bluuebunny/crossref_metadata_2025_split huggingface dataset:
Weldline strength in injection molded HDPE/PA6 blends: Influence of interfacial modification
Authors: Fellahi S. , Fisa B. , Favis B. D. 
Published: April 2003

AbstractMost injection molded objects contain defects known as weldlines. This defect may introduce an element of weakness affecting the object's performance. Weldlines are particularly problematic in multiphase materials where the situation may be exaggerated by component mismatch on the two sides of the interface that results in additional weakening when the two components do not adhere well to each other. In addition, weldline behavior is influenced by orientation and morphological effects. This paper deals with relationships between the structure and the mechanical properties in injection molded high density polyethylene polyamide‐6 blends. The weldline effect is investigated in detail. Two molds were used to generate weldlines: a double‐gated tensile bar cavity in which the weldline results from the meeting of two melt fronts flowing into each other from opposite directions, and a film‐gated rectangular plaque mold with a circular insert that divides the melt front in two. Following the recombination of the fronts, there is additional flow as the melt fills the mold cavity. Two preparations containing 75 vol % of polyamide‐6 and 25 vol % of polyethylene with and without compatibilizer were studied. In the first case, a compatibilizer was incorporated into the polyethylene prior to compounding with the polyamide‐6. In the directly molded tensile bar the minor phase is strongly oriented parallel to flow. Only in the core, which represents about 10% of the sample thickness, do the dispersed phase particles assume spherical shape. The morphology of the weldline is closely related to that of the skin: the elongated structures are oriented parallel to the weldline plane. The effect of the compatibilizer on the mechanical properties (without the weldline) of the directly molded tensile bars is minor: It is overshadowed by the flow‐induced morphology. The weldline strength loss is about 40% in the noncompatibilized blend. The introduction of the compatibilizer has restored the material's ability to yield and the properties are close to those measured without the weldline. For the second type mold, the effect of the weldline is less pronounced and the effect of the distance from the insert is negligible. The anisotropy is quite pronounced in the noncompatibilized blend. In compatibilized blends, all tensile properties are unaffected by the presence of weldline, except for the 2‐mm‐thick plaque in the position close to the insert. The properties in the direction parallel to flow are similar to the type I mold and not affected by the increase of plaque thickness. Consequently one may question the utility of the directly molded tensile specimens in studying various aspects of the mechanical behavior of multiphase materials where the flow‐generated structure is very different from that found in “real” injection molded parts. © 1995 John Wiley & Sons, Inc.
Surface reactive acetal functional waterborne core–shell particles
Authors: Kjellqvist Kerstin , Rassing Jörgen , Wesslén Bengt 
Published: April 2003

AbstractCore–shell particles were prepared using a two‐stage emulsion polymerization of styrene and ethyl acrylate. The particle surfaces were modified by introducing an acetal functionality, suitable for acid‐catalyzed crosslinking processes. Surface functionalization was performed in two principally different ways: In the first method, 4‐aminobutyraldehyde dimethylacetal was used for grafting through transesterification of ethyl acrylate residues at the surface or through reactions with epoxy groups introduced in the second‐stage polymerization. In the second method, 4‐acrylamidobutyraldehyde dimethylacetal was used as a comonomer to ethyl acrylate in the second‐stage polymerization. The reactive particles were used as crosslinking agents in an acid‐curing coating system. © 1995 John Wiley & Sons, Inc.
Absorption–desorption histories through a sphere with a change in dimensions, with constant concentration on surface during absorption, and finite volume of surrounding during desorption
Authors: Bouzon J. , Benghalem A. 
Published: April 2003

AbstractLiquids are transferred through nonporous polymers provoking a change in dimension. A mathematical treatment of the process of radial diffusion through a sphere with consequent change in dimension is made, as well as a numerical treatment of the process. The case is considered when the concentration of the liquid on the surface is constant during absorption and then the surrounding fluid is of finite volume and strongly stirred during the stage of desorption. The kinetics of absorption–desorption histories are calculated for various values of the volume expansion due to the presence of liquid. The profiles of concentration as well as the kinetics of change in dimension are also evaluated. Two parameters are introduced: the maximum of the volume expansion of the polymer and the ratio between the amount of liquid in the polymer and that contained in the surrounding at the final equilibrium of desorption. © 1995 John Wiley & Sons, Inc.
Mechanical instability of swollen PVC films
Authors: Teschke O. , Kleinke M. U. , Galembeck F. 
Published: April 2003

AbstractThe swelling of soft coating on a tough substrate immersed in solvent is investigated. Equilibrium aspects of the coating deformation due to swelling as well as its kinetics have been explored; in particular, the appearance of patterns on the originally smooth surface of the swollen film is described and modeled. The patterns are the result of a mechanical instability such as buckling or wrinkling. The time dependence of the wrinkles height is measured and, by using the energy dissipation criterion for wrinkle spread, the ratio of the adhesion energy by the bulk modulus is determined as a function of swelling time. © 1995 John Wiley & Sons, Inc.
Reactive diluents and properties of ultraviolet‐cured polycarbonate urethane acrylates
Authors: Krongauz Vadim V. , Tortorello Anthony J. 
Published: April 2003

AbstractPolymer films obtained from photocurable formulations were investigated by tensile methods and dynamic mechanical analysis. The polymer formulations contained photoinitiator, urethane diacrylate oligomer, and acrylic reactive diluent. It was found that diluent concentration may strongly affect the glass transition temperature and elastic modulus of the cured coating. When the diluent homopolymer glass transition temperature is larger than that of oligomer homopolymer, the glass transition temperature and elastic modulus of the coating film increase with the increase of the diluent concentration. When the diluent homopolymer has lower glass transition temperature than the homopolymer of the oligomer, the increase in diluent concentration leads to a decrease in glass transition temperature and elastic modulus of the UV‐cured coating film. The effect of the testing temperature on tensile storage modulus of the films containing different concentrations of reactive diluents was studied as well. The data indicated that a variety of coatings with wide ranging but predictable properties can be formulated from previously examined starting materials but used at different concentrations. © 1995 John Wiley & Sons, Inc.
Study on application of block copolymers composed of poly(vinyl alcohol) and polyacrylamide to paper sizing
Authors: Okaya Takuji , Sato Toshiaki , Ono Isao , Maruyama Hitoshi , Terada Kazutoshi 
Published: April 2003

AbstractBlock copolymers of poly(vinyl alcohol) (PVA) and polyacrylamide (PAAm) were investigated as paper additives. The mixture of both homopolymers in aqueous solution caused phase separation, which indicated incompatibility. The block copolymers were soluble in water without macrophase separation. In the case of surface sizing to paper, PVA–b‐PAAm as well as PAAm afforded stiffness to paper, whereas PVA could not. In the case of internal sizing, the block copolymers with anionically modified PAAm revealed excellent improvement in paper properties, whereas PAAm made the tearing strength worse. Brittle polymers such as PAAm appear to afford stiffness to paper, but also make the paper brittle. PVA that is a tough polymer due to high crystallinity and low glass transition temperature can afford toughness to paper, at the expense of stiffness. The block copolymers seem to retain the desirable properties of each simultaneously. © 1995 John Wiley & Sons, Inc.
Interfacial aspects of latex ipns for toughening polycarbonate. I. Synthesis and characterization
Authors: Hu R. , Dimonie V. L. , El‐Aasser M. S. , Pearson R. A. , Sperling L. H. , Hiltner A. , Mylonakis S. G. 
Published: April 2003

AbstractCore/shell structured latex particles with an interpenetrating polymer network (IPN) core(polymer A and polymer B) and glassy shell (polymer C) were synthesized by emulsion polymerization techniques. Polymer A was poly(butadiene‐stat‐styrene) (90/10) (P(Bd/S)). Polymer B was either poly(butyl acrylate‐stat‐methyl methacrylate) (60/40) or poly(butyl acrylate‐stat‐styrene) (60/40) prepared by a sequential IPN technique to form the cores. The glass transition temperatures, Tg, of polymer A and polymer B were around −70 and 10°C, respectively. The shell, polymer C, poly(styrene‐stat‐acrylonitrile) (72/28), was polymerized with grafting onto the IPN core by a semicontinuous process. The particle size and particle size distribution were measured by light‐scattering, capillary hydrodynamic fractionation, and transmission electron microscopy. The glass transition temperatures were determined by differential scanning calorimetry. The polymer A (particle sizes between 200–270 nm) with different gel fractions was used to characterize the effect of gel fraction on IPN morphology. A core/shell type phase separation was observed for IPN particles when using a polymer A with > 90% gel fraction. A distribution of polymer B domains in polymer A was obtained when using polymer A with a 40% gel fraction. A good coverage of polymer C on the IPN core particles was obtained at a core/shell ratio of one to one. A broad glass transition range for the core/shell structured latex particles was observed. In article II of this series, these latex particles will be used to toughen such engineering thermoplastics as polycarbonates to understand the particular toughening theories of these polymers. © 1995 John Wiley & Sons, Inc.
Adsorption properties and microporous structure of adsorbents produced from phenolic resin and biomass
Authors: Simitzis J. , Sfyrakis J. , Faliagas A. 
Published: April 2003

AbstractMixtures of novolac resin and olive stone biomass in proportions 20 : 80 (w : w) are cured, pyrolyzed up to 1000°C (material C20a), and activated with steam (material C20a). The adsorption properties of these materials and a commercial activated carbon (CC) are investigated based on the adsorption of nitrogen and pentane. The adsorption capacity, the surface area determined by the BET and DRK equation, and the pore volume determined as micropore volume by the DR equation, and as cumpulative pore volume related to the Kelvin equation, for the materials follow the order C20a > CC > C20. The DR equation can be applied for the adsorption of nitrogen on the materials examined in the region of P/Po = 0.005 up to 0.3 that exceeds in both sides the common range for the applicability of the DR equation. The activated materials C20a and CC are mainly microporous and reveal the type I isotherms of the Brunauer classification for nitrogen adsorption. The only pyrolyzed material, C20, contains both micropores and mesopores and reveals characteristics of both types I and II. The number of layers for C20a and CC is lower than 2 and for C20 is more than 2. © 1995 John Wiley & Sons, Inc.
Tensile mechanical property evaluation of natural and epoxide‐treated silk fibers
Authors: Dunaway Dwayne L. , Thiel Brad L. , Viney Christopher 
Published: April 2003

AbstractSilkworm cocoon silk and spider major ampullate (drag line) silk exhibit macroscopic tensile properties that, while impressive in the context of polymer fibers, are highly variable. The variability is linked to the cross‐sectional geometry being nonuniform: silk fiber cross section changes significantly over distances that are small compared to the scale on which diameters are averaged by typical characterization techniques. This characteristic must be taken into account when evaluating chemical treatments (in the present case infiltrating with crosslinkable epoxide) that are aimed at improving strength or stiffness. The magnitude of any change in mechanical property must be considered in relation to the spread in values recorded prior to treatment. An apparent improvement in the mean value of a tensile property may turn out to be statistically insignificant when compared to the standard deviations associated with those data. Previous authors do not address this simple assessment of significance. © 1995 John Wiley & Sons, Inc.
On the assessment of hydrogels for fluid absorbency
Authors: Dave Ashok , Vaishnav Ujval , Desai Rakesh , Shah Amrish , Ankleshwaria Bhupin , Mehta Mahesh 
Published: April 2003

AbstractHydrogels are capable of absorbing fluids like water to the extent of several fold. Since this is an important characteristic property of any hydrogel, it is necessary to employ a simple and accurate method for its assessment. Several methods reported in the literature have been discussed for their scope as well as limitations. A comprehensive approach on the basis of polymer structure–property application is made to evaluate suitable methodology for two types of hydrogels, continuous and discrete. Representative methods for both type are suggested with detailed experimental procedures and results. The work provides com parative data with suggested methods which could be useful to the practitioner. © 1995 John Wiley & Sons, Inc.
Structure–property relationship in fibers spun from poly(ethylene terephthalate) and liquid crystalline polymer blends. II. Effect of spinning temperature on fiber properties
Authors: Petrović Zoran S. , Farris Richard 
Published: April 2003

AbstractA series of fibers based on neat poly(ethylene terephthalate) (PET) and PET/10% liquid crystalline polymer (LCP) blends were spun at various temperatures, ranging from 250 to 310°C, and the effect of spinning temperature on properties was studied. Improved tensile strengths and higher moduli of hot‐drawn fibers were obtained with fibers spun at and above 300°C, which was explained by increased transesterification and the randomized structure of the PET/LCP blends. © 1995 John Wiley & Sons, Inc.
Highly dispersed titanium(IV) oxide on α‐cellulose surface: An XPS, SEM, and XRD study
Authors: Da Silva Lindomar R. Damasceno , Gushikem Yoshitaka , Gonçalves Maria Do Carmo , Filho Ubirajara P. Rodrigues , De Castro Sandra C. 
Published: April 2003

AbstractInteraction of titanium chloride with a cellulose surface and the decurrent modifications introduced on its morphology were studied by scanning, electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The chemical analysis of the surface was carried by X‐ray photoelectron spectroscopy (XPS) and changes in the crystallinity upon chemical treatment was determinded by the X‐ray diffraction (XRD) technique. Interaction of titanium with cellulose occurs only at the surface and a decrease of its crystallinity was observed with the amount of metal oxide incorporated into the solid matrix. © 1995 John Wiley & Sons, Inc.
Catalyzing the curing reaction of a new benzoxazine‐based phenolic resin
Authors: Ishida H. , Rodriguez Y. 
Published: April 2003

AbstractThe effect of potential catalysts on the curing reaction of a new type of phenolic resins obtained from benzoxazine precursors is studied. These novel resins solve the shortcomings of traditional phenolics because they cure by a ring‐opening mechanism that avoids the release of volatiles. Isothermal and nonisothermal differential scanning calorimetry (DSC) data is used to determine the influence of the catalysts on the curing kinetics. Fourier transform infrared (FTIR) spectroscopy is also applied. The benzoxazine chosen for this study is a purified benzoxazine monomer based on bisphenol‐A, formaldehyde, and aniline. The as‐synthesized benzoxazine precursor is also studied to determine the influence of the dimers and higher oligomers in the curing mechanism. The presence of these structures seems to catalyze the curing reactions. The activation energy and overall reaction order of the as‐synthesized precursor are determined. Among the catalysts tested, adipic acid shows the most promising results. For all the cases studied the curing reaction is autocatalyzed up to a diffusion‐controlled stage. © 1995 John Wiley & Sons, Inc.
Miscibility and shear creep resistance of acrylic pressure‐sensitive adhesives: Acrylic copolymer and tackifier resin systems
Authors: Kim Hyun‐Joong , Mizumachi Hiroshi 
Published: April 2003

AbstractThe miscibility between an acrylic copolymer and a tackifier resin was investigated in terms of phase diagrams, glass transition temperatures (Tg's), and dynamic mechanical properties of blends. Shear creep resistance (holding power, tb) of the blends was measured as a function of both temperature and stress (σ0) in order to obtain the master curves. It was found that the shear creep resistance of the pressure‐sensitive adhesives (PSAs) was closely related to the miscibility between the components and viscoelastic properties of the blends. The master curve of the miscible blends shifts toward a longer time scale as the amount of tackifier resin in the blend is increased as a result of the modification of the bulk properties, and their behavior greatly depends on the glass transition temperature (Tg) and storage modulus (G′) of the blends. However, the master curve of immiscible blends where two phases exist in the system does not shift greatly toward a longer time scale, because Tg and the storage modulus of the blend do not change greatly. © 1995 John Wiley & Sons, Inc.
Miscibility of blends of epoxidized natural rubber and poly(ethylene‐co‐acrylic acid)
Authors: Mohanty S. , Roy S. , Santra R. N. , Nando G. B. 
Published: April 2003

AbstractThe blends of epoxidized natural rubber (50 mol %) (ENR) and poly(ethylene‐co‐acrylic acid) (PEA) (6 wt %) are demonstrated to be partially miscible up to 50% by weight of PEA and completely miscible beyond this proportion. The miscibility has been confirmed by a DSC study which exhibits a single second‐order transition (Tg) for the 30 : 70 and 50 : 50 (ENR : PEA) blends. For the 70 : 30 (ENR : PEA) blend, the Tg's shift toward an intermediate value but do not merge to form a single Tg, making the blend partially miscible. The miscibility has been assigned to the esterification reaction between – OH groups formed in situ during melt blending of ENR and – COOH groups of PEA. The occurrence of such reactions have been confirmed by UV and IR spectroscopic studies. The existence of a single phase of the blends beyond 50 wt % of PEA has been shown by SEM studies. © 1995 John Wiley & Sons, Inc.
Chelate membrane from poly(vinyl alcohol)/poly(n‐salicylidene allyl amine) blend. II. Effect of co(II) content on oxygen/nitrogen separation
Authors: Choi Moon Jae , Park Chang Kyu , Lee Young Moo 
Published: April 2003

AbstractFacilitated transport of oxygen was performed through chelate membranes containing cobalt with selective oxygen binding ability as a fixed oxygen carrier. Chelate membranes were obtained from Schiff base membranes after treating a poly(allyl amine) (PAAm) and poly(vinyl alcohol) (PVA) blend with salicylaldehyde. It is confirmed that the OO stretching peak through a frequency change in FTIR could be seen at 1150 cm−1 between cobalt in the membrane and incoming oxygen. The permeability of oxygen through Schiff base membranes was 2.01−2.98 × 10−13 [cm3 (STP) cm2/cm s cmHg] and oxygen permselectivity was in the range of 1.83−3.27. For chelate membranes, both the permeability of oxygen and oxygen selectivity increased to 2.15−2.82 × 10−12 [cm3 (STP) cm2/cm s cmHg] and around 8, respectively. Permselectivity of chelate increased as a result of facilitation of O2 and inhibition of N2 transport. Detailed results and the mechanism of facilitation of oxygen are discussed on the basis of molecular interactions. © 1995 John Wiley & Sons, Inc.
Magnetic resonance image attributes of the bovine corpus luteum during development and regression
Authors: Hilton Jennifer L. , Baerwald Angela R. , Sarty Gordon E. , Adams Gregg P. , Pierson Roger A. 
Published: April 2003

AbstractTo determine whether magnetic resonance (MR) image attributes of the corpus luteum (CL) reflect its physiologic status at different phases of the bovine ovarian cycle, we analyzed the numerical pixel values (NPVs), relaxation rates, proton densities (PDs), and apparent diffusion coefficients (ADCs) from T1‐, T2‐, and diffusion‐weighted in vitro images and maps of the CL acquired at defined phases of luteal function. Ovaries were removed and serum samples taken on days 3, 6, and 10, or ≥17 (day 0 = ovulation), representing metestrus (n = 10), early diestrus (n = 7), mid‐diestrus (n = 9), and proestrus (n = 7), respectively. Regions of interest (ROIs) in each quadrant of the CL (which occupied at least 20% of the quadrant) were selected for analysis. Three MR image slices were analyzed: the slice with the greatest cross‐sectional area of the CL, and the slices acquired immediately before and after that slice. The mean NPVs of the CL in T1‐weighted images increased at each phase from metestrus (1,104 ± 40 msec) to early diestrus (1,119 ± 77 msec), to late diestrus (1,206 ± 43 msec) and proestrus (1446 ± 80 msec; P < 0.001). The mean NPVs in T1‐weighted images were higher in regressing CL (proestrous) than in any other phase (P < 0.002). Grayscale heterogeneity of CL in T1‐weighted images tended to increase during regression (P < 0.07). Regressing CL (proestrus) exhibited higher T1‐weighted mean NPVs (P < 0.01) and tended to have greater heterogeneity (P < 0.06) than growing (metestrus) and mature (diestrus) CL, even though similar progesterone concentrations were observed. The increased brightness and heterogeneity of regressing CL in T1‐weighted images appeared to be correlated with increased connective tissue and triglyceride content and decreased vascularity. It is anticipated that diagnostic markers for luteal viability and atresia in the in vitro bovine model will be applied to in vivo studies in women. Anat Rec Part A 272A:454–459, 2003. © 2003 Wiley‐Liss, Inc.
Improvement of RMI performance by generating efficient code
Authors: Maeda Kazuaki 
Published: April 2003

AbstractThe author developed an RMI (referred to here as xRMI) that includes a code generation function for object serialization and confirmed its effectiveness. The distinguishing characteristics of xRMI are that it combines runtime code generation for object serialization and migration of generated code while maintaining the ease of use of the Java RMI. This enables the time required for the second and subsequent client‐side serializations to be reduced and high‐speed deserialization to be done at the server side by migrating the code for deserialization, which is generated at the client side, to the server side. As a result, xRMI runs faster than standard Java RMI, and a significant performance improvement can be expected for network applications. This paper presents the background for the research and describes the basic design and implementation of xRMI, as well as experiments for confirming xRMI performance. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 79–88, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1178