bluuebunny/crossref_metadata_2025_split huggingface dataset:
Political Attitudes, Social Capital, and Political Participation: The United States and Mexico Compared
Authors: Klesner Joseph L. 
Published: February 2004

Political values have impact when they shape political participation. A comparison of political participation rates of Mexicans, Mexican-Americans, and the general U.S. population reveals that participation is highest among the general U.S. population, lowest among Mexicans, and at intermediate rates among Mexican-Americans. The article explores the attitudinal bases of political participation, finding that political engagement is a strong predictor of participation, while general perspectives on the political regime do not shape participation rates. The strongest predictors of political participation are variables generally grouped under the category social capital: involvement in non-political organizations, social trust, and an avoidance of television. Because Mexicans and Mexican-Americans have lower levels of social capital, political participation is lower among those groups than the general U.S. population. Yet, there remain unexplained differences in participation among the three groups that can be attributed to institutional and historical constraints on political involvement in Mexico and among Mexican-Americans.Los valores políticos tienen impacto cuando contribuyen a formar la participación política. Una comparación de las tasas de participación política de mexicanos, mexicano-americanos y la población general estadounidense revela que la participación más alta se da en la población general estadounidense, la más baja en los mexicanos, y el nivel intermedio en los mexicano-americanos. El artículo explora las bases de las actitudes en la participación política, encontrando que el involucramiento político es un fuerte indicador de la participación, mientras que las perspectivas generales sobre el régimen político no forman tasas de participación. Los pronósticos más fiables de participación política son las variables generalmente agrupadas bajo la categoría de capital social: participación en organizaciones no políticas, confianza social, y la anulación de la televisión. Dado que los mexicanos y los mexicano-americanos tienen niveles más bajos de capital social, la participación política es inferior entre estos grupos que en la población general estadounidense. No obstante, hay aún diferencias no explicadas de la participación en los tres grupos que pueden ser atribuidas a restricciones institucionales e históricas sobre la participación política en México y entre los mexicano-americanos.
No cuenten conmigo: La pólitica de repatriación del gobierno mexicano y sus nacionales en Estados Unidos, 1910–1928
Authors: Enciso Fernando Saúl Alanis 
Published: February 2004

This article examines the responses of Mexican governments to the repatriation of Mexican nationals from the United States during the period of 1910 to 1928. The author discusses the nationalist commitment to repatriation and concludes that government policy was less paternalistic and commited than other studies have suggested.
Este artículo examina las respuestas que los gobiernos de México dieron a la repatriación de sus nacionales procedentes de Estados Unidos en la etapa de 1910 a 1928. Presenta una interpretación diferente a la reproducida hasta ahora por la historiografía sobre el tema; replantea la idea del compromiso nacionalista de los gobiernos mexicanos en la repatriación, mostrando que la política que estos aplicaron fue menos paternalista y comprometida de lo que hasta ahora han planteado la mayoría de los estudios.
Synthesis and characterization of poly(ethylene isophthalate‐co‐ethylene terephthalate) copolyesters
Authors: Finelli L. , Fiorini M. , Siracusa V. , Lotti N. , Munari A. 
Published: February 2004

AbstractPoly(ethylene isophthalate‐co‐ethylene terephthalate) (PEIPET) copolymers of various compositions and molecular weights were synthesized by melt polycondensation and characterized in terms of chemical structure and thermal and rheological properties. At room temperature, all copolymers were amorphous and thermally stable up to about 400°C. The main effect of copolymerization was a monotonic increase of glass transition temperature (Tg) as the content of ethylene terephthalate units increased. The Fox equation accurately describes the Tg–composition data. The presence of ethylene terephthalate units was found to influence rheological behavior in the melt, with the Newtonian viscosity increasing as the content of ethylene terephthalate units increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 186–193, 2004
Thermotropic liquid‐crystalline polyphosphate esters containing phenolphthalein moiety
Authors: Srividhya D. , Senthil S. , Kannan P. 
Published: February 2004

AbstractA new series of thermotropic liquid‐crystalline (LC) polyphosphate esters containing phenolphthalein as a part of their mesogen has been synthesized by a solution polycondensation method. The even‐numbered methylene spacers were varied from 2–10, and ethyl phosphate was used as a phosphorus heterogeneity. Thermal analysis showed that these polymers are stable up to 275–342°C with high char yield. All of the polymers exhibited liquid‐crystalline properties except for Polymers I and VI. Differential scanning calorimetry (DSC) confirmed the mesophase formation of the polymers. The glass transition temperature (Tg) and melting temperature (Tm) of the polymers were considerably low. A polymer containing phenolphthalein alone as a rigid segment with decamethylene spacers was also synthesized, but it did not show birefringent melt properties. These results reveal that phenolphthalein alone cannot act as a mesogen, whereas phenolphthalein phenylester can. Molecular modeling studies and conformational analysis confirmed that the steric hindrance of phenylester and the conjugation effect could explain the promotion of mesogenic behavior by phenolphthalein phenylester. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 194–200, 2004
Enhanced corrosion prevention effect of polysulfone–clay nanocomposite materials prepared by solution dispersion
Authors: Yeh Jui‐Ming , Chen Chi‐Lun , Chen Yen‐Chen , Ma Chin‐Yi , Huang Hsi‐Ya , Yu Yuan‐Hsiang 
Published: February 2004

AbstractA series of polymer–clay nanocomposite (PCN) materials containing polysulfone (PSF) and layered MMT clay were successfully prepared by effectively dispersing inorganic nanolayers of MMT clay in an organic PSF matrix via a solution dispersion technique. The synthesized PCN materials were subsequently investigated with a series of characterization techniques, including Fourier transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The prepared PCN coatings with low clay loading (1 wt %) on cold‐rolled steel (CRS) were found to be superior in corrosion prevention to those of bulk PSF, based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current and electrochemical impedance spectroscopy (EIS) in a 5 wt % aqueous NaCl electrolyte. The effects of material composition on the molecular barrier, mechanical strength and optical clarity of PSF and PCN materials, in the form of membranes, was also studied by molecular permeability analysis (GPA), dynamic mechanical analysis (DMA) and UV‐Visible transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 631–637, 2004
Miscibility of poly(vinylidene fluoride) and atactic poly(methyl methacrylate)
Authors: Huang Cheng , Zhang Li 
Published: February 2004

AbstractDifferent results for the miscibility between poly(vinylidene fluoride) (PVDF) and atactic poly(methyl methacrylate) (at‐PMMA) have been reported. In this study, the interaction between PVDF and at‐PMMA was confirmed, although such a kind of force was weak. With increasing PVDF weight fraction, the blends exhibited more heterogeneous properties, and the films thus appeared more opaque. The difference spectra after subtraction of PVDF and poly(methyl methacrylate) (PMMA) showed that the interaction between the carbonyl groups of PMMA and the hydrogen atoms of PVDF increased as the stretch vibration of CO bonds band shifted to a lower frequency with higher PVDF content. From the computer analysis, the sum spectra of the blends could not be obtained by simple addition of the separate spectra of the homopolymers. The contact angle measurement demonstrated that the hydrophobicity against water increased with PVDF content and that contact angles against water were larger than 90° when the PVDF content exceeded 30%, indicating good water repellency. The contact angles against n‐hexane, however, could not be measured because of the complete wetting of the film by n‐hexane. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1–5, 2004
Steady viscosity of a polymer/liquid crystal biphasic system
Authors: Yang I‐Kuan , Lai Wei Yuan 
Published: February 2004

AbstractSteady shear viscosities of blends of poly(butyl acrylate) and cholesteryl oleyl carbonate were studied under a cone and plate fixture. Unique shear behavior was observed for the polymer/low molar mass liquid crystal mixture. The viscosity of the liquid crystal‐rich phase increases with polymer content until a maximum is reached. The height of the viscosity maximum decreases with the magnitude of the shear stress and disappears when the stress reaches 200 Pa. Addition of liquid crystal to the polymer‐rich phase causes a viscosity reduction, and at higher stress levels, the viscosity reduction becomes more effective with the same amount of liquid crystal addition. The viscosity reduction may be related to the fibril morphology of the liquid crystal and the viscosity maximum can be interpreted by the emulsion effect being counteracted by a viscosity reduction effect. A shear‐thickening behavior was observed in the intermediate shear rates for the blends with a volume fraction of poly(butyl acrylate) between 9.4 and 49.8%. This is a novel liquid–liquid system that exhibits a shear thickening behavior. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 25–30, 2004
Studies on the fabrication of strong‐acid/weak‐base amphoteric ion exchange fibers and their adsorption property for amino acids
Authors: Fu Ruowen , Wang Fei , Tang Liyuan , Lei Yongqiang , Lui Ning , Liang Minling 
Published: February 2004

AbstractThe strong acid/weak base amphoteric ion exchange fibers with different ratios of acidic and basic groups and different grafting percentages were prepared by grafting styrene and 4‐vinylpyridine onto polypropylene fiber and then sulfonating with chlorosulphonic acid, under various reaction conditions, such as the feed ratio of styrene and 4‐vinylpyridine, monomers concentration, sulfonation temperature, and sulfonation time, swelling time, etc. The produced strong acidic and basic groups are the sulfonic group and the pyridyl group, respectively. Only one sulfonic group is induced into an aromatic ring in most of PP‐g‐St‐4VP and it is located in the para‐position of styrene. The contents of the strong‐acid group and the weak‐base group of the PP‐g‐SO3H‐Py fibers produced in this work are in the range of 1.98 to 4.22 and 2.33 to 4.24 mmol/g, respectively. The strong acid/weak based amphoteric fibers obtained possess good static adsorption property for basic and acidic amino acids, and they also have a good dynamic adsorption and elution property for amino acids like related strong acid ion exchange fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 418–425, 2004
Modification of LLDPE using esterified styrene maleic anhydride copolymer: Study of its properties and environmental degradability
Authors: Pal Jaykisor , Singh Harpal , Ghosh Anup. K. 
Published: February 2004

AbstractLinear low‐density polyethylene (LLDPE) was blended with decanol‐esterified styrene maleic anhydride copolymer (MDESMA) with an aim to enhance the environmental degradability of polyethylenes. Styrene‐maleic anhydride copolymer (SMA) was synthesized by precipitation polymerization, using benzoyl peroxide (BPO) as initiator. SMA was esterified with a long‐chain monoalcohol, n‐decanol, using methyl ethyl ketone (MEK) as solvent at 80°C to obtain monoesterified styrene‐maleic anhydride (MDESMA). Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA) were performed to characterize SMA and MDESMA. IR spectra of MDESMA showed a decrease in intensity of peak responsible for carbonyl absorption of a five‐membered ring anhydride group along with broadening of carboxyl OH stretching peak. TGA showed two‐stage degradation for SMA and MDESMA. LLDPE was blended with MDESMA in single‐screw extruder and blends were characterized thermally by DSC and TGA. A single endothermic melting peak of LLDPE/MDESMA blend was observed. Films of the blends, formed by compression molding, showed an increase in modulus of elasticity but a decrease in elongation at break with increasing concentration of MDESMA. LLDPE/MDESMA blend compositions when kept in phosphate/citric acid buffer solution (pH ∼ 8) showed initial weight gain because of water absorption and subsequently loss in weight due to dissolution of soluble component of blends. Film samples of blends kept for soil burial also showed similar behavior. Contact‐angle measurement of film samples of the blends showed an increase in value on soil burial, indicating degradation/dissolution of MDESMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 102–108, 2004
Synthesis, characterization, and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid)–metal complexes
Authors: John Magi , Jose Jincy , Mathew Beena 
Published: February 2004

AbstractThe metal‐ion complexation behavior and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid) were investigated. The polymeric ligand was prepared by solution polymerization. The metal‐ion complexation was studied with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) ions. The metal uptake followed the order: Cu(II) > Cr(III) > Mn(II) > Co(II) > Fe(III) > Zn(II) > Ni(II). The polymeric ligand and the metal complexes were characterized by various spectral methods. The catalytic activity of the metal complexes were investigated toward the hydrolysis of p‐nitrophenyl acetate (NPA). The Co(II) complexes exhibited high catalytic activity. The kinetics of catalysis was first order. The hydrolysis was controlled by pH, time, amount of catalyst, and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 272–279, 2004
Crystallization of poly(tetramethylene succinate) in blends with poly(ϵ‐caprolactone) and poly(ethylene terephthalate)
Authors: Chong K. F. , Schmidt H. , Kummerlöwe C. , Kammer H. W. 
Published: February 2004

AbstractThe crystallization behavior of polymer blends of poly(tetramethylene succinate) (PTMS) with poly(ϵ‐caprolactone) (PCL) or poly(ethylene terephthalate) (PET) was investigated with differential scanning calorimetry under isothermal and nonisothermal conditions. The blends were prepared by solution casting and precipitation, respectively. The constituent polymers were semicrystalline materials and crystallized nearly independently in the blends. The addition of the second component to PTMS showed that PCL did not significantly influence the crystallinity of the constituents in the blends under isothermal conditions, whereas the crystallization of PTMS was slightly suppressed by crystalline PET. Nonisothermal crystallization under constant cooling rates was examined in terms of a quasi‐isothermal Avrami approach. In blends, the rates of crystallization were differently influenced by the second component. The rate of the constituent that crystallized at the higher temperature was barely influenced by the second component being in the molten state, whereas the rate of the second component, crystallizing when the first component was already crystalline, was altered differently under isothermal and nonisothermal conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 149–160, 2004
A novel chemically and mechanically stable glycerol‐based crosslinked polystyrene support for polypeptide synthesis: A comparative study with Merrifield resin
Authors: Sasikumar P. G. , Kumar K. S. , Pillai V. N. Rajasekharan 
Published: February 2004

AbstractA novel chemically and mechanically stable polymer support for solid‐phase peptide synthesis with excellent swelling performance in various organic solvents is described. The crosslinked polymer in its bead form was prepared by the aqueous suspension polymerization of the styrene and tri(propylene glycol) glycerolate diacrylate. The support is unique because the hydroxyl group is introduced into the polymer support in the polymerization step itself, which makes it highly cost effective. The hydroxyl functionality of the crosslinker in the polymer was used as a growth site for peptide synthesis, thus minimizing the incompatibility arising because of the styrene core as compared to styrene‐based polymer supports currently used in polypeptide synthesis. The utility of the resin for solid‐phase peptide synthesis was tested by the synthesis of a 19‐residue peptide amide of the envelope region of hepatitis C viral polyprotein and was compared with Merrifield resin by the 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyl uronium hexafluoro phosphate/1‐hydroxy benzatriazole method with a Rink amide linker. The molecular character of the polymer and the extent of crosslinking density on the dependence of the reactivity of the attached amino groups were investigated by a reactivity study of the amide bond formation of a model Val‐Ala dipeptide. Enhanced swelling, the increased rate of aminoacylation, and the high purity of the peptides synthesized on the novel support highlighted the influence of the polarity of the solid support in the solid‐phase synthesis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 288–294, 2004
Synthesis and characterization of biodegradable block copolymers of poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol)
Authors: Najafi Farhood , Sarbolouki Mohammad N. 
Published: February 2004

AbstractThe synthesis of two low molecular weight linear unsaturated oligoester precursors, poly(propylene fumarate‐co‐sebacate) (PPFS) and poly(ethylene fumarate‐co‐sebacate) (PEFS), are described. PPFS, PEFS, and poly(ethylene glycol) are then used to prepare poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PPFS‐co‐PEG) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PEFS‐co‐PEG) block copolymers. The products thus obtained are investigated in terms of the molecular weight, composition, structure, thermal properties, and solubility behavior. A number of design parameters including the molecular weights of PPFS, PEFS, and PEG, the reaction time in the polymer synthesis, and the weight ratio of PEG to PPFS or to PEFS are varied to assess their effects on the product yield and properties. The hydrolytic degradation of PPFS‐co‐PEG and PEFS‐co‐PEG in an isotonic buffer (pH 7.4, 37°C) is investigated, and it is found that the fumarate ester bond cleaves faster than does the sebacate ester bond. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 295–300, 2004
Study of the effect of poly(acrylonitrile‐co‐butadiene‐co‐styrene) on the mechanical properties of an epoxy system
Authors: Torres A. , López‐de‐Ullibarri I. , Abad M. J. , Barral L. , Cano J. , García‐Garabal S. , Díez F. J. , López J. , Ramírez C. 
Published: February 2004

AbstractThe mechanical properties of an epoxy system containing a diglycidyl ether of bisphenol A and 1,3‐bis(aminomethylcyclohexane) modified with different amounts of poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) were studied. Properties examined include tensile stress, percentage strain, tensile modulus, and tensile toughness determined in tensile tests, Rockwell hardness, and energy and maximum force to break a specimen in Charpy impact tests. The effect of the modification produced with the ABS was also studied using statistical methods including analysis of variance and multiple comparisons. The obtained data showed a significant effect of the modification produced with the ABS on the mechanical properties of this epoxy system, especially with the amount of 5 ABS per hundred parts of resin on the tensile properties and on the hardness. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 461–467, 2004
Fluorescence property of polycarbonate related to radial‐pattern formation
Authors: Tanimura M. , Tachibana M. , Kojima K. 
Published: February 2004

AbstractThe pattern change in a laminar flow of molten polycarbonate in a disk mold was experimentally investigated by altering the flow velocity. By use of a light‐scattering method, a radial pattern characterized by a periodic array of needlelike regions and the matrix was found to form as the flow velocity was increased. The density distribution of the polycarbonate molecules was an essential factor for pattern formation. As a result of the formation of this pattern, it was found that the boundaries between the needlelike regions and the matrix emitted weak fluorescence in the wavelength range of 600–700 nm under laser irradiation. An analysis indicated that transitions between excited π electron states in the phenylene groups were the sources of this fluorescence and that a key factor behind its occurrence was a decrease in the molecule density at the boundaries. These results reveal that the radial‐pattern formation changes the fluorescence property of polycarbonate in the visible and near‐infrared regions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 468–473, 2004
Biocidal polystyrene beads. III. Comparison of N‐halamine and quat functional groups
Authors: Chen Y. , Worley S. D. , Huang T. S. , Weese J. , Kim J. , Wei C.‐I. , Williams J. F. 
Published: February 2004

AbstractA comparison has been made between the biocidal efficacies of N‐chlorinated polymeric beads and two derivatives of polyquat beads. Biocidal effects were measured after brief contact exposures of aqueous suspensions of either Staphylococcus aureus or Escherichia coli to the water‐insoluble beads. The polymeric backbone was held the same in all three types of beads, so they differed only in their biocidal derivative moieties. In all cases, functionalization of crosslinked chloromethylated polystyrene beads was performed to introduce the biocidal properties. Synthetic methods and test data will be presented. The most effective biocide, as measured by degree of inactivation in the shortest contact time of the two species of bacteria, was the N‐chlorinated hydantoinyl derivative of methylated polystyrene. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 363–367, 2004