bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on PVC composites containing Eugenia jambolana wood flour
Authors: Saini Gajender , Choudhary Veena , Bhardwaj Rashmi , Narula A. K. 
Published: November 2007

AbstractThis article describes the properties of composites using unplasticized PVC matrix and wood flour (obtained by crushing the bark of Eugenia jambolana) as filler. Composites were prepared by mixing PVC with varying amounts of wood flour (ranging from 10–40 phr; having particle sizes of 100–150 μm and <50μm) using two‐roll mill followed by compression molding. The effect of wood flour content and its particle size on the properties, i.e., mechanical, dynamic mechanical, and thermal was evaluated. Tensile strength, impact strength, and % elongation at break decreased with increasing amounts of wood flour. Stiffness of the composites (as determined by storage modulus) increased with increasing amounts of the filler. Modulus increased significantly when wood flour having particle size <50 μm was used. Morphological characterization (SEM) showed a uniform distribution of wood flour in the composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Study of the formulations and process conditions in the crosslinking of polyethylene foams at atmospheric pressure
Authors: Marcilla A. , García‐Quesada J. C. , Beltran M. I. , Ruiz‐Femenia R. 
Published: October 2007

AbstractThe aim of this work is the study of the foaming process of a commercial polyethylene in the presence of a crosslinking agent. Foams have been produced under nearly atmospheric pressure conditions, which commonly occur during polymer rotomolding. Different processingtemperatures and different combinations of blowing agent/kicker (azodicarbonamide/zinc oxide) and crosslinking agent (dicumyl peroxide) concentrations have been employed. Thus, the melt viscosity, crosslinking degree, and temperature of the gas evolution and its rate have been changed to a certain degree. The obtained results have revealed that all these factors are critical to obtaining uniform and low‐density foams. Under certain processing temperatures and with an appropriate formulation, foam densities have been reduced up to 70% with respect to nonfoamed polymer. The interactions among the different components of the formulation have also been observed, and the results have led to the conclusion that in this kind of process, when a low pressure is applied, the foam density can be controlled by an adequate synchronization of the melt‐crosslinking, foaming, and gas‐expansion processes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Graft copolymerization of methyl methacrylate with an N‐substituted maleimide–liquid‐crystalline copolymer by atom transfer radical polymerization
Authors: Çakır T. , Önen A. , Serhatlı I. E. 
Published: October 2007

AbstractThe synthesis of novel copolymers consisting of a side‐group liquid‐crystalline backbone and poly (methyl methacrylate) grafts were realized by the use of atom transfer radical polymerization (ATRP). In the first stage, the bromine‐functional copolymers 6‐(4‐cyanobiphenyl‐4′‐oxy)hexyl acrylate and (2,5‐dioxo‐2,5‐dihydro‐1H‐pyrrole‐1‐yl)methyl 2‐bromopropanoate were synthesized by free‐radical polymerization. These copolymers were used as initiators in the ATRP of methyl methacrylate to yield graft copolymers. Both the macroinitiator and graft copolymers were characterized by 1H‐NMR, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. The ATRP graft copolymerization was supported by an increase in the molecular weight of the graft copolymers compared to that of the macroinitiator and also by their monomodal molecular weight distribution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Characterization of oxidized cellulose with ultraviolet–visible spectroscopy
Authors: Milichovsky Miloslav , Milichovska Svatava 
Published: October 2007

AbstractThis article describes some properties and behavior of oxidized cellulose evaluated with ultraviolet–visible spectroscopy. Newly defined analytical parameters are described. Mechanisms of poly(1,4‐β‐D‐anhydroglucuronic acid) degradation and destruction are formulated. The feasibility of using the same Staudinger–Mark–Houwink equation to calculate the degree of polymerization of cellulose and the degree of polymerization of oxidized cellulose is demonstrated. Utilization of ultraviolet–visible spectroscopy is shown for the optimization of oxidized cellulose production and aging. Advantages and limitations of this method are discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Modeling the solids conveying zone of a novel extruder
Authors: Jia Mingyin , Wang Kejian , Xue Ping , Zhu Fuhua 
Published: October 2007

AbstractOn the basis of the theory of relative motions, a novel nested screw extruder was invented in which one rotating outer screw acted as the barrel for an inner screw; the combination of the outer screw and outer barrel was the other extrusion system. It was realized that centrifugal force resulted in the difference between the forces acting on the solids by the screw and by the barrel, which further compacted the solid pellet or powder. These factors benefited the frictional drag of solids and the early melting. This was consistent with the fact that the solids conveying flow rate increased greatly when the barrel and screw rotated oppositely at the same time. Thus, centrifugal force and material compressibility were significant in the feeding zone. A mathematical model was developed to calculate the output, pressure, and velocity of the solids in the screw down‐channel with consideration of the centrifugal force and material compressibility. The predicted pressure distribution and output were better than those by previous models in fitting the experimental data. The simulations revealed that the maximum traction angle was close to 90° − the helix angle for maximum output in contrast to the maximum traction angle of 90° predicted by the Darnell–Mol theory. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of polyurea microcapsules containing pyrethroid insecticide with hexamethylene diisocyanate isocyanurate
Authors: Takahashi Tadatsugu , Taguchi Yoshinari , Tanaka Masato 
Published: October 2007

AbstractPolyurea microcapsules containing a pyrethroid insecticide were prepared by the reaction between hexamethylene diisocyanate isocyanurate and ethylenediamine in an oil‐in‐water emulsion. This study was performed to establish the operational conditions of preparing microcapsules by interfacial polymerization and to investigate how the operational conditions affected the characteristics of microcapsules such as the morphology, wall thickness, mean diameter, and particle size distribution. Microcapsules prepared in this study were found to be spherical and monocore. The microcapsule yields, ranging from 94 to 98%, were almost equal to the theoretical values. The wall thickness of the microcapsules increased with the diameter of the microcapsules and the concentration of hexamethylene diisocyanate isocyanurate. In comparison with the results for microcapsules prepared with a mixture of hexamethylene diisocyanate uretidione and isocyanurate, the diameters and wall thickness of the microcapsules were found to be larger. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Microwave hall mobility studies on polymer–metal oxide nanocomposites
Authors: Murthy D. V. B. , Subramanian V. , Pavan Kumar V. S. , Natarajan T. S. , Raghuraman G. K. , Dhamodharan R. , Murthy V. R. K. 
Published: October 2007

AbstractFilms of polymer metal oxide composites with poly(methyl methacrylate) and metallic powders (CuO, Ni, and brushed Fe3O4) were prepared with a spin‐casting method. Electric transport studies indicated that the compositions surpassed the percolation threshold limit. Alternating current (AC) conductivity studies confirmed a hopping mechanism with power‐law behavior in frequency. For the first time, the mobility values of the carriers in these films were measured by the contactless microwave Hall effect technique with a bimodal cavity operating at 14 GHz. In this technique, a circular bimodal cavity is used to measure the change in the transmission coefficient (proportional to the carrier mobility) due to the application of a static magnetic field perpendicular to the microwave electric fields. The mobility measurements indicated a decrease in mobility with increasing quantity of CuO and Ni and showed an increase in the carrier–lattice scattering, whereas the mobility increased with increasing Fe3O4 due to the negative magneto resistance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Mechanical properties of thermoplastic elastomeric blends of chitosan and natural rubber latex
Authors: Rao Vijayalakshmi , Johns Jobish 
Published: November 2007

AbstractThermoplastic chitosan/natural rubber blends (Cs/NR) were prepared from natural rubber latex and chitosan by solution casting technique. The blends were characterized by mechanical analysis (stress–strain) and the mechanical properties were found to vary with chitosan/natural rubber ratios. Experimental values were compared with different theoretical models. Effect of thermal aging on mechanical properties was also investigated. Dicumyl peroxide was used as the crosslinking agent. The effect of crosslinking on mechanical properties of Cs/NR has also been studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Using anionic polymerizable surfactants in ultrasonically irradiated emulsion polymerization to prepare polymer nanoparticles
Authors: He Yuhui , Cao Ya , Fan Ying 
Published: October 2007

AbstractAn ionic polymerizable surfactant, sodium sulfopropyl‐laurylmaleate (M12), was synthesized and used as an emulsifier, an initiator, and a comonomer in ultrasonically irradiated emulsion polymerization. FTIR spectra and gravimetric method results indicated that copolymers P(Styrene‐M12) and P(Butylacrlate‐M12) were prepared successfully by ultrasonically irradiated emulsion polymerization and the composition of M12 elevated with the increasing concentration of M12 added. TEM photographs of P(St‐M12) showed that the nanoparticles with small diameters (20–45 nm) were prepared. With the increase of M12 concentration, the particle size became smaller and the size distribution became wider. The P(BA‐M12) particles size was also small (<100 nm) but the size distribution was wide due to the high reactivity of BA. Because surfmer M12 was chemically bonded with the latex particles, the stability of the copolymer latex prepared by ultrasonically irradiated emulsion polymerization was much better than that of the homopolymer latex (PSt or PBA) prepared by the same way. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Development of a mathematical model for studying bioethanol–water separation using hydrophilic polyetherimide membrane
Authors: Alvarez M. E. T. , Moraes E. B. , Araujo W. A. , Maciel Filho R. , Wolf‐Maciel M. R. 
Published: November 2007

AbstractAn essentially predictive mathematical model was developed to simulate pervaporation process. The group contribution method UNIFAC was used for calculating the upstream activity coefficients. The diffusion coefficient in the membrane was predicted using free‐volume theory. Free‐volume parameters were determined with viscosity and temperature data, and the binary interaction solvent–polymer parameter was calculated by a group‐contribution lattice‐fluid equation of state (GCLF‐EOS). A simulator named PERVAP was developed applying the mathematical model. Pervaporation process was simulated for separating bioethanol–water through polyetherimide membrane. The simulated results were validated using experimental data of bioethanol/water separation through polyetherimide membrane. The model presented a satisfactory performance compared to experimental data. Related to the simulation of the studied separation, a 99% molar enriched bioethanol stream was obtained with a recovery of 94%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and electrorheological properties of polyaniline‐coated barium titanate composite particles
Authors: Yan Hua , Liao Zi Jun , Zhu Xia , Wang Xue Mei , Chen Yong , Zhang Bin , Chen Shui Lian , Za Zhong Yong 
Published: October 2007

AbstractPolyaniline‐coated barium titanate composite particles were synthesized by surface grafting polymerization, in which five silane coupling agents with different terminal groups were used. The structure of composite particles was characterized by SEM, XRD, FTIR, and TGA, and the electrorheological properties were tested by rotational rheometer. The results show that polyaniline was coated on the surface of barium titanate particles to form the shell‐core structure. The yield stress of the electrorheological fluids based on polyaniline‐coated barium titanate composite particles is higher than that of polyaniline and barium titanate. Compared with PANI‐based electrorheological fluids (ERFs), the composite particles‐based ERFs have lower field‐off viscosity due to the molecular interaction. The yield stress of the ERFs, as well as density of the composite particles, was affected by the groups at terminal of silane coupling agents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Correlation between current–voltage (I–V) characteristic in the electric–thermal equilibrium state and resistivity‐temperature behavior of electro‐conductive silicone rubber
Authors: Zhang Jie , Feng Dacheng , Feng Shengyu , Han Jianjun , Diao Guangzhao , Liu Da 
Published: October 2007

AbstractIn the electric–thermal equilibrium state the current–voltage (I–V) characteristics of conductive silicone rubbers above the percolation threshold are found to be nonlinear. A mathematic model as I = a1U ± (a2U2 + C) has been built for the nonlinear I–V relations. Constant C and quadratic term a2U2 can be considered as deviation from Ohm's law. For the first time, a correlation is found for conductive silicone rubber between the I–V characteristic in the electric–thermal equilibrium state and the resistivity–temperature characteristic. Samples with positive temperature coefficient (PTC) resistivity effect exhibit negative deviation from linearity, with an I–V relation as I = a1U − (a2U2 + C). Samples with negative temperature coefficient (NTC) resistivity effect exhibit positive deviation, with an I–V relation as I = a1U + (a2U2 + C). The higher the loaded voltage, the more pronounced the deviation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Novel jute yarns grafted with methyl methacrylate
Authors: Montazer M. , Salehi A. 
Published: October 2007

AbstractThis research work involves graft copolymerization of jute fibers with methyl methacrylate (MMA), initiated by cerric ions, and optimization of the grafting parameters as a function of different polymerization conditions. It was considered to produce a hydrophobic jute fiber with enhanced properties. To achieve this, the effects of monomer concentration and grafting percentage on FTIR spectra, mechanical properties, moisture regain, oil‐adsorption capacity, and surface morphology were investigated, and optimum percentage of MMA with reasonable properties was suggested. The results indicated that cerric ions initiated graft copolymerization of MMA onto jute with 30% of weight of monomers at optimum conditions of acid concentration and temperature. The FTIR studies proposed grafting of MMA onto jute at hydroxyl groups. The results showed that mechanical properties and moisture regain (%) of samples decrease with increasing of graft percentage. The most remarkable features of this investigation include reducing oil‐adsorption capacity with increasing of lipophilic monomer percentages after one limitation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal and rheological behavior of ultrafine fly ash filled LDPE composites
Authors: Hashmi S. A. R. , Sharma Pratibha , Chand Navin 
Published: November 2007

AbstractThe specimens containing different volume fractions of ultrafine fly ash in LDPE were prepared with the help of two roll mixing mill and the hot‐plate compression‐molding machine. Thermal and rheological properties were evaluated using DSC and parallel‐plate rotational‐rheometer. The effect of composition variation on melt enthalpy, crystallinity, shear viscosity, shear stress and first normal stress difference was studied and reported here. The addition of ultrafine fly ash in LDPE decreased the melt enthalpy of the specimen. Slight decrease in the crystallinity of LDPE was observed on addition of fly ash. The shear stress as well as the shear viscosity both increased with the addition of ultrafine fly ash in LDPE. Two regions of shear thinning were observed at 200°C for fly ash filled LDPE. The first normal stress difference (N1) reduced with fly ash content and with the increased temperature. The values of N1 remained almost invariable at low shear region however a proportional increase was observed beyond the shear stress of 10 kPa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
New Method for Predicting the Lumbar Lordosis Angle in Skeletal Material
Authors: Been Ella , Pessah Hayuta , Been Laurence , Tawil Arie , Peleg Smadar 
Published: October 2007

AbstractReconstructing the lordotic curvature of the lumbar spine in humans is essential for understanding their posture and locomotion. To date there is still no reliable method for predicting the lordotic curvature of disarticulated spines (in the absence of intervertebral disks). This article examines two possible methods for predicting the lordotic curvature of the lumbar spine. The first—the traditional method—is based on the degree of wedging of the vertebral bodies, and the second—the suggested new method—is based on a lateral view of the orientation of the inferior articular processes. We propose a linear regression model for predicting the lordotic curvature of the lumbar spine (lordosis angle) in disarticulated human spines. This model, derived directly from our new method, is a more reliable predictor of the lumbar lordosis angle in disarticulated spines. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Classification and Development of Myofiber Types in the Superior Oblique Extraocular Muscle of Chicken
Authors: Baryshnikova Larisa M. , Croes Scott A. , von Bartheld Christopher S. 
Published: October 2007

AbstractPrecise control of contractile force of extraocular muscles is required for appropriate movements and alignment of the eyes. It is unclear how such precise regulation of contractile force is achieved during development and maturation. By using the posthatch chicken as a model, we describe and quantify critical parameters of the developing superior oblique extraocular muscle from hatching to 16 weeks of age, including contractile force, muscle mass, myofiber diameters, classification of fiber types, and distribution and quantification of mitochondria. Analysis at the light‐ and electron microscopic levels shows that chicken myofiber types largely correspond to their mammalian counterparts, with four fiber types in the orbital and four types in the global layer. Twitch tension muscle force and muscle mass gradually increase and stabilize at approximately 11 weeks. Tetanic tension continues to increase between 11 and 16 weeks. Myofiber diameters in both the orbital and global layer increase from hatching to six weeks, and then stabilize, whereas the myofiber number is constant after hatching. This finding suggests that muscle mass increases during late maturation due to increasing fiber length rather than fiber diameter. Quantitative ultrastructural analysis reveals continuing changes in the composition of the four muscle fiber types, suggesting ongoing fiber type conversion or differential replacement of myofiber types. Muscle fiber composition continues to change into late juvenile and adult age. Our study provides evidence for gradual, incremental, and continuing changes in avian myofiber composition and function that is similar to postnatal oculomotor maturation in visually oriented mammals such as kitten. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Rechnerischer Nachweis der Randverformungen bei Wärmedämmverbundsystemen (WDVS) mit Holzfaserdämmplatten und großer Dämmdicke bis ca. 200 mm
Authors: Rüther Norbert 
Published: October 2007

AbstractIn Deutschland unterliegen Wärmedämmverbundsysteme (WDVS) mit Holzfaserdämmplatten einer bauaufsichtlichen Zulassung. Bisher war die Dämmdicke auf 120 mm begrenzt. Einige Firmen sind bestrebt, größere Dämmdicken einzusetzen, was eine genauere Untersuchung der Spannungen und Verformungen im System erforderlich macht. Dieser Artikel beschreibt Methoden zur Beurteilung von Verformungen in WDVS mit mechanisch befestigten Holzfaserdämmplatten. Aufgrund der komplexen Thematik ist der Artikel wie folgt strukturiert:– hygrische und thermische Dehnung der Wärmedämmung und– hygrische und thermische Dehnung des Putzes planparallel zur Oberfläche.Der Artikel kommt zu dem Ergebnis, dass für Dämmstärken von mehr als 120 mm keine zusätzlichen Maßnahmen erforderlich sind. Die berechnete Verformung von ca. 1,8 mm im Belastungszustand “Primärschwindung und Temperaturänderung” eines theoretisch unendlichen WDVS führt zu Haarrissen, die im Allgemeinen unkritisch sind. Der Artikel beschreibt außerdem Methoden zur genaueren Berechnung der Verformungen von WDVS.
Vergleichende Untersuchung raumakustischer Konzepte von Mehrpersonenbüros hinsichtlich Sprachverständlichkeit, Arbeitsgedächtnisleistung und Arbeitsbehaglichkeit durch Hörversuche
Authors: Schröder Elmar , Schanda Ulrich 
Published: October 2007

AbstractDie vermehrt verwendete Betonkernaktivierung von Stahlbetondecken zur Kühlung und ggf. Beheizung von Mehrpersonenbüros schränkt die sonst übliche Ausführung einer schallabsorbierenden Decke stark ein. Das klassische Bürokonzept mit vollflächig schallabsorbierenden Decken und Stellwänden ist in diesen Fällen nicht mehr anwendbar. Alternativ zu diesem Stellwandkonzept wird in diesen Mehrpersonenbüros zunehmend ein sog. Trennwandkonzept umgesetzt. Dabei wird auf die Schallabsorption an der Decke vollständig verzichtet, aber dafür raumhohe, beidseitig hoch schallabsorbierende Stellwände ausgeführt. Ziel der vorliegenden Untersuchung war es, diese beiden Konzepte für Mehrpersonenbüros auf die Sprachverständlichkeit am Telefon, auf die Konzentrationsfähigkeit und auf die akustische Behaglichkeit am Arbeitsplatz zu vergleichen. Darüber hinaus wurde die Wirkung von tieffrequenten Absorbern untersucht. Zur Beurteilung der Bürokonzepte wurden Hörversuche durchgeführt. Hierzu wurden die raumakustischen Verhältnisse der Bürosituationen in realen Büroräumen mit Hilfe gemessener, binauraler Raumimpulsantworten auralisiert. Zum Vergleich wurde ein Mehrpersonenbüro ohne raumakustische Maßnahmen hinzugezogen. Mit diesem Verfahren sind unterschiedliche Bürosituationen direkt miteinander vergleichbar.