bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel amine terminated elastomeric oligomers and their effects on properties of epoxy resins as a toughener
Authors: Özarslan Özdemir , Yıldız Emel , İnan Tülay Y. , Kuyulu Abdülkadir , Güngör Attila 
Published: August 2009

AbstractThe objective of this study was to investigate the effects of amine terminated elastomeric epoxy tougheners on the mechanical and thermal properties of diglycidyl ether of bisphenol A based epoxy resin. The amine terminated polycaprolactone (PCL) (1) and PCL‐PDMS‐PCL (2) based oligomers were synthesized and characterized by FTIR spectroscopy. The stoichiometrical amount of the reactive oligomers as toughener, reactive epoxy resin and the curing agent, 4,4′‐diaminodiphenyl sulfone (DDS) were mixed and degassed. The homogenous mixtures were cured at 120°C into the preheated molds. The mechanical and thermal characterizations of toughened epoxy resin system were evaluated. It has been shown that the mechanical and thermal properties of toughened epoxy system vary as a function of the chemical structure and the concentration of rective oligomers. Higher mechanical properties were obtained for epoxy resin toughened by PCL‐PDMS‐PCL (2) based oligomer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of novel pour point depressants based on maleic anhydride‐alkyl acrylates terpolymers
Authors: El‐Ghazawy Rasha A. , Farag Reem K. 
Published: August 2009

AbstractThe (Docosanyl acrylate‐co‐(octadecyl or hexadecyl acrylate)‐co‐maleic anhydride) terpolymers were prepared using different compositions of the used alkyl acrylates (namely, 90 : 10, 70 : 30, 50 : 50, 30 : 70, and 10 : 90) (DCA‐ODA)/(MA) or (DCA‐HDA)/(MA). The efficiency of these terpolymers as pour point depressants was discussed. Two western desert waxy crude oils with different wax content were used for evaluation. Correlation between pour point depression efficiency and rheological properties were performed. Rheological parameters were also computed and discussed. It was observed that the synthesized terpolymers showed non‐Newtonian pseudoplastic relationships at different concentrations of synthesized terpolymeres with monomer feed ratios of (DCA‐ODA (1 : 1))/(MA) or (DCA‐HDA (1 : 1))/(MA) = 90/10 mole %. This ratio showed a good ability to disperse wax crystals and improve the flow behaviors of tested two crude oils even at low temperatures below their pour points. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis, characterization, and thermo‐optical properties of azobenzene polyurethane containing chiral units
Authors: Qiu Fengxian , Zhang Wei , Yang Dongya , Zhao Minjian , Cao Guorong , Li Pingping 
Published: August 2009

AbstractAn optically active levoazobenzene polyurethane (PU) was synthesized and was based on the chromophore 4‐(4′‐nitrophenylazo) phenylamine, the chiral reagent L(−)‐tartaric acid, and toluene diisocyanate. The chemical structure and thermal properties were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and differential scanning calorimetry. The PU had high number‐ and weight‐average molecular weights up to 52 300, a large glass‐transition temperature of 235.7°C, and an optical rotation of −18.06°, The optical parameters, including the refractive index (n) and thermo‐optic coefficient (dn/dT); the dielectric constant (ϵ) and its variation with temperature; and the thermal volume expansion coefficient and its variation with temperature of PU were obtained. The dn/dT and ϵ values for the polymer were in the range −4.1200 to 3.6257 × 10−4 °C−1 and 2.00 ± 0.11, respectively. The dn/dT values were one order of magnitude larger than those of inorganic glasses, such as zinc silicate glass (5.5 × 10−6 °C−1) and borosilicate glass (4.1 × 10−6 °C−1), and were larger than organic materials, such as polystyrene (−1.23 × 10−4 °C−1) and poly(methyl methacrylate) (−1.20 × 10−4 °C−1). The ϵ values were lower than that of alicyclic polyimide and semiaromatic polyimide. The obtained PU is expected to be useful for optical switching and optical waveguide areas. The conclusion has a little significance for the development of a new digital optical switch. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structural and ultraviolet‐protective properties of nano‐TiO2‐doped polypropylene filaments
Authors: Erdem Nilüfer , Erdogan Umit Halis , Cireli Aysun Aksit , Onar Nurhan 
Published: August 2009

AbstractTextiles, with appropriate light absorbers and suitable finishing methods, can be used as ultraviolet (UV) protection materials. In this study, we investigated the effects of nano‐TiO2particles on the UV‐protective and structural properties of polypropylene (PP) textile filaments. Master batches of PP/TiO2nanoparticles were prepared by melt compounding before spinning, and filaments incorporating 0.3, 1, and 3% TiO2nanoparticles were spun in a pilot melt‐spinning machine. The structural properties of the nanocomposite fibers were analyzed with scanning electron microscopy, X‐ray diffractometry, differential scanning calorimetry, and tensile tests. The UV‐protection factor was determined to evaluate the UV‐protective properties of the filaments. In conclusion, although the structure and mechanical properties of the nanocomposite filaments were slightly affected by the addition of nano‐TiO2, the UV‐protective properties of the PP filaments improved after treatment with nano‐TiO2, and the nanocomposite filaments exhibited excellent UV protection. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Pilot plant study of water‐borne high molecular weight amine adduct as corrosion inhibitor in emulsion paints
Authors: Mohamed H. A. , Badran B. M. 
Published: August 2009

AbstractEthylamine adduct (30 Kg) was prepared in an industrial field by reaction of ethylamine with epoxydized soybean oil, oxiran content 6.5, and identified by infra‐red spectroscopy. The prepared adduct was emulsified using both polyoxyethylene sorbitan monooleate in the continuous medium and sorbitan monooleate in the dispersed medium, using high speed homogenizer, 4000 round per minute. Surface tension measurements were determined by platinum ring technique. The stability of the prepared emulsions was determined thermally. The emulsified adduct was scaled up to ¼ ton using 50 L capacity homogenizer. The emulsified adduct was added to emulsion paint formulations by three different concentrations. Physical, chemical, mechanical, corrosion resistance, water uptake, and weight loss tests had been done in absence and presence of the corrosion inhibitor, to evaluate the corrosion inhibition efficiency of the emulsified adduct. Chosen formulations were scaled up to 5 ton using a 100 L capacity mixer. Carbon steel plates of 15× 15 cm were coated and exposed to natural weather on the roof of National Research Center. The effect of the emulsified ethylamine adduct as corrosion inhibitor was followed up by taking pictures every month for more than 2 years. It was found that the prepared ethylamine adduct was successfully emulsified and could protect steel from corrosion. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Cure kinetics and morphology of natural rubber reinforced by the in situ polymerization of zinc dimethacrylate
Authors: Nie Yijing , Huang Guangsu , Qu Liangliang , Zhang Peng , Weng Gengsheng , Wu Jinrong 
Published: August 2009

AbstractPeroxide‐cured natural rubber (NR) reinforced by zinc dimethacrylate (ZDMA) was prepared. The cocrosslinking action of ZDMA and the formation and evolution of the phase morphology induced by ZDMA during the curing process were systematically investigated. A curemeter and a differential scanning calorimeter were used to investigate the cure kinetics, and the kinetic parameters and the apparent activation energy were obtained. The phase morphology of the composites obtained from transmission electron microscopy revealed that separated nanophases of poly(zinc dimethacrylate) (PZDMA) existed in the rubber matrix. Covalent crosslinking, physical adsorption, and ionic crosslinking simultaneously existed in the composites, and they were determined with an equilibrium swelling method. On the basis of this, new microstructure models of NR/ZDMA composites and ionic crosslinking were put forward. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Morphology transition in electrospinning polymers by a dual‐capillary system
Authors: Mei Fan , Chen Da‐Ren 
Published: August 2009

AbstractAn experimental investigation of the fiber morphology change of fibers prepared by a dual‐capillary electrospinning system, operated in the cone‐jet mode, was carried out for poly(vinyl acetate) polymers of three molecular weights. The substrate morphology of the electrospun poly(vinyl acetate) could be changed significantly when the polymer's molecular weight, concentration, solvent, and outer liquid flow rate were varied. The onset of bead‐to‐fiber transition was determined by the critical chain overlap concentration. For solutions with a high concentration, the fiber diameter and surface were significantly affected by the physical properties of the solvents. To produce fibers of small diameter, electrospinning with a higher conductivity solution was desirable. On the other hand, a high‐conductivity solution needed to be avoided to keep the fiber uniform in diameter and smooth on the surface. The comparison of electrospun fibers produced by both single‐capillary and dual‐capillary systems was also addressed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Electron‐beam‐radiation‐induced grafting of acrylonitrile onto polypropylene fibers: Influence of the synthesis conditions
Authors: Jeun Joon‐Pyo , Hua Zu Jian , Kang Phil‐Hyun , Nho Young‐Chang 
Published: August 2009

AbstractElectron‐beam‐radiation‐induced grafting of acrylonitrile onto polypropylene fibers was investigated with a pre‐irradiation method. Grafting conditions such as the solvents, additives, monomer concentration, radiation dose, and temperature were varied, and the effects on the degree of grafting were studied. The nature of the reaction medium and additives had a considerable influence on the degree of grafting. The dilution of acrylonitrile with N,N‐dimethylformamide significantly enhanced the degree of grafting in comparison with other solvents. The addition of sulfuric acid to the reaction mixture led to an increase in the degree of grafting and an acceleration of the rate of grafting. The order of dependence of the rate of grafting on the pre‐irradiation dose and monomer concentration was found to be 1.31 and 1.21, respectively, in the presence of sulfuric acid. The activation energy for grafting was calculated to be 21.9 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Glycolysis of postconsumer polyethylene terephthalate waste
Authors: Pingale Navnath D. , Palekar Vikrant S. , Shukla S. R. 
Published: August 2009

AbstractGlycolytic depolymerization of polyethylene terephthalate (PET) bottle waste was attempted using ethylene glycol (EG) in the presence of chlorides of zinc, lithium, didymium, magnesium, and iron as catalysts. Virtual monomer bis (2‐hydroxyethyl terephthalate) (BHET) was obtained in all cases with nearly 74% yield, the highest yield being achieved with zinc chloride catalyst 0.5% w/w, PET : EG ratio 1 : 14 and 8 h under reflux conditions. The results were comparable to other catalysts like common alkalis, acids, and salts of some earth metals and zeolites used earlier although parameters of glycolysis were observed to vary depending on the catalyst. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of polypropylene/clay nanocomposites using bisupported Ziegler‐Natta catalyst
Authors: Ramazani S. A. Ahmad , Tavakolzadeh Fahimeh , Baniasadi Hossein 
Published: August 2009

AbstractIn this article, preparation of polypropylene/clay nanocomposites (PPCNC) via in situ polymerization is investigated. MgCl2/montmorillonite bisupported Ziegler‐Natta catalyst was used to prepare PPCNC samples. Montmorillonite (MMT) was used as an inert support and reinforcement agent. The nanostructure of the composites was characterized by X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. Obtained results showed that silica layers of the MMT in these PPCNC were intercalated, partially exfoliated, and uniformly dispersed in the polypropylene matrix. Thermogravimetric analysis showed good thermal stability for the prepared PPCNC. Differential scanning calorimetric was used to investigate both melting and crystallization temperatures, as well as the crystallinity of the PPCNC samples. Results of permeability analysis showed significant increase in barrier properties of PPCNC films. Effective parameters on molecular weight and flow ability of produced samples such as Al/Ti molar ratio and H2 concentration were also investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Modification of cyanate ester resin by hydroxyl‐terminated liquid butadiene‐acrylonitrile rubber and free volume properties of their composites
Authors: Minfeng Zeng , Xudong Sun , Xiandong Yao , Yun Wang , Mingzhu Zhang , Baoyi Wang , Chenze Qi 
Published: August 2009

AbstractThe toughness of cyanate ester resin (CE) matrix is improved significantly with addition of hydroxyl‐terminated liquid butadiene‐acrylonitrile rubber (HTBN). The impact strength increased from 4.4 KJ/m2 (pure CE) to 13.3 KJ/m2 (CE/HTBN, HTBN 10 wt %). The curing behavior of the system is studied by differential scanning calorimetric and Fourier transform infrared spectroscope. The results showed that hydroxyl groups on the HTBN chains have slight activation effect to CE curing reaction at the beginning of the cure process. The toughening mechanism is mainly caused by the flexibilizing effects of the homogeneously dispersed HTBN molecules in the CE matrix. The toughening mechanism was demonstrated from the aspect of free volume using positron annihilation lifetime spectroscopy. With addition of HTBN, the mean free‐volume size of the composite is smaller than pure CE. The decrease in the mean free‐volume size of the system is mainly related to the partition effects of the finely dispersed HTBN molecules to the free‐volume holes of CE matrix. A dramatic increase in the interfacial area occurs in this highly miscible system. Good interfacial adhesion is also reflected from the higher I2 of the composite. Therefore, more positrons annihilation in their free state occurs in the composites containing HTBN than pure CE. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Femoral Strength and Posture in Terrestrial Birds and Non‐Avian Theropods
Authors: Farke Andrew A. , Alicea Justy 
Published: August 2009

AbstractOsteological and experimental evidence suggest a change in femoral posture between non‐avian dinosaurs (in which the femur presumably was carried in a subvertical position) and birds (in which the femur is held nearly horizontal during most phases of terrestrial locomotion). In this study, we used a broad comparative sample to test the hypothesis that cross‐sectional properties of the femur records evidence of this presumed change in posture. Imax and Imin (second moment of area, related to resistance to bending) and cross‐sectional area (indicating resistance to compression) were measured from computed tomography scans of the femora of 30 species of flightless or primarily terrestrial birds, one probable non‐dinosaur dinosauromorph, and at least four species of non‐avian theropods. It was predicted that birds should have more eccentrically shaped femoral midshafts as measured by Imax/Imin (reflecting greater bending) and comparatively smaller cross‐sectional areas than non‐avians. Results show that no significant differences occur between non‐avian dinosaurs and birds for any parameter, and the samples overlapped broadly in many cases. Thus, cross‐sectional properties cannot be used to infer differences in femoral posture between the two groups. This surprising finding might be explained by the fact that femoral postures were not drastically different or that a gradation of postures occurred in each sample. It is also possible that bone loading during life was not closely correlated with cross‐sectional morphology. We conclude that cross‐sectional properties should be used with caution in determining the posture and behaviors of extinct animals, and only in conjunction with other morphological information. Anat Rec, 292:1406–1411, 2009. © 2009 Wiley‐Liss, Inc.
Variation in Center of Mass Estimates for Extant Sauropsids and its Importance for Reconstructing Inertial Properties of Extinct Archosaurs
Authors: Allen Vivian , Paxton Heather , Hutchinson John R. 
Published: August 2009

AbstractInertial properties of animal bodies and segments are critical input parameters for biomechanical analysis of standing and moving, and thus are important for paleobiological inquiries into the broader behaviors, ecology and evolution of extinct taxa such as dinosaurs. But how accurately can these be estimated? Computational modeling was used to estimate the inertial properties including mass, density, and center of mass (COM) for extant crocodiles (adult and juvenile Crocodylus johnstoni) and birds (Gallus gallus; junglefowl and broiler chickens), to identify the chief sources of variation and methodological errors, and their significance. High‐resolution computed tomography scans were segmented into 3D objects and imported into inertial property estimation software that allowed for the examination of variable body segment densities (e.g., air spaces such as lungs, and deformable body outlines). Considerable biological variation of inertial properties was found within groups due to ontogenetic changes as well as evolutionary changes between chicken groups. COM positions shift in variable directions during ontogeny in different groups. Our method was repeatable and the resolution was sufficient for accurate estimations of mass and density in particular. However, we also found considerable potential methodological errors for COM related to (1) assumed body segment orientation, (2) what frames of reference are used to normalize COM for size‐independent comparisons among animals, and (3) assumptions about tail shape. Methods and assumptions are suggested to minimize these errors in the future and thereby improve estimation of inertial properties for extant and extinct animals. In the best cases, 10%–15% errors in these estimates are unavoidable, but particularly for extinct taxa errors closer to 50% should be expected, and therefore, cautiously investigated. Nonetheless in the best cases these methods allow rigorous estimation of inertial properties. Anat Rec, 292:1442–1461, 2009. © 2009 Wiley‐Liss, Inc.
A Functional Explanation for Denticulation in Theropod Dinosaur Teeth
Authors: D'Amore Domenic C. 
Published: August 2009

AbstractThe serrated, or denticulated, ziphodont teeth of theropod dinosaurs display variability in their extent of denticulation. The functional model proposed here tests the hypothesis that denticles will not exist in areas that do not frequently contact the substrate. This area, defined as the “dead‐space,” is determined by the direction the tooth moves through the fleshy substrate. The extent of denticulation, as well as the dead‐space dimensions, is measured from photographs of 235 isolated and in situ theropod teeth, to determine a meaningful relationship between the two variables. Both Euclidean and geometric morphometric methods are employed, and the data are expressed in bivariate and ordination plots. The model predicts the direction of tooth movement through the curvature of the tip/apex. Tooth position and taxon are considered. The results show that the mesial margin is usually partially denticulated, while the distal margin is usually totally denticulated. Curved teeth have large dead‐spaces, and tend to be less denticulated mesially. Straighter teeth are more extensively denticulated, to the point where they became symmetrical. The mesial denticulation is determined by the dead‐space, and dictated by the substrate contact. The dead‐space almost always predicted less extensive denticulation; a consequence of the model's limitations. Tooth curvature increases with a more distal position, due to rotation based on the proximity to the hinge. Denticulation indicates that theropods used a distally oriented puncture to modify the substrate, similar to modern analogues. Although there is little taxonomic variation, Troodontidae show unique and extreme degrees of mesial denticulation. Anat Rec, 292:1297–1314, 2009. © 2009 Wiley‐Liss, Inc.
Dinosaurs in the Year of Darwin
Authors: Dodson Peter 
Published: August 2009

AbstractThis special issue of The Anatomical Record explores the recent advances in the functional morphology and paleobiology of dinosaurs. Although Darwin did not study dinosaurs because paleontology was in its infancy a century and half ago, he considered both paleontology and anatomy as essential subjects for establishing the validity of evolution. The study of dinosaurs constitutes a vigorous subdiscipline within vertebrate paleontology, and anatomists and evolutionary functional morphologists constitute an especially creative subgroup within dinosaur paleontology. The collection of 17 papers presented in this issue encompass cranial anatomy, postcranial anatomy, and paleobiology of dinosaurs and other archosaurs. Soft tissue subjects include studies of brain structure, jaw adductor muscles, and keratinous appendages of the skull. Taxonomically, it includes four papers with a focus on theropods, including Tyrannosaurus, five papers dealing with ceratopsians, three papers on hadrosaurs, and one on ankylosaurs. Modern anatomical techniques such as CT scanning, finite element analysis, and high resolution histology are emphasized. The visual presentation of results of these studies is spectacular. Results include the first‐ever life history table of a plant‐eating dinosaur; a determination of the head orientation of Tyrannosaurus and its relatives based on interpretation of the semicircular canals. The claws of Velociraptor appear to best adapted for tree climbing, but not for horrific predatory activities. Pachyrhinosaurus evidently used its massive head for head butting. The tail club of the armored dinosaur Euoplocephalus had the structural integrity to be used as a weapon. The pages abound with insights such as these. Dinosaurs once dead for millions of years live again! Anat Rec, 292:1240–1245, 2009. © 2009 Wiley‐Liss, Inc.