bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntactic foam composites of epoxy‐allyl phenol‐bismaleimide ternary blend—Processing and properties
Authors: Ambika Devi K. , John Bibin , Reghunadhan Nair C. P. , Ninan K. N. 
Published: June 2007

AbstractSyntactic foams based on a reactive polymer blend of Epoxy‐Allyl Phenol‐Bismaleimide were processed using hollow glass microballoons. The effect of microballoon concentration on the mechanical and thermophysical properties of the foam composites was investigated. The mechanical properties, specific strength, coefficient of linear expansion, and density of the foam composites showed decreasing trend with increase in microballoon concentration whereas the specific heat showed a marginal increase. The temperature dependence of the thermophysical properties revealed an increase in coefficient of linear expansion, whereas the specific heat was more or less insensitive to the test temperature. Syntactic foams of fixed filler loading (50% by weight) were processed using a blend of two types of microballoons of different shell thickness. The mechanical properties increased proportional to the concentration of the higher shell thickness microballoon. At moderate filler load microballoon breakage dominated the failure mode. The compositional dependency of the mechanical properties was corroborated by SEM analysis of the fracture surfaces. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Adhesion properties of swollen hydrogels evaluated by a point‐contact method
Authors: Suzuki Atsushi , Sato Takaya , Sakasegawa Daisuke , Sawada Hidenori , Goto Motoaki 
Published: June 2007

AbstractThe adhesion of swollen hydrogels was studied with the use of a simple tack‐evaluation technique using a point contact in the air at room temperature. The hydrogels used here were poly(sodium acrylate) gel physically crosslinked by aluminum ions. The adhesion properties were examined under different experimental parameters, i.e., separation velocities, normal loads, and waiting periods prior to separation. The effects of the material parameters resulting from the different degrees of the crosslinking on the adhesive properties were also examined. As a result, the adhesion force and the separation energy showed a power‐law behavior with different powers, which depended on the experimental and material parameters. The adhesion properties were determined by the bulk viscoelasticity as well as the surface physical and chemical properties. The results were discussed in terms of the surface molecular interaction and the bulk viscoelastic and viscous properties on the basis of the measurements of the apparent contact area, the ATR FTIR spectrum, and the dynamic viscoelasticity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Development of flame retardancy properties of new halogen‐free phosphorous doped SiO2 thin films on fabrics
Authors: Cireli Aysun , Onar Nurhan , Ebeoglugil M. Faruk , Kayatekin Isil , Kutlu Bengi , Culha Osman , Celik Erdal 
Published: June 2007

AbstractIn this study, flame retardancy properties of fabrics treated with phosphorous (P) doped and undoped SiO2 thin films were developed by sol–gel technique. As to this aim, P‐doped and undoped SiO2 film were coated on cotton fabric from the solutions prepared from P, Si‐based precursors, solvent, and chelating agent at low temperature in air using sol–gel technique. To determine solution characteristics, which affect thin film structure, turbidity, pH values, and rheological properties of the prepared solutions were measured using a turbidimeter, a pH meter, and a rheometer machines before coating process. The thermal, structural, and microstructural characterization of the coating were done using differential thermal analysis/thermograviometry, fourier transform infrared spectroscopy, X‐ray diffractometry, and scanning electron microscopy. In addition, tensile strength, wash fastness, flame retandancy, and lightness properties of the coated fabrics were determined. To compensate the slight loss of tensile strength of samples, which occurred at the treated fabrics with P‐doped Si‐based solutions, the cotton fabrics were coated with polyurethane films during second step. In conclusion, the flame retardant cotton fabric with durability of washing as halogen‐free without requiring after treatment with formaldehyde was fabricated using sol–gel processing for the first time. Moreover the cotton fabrics, which were treated with P‐doped Si‐based solutions and then coated with polyurethane at second step, still has got nonflammable property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Morphological analysis of highly filled propylene/ethylene copolymers
Authors: Ionescu‐Vasii L. L. , Wood‐Adams Paula M. , Duchesne Eric , L'Espérance Gilles , Karjala Teresa , Ansems Patricia 
Published: June 2007

AbstractA series of particulate composites based on a new family of propylene/ethylene (P/E) copolymers produced by Dow Chemical Co. were studied with microscopy and differential scanning calorimetry (DSC). To understand the good processability exhibited by the composites, we studied the composite microstructure and the bulk rheological properties. Here we report the results of a study of the microstructure and thermal behavior. Electron micrographs of the composites showed a uniform dispersion of the particles in the copolymer matrices at all experimental concentrations with very little particle agglomeration. The images suggested low adhesion between the matrices and the particles. The copolymers were semicrystalline, and their morphologies changed with the ethylene content. An increase in the ethylene content led to a decrease in the crystallinity and changes in the shape and size of the crystallites. Tapping‐mode atomic force microcopy images of a 9 wt % ethylene copolymer contained spherulites, lamellae, and a crosshatched structure characteristic of α‐isotactic polypropylene. The crosshatched structure was not present at higher ethylene contents. A DSC study of the pure copolymers and their composites revealed that only very small modifications to the thermal behavior of the P/E copolymers were induced by calcium carbonate particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Effect of adding sulphur to the dope on properties of modified polyacrylonitrile fibers
Authors: Wang Yan‐Xiang , Wang Cheng‐Guo 
Published: June 2007

AbstractAmmonium‐modified polyacrylonitrile (PAN) dope was prepared by free‐radical solution copolymerization of acrylonitrile (AN) and ammonium itaconate (AIA), adding different weight percent amount of sulphur into quantitative dope and then the dope was spun into precursor fibers. Effects of sulphur on the characteristics of the copolymers and precursor fibers even the oxidated fibers or the resultant carbon fibers were studied. It has been found that the adding sulphur could obviously increase the hydrophilicity of the copolymer. But in the spinning processes, with the concentration of the adding sulphur increasing, the apparent minus jet stretch of as‐spun fibers varied from −21% to −66%, the crystallinty increased from 21.2% to 40.5%, the void volume, fineness, tenacity and elongation at‐break of the ammonium‐modified precursors all decreased, which could result in the increase of the comprehensive properties of the resultant precursors. It was testified that the precursors developed from the copolymer with the higher concentration of adding sulphur have higher degree of orientation. The resultant carbon fibers developed from precursors of the adding sulphur show an improvement in tensile strength of about 30%. The activation energy of cyclization can be reduced from the original 150 kJ mol−1 to about 110 kJ mol−1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Effects of ion group content and polyol molecular weight on physical properties of HTPB‐based waterborne poly(urethane‐urea)s
Authors: Min Huang Shih , Ko Chen Teng 
Published: June 2007

AbstractA series of waterborne poly(urethane‐urea)s, WPUUs, based on using nonpolar hydroxyl‐terminated polybutadiene (HTPB) as the soft segment, were successfully synthesized in this article. The effects of the COOH group content and soft‐segment molecular weight (Mns) on the dispersion, morphology, and physical properties were investigated. Variations of the particle size, viscosity, and zeta potential were first governed by the hydrophilicity of the polymer chain, and then by the swelling derived from water. Fourier transfer infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) indicated that the degree of phase separation decreased as the COOH group content increased or as Mns decreased. However, the hydrogen bonding between the soft and hard segments and the two‐phase mixing could not occur in this nonpolar HTPB‐based WPUU system, indicating that the hard segments tended to form smaller domains and to pack more loosely. It was attributed to the fact that the presence of bulky ionic salt groups destroyed the ordered arrangement of the hard segments. In this case, the increases of the interface area between the soft and hard phases resulted in that the present behaviors were similar to the phase mixing. In tensile properties, HTPB‐based WPUUs exhibited higher tensile stress, elongation at break, and modulus as the COOH group content decreased or as Mns decreased. In thermal degradation, the introduction of HTPB polyol improved the thermal stability of WPUU. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
In situ composites from blends of polycarbonate and a thermotropic liquid‐crystalline polymer: The influence of the processing temperature on the rheology, morphology, and mechanical properties of injection‐molded microcomposites
Authors: Kalkar A. K. , Deshpande A. A. , Kulkarni M. J. 
Published: June 2007

AbstractThis work was aimed at understanding how the injection‐molding temperature affected the final mechanical properties of in situ composite materials based on polycarbonate (PC) reinforced with a liquid‐crystalline polymer (LCP). To that end, the LCP was a copolyester, called Vectra A950 (VA), made of 73 mol % 4‐hydroxybenzoic acid and 27 mol % 6‐hydroxy‐2 naphthoic acid. The injection‐molded PC/VA composites were produced with loadings of 5, 10, and 20 wt % VA at three different processing barrel temperatures (280, 290, and 300°C). When the composite was processed at barrel temperatures of 280 and 290°C, VA provided reinforcement to PC. The resulting injection‐molded structure had a distinct skin–core morphology with unoriented VA in the core. At these barrel temperatures, the viscosity of VA was lower than that of PC. However, when they were processed at 300°C, the VA domains were dispersed mainly in spherical droplets in the PC/VA composites and thus were unable to reinforce the material. The rheological measurements showed that now the viscosity of VA was higher than that of PC at 300°C. This structure development during the injection molding of these composites was manifested in the mechanical properties. The tensile modulus and tensile strength of the PC/VA composites were dependent on the processing temperature and on the VA concentrations. The modulus was maximum in the PC/VA blend with 20 wt % VA processed at 290°C. The Izod impact strength of the composites tended to markedly decrease with increasing VA content. The magnitude of the loss modulus decreased with increasing VA content at a given processing temperature. This was attributed to the anisotropic reinforcement of VA. Similarly, as the VA content increased, the modulus and thus the reinforcing effect were improved comparatively with the processing temperature increasing from 280 to 290°C; this, however, dropped in the case of composites processed at 300°C, at which the modulus anisotropy was reduced. Dynamic oscillatory shear measurements revealed that the viscoelastic properties, that is, the shear storage modulus and shear loss modulus, improved with decreasing processing temperatures and increasing VA contents in the composites. Also, the viscoelastic melt behavior (shear storage modulus and shear loss modulus) indicated that the addition of VA changed the distribution of the longer relaxation times of PC in the PC/VA composites. Thus, the injection‐molding processing temperature played a vital role in optimizing the morphology‐dependent mechanical properties of the polymer/LCP composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Compatibility study of recycled poly(vinyl chloride)/styrene‐acrylonitrile blends
Authors: Garcia David , Balart Rafael , Parres Francisco , López Juan 
Published: June 2007

AbstractThe aim of the present study is to analyze the compatibility between recycled Poly(vinyl chloride) (PVC) and styrene‐acrylonitrile copolymer (SAN). With this objective recycled PVC coming from credit cards have been blended with both virgin and recycled SAN with the aim of increase the benefits of recycled PVC. The compatibility of the components will be crucial for the final properties of the material. Furthermore, the recycled nature of some of the components will determine the compatibilization capability of the blend. The degradation level in the recycled materials was determined using Fourier transform infrared spectroscopy (FTIR). The compatibility between the PVC and the SAN was studied using differential scanning calorimetry and dynamic mechanical analysis. A greater compatibility was observed in mixtures of PVC and virgin SAN than in mixtures of PVC and recycled SAN. Finally, a morphological study of the fracture surface under cryogenic conditions was carried out using scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Transparent antifouling coatings via nanoencapsulation of a biocide
Authors: Zhang M. , Cabane E. , Claverie J. 
Published: June 2007

AbstractTransparent coatings releasing an antifouling agent (AF) can be used to reduce the marine fouling of optical lenses. A variety of water‐borne coatings based on poly(methyl methacrylate‐co‐butyl acrylate) (PMMA‐co‐PBA) were synthesized using a two‐stage miniemulsion process. During this process, the AF, SeaNine 211, was nanoencapsulated in domains small enough not to scatter light. The release rate of SeaNine 211 was studied for the polymers of different Tg, and found to be sufficient to impart AF properties. However, over time, the coatings were found to develop a whitish aspect (blushing) due to water retrodiffusion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Mechanical properties and microstructure of acrylonitrile–butadiene rubber vulcanizates reinforced by in situ polymerized phenolic resin
Authors: Ye Linzhong , Zhang Yongheng , Wang Zhaobo 
Published: June 2007

AbstractThe phenolic resin (PF) was incorporated into acrylonitrile–butadiene rubber (NBR) vulcanizates by in situ polymerization during the vulcanization process. It was found that the tensile strength, tearing strength, and tensile strength (300% elongation) could be considerably enhanced 59.4, 80.2, and 126.4%, respectively, at an optimum PF content of only 15 phr, but the elongation at break and shore A hardness were only slightly affected on the basis of silica‐reinforced NBR vulcanizates. A systematic study of the PF structure formed within the NBR matrix using various experimental schemes and procedures has revealed that the PF resin would form the localized discontinuous three‐dimensional interconnected network structures in the NBR matrix. The substantial reinforcement of PF on the mechanical properties of vulcanized NBR were attributed to the morphology, high flexibility, and moderate stiffness of the PF phases and their excellent bonding with rubbers through “rubber to rubber” and interface layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Measurement of the Vertebral Canal Dimensions of the Neck of the Rat with a Comparison to the Human
Authors: Flynn Jamie R. , Bolton Philip S. 
Published: June 2007

AbstractThe aim of this study was to determine the dimensions of the vertebral canal in the neck of the rat, because little is known about the morphology of the rat's cervical spine. A comparison then was made to the vertebral canal in the neck of the human. In part 1 of this study, we determined the precision of three different methods to measure the vertebral canal. The error (coefficient of variation) in these methods was found to range from 1 to 8%. In part 2, we used a computer‐based system to measure digital images of the vertebra and determined the anterior to posterior and the transverse vertebral canal dimensions in the neck of 19 young adult Sprague‐Dawley rats. The anterior to posterior dimension of the vertebral canal was greatest at the upper cervical (C1–C2) level and progressively decreased in the more caudal segments (C3–T1). The transverse dimension was greatest at the atlas (C1) vertebra and smallest at the axis (C2) vertebra with a steady increase in the transverse dimension with more caudal segments and a maximum transverse dimension at the level of the C6 and C7 vertebra. This study has demonstrated that the vertebral canal in the neck of young adult rats is similar in some regards to that of human. However, there are clear differences between the rat and human. These may be associated with differences in the morphology of the spinal cord or postural differences such as the cervicothoracic lordosis in bipeds compared with that in quadrupeds. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Acetylcholine Receptor Organization at the Dystrophic Extraocular Muscle Neuromuscular Junction
Authors: Marques Maria Julia , Pertille Adriana , Carvalho Candida Luiza T. , Santo Neto Humberto 
Published: June 2007

AbstractSpared extraocular muscles of dystrophic mice are not subjected to regeneration process and can be used to verify whether the lack of dystrophin per se could cause changes in acetylcholine receptor (AChR) distribution. In the present study, rectus and oblique (spared) and retractor bulbi (nonspared) muscles were dissected from adult control (C57Bl/10) and mdx mice. AChRs and nerve terminals were labeled with rhodamine–α‐bungarotoxin and anti–NF200‐IgG‐FITC, respectively, and visualized by confocal microscopy. Rectus and oblique muscles presented 0.5% central nucleation, while retractor bulbi had central nucleation in 45% of muscle fibers. In mdx rectus, AChRs were distributed in branches in 99% of the junctions examined (n = 200), similar to that observed for controls. Nerve terminals covered the AChR branches in 100% of the junctions examined. In control retractor bulbi, AChRs were distributed in regular branches. In mdx retractor bulbi, multiple fragmented islands of receptors were seen in 56% of the endplates examined (n = 200). These results suggest that the lack of dystrophin per se does not influence the distribution of acetylcholine receptors at the neuromuscular junction of spared extraocular muscles. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Contribution to the Knowledge of Anatomy of Species of Genus Mobula Rafinesque 1810 (Chondricthyes: Mobulinae)
Authors: Montes Domínguez Héctor Marcos , González‐isáis Mónica 
Published: June 2007

AbstractA comparative anatomical study was conducted among four mobulid species (Mobula japanica, M. munkiana, M. tarapacana, and M. thurstoni), from the coasts of the Gulf of California. Characters of the skeleton (neurocranium, mandibles, scapular girdle, pelvic girdle, and synarcual) were described. Mobula species had a wide structural variation. In the skeleton, M. tarapacana displayed the most plesiomorphic characters, mainly at the cranial level (cranium longer than wide, reduced internasal width, fontanelle longer than wide), while M. japanica had the most derived characters (cranium wider than longer, fontanelle wider than longer). Based on the observations, the dorsal cephalic musculature were similar in all species; however, oppositely to other batoid species, the epiaxilis is strongly developed, as it extends toward the cephalic part of the neurocranium, at level of the postorbital processes. In the ventral musculature, ventral constrictor muscles are quite reduced, whereas complex mandibular muscles are very developed. Muscles showing the highest variation are the coracohioideus and the coracoarcual. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Angiogenesis in the Caprine Caruncles in Non‐Pregnant and Pregnant Normal and Swainsonine‐Treated Does
Authors: Hafez S.A. , Caceci T. , Freeman L.E. , Panter K.E. 
Published: June 2007

AbstractMicrovascular corrosion casts of caruncles from non‐pregnant and pregnant doe goats at 4, 7, 10, 13, 16, and 18 weeks were examined with scanning electron microscopy. The internal convex surface of the caruncles of non‐pregnant does was covered with capillary meshes of regular diameter and form, without crypts. As pregnancy advanced the complexity of the vasculature increased: at 4 weeks the surface showed a pattern of ridges separated by troughs. At later stages, branches of radial arteries penetrated the periphery forming an extensive mesh of capillaries on the concave surface. Capillary diameters increased significantly during pregnancy, especially after 4 weeks, when large flattened sinusoids formed. These sinusoids had a great deal of surface area for potential contact with the fetal component. The caprine placenta is usually considered to have increased interhemal distance compared with endotheliochorial and hemochorial types: our results suggest that the very extensive development of sinusoids and crypts may compensate for any negative consequences of the placental architecture. Placental angiogenesis, which is physiologically normal, may serve as a general model of this process in other circumstances, such as tumor. The effect of swainsonine (active compound of locoweed and a potential anticancer drug) on vascular development showed no differences in sinusoidal diameters at 7 weeks, but a decrease in capillary density was noted. Swainsonine caused a great distortion to the vasculature at 18 weeks. The effects of this compound on the vascular development lend credibility to its potential as an anticancer agent. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Description of a Cranial Endocast from the Fossil Mammal Vincelestes neuquenianus (Theriiformes) and its Relevance to the Evolution of Endocranial Characters in Therians
Authors: Macrini Thomas E. , Rougier Guillermo W. , Rowe Timothy 
Published: June 2007

AbstractWe generated a digital cranial endocast (infilling of the braincase) of Vincelestes neuquenianus, a Cretaceous theriiform mammal from Argentina, to achieve two goals. First, we described this endocast of Vincelestes to reconstruct the brain, associated soft‐tissue structures, and internal osteological features. This report represents the first description of an endocast from a stem therian that is near crown group Theria (marsupials, placentals, and all descendants of that ancestor). Second, we examined 21 morphological characters related to the morphology of endocasts and endocranial osteology across 19 taxa (including Vincelestes) in the context of a current hypothesis about mammal phylogeny to identify potential synapomorphies for Theria. The digital endocast of Vincelestes is mostly complete, facilitating description in all views and allowing collection of accurate linear and volumetric measurements. However, it is unclear if the midbrain is exposed on the dorsal surface of the brain because of damage to this region of the endocast. Other portions of this specimen are extraordinarily well preserved, allowing identification of the accessory olfactory bulbs on the endocast, an ossified falx cerebri, and an osseous tentorium. The encephalization quotient (EQ) calculated for Vincelestes falls within the range of EQs of crown therians. Comparison of the endocranial characters across different mammalian taxa did not reveal any new synapomorphies for the clade Theria. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.