g‐PEI microspheres by using an oil‐in‐water (O/W) single emulsion method. The presence of PEI moiety dramatically improved the chemical stability of vitamin A in microspheres. Vitamin A encapsulated within PMMA‐g‐PEI microspheres maintained 91% of its initial activity after 30‐day incubation at 40°C, while only maintaining 60% within plain PMMA microspheres. This study demonstrates that proton‐buffering within hydrophobic polymer matrix is a useful strategy for stabilizing “acid‐labile” active ingredients. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 517–522, 2004
Polypropylene/montmorillonite composites and their application in hybrid fiber preparation by melt‐spinning
Authors: Zhang Xiuqin , Yang Mingshu , Zhao Ying , Zhang Shimin , Dong Xia , Liu Xuexin , Wang Dujin , Xu Duanfu 
Published: February 2004

AbstractPolypropylene (PP)/organomontmorillonite (OMMT) nanocomposites have been successfully prepared by melt intercalation by using the conventional method of twin‐screw extrusion and subsequently submitted for melt‐spinning. The structure and properties of the PP/clay nanocomposites and hybrid fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and crystallization dynamics, etc. The organoclay layers were found to disperse in the PP resin at the nanometer level. The nanoscaled OMMT layers, dispersed in the PP matrix, actually played the role of heterogeneous nuclei species in the process of PP crystallization and increased the nucleation speed of the composites, hereby leading to the increase of crystallization rate of the as‐spun fiber. Meanwhile, it was found that the crystallinity of PP/OMMT hybrid fibers is much higher than that of pure PP fiber at the same draw ratios, whereas the orientation of PP/OMMT hybrid fibers is much lower than that of pure PP fiber at the same draw ratios. Because of the effective intercalation of OMMT into PP matrix, the nanocomposites have good spinnability, and the moisture absorption of the final PP fiber is improved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 552–558, 2004
Kinetic study by FTIR, TMA, and DSC of the curing of a mixture of DGEBA resin and γ‐butyrolactone catalyzed by ytterbium triflate
Authors: Ramis Xavier , Salla Josep Maria , Mas Cristina , Mantecón Ana , Serra Angels 
Published: February 2004

AbstractA mixture of diglycidylether of bisphenol A (DGEBA) and γ‐butyrolactone (γ‐BL) was cured in the presence of ytterbium triflate as a catalyst. The kinetics of the various elemental processes that occur in the curing process were studied by means of isothermal curing in the FTIR spectrometer. The kinetics of the contraction during the curing was also evaluated by TMA. In both cases, the kinetics was analyzed by means of isoconversional procedure and the kinetic model was determined with the so‐called compensation effect (isokinetic relationship). The isothermal kinetic analysis was compared with that obtained by dynamic curing in DSC. We found that all the reactive processes and the contraction follow a surface‐controlled reaction type of kinetic mechanism, R3. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 381–393, 2004
Effect of non‐exponential and multi‐exponential decay behavior on the performance of the direct exponential curve resolution algorithm (DECRA) in NMR investigations
Authors: Alam Todd M. , Alam M. Kathleen 
Published: January 2004

AbstractThe effect of non‐exponential and multi‐exponential decay or relaxation behavior on the performance of the direct exponential curve resolution algorithm (DECRA) is investigated through a series of numerical simulations. Three different combinations of decay or relaxation behavior were investigated through DECRA analysis of simulated pulse gradient spin echo (PGSE) NMR diffusion spectra that contained the combination of two individual components. The diffusion decay behavior of one component was described by a single‐exponential decay, while the second component was described by either (1) a multi‐exponential decay, (2) a decay behavior described by the empirical Kohlrausch–Williams–Watts (KWW) relation or (3) a multi‐exponential decay behavior correlated with variations in the NMR spectral line shape. The magnitudes and types of errors produced during the DECRA analysis of spectral data with deviations from a pure single‐exponential decay behavior are presented. It is demonstrated that the deviation from single‐exponential decay impacts the resulting calculated line shapes, the calculated relative concentrations and the quantitative estimation of the decay or relaxation time constants of both components present in the NMR spectra. Copyright © 2004 John Wiley & Sons, Ltd.
Polytopal Rearrangement of [Ni(acac)2(py)]: A New Square Pyramid⇄Trigonal Bipyramid Twist Mechanism
Authors: Daul Claude , Niketic Svetozar , Rauzy Cédrick , Schläpfer Carl‐Wilhelm 
Published: February 2004

AbstractThe interconversion mechanisms between three idealized polytopal forms (a square pyramid and two trigonal bipyramids) of [M(bidentate)2(unidentate)] were investigated by an original combination of molecular mechanics (MM) and density functional theory (DFT) approaches. MM was used to model the mechanistic rearrangement path, and DFT to study selected points along this path. The test case was a five‐coordinate [Ni(acac)2(py)] species. In the case of [Ni(acac)2(py)] it was confirmed (both by MM and by DFT) that the three polytopal forms do indeed represent shallow local minima, of which the square pyramid (SQP) is more stable than the other two. Small energy barriers that separate the three minima prevent spontaneous rearrangement among the polytopal forms in geometry‐optimization simulations. The driving force for MM simulation of the polytopal rearrangements was supplied through the L‐M‐L angle bending terms. MM results for relative energies and geometries are fully supported by DFT. Finally, the implication of the present results to explain some racemization mechanisms of octahedral complexes (namely, the intramolecular bond rupture of tris(chelate) species, and intermolecular dissociation of bis(bidentate) species) is briefly discussed.