bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheological properties of water solutions of syndiotactic poly(vinyl alcohol) of different molecular weights
Authors: Kim Sam Soo , Seo In Seok , Yeum Jeong Hyun , Ji Byung Chul , Kim Joon Ho , Kwak Jin Woo , Yoon Won Sik , Noh Seok Kyun , Lyoo Won Seok 
Published: March 2004

AbstractTo precisely identify the effect of the molecular weight of syndiotacticity‐rich poly(vinyl alcohol) (s‐PVA) on the rheological properties of s‐PVA/water solutions, we prepared four s‐PVAs with a syndiotactic dyad content of 57%, a degree of saponification (DS) of 99.9%, and number‐average degrees of polymerization (Pn's) of 300, 1300, 2700, and 4000. Through a series of experiments, we found that the molecular weight of poly(vinyl alcohol) had a significant influence on the rheological properties of s‐PVA/water solutions. Over a frequency range of 10−1 to 102 rad/s, the s‐PVA/water solution with the highest Pn value showed the largest values of the complex viscosity, storage modulus, and loss modulus at similar syndiotacticity and DS values of s‐PVA, and this suggested that the higher Pn was, the stronger the internal ordered structure was in the molecules. All the s‐PVA/water solutions showed shear‐thinning behavior, which implied heterogeneity. In a modified Casson plot, Bingham flow behaviors, which gave rise to non‐zero yield stress, were evident. This suggested that some pseudostructure existed in the s‐PVA/water solutions. The yield stress increased with Pn, and this implied that the pseudostructure was developed as Pn increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1426–1431, 2004
Design of organic electroluminescent displays with ultraviolet‐shielding filters
Authors: Lee Rong Ho , Huang Chen Yang , Chen Chin‐Ti 
Published: March 2004

AbstractThe electroluminescence properties of polymer light‐emitting devices with and without an ultraviolet (UV)‐shielding filter were studied. The polymer light‐emitting devices were fabricated with poly(2‐methoxy‐5,2′‐ethyl‐hexyloxy‐1,4‐phenylene vinylene) as the light emitter and poly(ethylenedioxy thiophene) as the hole‐transporting material. The UV‐shielding filter was composed of alternating TiO2 and SiO2 dielectric multilayers made by a physical vacuum deposition process. The current density, brightness, and photometric efficiency decreased significantly for the polymer light‐emitting device without the UV‐shielding filter after irradiation by UV light. The decay of PLEDs due to UV degradation was greatly reduced by the UV‐shielding filter. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1432–1436, 2004
Preparation and properties of hydrophilic–hydrophobic chitosan derivatives
Authors: Yang Hua , Zhou Shaobing , Deng Xianmo 
Published: March 2004

AbstractHydrophilic–hydrophobic chitosan derivatives were obtained through the attachment of lactose and alkyl groups to the amino group of chitosan with potassium borohydride. The carboxymethylation of the chitosan derivatives was completed. They had excellent solubility in water. When they were prepared as hydrogels, the hydrogels had adjustable hydrophobicity and excellent hydrophilicity according to swelling measurements. All of them showed potential for applications in medical fields. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1625–1632, 2004
Dynamically cured polypropylene/epoxy blends
Authors: Jiang Xueliang , Huang Hua , Zhang Yong , Zhang Yinxi 
Published: March 2004

AbstractThe dynamic vulcanization process, usually used for the preparation of thermoplastic elastomers, was used to prepare polypropylene (PP)/epoxy blends. The blends had crosslinked epoxy resin particles finely dispersed in the PP matrix, and they were called dynamically cured PP/epoxy blends. Maleic anhydride grafted polypropylene (MAH‐g‐PP) was used as a compatibilizer. The effects of the reactive compatibilization and dynamic cure were studied with rheometry, capillary rheometry, and scanning electron microscopy (SEM). The crystallization behavior and mechanical properties of PP/epoxy, PP/MAH‐g‐PP/epoxy, and dynamically cured PP/epoxy blends were also investigated. The increase in the torque at equilibrium for the PP/MAH‐g‐PP/epoxy blends indicated the reaction between maleic anhydride groups of MAH‐g‐PP and the epoxy resin. The torque at equilibrium of the dynamically cured PP/epoxy blends increased with increasing epoxy resin content. Capillary rheological measurements also showed that the addition of MAH‐g‐PP or an increasing epoxy resin content increased the viscosity of PP/epoxy blends. SEM micrographs indicated that the PP/epoxy blends compatibilized with PP/MAH‐g‐PP had finer domains and more obscure boundaries than the PP/epoxy blends. A shift of the crystallization peak to a higher temperature for all the PP/epoxy blends indicated that uncured and cured epoxy resin particles in the blends could act as effective nucleating agents. The spherulites of pure PP were larger than those of PP in the PP/epoxy, PP/MAH‐g‐PP/epoxy, and dynamically cured PP/epoxy blends, as measured by polarized optical microscopy. The dynamically cured PP/epoxy blends had better mechanical properties than the PP/epoxy and PP/MAH‐g‐PP/epoxy blends. With increasing epoxy resin content, the flexural modulus of all the blends increased significantly, and the impact strength and tensile strength increased slightly, whereas the elongation at break decreased dramatically. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1437–1448, 2004
Nylon 6 microfiber prepared by carbon dioxide laser heating
Authors: Suzuki Akihiro , Kamata Kaori 
Published: March 2004

AbstractA nylon 6 microfiber was easily obtained through carbon dioxide laser heating. The laser heating was carried out in two steps: the first laser heating was performed under an applied tension of 36.7 MPa at a power density of 17.3 W cm−2, and the second was performed under 0.18 MPa at 51.81 W cm−2. The microfiber was obtained by the second laser heating of the fiber. The microfiber prepared under the optimum thinning conditions had a diameter of 1.9 μm and a birefringence of 46.2 × 10−3. Its draw ratio, estimated from the diameter, was 9895× (so far, it has been impossible to achieve such a high draw ratio by drawing). A (200) reflection and a (002/202) doublet due to an α form were observed on the equator, but no (200) reflection due to a γ form was observed. The morphology of the crystallites existing in the microfiber was only the α form. Laser heating made the microfiber more easily than conventional technologies, such as conjugate spinning, melt blowing, and flash spinning. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1449–1453, 2004
Nylon 6 microfiber obtained by a continuous‐thinning method with a carbon dioxide laser
Authors: Suzuki Akihiro , Kamata Kaori 
Published: March 2004

AbstractWe succeeded in producing nylon 6 microfibers with a continuous‐thinning method with a carbon dioxide (CO2) laser. A laser‐thinning apparatus used to continuously prepare microfibers was developed in our laboratory; it consisted of spools supplying and winding the fibers, a continuous‐wave CO2‐laser emitter, a system supplying the fibers, and a traverse. The laser‐thinning apparatus produced microfibers in the range of 100–2500 m min−1. The diameter of the microfibers decreased as the winding speed increased, and the birefringence increased as the winding speed increased. When microfibers, obtained through the laser irradiation (at a power density of 19.8 W cm−2) of the original fiber supplied at 0.32 m min−1, were wound at 848 m min−1, they had a diameter of 3.2 μm and a birefringence of 47 × 10−3. The draw ratio calculated from the supplying and winding speeds was 2650×. Scanning electron microscopy showed that the microfibers obtained with the laser‐thinning apparatus had smooth surfaces not roughened by laser ablation that were uniform in diameter. Wide‐angle X‐ray diffraction photographs of the microfibers wound at 566 and 848 m min−1 showed equatorial and meridional reflections due to the γ from. These reflections gradually became clear as the winding speed increased. The developed apparatus more easily produced microfibers than conventional technologies, such as conjugate spinning, islands‐in‐a‐sea fiber spinning, melt blowing, and flash spinning. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1454–1458, 2004
Hyperbranched conjugated polymers for photovoltaic applications
Authors: Qiao Jing , Yang Chunhe , He Qingguo , Bai Fenglian , Li Yongfang 
Published: March 2004

AbstractThree hyperbranched phenylene vinylenes (HPVs)—H‐mn, H‐es, and H‐py—were used in fabricating polymer photovoltaic cells (PVCs). PVCs with photoactive layers composed of pure HPV, a blend of HPV and C60, and a blend of HPV, poly(2‐methoxyl‐5,2′‐ethylhexyoxyl‐1,4‐phenylene vinylene) (MEH‐PPV), and C60, were fabricated, and their current–voltage characteristics were measured and investigated. The PVC with photoactive layers composed of H‐es and C60 showed promising photovoltaic characteristics, with an energy‐conversion efficiency of 0.035%, when illuminated under 85 mW/cm2 white light. The short‐circuit current and energy‐conversion efficiency of the PVCs based on H‐mn/C60 and H‐py/C60 were greatly improved when they were blended with a small amount of MEH‐PPV. The incident photon‐to‐collected‐electron efficiency of the HPV/MEH‐PPV/C60 PVCs indicated that both HPVs and MEH‐PPV contributed to the photocurrent. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1459–1466, 2004
Pseudo‐first‐order kinetic studies of the sorption of acid dyes onto chitosan
Authors: Wong Y. C. , Szeto Y. S. , Cheung W. H. , McKay G. 
Published: March 2004

AbstractThe adsorption of five acid dyes onto chitosan, derived through the deacetylation of crab‐shell chitin, from aqueous solutions was studied. The equilibrium isotherms were measured and analyzed with the Langmuir, Freundlich, and Redlich–Peterson equations; the results correlated well with the Langmuir equation. Kinetic studies were also performed in an agitated batch adsorber to study the effect of the initial dye concentration and the mass of chitosan. The kinetics were analyzed with the pseudo‐first‐order rate equation, and the rate constants were determined. The first‐order kinetic model correlated the experimental concentration and time data at short times and even up to 60% of the total adsorption period in a number of systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1633–1645, 2004
Characterization of the water state of hyaluronic acid and poly(vinyl alcohol) interpenetrating polymer networks
Authors: Kim Seon Jeong , Lee Chang Kee , Kim Sun I. 
Published: March 2004

AbstractInterpenetrating polymer networks (IPNs) composed of hyaluronic acid and poly(vinyl alcohol) hydrogels were prepared, and the influence of water and the drying kinetics were investigated. The IPN hydrogels were characterized with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The glass‐transition temperatures of the IPN hydrogels decreased with increasing water content. The bound water was the sum of the nonfreezing bound water and freezing bound water. From the DSC melting curves, the values of the total water and freezing bound water were evaluated for IPN hydrogels containing large amounts of water. At the same time, the bound water value was estimated with TGA. In the TGA curves, one‐step and two‐step weight losses, corresponding to free water and nonfreezing bound water, were observed. The bound water of the hydrophilic polymers broke the hydrogen bonding between the hydroxyl groups of the polymers. The swollen IPN hydrogels exhibited relatively high bound water contents (43.04–59.17%) by DSC and TGA. The bound water contents of the dry IPN hydrogel films were 10.2–15.29% by TGA. The drying reaction rate constant of the IPN hydrogel increased with increasing temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1467–1472, 2004
Electrostimulus responsive behavior of poly(acrylic acid)/polyacrylonitrile semi‐interpenetrating polymer network hydrogels
Authors: Kim Seon Jeong , Lee Ki Jung , Kim Sun I. 
Published: March 2004

AbstractInterpenetrating polymer network (IPN) hydrogels composed of poly(acrylic acid) and polyacrylonitrile were prepared with UV irradiation, and their bending behaviors between two electrodes were studied under various conditions. The swelling ratio of the IPN hydrogels decreased with an increasing NaCl concentration in an aqueous solution. The fastest bending speed was observed in a gel synthesized in a 0.6 wt % NaCl aqueous solution. As the applied voltage increased, the bending speed increased. The deformation of the IPN hydrogels was reversible when the applied voltage was turned on and off. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1473–1477, 2004
Preparation of novel semihomogeneous cation‐permeable membranes from blends of sulfonated poly(phenylene sulfide) and sulfonated phenolphthalein poly(ether ether ketone)
Authors: Hu Keyan , Xu Tongwen , Fu Yanxun , Yang Weihua 
Published: March 2004

AbstractA series of semihomogeneous cation‐exchange membranes were prepared with binary blend systems, such as sulfonated phenolphthalein poly(ether ether ketone) (SPEEK‐C)/sulfonated poly(phenylene sulfide) (SPPS), or ternary blend systems, such as phenolphthalein poly(ether ether ketone) (PEEK‐C)/SPEEK‐C/SPPS, by solution blending and phase inversion, in which PEEK‐C and SPEEK‐C acted as binders and SPPS powder acted as a polyelectrolyte. Compared with homogeneous and heterogeneous membranes, the prepared semihomogeneous membranes had good electrochemical properties and mechanical strength as well as good dimensional stability. The fundamental properties of the membranes, such as the ion‐exchange capacity, water content, electrical resistance, transport number, diffusion coefficient of the electrolytes, and streaming potential, were largely dependent on both the loading of the SPPS resin and the sulfonation degree of PEEK‐C. Through the adjustment of these two important parameters, a series of semihomogeneous membranes with the desired conductivity and selectivity and the proper water content for different industrial purposes, such as electrodialysis, diffusional dialysis, and proton exchange, were achieved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1478–1485, 2004
Fundamental study of the effect of the fiber wall thickness and inner diameter on the structure of polyamide and polypropylene hollow fibers
Authors: Petrulis Donatas 
Published: March 2004

AbstractSome properties of the structure of polyamide (PA) and polypropylene (PP) hollow fibers were investigated in a theoretical fashion. These fibers were simultaneously compared with solid fibers. The structural indices of the hollow fibers, that is, the wall thickness and inner diameter, were systematically examined with the aim of determining their effect on the four conventional structural indices suitable for hollow fibers and for solid fibers. The fiber outer diameter and fiber outer lateral area were examined as well, and the ratio of the fiber outer lateral area to the fiber whole volume and the ratio of this area to the fiber mass were considered. Under assumptions about the fixed level and equal values of the linear density of PA and PP fibers, comments on the aforementioned effect were presented. The structural properties of these fibers with different wall thicknesses and inner diameters were examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2017–2022, 2004
Surface modification of silicone rubber with poly(ethylene glycol) hydrogel coatings
Authors: Vladkova T. 
Published: March 2004

AbstractHydrogel coatings of monoacrylated poly(ethylene glycol) (PEG) methyl ethers of different molecular weights were attached to silicon rubber surfaces and crosslinked with hexanediol diacrylate or ethoxylated trimethylolpropane diacrylate by UV polymerization. The wetting, evaluated with the water contact angles, correlated with the surface oxyethylene chain density, which was evaluated with the ESCA >CO/CH2 ratio obtained from the C(1s) peak. As measured by the ESCA N(1s) peak, bovine serum albumin formed very thin protein adsorbates on the PEG‐coated surfaces. A strong correlation was found between low protein adsorption and a high >CO/CH2 ratio of the PEG‐coated substrate. The PEG‐coated silicon rubber also demonstrated very low cell and platelet adhesion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1486–1492, 2004
In situ atomic oxygen erosion study of fluoropolymer films using X‐ray photoelectron spectroscopy
Authors: Gonzalez Rene I. , Phillips Shawn H. , Hoflund Gar B. 
Published: March 2004

AbstractThe surfaces of a homologous series of fluoropolymers were characterized in situ using X‐ray photoelectron spectroscopy before and after a 15‐min exposure to the flux produced by a unique hyperthermal atomic oxygen (AO) source, which produces a flux of about of 1015 atoms cm−2 s−1. The linear polymers investigated in this study include high‐density polyethylene (HDPE), poly(vinyl fluoride) (PVF), poly(vinylidene fluoride) (PVdF), and poly(tetrafluoroethylene) (PTFE). They possess a similar base structure with increasing fluorine‐to‐carbon ratios of 0, 1 : 2, 1 : 1, and 2 : 1, respectively. No interaction of the AO with the nonfluorine‐containing linear polymer HDPE was detected over this short exposure. However, a correlation exists between the chemical composition of the fluorinated polymers and the induced chemical and structural alterations occurring in the near‐surface region as a result of exposure to AO. The data indicate that AO initially attacks the fluorine portion of the polymers, resulting in a substantial decrease in the near‐surface fluorine concentration. The near‐surface fluorine‐to‐carbon ratios of PVF, PVdF, and PTFE decreased during the 15‐min AO exposure by 68, 39, and 18.5%, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1977–1983, 2004
Raman spectroscopic study of CdS, PVA composite films
Authors: Badr Y. A. , Abd El‐Kader K. M. , Khafagy Rasha M. 
Published: March 2004

AbstractA new material, which can be used in solar energy utilization, is obtained here by adding different weights of poly(vinyl alcohol) (PVA) to the semiconducting material CdS. The effect of this addition was studied by using FT‐Raman spectrometer (based on 1500 mW Nd : YAG laser at 1064 nm), UV–Vis‐IR (190–800 nm) spectrophotometer, and X‐ray diffractometer. Our experimental results indicated the appearance of several new Raman bands, which have not existed in both CdS and PVA. Some of the bands which are already existing in the Raman spectra of PVA showed an unexpected systematic increase in their intensities after the addition of CdS to the matrix. On the other hand, some of the new Raman bands appeared in special concentrations of PVA only, whereas some of the Raman bands of CdS were found to disappear after adding PVA. Finally, shifts in some bands associated with random increase in their intensities after adding PVA to CdS was detected in the FT‐Raman analysis. The experimental evidence given here might be attributed to the occurrence of new bonds, indicating that the produced mixture is a new material. The assignment of the new bands as well as an interpretation of the obtained variations is given here. Our X‐ray diffraction data confirmed the interpretation introduced here. Moreover, the UV–Vis spectra confirmed the existence of new absorption bands in the Visible region. The I‐V characteristic curve was measured for a selected concentration of the new composite material, showing a remarkable increase in the values of the conduction current of about two orders of magnitude as compared with the pure PVA material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1984–1992, 2004
Preparation and evaluation of chitosan‐coated polyphosphazene hydrogel beads for drug controlled release
Authors: Qiu Liyan 
Published: March 2004

AbstractChitosan‐coated polyphosphazene‐Ca2+ hydrogel beads were fabricated by dropping polyphosphazene into CaCl2/chitosan gelling solution. Polyphosphazene used here was a water‐soluble degradable polyanion (PCPAP), which carried almost two carboxylatophenamino groups on each phosphorus atom of the polymer backbone. Two kinds of turbidimetric titration were applied in this study to reveal the interaction between PCPAP and chitosan within the pH range of 4.57≈7.14. The effect of gelling solution pH on the properties of chitosan‐coated PCPAP beads was especially emphasized. It was found that the PCPAP/chitosan complex prepared at relatively high pH (pH 6.5) dissociated most slowly in pH 7.4 phosphate‐buffered solution (PBS). The erosion of chitosan‐coated beads and the release of model drug (Coomassie brilliant blue and myoglobin) in PBS were both obviously prolonged with the increase of gelling solution pH, exhibiting perfect accordance with the behavior of complex dissociation. In addition, the coating of PCPAP/chitosan complex on the bead surface facilitated the improvement of drug loading efficiency. The higher the gelling solution pH, the more the drug loading efficiency improved. At pH 6.5 (PCPAP 5%, CaCl2 7%, chitosan 0.3%), the loading efficiency of myoglobin in beads reached as high as 93.2%. These results indicate that the chitosan‐coated polyphosphazene‐ Ca2+ bead is a potential formulation for drug controlled release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1993–1999, 2004
Silica‐reinforced dynamically vulcanized ethylene–propylene–diene monomer/polypropylene thermoplastic elastomers: Morphology, rheology, and dynamic mechanical properties
Authors: Bazgir S. , Katbab A. A. , Nazockdast H. 
Published: March 2004

AbstractAttempts were made to prepare dynamically crosslinked ethylene–propylene–diene monomer/polypropylene (EPDM/PP, 60/40 w/w) blends loaded with various amounts of silica as a particulate reinforcing agent. The dispersion of silica between the two phases under mixing conditions, and also extent of interaction, as the two main factors that influence the blend morphology were studied by scanning electron microscopy. Increasing the silica concentration led to the formation of large‐size EPDM aggregates shelled by a layer of PP. Dynamic mechanical thermal analysis performed on the dynamically cured silica‐loaded blend samples showed reduction in damping behavior with increasing silica content. Higher rubbery‐like characteristics under tensile load were exhibited by the silica‐filled EPDM/PP‐cured blends. However, increasing the silica level to 50 phr led to the enhancement of interface, evidenced by increases in the tensile modulus and extensibility of the blend compared with those of the unloaded sample. Addition of a silane coupling agent (Si69) into the mix improved the mechanical properties of the blend, attributed to the strengthening of interfacial adhesion between the PP matrix and silica‐filled EPDM phase. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2000–2007, 2004
Effect of supercritical carbon dioxide dyeing conditions on the chemical and morphological changes of poly(ethylene terephthalate) fibers
Authors: Hou Aiqin , Xie Kongliang , Dai Jinjin 
Published: March 2004

AbstractCommercially available regular denier poly(ethylene terephthalate) (PET) fabrics were used in this investigation. PET fabric samples were wound on a bobbin and then exposed to supercritical CO2 under conditions representing a typical supercritical CO2 dyeing cycle. Infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, and scanning electron microscopy were used to characterize the chemical and morphological changes of the PET fibers. The results showed that exposure to supercritical CO2 did not cause chemical changes in the fibers; the crystal size and the Tmp of the PET fabric after treatment in supercritical CO2 did not significantly change; the crystallinity decreased; and the treatment in supercritical CO2 at higher temperature caused surface morphology changes (increased oligomer migration). However, there was no pitting, cracking, or crazing on the surface of the treated fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2008–2012, 2004