bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyacrylic acid macromolecule—complexed zinc phosphate crystal conversion coatings
Authors: Sugama T. , Kukacka L. E. , Carciello N. , Warren J. B. 
Published: April 2003

AbstractWhen water‐soluble polyacrylic acid (PAA) macromolecules are introduced into zinc phosphating liquids, significant improvements in the yield of conventional zinc phosphate conversion films deposited on carbon steel surfaces are obtained. The improvements include controllability of crystal dimensions, degree of crystallinity, and coating weight. The conversion layer formed is a composite microstructure consisting of a bulk PAA polymer and complexed PAA continuously overlaying a uniform array of fine dense zinc phosphate crystals. Interfacial studies of the composite layer using infrared spectroscopy, energy‐dispersive X‐ray spectrometry associated with scanning electron microscopy, and X‐ray photoelectron spectroscopy indicated that the functional carboxylic acid groups in the PAA molecules were strongly chemisorbed by the Zn atoms at the outermost surface sites of the crystal layers. The intermolecular bridging action of the surface Zn atoms which connect the PAA and the zinc phosphate crystal layers results in good adhesion at the PAA–crystal interfaces. In addition, the plasticized complex formation plays an essential role in increasing the stiffness and the ductility of the normally conventional crystal films. The flexibility of the complex coating surface and the thickness and surface roughness of the thin PAA overlayer all affect the adhesive force at the interface between the organic polymer topcoat and the complexed coating.
The application of coherent optics to the study of adhesive joints. I. Speckle photography
Authors: Vallat M. F. , Martz P. , Fontaine J. , Schultz J. 
Published: April 2003

AbstractA new technique of coherent optics, speckle photography, has been applied to the study of the behavior of adhesive joints under shear stress. This technique allows the determination of the in‐plane motion by a point‐by‐point analysis with a sensitivity of about 3 μm. This property has been used to measure the interfacial displacement of model glass‐glass joints bonded by different types of adhesive when submitted to shear. The experimental results permit direct verification of Volkersen's theory as well as the determination of the actual shear modull of the thin adhesive layer. The simplicity of use and interpretation of the technique of speckle photography should lead to significant application of this method in the future for the study of adhesive joints.
Plasma surface modification of polymer powders with application to thermal energy storage
Authors: Loh In‐Houng , Cohen R. E. , Baddour R. F. 
Published: April 2003

AbstractThe rotating bed plasma reactor described here permits uniform surface modification of relatively large amounts of powder materials. Scale‐up to even larger batches of solids appears to be feasible. Some preliminary experimental data on the plasma surface modification of polymer powders have been presented. The results show that the flow rate, time of treatment, and type of feed gas are important operating parameters which influence the final surface character. One particular application of plasma‐modified polymer powders was explored; by crosslinking and/or chemically modifying only the outermost surface regions of these powders, various polymeric materials may be rendered useful for use in thermal storage slurries. The major advantage of the surface‐modified plasma treated powders over the bulk‐modified powders used previously is the retention of essentially all of the pristine polymer heat of fusion in the surface‐modified materials.
Analysis of nonsolvent–solvent–polymer phase diagrams and their relevance to membrane formation modeling
Authors: Yilmaz L. , McHugh A. J. 
Published: April 2003

AbstractCalculations have been carried out, based on Flory–Huggins solution theory, to analyze the behavior of the ternary nonsolvent–solvent–polymer phase diagram for typical membrane‐forming systems. Consideration is given to the behavior of the spinodal as well as binodal curves, tie‐line slopes, and critical points as a function of various parameters, most especially those related to the concentration dependency of the interaction parameters. Implications regarding membrane structure formation are discussed, and the suitability of different functional forms for the interaction parameter concentration dependence is also analyzed.The net result of these calculations is to demonstrate the importance of the various parameters in controlling the phase‐diagram behavior and particularly to show the critical role of the concentration dependence of the solvent–polymer interaction parameter in affecting the nature of the miscibility gap.
Dielectric studies of the cure of epoxy matrix systems
Authors: Lane John W. , Seferis James C. , Bachmann Michael A. 
Published: April 2003

AbstractDielectric spectroscopy was used to monitor the curing process of two epoxy resin systems. The basic system (system I) consisted of DGEBA (a difunctional epoxy) and a polyamide in a 50–phr mixture. In addition, a comparative analysis was performed on a high–performance resin system (system II) used primarily in unidirectional composite applications. This system contained TGDDM (a tetrafunctional epoxy) and DDS (a tetrafunctional amine) in a 25–phr mixture. The dielectric data were obtained using a simple yet functional sample cell electrode designed and constructed in the laboratory. For system I, isothermal dielectric data were used to determine apparent activation energies for the temperature range from 22 to 70°C. The data showed that the activation energy was a function of temperature and increased as the temperature of the cure increased. This indicated that the reaction mechanism was also a function of temperature. For system II, data were collected between 140 and 190°C and an overall activation energy for that temperature range was determined. The overall activation energies for both systems, calculated using dielectric spectroscopy, compared favorably to those obtained using differential scanning calorimetry. Also, using a wider frequency range (240 Hz to 2 MHz), Argand diagrams were constructed and modeled with the Cole–Cole empirical equation for systems with a distribution of relaxation times. This justified the calculation of average relaxation times, which could then be related to the bulk physical properties of the polymer, such as viscosity. Modified Argand diagrams, where ε″ is plotted against ε′ at one frequency as a function of time, were also constructed, which aided in the understanding of the curing processes for these thermosetting systems.
Studies on chitin. IX. Crosslinking of water‐soluble chitin and evaluation of the products as adsorbents for cupric ion
Authors: Kurita Keisuke , Koyama Yoshiyuki , Taniguchi Akihiko 
Published: April 2003

AbstractWater‐soluble chitin was successfully crosslinked to varying extents with glutaraldehyde in homogeneous aqueous solutions to improve the properties as an adsorbent for metal cations, and the effects of crosslinking were discussed. Complete insolubilization was achieved with the fivefold excess aldehyde, but, in terms of adsorptivity of Cu2+, the chitin crosslinked at an aldehyde/amino group ratio of 1.0 was found to exhibit remarkable capacity and was much superior to others. The desorption of Cu2+ from the adsorption complex was also attained effectively at pH 2.0. These results indicated that the loose crosslinking was quite simple and efficient to produce high capacity adsorbents for practical use. Thermal behavior of the crosslinked chitin was examined by TMA and TGA; a softening phenomenon was observed at 145°C.
Static tensile and dynamic mechanical properties of hydroxypropylcellulose films prepared under various conditions
Authors: Suto Shinichi , Kudo Masataka , Karasawa Mikio 
Published: April 2003

AbstractThe films of hydroxypropyl cellulose (HPC), which is a lyotropic and thermotropic liquid crystal, were cast under various conditions of temperature and concentration. The effects of the casting conditions on the static tensile and dynamic mechanical properties of the cast films were determined, and the results were compared with those of films prepared by means of hot compression. The tensile properties of the films prepared by both processes (cast and hot compression) were unsatisfactory in comparison with other liquid crystalline polymers, and this was partly due to water absorbed during the test. In dynamic properties, two distinct transitions were detected. The higher one, around 110°C, was associated with the rotation of an unhydroglucose ring and the lower one, around 25°C, was associated with the Tg. There were no marked differences in the properties between cast films and hot‐compressed films, except the disappearance of the Tg for hot‐compressed film prepared at a relatively higher temperature. The basis for defining the liquid crystalline structure in cast and hot‐compressed films are not directly given in this preliminary paper. However, judging from the dynamic mechanical properties and refractive index data for films prepared by both processes, it appears that dimethylacetamide‐cast films and films compressed at 180 and 200°C may have some structures related to liquid crystalline phase and that inter‐ and intramolecular hydrogen bonding play an important role in lyotropic and thermotropic liquid crystalline behavior for HPC.
Effect of temperature on the soda and kraft cooking of corn stalks
Authors: Nagieb Zeinat A. 
Published: April 2003

AbstractThis study included soda and kraft process of corn stalks at constant active alkali, the kraft liquor having 25% sulfidity. Five cookings were made at different temperatures, 80, 120, 140, 160, and 180°C, each for 1 h. Under the condition of the study the following temperature effects were noted: (1) Delignification could be approximated by a first‐order reaction. (2) The kraft process exhibited twice the rate of lignin removal as the soda of the same digestion temperature. (3) The rate of removal of carbohydrates in the kraft process is faster than soda process due to presence of sulfide ion. (4) The carbon content of thiolignin increased hydrogen and oxygen content decreased while in soda lignin the opposite occurs. (5) The amount of phenolic OH increased with increasing the cooking temperature and was more noticeable in thiolignins than in soda lignins. (6) Demethoxylation occurs in kraft cooking at elevated temperature rather than soda cooking.
Cold‐drawing behavior of naturally aged poly(ethylene terephthalate)
Authors: Avramova N. , Fakirov S. , Schultz J. M. 
Published: April 2003

AbstractThe cold‐drawing behavior of naturally aged poly(ethylene terephthalate) (PET) is investigated and an attempt is made to compare the mechanical behavior of unaged commercial PET and material which has been naturally aged for 11 years. Mechanical, viscometric, DSC and IR measurements are applied. The previously observed unusual ability of fresh PET bristles to be cold drawn up to 15:1 is not achieved for the naturally aged material. This fact is related to chemical cross‐linking occurring on the surface of bristles after drawing and thermal treatment. The cross‐linked skin is unsoluble, infusible, and uncrystallizable. The natural aging defeats the ability of PET to respond to external treatments which would otherwise change the internal structure. Such a “stabilization” of material properties is a result of the transformation, during natural aging, of the original physical network into a chemical network consisting of covalent bonds.
Chelating polymer bearing triazolylazophenol moiety as the functional group
Authors: Onari Yasuo 
Published: April 2003

AbstractThe chelating polymer‐bearing triazolylazophenol moiety as the functional group was synthesized, its metal adsorption properties for 6 divalent heavy metal ions; Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Pb2+ were investigated. The capacity of the polymer for Cu2+ achieved 8.7 mEq/g in pH 5.3 solution. The polymer showed remarkable color changes from orange to red violet or blue violet with its chelations to the heavy metal ions. The metal adsorption rates of the polymer were rapid in performing complete capacity saturation of heavy metal ions in about 30 min. The capacities varied little the presence of alkali or alkaline earth metal ions in solutions. The perfect elimination of metals from the polymer–M2+ chelates were performed with mineral acid solutions. The metal ions; Cu2+ and Ni2+ in plating‐process solutions were effectively removed by the chelating polymer, and the polymer can be practically used for the removal of these ions from waste water.
Gas chromatographic determination of acid‐catalyzed transesterified antioxidant additive irganox 1076® in polypropylene
Authors: Hayashi Hiromichi , Matsuzawa Shuji 
Published: April 2003

AbstractThe transesterification by means of methyl alcohol of a low vapor pressure antioxidant additive, n‐octadecyl‐β‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)propionate‐Iraganox 1076® (produced by Ciba‐Geigy) was studied. The classical method to prepare methyl esters from triglycerides in lipids was applied with use of sulfuric acid as a catalyst. The optimum reaction conditions were sulfuric acid concentration of 1 w/v% in methyl alcohol, temperature of 75°C, and time of 2 hours. The contents of the additive were determined by gas‐liquid chromatography (GLC) of a portion of transesterificate using 10% SE‐30 on Gaschrom Q (60–80 mesh) or 5% Silicone OV‐17 on Shimalite W (80–100 mesh) as a packing reagent. Irganox 1076 in polypropylene was extracted with n‐hexane. Many interfering substances in the GLC could be completely removed by the Florisil column treatment of n‐hexane extract. The relative standard deviation was 2.7% for Irganox 1076 at levels corresponding to 0.0142 wt% in polypropylene. The limit of detection was 5 μ/g in polypropylene.
Effect of nucleating agents on the temperature‐dependent melt crystallization kinetics of poly(1‐butene)
Authors: Icenogle R. D. , Chatterjee A. M. 
Published: April 2003

AbstractThe effect of additives (mostly nucleating agents) on the crystallization rate of isotactic poly(1‐butene) has been investigated by differential scanning calorimetry. Isothermal crystallization half‐times and crystallization temperatures have been measured for polymer‐additive blends. The crystallization temperature and the cooling rate at which the ultimate fraction transformed becomes less than 1 is calculated as a function of nucleation density, and this is used to characterize the effect of the additives on crystallization rate. The relationship between the isothermal crystallization half‐time and the crystallization temperature is also calculated theoretically and is compared with experimental results.
Rheological measurements of cure rate of UV inks
Authors: Otsubo Yasufumi , Amari Takeshi , Watanabe Koichiro 
Published: April 2003

AbstractThe dynamic viscosity of UV inks during curing was measured at various film thickness using an oscillating plate rheometer. Logarithmic plots of the dynamic viscosity versus exposure energy are closely related by two‐straight lines. A useful concept in discussing the curability is the minimum exposure energy difined as the exposure energy at the intersection of two lines. On exposure to a monochromatic light of 365 nm, the minimum exposure energy increases exponentially with film thickness; this resulting from an exponential decay of the light intensity with depth in the film. Magenta ink shows the fatest cure rate at a given thickness, followed by yellow, cyan, and black inks in that order. The difference in cure rate is attributed to different absorbances of pigments. The UV curability on direct exposure to UV lamp is predicted from the spectral sensitivity of the photoinitiator and the viscosity data obtained during curing under 365 nm light. The model calculation shows good agreement with the experimental results.
Preparation of cellulose graft copolymers having polypeptide side chains and their blood compatibility
Authors: Miyamoto Takeaki , Takahashi Shin‐Ichi , Tsuji Sin‐Ichi , Ito Hiraku , Inagaki Hiroshi , Noishiki Yasuharu 
Published: April 2003

AbstractBlood compatibility of cellulose graft copolymers with poly(γ‐benzyl‐L‐glutamate) and poly(N5‐2‐hydroxyethyl‐L‐glutamine) (Cell‐g‐PBLG and Cell‐g‐PHEG) was examined in vivo blood tests. For this purpose, Cell‐g‐PBLG graft copolymers with PBLG contents ranging from 7 to 60 mol % were prepared by polymerizing N‐carboxy‐γ‐benzyl‐L‐glutamate(γ‐BLG NCA) using aminoethyl cellulose (AE‐Cell) with degree of substitution of 0.05 as macroinitiator. Graft copolymerization was carried out under a variety of conditions at 20°C in dimethyl‐sulfoxide. Monomer conversion higher than 60% were obtained for all the polymerization runs. The solubility tests revealed that all of the AE‐Cell and the polypeptides formed were grafted. The Cell‐g‐PHEG graft copolymers were prepared by treating Cell‐g‐PBLG graft copolymers with 2‐amino‐1‐ethanol. Characterization of these graft copolymers were carried out by IR spectroscopy, DSC, and water content measurement. Tests for blood compatibility, in vivo, were made by a method of peripheral vein indwelling suture which was developed by one of the authors. The coating of graft copolymers on the polyester suture was made by casting either from formic acid solution of LiCl/dimethylacetamide solutions using water as the regenerating medium, and the polymer‐coated sutures were implanted into a jugular and femoral vein of a dog. The results showed that the graft copolymers examined have excellent antithrombogenic properties.
Thermal degradation of cellulose model compounds in inert atmosphere
Authors: Šimkovic Ivan , Ďurindová Mária , Mihálov Vincent , Königstein Jozef , Ambrovič Peter 
Published: April 2003

AbstractThermal degradation of cellulose model compounds was studied using thermogravimetry (TG), electric spin resonance (ESR) spectroscopy, and gas chromatography–mass spectrometry (GS–MS). The molecular weight of samples did not influence the activation energy of gasification. In the case of catalytic influence of NaOH on cellulose thermolysis formation of gaseous products in the temperature range 250–350°C increased and a greater amount of residue was formed at 350–400°C compared to noncatalytic thermolysis. Residues of compounds with hemiacetal groups showed higher concentration of unpaired electrons than residues obtained from models with the blocked hemiacetal group.
Calendering of non‐newtonian fluids
Authors: Wan Daud Wan Ramli 
Published: April 2003

AbstractThe calendering of non‐Newtonian fluids by two rotating cylinders to produce thin films of fluids finds wide application in polymer sheet‐making and food‐drying industries. Theoretical work has previouly been devoted to the symmetrical case where the cylinders are of equal diameters rotating at the same speed. The present work proposes a new one‐film theory of calendering of power law fluids for unequal radii and surface velocities of the calendering cylinders. The relationship between the dimensionless thickness of the calendered fluid, Δe* and that of the incoming fluid, Δi* is shown to be a function of the ratio of the surface velocities of the cylinders and the power law index. The result further shows that Δe* tends to asymptote after the second decade of Δi*
Determination of intrinsic viscosity by single specific viscosity measurement
Authors: Rao M. V. Ram Mohan , Yaseen M. 
Published: April 2003

AbstractSingle point determination of intrinsic viscosity saves considerable amount of time, effort and materials. Quite a few equations are available in the literature which require relative viscosity of the polymer solution at a single concentration for calculation of [η]. A comparative assessment of the applicability of two such equations and that of a proposed one has been made by using reported data as well as the practical data on viscosity of alkyd solutions in different solvents. It is inferred from the findings that, for good results from single point methods, the concentration should not be the sole criterion, as suggested by earlier workers; ηsp may also be considered as one of the criteria. The single point technique is found to be applicable to alkyd solutions in different solvents.
Residual stresses and birefringences in large, quenched samples
Authors: Lee Sangmoon , De La Vega Javier , Bogue Donald C. 
Published: April 2003

AbstractAs large polymer samples are quenched rapidly, residual stresses (and birefringence) are frozen into the final part due to the different thermal/contraction histories of the surface and center portions. The present work on polystyrene, a continuation of earlier studies, deals with the effects of sample size and initial temperature; these results are treated with the genral theory of Lee, Rogers, and Woo. Finally, data for two other amorphous polymers, poly(methyl methacrylate) and polycarbonate, are presented; in these cases the simpler theory of Aggarwala and Saibel is used. The theories help explain the relative behavior of the three materials and are qualitatively useful. However, the compexity of the rheooptical response precludes doing a completely rigorous treatment.
Studies on NBR/PVC blends
Authors: George K. E. , Joseph Rani , Francis D. Joseph 
Published: April 2003

AbstractStudies conducted on butadiene–acrylonitrile copolymer (NBR)/poly(vinyl chloride) (PVC) blends at different temperatures indicate that an optimum temperature exists for the formation of a particular blend. The mechanical properties of the blends confirm this observation. PVC stabilizer based on magnesium oxide, zinc oxide, and stearic acid was found to be very useful in NBR/PVC blends.
Time‐dependent changes in morphology of neat and reinforced epoxy resins part I. Neat epoxies
Authors: Mijovic Jovan , Lin King‐Fu 
Published: April 2003

AbstractAn investigation was conducted of the morphological changes in neat epoxy resins after cure, that is, during cooling and subsequent “annealing” at a temperature below the glass transition. A series of bifunctional and tetrafunctional epoxy formulations were prepared and studied. A simultaneous drive toward thermodynamic equilibrium (homogeneity) and morphological inhomogeneity was found to take place in the glassy network. A conceptual model was advanced to explain the time‐dependent development of inhomogeneous morphology in the glassy state. After a certain sub‐Tg annealing time, “morphological equilibrium” is reached while physical aging of the glassy network (decrease in enthalpy and/or free volume) continues to occur. The proposed model, based upon the variation of contractive forces throughout the epoxy network, was corroborated by experimental evidence obtained from calorimetric and viscoelastic measurements and electron microscopy.
On‐line monitoring of polymer quality in a batch polymerization reactor
Authors: Ponnuswamy S. , Shah S. L. , Kiparissides C. 
Published: April 2003

AbstractA novel experimental reactor system has been designed to study a variety of problems related to on‐line measurements and computer control of batch polymerization reactors. A number of measuring devices such as densitometer, viscometer, size exclusion chromatograph, and torquemeter have been put on‐line to a batch reactor and interfaced to a real time computer to monitor monomer conversion and molecular weight during polymerization. A new feature of the experimental setup is its microprocessor‐based sampling system which automatically collects samples from the reactor and injects them into the SEC analyzer. Computer software has been developed for on‐line acquisition and processing of SEC data. This work demonstrates the feasibility of on‐line measurement of monomer conversion and molecular weight. Furthermore, it presents a comparative study of some common techniques employed for off‐and on‐line measurement of polymer quality.