bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy
Authors: Benz Marcel , Euler William B. 
Published: May 2003

AbstractA method with good precision has been developed to quantitatively measure the degree of α‐, β‐, and γ crystallinity in poly(vinylidene fluoride) (PVDF) by means of infrared spectroscopy. The phase composition of solution‐deposited PVDF films was found to be strongly influenced by the presence of hydrophilic residues on the silicon substrate, the relative humidity present at film deposition, the spatial position on the substrate, and the thermal treatment of the deposited film. Films produced on pristine surfaces gave predominantly α‐phase PVDF, but when a layer of polar solvent (acetone or methanol) remained on the surface, the films produced were predominantly γ phase. Higher humidity promoted a higher fraction of γ crystallinity in the solution‐deposited PVDF films. Solution‐cast films had highly variable composition across the substrate, whereas spin‐cast films were uniform. High‐temperature annealing of PVDF films normally converts the polymer to the γ phase, but annealing the film while still attached to the silicon substrate inhibited this phase transformation. Low‐temperature annealing of freestanding films led to a previously unreported thermal event in the DSC, a premelting process that is a kinetic event, assigned to a crystalline relaxation. Higher‐temperature annealing gave a double endotherm, assigned to melting of different‐sized crystalline domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1093–1100, 2003
A comparative study of swelling properties of hydrogels based on poly(acrylamide‐co‐methyl methacrylate) containing physical and chemical crosslinks
Authors: Begam Tamanna , Nagpal A. K. , Singhal Reena 
Published: May 2003

AbstractPoly (acrylamide‐co‐methyl methacrylate) hydrogels of different ratios were prepared by using chemical and physical crosslinks to study the effect of nature of crosslinks on swelling behavior of hydrogels. The chemically crosslinked gels were prepared by using NN′‐methylene bis acrylamide, while physically crosslinked hydrogels were prepared by precipitation polymerization method, using dioxane as solvent. Detailed swelling kinetics such as swelling ratio, transport exponent n, diffusion coefficient D and the effect of pH on equilibrium swelling studies. The study revealed that the nature of crosslinks alter the swelling characteristics of the hydrogel. In chemically crosslinked hydrogels the water transport is Fickian in nature, while in the case of the physically crosslinked hydrogels the water transport mechanism is anomalous indicating major change in relaxation mechanism due to nature of crosslinks. The results also indicate that with increasing acrylamide content the swelling ratio of the hydrogels were also increased, but the transport exponent n remains nearly constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 779–786, 2003
Chelation ion‐exchange properties of copolymer resin derived from 4‐hydroxyacetophenone, oxamide, and formaldehyde
Authors: Gurnule W. B. , Rahangdale P. K. , Paliwal L. J. , Kharat R. B. 
Published: May 2003

AbstractA copolymer (4‐HAOF) prepared by condensation of 4‐hydroxyacetophenone and oxamide with formaldehyde in the presence of an acid catalyst proved to be a selective chelating ion‐exchange copolymer for certain metals. Chelating ion‐exchange properties of this copolymer were studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+, Pb2+, and Hg2+ ions. A batch equilibrium method was employed in the study of the selectivity of metal‐ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for Fe3+ ions than for Co2+, Zn2+, Cd2+, Pb2+, Cu2+, Ni2+, and Hg2+ ions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 787–790, 2003
Fourier transform rheometry on gum elastomers
Authors: Leblanc Jean L. 
Published: May 2003

AbstractUsing a modified torsional dynamic rheometer, strain and torque signals are captured and analyzed through Fourier transform. A thorough analysis of strain signal is first performed to document the quality of the applied deformation and to define the optimum conditions for signal capture, and hence, for Fourier transform calculation. A specific calculation procedure is developed that allows the error associated with FT calculation to be estimated, in terms of mean harmonic peaks and their standard deviation. Scatter is observed on low strain results that nearly vanishes when the applied deformation is larger than 14%, thus giving confidence in data gathered under non‐linear viscoelastic conditions. Results on a series of gum EPDM with different macromolecular characteristics (MWD and long chain branching, LCB) are reported and discussed, with respect to a simple four parameters model for the variation on deformation of the relative third harmonic component. Processing additives are found to mask expected LCB effects. Results on a series of SBR 1500 samples, collected from various manufacturers, are presented that illustrate the capability of FT rheometry to detect differences between materials expected to be similar. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1101–1115, 2003
Rheological behavior of ethylene–octene copolymer vulcanizates: Effect of blowing agent and precipitated silica filler
Authors: Nayak N. C. , Tripathy D. K. 
Published: May 2003

AbstractAn experimental study of the rheological behavior of ethylene–octene copolymer vulcanizates in extrusion containing blowing agent has been carried out. The cell morphology development has been studied through a scanning electron microscope. Rheological properties of unfilled and precipitated silica‐filled systems with variations of blowing agent, extrusion temperature, and shear rate have been studied by using a Monsanto processibility tester (MPT). The total extrusion pressure (PT), apparent shear stress (τwa), apparent viscosity (ηa), and die swell (%) of the unfilled and silica‐filled compounds have been determined by using MPT. The effect of blowing agent (ADC) on the rheological properties of the vulcanizates has also been investigated. There is a reduction of stress and viscosity with blowing agent loading. It was observed that the incorporation of a blowing agent led to decreased shear thinning behavior resulting in an increase in power law index. The viscosity reduction factor (VRF) of unfilled vulcanizates is found to be dependent on the concentration of the blowing agent, shear rate, and temperature, whereas VRF of silica‐filled vulcanizates is found to be dependent on shear rate, temperature, and blowing agent concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1132–1138, 2003
Synthesis, characterization, and metal ions adsorption properties of chitosan–calixarenes (I)
Authors: Li Hai‐Bing , Chen Yuan‐Yin , Liu Shi‐Lan 
Published: May 2003

AbstractCalixarene‐modified chitosans (CTS–CA‐I and CTS–CA‐II) were first synthesized by the reaction of chitosan (CTS‐NH2) with 1,3‐bis‐chloroethoxyethoxy‐2,4‐dihydroxy‐p‐tert‐butylcalix[4]arene (CA‐I) or its benzoyl derivative (CA‐II). Their structures were characterized by infrared and X‐ray diffraction spectroscopy and scanning electron microscopy (SEM). The adsorption of Ni2+, Cd2+, Cu2+, Pd2+, Ag+, and Hg2+ by CTS–CA‐I and CTS–CA‐II was studied and the thermodynamic parameter of two calixarene‐modified chitosans toward Hg2+ was deduced. The adsorption properties of CTS–CA‐I and CTS–CA‐II were greatly varied compared with that CTS‐NH2, especially with the adsorption capacity toward Ag+ and Hg2+, because of the presence of the calixarene moiety. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1139–1144, 2003
Increased stability of polythiophene in the presence of aniline in acetonitrile
Authors: Pekmez Özçiçek Nuran , Pekmez Kadir , Holze Rudolf , Yıldız Attila 
Published: May 2003

AbstractThe conductance behavior of copolymers of aniline and thiophene with varying concentration ratios were studied in acetonitrile/tetrabutylammonium tetrafluoroborate using cyclic voltammetry and in situ conductance measurements. These studies revealed that compared with homopolymers, the copolymers have extended ranges of stability (even at very positive applied potentials), lower conductivities, and reversible doping/undoping characteristics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 862–866, 2003
Polyimides possessing bulky phosphorus groups: Synthesis and characterization
Authors: Liu Ying‐Ling , Hsu Chih‐Yuan , Wu Chuan‐Shao 
Published: May 2003

AbstractA series of polyimides with bulky pendent groups containing phosphorus were obtained from polymerization of various dianhydrides with a new diamine (2DOPO‐A) bearing two bulky (9,10‐dihydro‐9‐oxa‐10‐oxide‐10‐phosphaphenanthrene‐10‐yl) (DOPO) substituents. The resulting polymers had inherent viscosities of 0.15–0.32 dL/g and glass transition temperatures of 260–283°C. The polyimides were soluble in some organic solvents due to the incorporation of bulky and polar DOPO groups. The non‐coplanar cardo structure of 2DOPO‐A also contributed to the improvement in the solubility of the polyimides. Incorporating DOPO groups into polyimides resulted in polymers with low initial decomposition temperatures (IDT; 310–362°C) due to the independent decomposition of the DOPO groups. Thermogravimetric analysis showed that the DOPO‐containing polyimides exhibited high integral procedural decomposed temperatures (IPDT) of 891–950°C. Incorporation of DOPO group into polyimides also improved their weight loss rate, thermal stability, thermal‐oxidative stability, and heat insulating property in the high temperature region. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 791–796, 2003
Physical and electroresponsive characteristics of the intercalated styrene‐acrylonitrile copolymer/clay nanocomposite under applied electric fields
Authors: Kim J. W. , Jang L. W. , Choi H. J. , Jhon M. S. 
Published: May 2003

AbstractStyrene‐acrylonitrile copolymer (SAN)/clay nanocomposites were synthesized through an emulsion copolymerization of styrene and acrylonitrile in the presence of sodium montmorillonite, and their physical properties and electroresponsiveness under an applied electric field were characterized. Thermogravimetric analysis (TGA) showed that the thermal stability of the synthesized polymer was sustained. X‐ray diffraction (XRD) analysis confirmed the insertion of SAN into the interlayers of clay, whose separation consequently increased, as compared to those of the pristine clay. Transmission electron microscopy (TEM) was used to observe the suspended state of clay. Dry‐base electrorheological (ER) fluids were prepared by mixing intercalated SAN nanocomposite particles into silicone oil. Typical ER behavior, i.e., enhancement of shear and yield stresses in the presence of an applied electric field, was observed using a rotational rheometer equipped with a high‐voltage generator. A universal yield stress scaling equation was also found to fit our experimental data well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 821–827, 2003
Surfactant‐free nanoparticles of poly(DL‐lactide‐co‐glycolide) prepared with poly(L‐lactide)/ poly(ethylene glycol)
Authors: Jeong Young‐Il , Shim Yong‐Ho , Choi Changyong , Jang Mi‐Kyeong , Shin Gil Man , Nah Jae‐Woon 
Published: May 2003

AbstractSurfactant‐free nanoparticles of poly(DL‐lactide‐co‐glycolide) (PLGA) nanoparticles were prepared with or without poly(L‐lactide)‐poly(ethylene oxide) (LE) diblock copolymer (abbreviated as PLGA/LE and PLGA nanoparticles) by dialysis method. LE diblock copolymer was used to make PLGA nanoparticles to alternate conventional surfactant. The size of PLGA and PLGA/LE nanoparticles was 295.3 ± 171.3 and 307.6 ± 27.2 nm, respectively, suggesting LE diblock copolymer might be coated onto the surface of nanoparticles. Observation of scanning electron microscope (SEM) showed that PLGA/LE nanoparticles have spherical shapes ranging ∼ 200–500 nm. In 1H‐NMR study, characteristic peaks of the methyl protons of PLGA disappeared in D2O, whereas characteristic peaks of the methyl proton of both PEG and PLGA were shown in both CDCl3 and D2O, indicating that LE diblock copolymer coated on the surface of the PLGA nanoparticles. The higher the initial content of drug, the higher the drug contents and the lower the loading efficiency. PLGA/LE nanoparticles at higher drug contents resulted in slower adriamycin·HCl (ADR) release rate than that of lower drug contents. Also, slower release rate of ADR was achieved by entrapped into the PLGA/LE nanoparticles, whereas LE polymeric micelles showed rapid ADR release. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1116–1123, 2003
Synthesis and characterization of submicron PMMA particles containing rare earth ions on the surface
Authors: Hu Jun , Zhao Hui , Zhang Qijin , He Weidong 
Published: May 2003

AbstractEmulsifier‐free emulsion polymerization was adopted to synthesize rare earth containing submicron polymer particles under microwave irradiation. To control the size and distribution of the particle, the relationship between reaction time, monomer content, and particle radius was studied for the polymerization of methyl methacrylate (MMA) in the absence and presence of rare earth ions, in which water was used as solvent, and potassium persulfate was used as initiator. In the latter polymerization, the solution of MMA and europium octanoate (EOA) was used instead of MMA itself as EOA can be dissolved in MMA within certain concentrations, and the result shows that the polymerization process is affected by existence of EOA except when the amount of MMA is 2 ml. For particles containing rare earth ions, characterization shows that mole percentage of Eu(III) ion in the surface layer with a thickness of 5 nm, which is estimated from X‐ray photo electron spectroscopy (XPS), is always larger than the value estimated by inductively coupled plasma atomic emission spectrometer (ICP‐AES) for the whole particle, indicating that surface enrichment of rare earth ions took place during the polymerization. Further characterization by XPS depth measurement after Ar+ sputtering shows the same result. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1124–1131, 2003
Grafting of itaconic acid onto LDPE by the reactive extrusion: Effect of neutralizing agents
Authors: Krivoguz Y. M. , Pesetskii S. S. , Jurkowski B. 
Published: May 2003

AbstractGrafting of itaconic acid (IA) onto low‐density polyethylene (LDPE) was performed by reactive extrusion where the initiator was dicumyl peroxide, and the neutralizing agents (NAs) were zinc oxides and hydroxides as well as magnesium oxides and hydroxides. The carboxyl groups were neutralized in molten LDPE directly in the course of acid grafting, and in prefabricated functionalized polyethylene (LDPE‐g‐IA). It was found that neutralizing agents introduced into the initial reaction mixture increase the yield of LDPE‐g‐IA while the carboxyl groups were neutralized partially or totally through chemical reactions. The physical structure of LDPE‐g‐IA did not in fact suffer any substantial changes. From the standpoint of neutralization activity, the NAs studied could be arranged as follows: Zn(OH)2 > ZnO > Mg(OH)2 > MgO. NA, added into the initial reaction mixture improved the grafting efficiency of IA onto LDPE. In case of the one‐step process (neutralization simultaneously with grafting), the neutralizing effect appears stronger than that in the two‐step process (neutralization of prepared LDPE‐g‐IA). This means that neutralization of carboxyl groups in IA was less effective when NA was introduced into LDPE‐g‐IA than for the case of the initial reactive mixture. Chemical neutralization of grafted IA results in products of improved resistance to thermal oxidation and thermal stability of melt. This result is of practical importance to the opportunities for widening the application range for PE modified by grafting IA, while preparing polymer blends to be compounded, processed, and used at elevated temperatures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 828–836, 2003
Solid‐phase microextraction (SPME) in polymer characterization—Long‐term properties and quality control of polymeric materials
Authors: Hakkarainen Minna , Gröning Mikael , Albertsson Ann‐Christine 
Published: May 2003

AbstractSolid‐phase microextraction (SPME) in combination with GG‐MS was applied to quality control polyamide 6.6 collected for recycling and to study the long‐term properties and degradation of nitrile rubber, polyethylene, and polyamide 6.6. The migration of plasticizer and other additives reduces the service‐life and changes the properties of the material. It is also a possible health hazard, for example, legislation against the use of brominated flame retardants in plastic materials, is under discussion, and fast and reliable methods are required to detect such compounds in plastic materials collected for recycling. SPME rapidly and effectively extracted several brominated compounds from in‐plant collected polyamide 6.6. Migration of tris(2‐butoxyethyl)phosphate plasticizer and its degradation products from nitrile rubber during long‐term thermal ageing at 60 and 80°C was shown by SPME‐GC‐MS, while the plasticizer was not volatile enough to be detected by traditional HS‐GC‐MS. In accordance the number of degradation products extracted from thermo‐oxidized PE by HS‐SPME was three times larger than the number detected after HS‐GC‐MS analysis. SPME‐GC‐MS could also detect early signs of degradation in thermo‐oxidized virgin and in‐plant recycled polyamide 6.6 before any signs of degradation were observed by, for example, tensile testing or FTIR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 867–873, 2003
Study of polypropylene/poly(ethylene terephthalate) bicomponent melt‐blowing process: The fiber temperature and elongational viscosity profiles of the spinline
Authors: Zhao Ron (Rongguo) , Wadsworth Larry C. 
Published: May 2003

AbstractAlthough there are significant differences between high‐speed melt spinning and melt blowing (MB), they are similar in many important components. This study, motivated by the need to better understand the bicomponent MB process, used the basic theories of high‐speed melt spinning to estimate the fiber temperature and elongation viscosity profiles of the polypropylene/poly(ethylene terephthalate) (PP/PET) bicomponent MB process. During the MB process, the filament temperature decreased dramatically within the first 2 in. from the MB die. The fiber temperature‐decay profiles of PP, PET monocomponent, and PP/PET bicomponent filaments followed similar trends. PP filaments attenuated faster than PET filaments and the bicomponent filaments attenuated at a medium rate between that of PP and PET. Accordingly, the elongational viscosity increased significantly in the first 2 in. from the die. PET filaments exhibited higher elongational viscosity than that of 100% PP filaments. The elongational viscosity profile of 75%PP/25%PET was between that of PP and PET monocomponent filaments. These data provided important information on understanding the MB process and filament attenuation. It also suggested that the filament elongational viscosity profile is the key factor in production of finer bicomponent MB fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1145–1150, 2003
Electroactive characteristics of interpenetrating polymer network hydrogels composed of poly(vinyl alcohol) and poly(N‐isopropylacrylamide)
Authors: Kim Seon Jeong , Park Sang Jun , Lee Sang Min , Lee Young Moo , Kim Hee Chan , Kim Sun I. 
Published: May 2003

AbstractAn interpenetrating polymer network (IPN) composed of poly(vinyl alcohol) (PVA) and poly(N‐isopropylacrylamide) (PNIPAAm) was prepared by the sequential IPN method. The equilibrium swelling ratio and bending behavior under electric fields of the IPN hydrogel were measured in an aqueous NaCl solution. The IPN exhibited a high equilibrium swelling ratio, in the range 280–380%. When the IPN in aqueous NaCl solution was subjected to an electric field, the IPN showed significant and quick bending toward the cathode. The IPN hydrogel also showed stepwise bending behavior, depending on the electric stimulus. In addition, the ionic conductivity of the IPN hydrogel was measured using dielectric analysis, and its conductive behavior followed the Arrhenius equation. The conductivity of the IPN hydrogel and the activation energy for the form of the IPN were 1.68 × 10−5 S/cm at 36°C and 61.0 kJ/mol, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 890–894, 2003
Dynamic percolation phenomenon of poly(methyl methacrylate)/surface fluorinated carbon black composite
Authors: Katada A. , Konishi Y. , Isogai T. , Tominaga Y. , Asai S. , Sumita M. 
Published: May 2003

AbstractThe electrical resistivity of polymer filled with conductive filler, such as carbon black (CB) particles, is greatly decreased by incorporating the conductive filler. This is called the percolation phenomenon and the critical CB concentration is called the percolation threshold concentration (Φ*). For CB particle–filled insulating polymer composite at lower than Φ*, the conductive CB network is constructed in the polymer matrix when the composite is maintained at a temperature higher than the glass‐transition temperature or the melting temperature of the polymer matrix. This phenomenon is called dynamic percolation and the time to reach the substantial decrease in resistivity is called percolation time (tp). To investigate the relationship between the dynamic percolation process and the surface state of CB particles, we used three kinds of carbon black particles such as original carbon black (CB0) and fluorinated carbon black (FCB010 and FCB025)–filled poly(methyl methacrylate) (PMMA). It was observed that the dynamic percolation curves for CB0‐filled PMMA and FCB‐filled PMMA composites shifted to a shorter percolation time with increases in both the annealing temperature and the filler concentration. However, the dynamic percolation curves of FCB‐filled PMMA showed a gradually decreasing trend compared to that of CB0‐filled PMMA composites. The activation energy calculated from an Arrhenius plot of the tp against the inverse of the annealing temperature was decreased by surface fluorine treatment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1151–1155, 2003
Cell and organ printing 1: Protein and cell printers
Authors: Wilson W. Cris , Boland Thomas 
Published: May 2003

AbstractWe have developed several devices for positioning organic molecules, molecular aggregates, cells, and single‐cell organisms onto solid supports. These printers can create stable, functional protein arrays using an inexpensive technology. The cell printer allows us to create cell libraries as well as cellular assemblies that mimic their respective position in organs. The printers are derived from commercially available ink‐jet printers that are modified to dispense protein or cell solutions instead of ink. We describe here the modifications to the print heads, and the printer hardware and software that enabled us to adapt the ink‐jet printers for the manufacture of cell and protein arrays. The printers have the advantage of being fully automated and computer controlled, and allow for the high‐throughput manufacture of protein and cell arrays. Anat Rec Part A 272A:491–496, 2003. © 2003 Wiley‐Liss, Inc.