bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategies for the Fabrication of Porous Platinum Electrodes
Authors: Kloke Arne , von Stetten Felix , Zengerle Roland , Kerzenmacher Sven 
Published: October 2011

AbstractPorous platinum is of high technological importance due to its various applications in fuel cells, sensors, stimulation electrodes, mechanical actuators and catalysis in general. Based on a discussion of the general principles behind the reduction of platinum salts and corresponding deposition processes this article discusses techniques available for platinum electrode fabrication. The numerous, different strategies available to fabricate platinum electrodes are reviewed and discussed in the context of their tuning parameters, strengths and weaknesses. These strategies comprise bottom‐up approaches as well as top‐down approaches. In bottom‐up approaches nanoparticles are synthesized in a first step by chemical, photochemical or sonochemical means followed by an electrode formation step by e.g. thin film technology or network formation to create a contiguous and conducting solid electrode structure. In top‐down approaches fabrication starts with an already conductive electrode substrate. Corresponding strategies enable the fabrication of substrate‐based electrodes by e.g. electrodeposition or the fabrication of self‐supporting electrodes by dealloying. As a further top‐down strategy, this review describes methods to decorate porous metals other than platinum with a surface layer of platinum. This way, fabrication methods not performable with platinum can be applied to the fabrication of platinum electrodes with the special benefit of low platinum consumption.
Correlation between molecular structure parameters and network properties of silane‐grafted and moisture cross‐linked polyethylenes
Authors: Azizi H. , Morshedian J. , Barikani M. , Wagner M. H. 
Published: October 2011

AbstractThe degree of silane grafting and cross‐linking of several high‐density polyethylenes (HDPE) was studied. The results are compared with those of a low‐density polyethylene (LDPE) and a linear low‐density polyethylene (LLDPE). Molecular characterization was done by gel permeation chromatography. The differences in grafting and cross‐linking performance are correlated to the different structural parameters of the polymers such as molecular weight, molecular weight distribution, polydispersity index (PDI), and branching. The results show that molecular weight plays the main role in silane‐grafting and cross‐linking performance. For samples with approximately similar PDI, the grafting level increased with both increasing number average molecular weight and weight average molecular weight, whereas the gel content increased with increasing weight average molecular weight. However, a zigzag relation was observed for the variation of grafting and cross‐linking performances with PDI. The presence of long‐chain branching affects the size of molecules and reduces the grafting efficiency due to coil contraction and more intramolecular entanglements. The order of the degree of grafting for the different polyethylenes investigated was LLDPE > HDPE > LDPE, whereas the order for the gel content was LDPE > LLDPE > HDPE. The presence of unsaturated groups led to increase in the grafting level. However, there is no overall rule based on the density of polyethylene. Different grades of polyethylene show different behaviors depending on the silane and peroxide concentration. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 286–300, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20224
On the characterization and spinning of an organic‐purified lignin toward the manufacture of low‐cost carbon fiber
Authors: Baker Darren A. , Gallego Nidia C. , Baker Frederick S. 
Published: October 2011

AbstractA Kraft hardwood lignin (HWL) and an organic‐purified hardwood lignin (HWL‐OP) were evaluated as potential precursors for the production of low‐cost carbon fibers. It was found that the unpurified HWL exhibited poor spinnability while the HWL‐OP exhibited excellent spinnability characteristics. Fibers of various diameters were obtained from the HWL‐OP. Thermostabilization studies showed that oxidative stabilization can only be used to convert HWL‐OP‐based fibers into carbon fibers if extremely low heating rates are applied. Carbonized lignin‐based fibers had tensile strength of 0.51 GPa and tensile modulus of 28.6 GPa. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of hydrophilic chain length on the aqueous solution behavior of block amphiphilic copolymers PMMA‐b‐PDMAEMA
Authors: Xiao Guilin , Hu Zhibiao , Zeng Guangpeng , Wang Yongqiang , Huang Yaqun , Hong Xinlin , Xia Bilai , Zhang Gaoyong 
Published: October 2011

AbstractA series of amphiphilic block copolymers, polymethyl methacrylate (PMMA)‐b‐poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA), were synthesized by atom transfer radical polymerization (ATRP) method. Surface tension, dynamic light scattering (DLS), transmission electron microscope (TEM), and atomic force microscopy (AFM) studies were performed to investigate the aqueous micellar behavior of these block amphiphiles. At a fixed degree of polymerization (DP) of PMMA block (DP = 55), the PDMAEMA block length was found to have a significant influence on the critical micelle concentration (cmc) values and hydrodynamic size of aggregates. An increase in the DP of PDMAEMA from 11 to 337, resulted in a decrease in the cmc from 1.44 × 10−5 to 5.81 × 10−7 M (a factor of almost 24.8), and a decrease in the Z (2Rh) from 85.5 to 15.5 nm (pH = 4), respectively. TEM and AFM results indicated that by changing the soluble block lengths, spherical, short rod, crew‐cut, vesicles or large aggregates can be observed in the solution. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterization of linear low‐density polyethylene/poly(vinyl alcohol) blends and their biodegradability by Vibrio sp. isolated from marine benthic environment
Authors: Francis Vidya , Subin S. Raghul , Bhat Sarita G. , Thachil Eby Thomas 
Published: October 2011

AbstractIncreasing amounts of plastic waste in the environment have become a problem of gigantic proportions. The case of linear low‐density polyethylene (LLDPE) is especially significant as it is widely used for packaging and other applications. This synthetic polymer is normally not biodegradable until it is degraded into low molecular mass fragments that can be assimilated by microorganisms. Blends of nonbiodegradable polymers and biodegradable commercial polymers such as poly (vinyl alcohol) (PVA) can facilitate a reduction in the volume of plastic waste when they undergo partial degradation. Further, the remaining fragments stand a greater chance of undergoing biodegradation in a much shorter span of time. In this investigation, LLDPE was blended with different proportions of PVA (5–30%) in a torque rheometer. Mechanical, thermal, and biodegradation studies were carried out on the blends. The biodegradability of LLDPE/PVA blends has been studied in two environments: (1) in a culture medium containing Vibrio sp. and (2) soil environment, both over a period of 15 weeks. Blends exposed to culture medium degraded more than that exposed to soil environment. Changes in various properties of LLDPE/PVA blends before and after degradation were monitored using Fourier transform infrared spectroscopy, a differential scanning calorimeter (DSC) for crystallinity, and scanning electron microscope (SEM) for surface morphology among other things. Percentage crystallinity decreased as the PVA content increased and biodegradation resulted in an increase of crystallinity in LLDPE/PVA blends. The results prove that partial biodegradation of the blends has occurred holding promise for an eventual biodegradable product. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Use of polyester/glass‐fiber residues as fillers for composites
Authors: Silva L. V. , Angrizani C. C. , Souza J. R. , Amico S. C. , Medeiros J. T. N. 
Published: October 2011

AbstractIn this work, the performance of polyester (P)/glass fiber mats (G) and P/G/calcium carbonate (CaCO3) composites was compared with that of P/G/fiberglass waste composites. The residues used were conventional P/G postconsumer light resin‐transfer‐molding parts, obtained via knife or ball milling. Composites with up to 50 wt % reinforcement were prepared by hot compression molding and characterized via physical (density and water sorption), thermal (thermogravimetry and burnout), and mechanical (impact, Barcol hardness, and tensile) testing. The results show that the simple grinding and reincorporation of the composite residues yielded new composites with generally worse characteristics than the ones with calcium carbonate. Then, the waste was sorted by removing most of the pure resin particles from it. This yielded a resin‐rich fraction, which could be better used for energy recovery and resin‐covered fibers. The use of the latter as a filler yielded composites with better overall properties than those with calcium carbonate for a controlled amount of W; thus showing potential use as a replacement for the commonly used inorganic filler, maintaining the mechanical properties, decreasing the raw material cost, and reducing the amount of composite waste discarded in the environment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Application of cellulose sulfoacetate obtained from sugarcane bagasse as an additive in mortars
Authors: Nascimento Bárbara , Filho Guimes Rodrigues , Frigoni Elaine Selaro , Soares Heline Mendes , da Silva Meireles Carla , Cerqueira Daniel Alves , Valente Artur José Monteiro , de Albuquerque Carvalho Rui , de Assunção Rosana Maria Nascimento , de Castro Motta Leila Aparecida 
Published: October 2011

AbstractIn this study, cellulose sulfoacetate (CSA) was produced with cellulose extracted from sugarcane bagasse with sulfuric acid as a catalyst under homogenous conditions so that the derivative could be applied as an additive for mortar of Portland (Cimento Portland de alta resistência inicial, CPV‐ARI) cement. The IR spectra showed that only precipitate C presented the characteristic band of sulfate groups (807 cm−1) and was, therefore, the sulfoacetylated derivative. CSA presented a degree of acetylation of 2.70 and a degree of sulfonation of 0.063, and the presence of sulfate groups in the derivative displaced the position of C(6) to a lower field in the 13C‐NMR spectrum and influenced reduced viscosity as a function of concentration. The evaluation of CSA as an additive showed that for a polymer/cement ratio of 0.6%, an increase of 13.80% was achieved consistently, and an increase of 21.05% in the potential tensile of adhesion strength was also achieved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The role of synthetic and natural fillers on three‐body abrasive wear behaviour of glass fabric–epoxy hybrid composites
Authors: Mohan N. , Natarajan S. , KumareshBabu S. P. 
Published: October 2011

AbstractPolymer matrix composites are a promising candidate in tribological applications due to possibility of tailoring their properties with special fillers. The comparative performance of Glass–Epoxy (G‐E) composites with influence of synthetic fillers such as graphite (Gr) and silicon carbide (SiC) and biobased natural filler jatropha oil cake (JOC) was experimentally investigated. All the composites were fabricated using vacuum‐assisted resin infusion (VARI) technique. The mechanical properties were studied in accordance with ASTM standards. The three‐body abrasive wear studies were carried out with rubber wheel abrasion tester as per ASTM‐G65 standard. Two different loads namely 22 N and 32 N with different abrading distances viz, 135, 270, 405, and 540 m are test parameters. The results reveal that addition of JOC in G‐E composites has significant influence on wear under varied abrading distance/load. Further, it was found that SiC filled G‐E composites exhibited better wear resistance compared to Gr/JOC filled G‐E composites. The operating wear mechanisms have been studied by using scanning electron microscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterization of macroporous 1‐vinyl‐2‐pyrrolidone copolymers obtained by suspension polymerization
Authors: Maciejewska Małgorzata 
Published: October 2011

AbstractRadical suspension copolymerization of 1‐vinyl‐2‐pyrrolidone (VP) with three different cross‐linkers: divinylbenzene (DVB), trimethylolpropane trimethacrylate (TRIM), and di(methacryloxymethyl) naphthalene (DMN) was used to prepare macroporous microspheres. During the copolymerization, the mixture of toluene and n‐dodecane as a pore‐forming diluent was used. All samples were characterized in terms of particle size and distribution, nitrogen content, specific surface area total pore volume, and pore size distribution. It was found that specific surface area of the obtained beads is strongly dependent on the diluent system and the type of cross‐linker and achieves value from 27 to 845 m2/g. To determine the influence of chemical structure of cross‐linkers on the selectivity and polarity of the copolymers, inverse gas chromatography was applied. In addition, VP–DVB and VP–DMN copolymers were modified by sulfonation into cation‐exchangers with cation exchange capacity equal 1.98 and 2.31 mmol/g, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
PTCR characteristics of poly(styrene‐co‐acrylonitrile) copolymer/stainless steel powder composites
Authors: Kar Prativa , Shrivastava Nilesh K. , Mallick Sumana , Khatua B. B. 
Published: October 2011

AbstractPositive temperature coefficient of resistivity (PTCR) characteristics of poly(styrene‐co‐acrylonitrile) copolymer (SAN)/stainless steel (SS) powder (80 wt %) composites prepared by melt‐mixing method has been investigated with reference to SAN/carbon black (CB) composites. The SAN/CB (10 wt %) composites showed a sudden rise in resistivity (PTC trip) at 125°C, above the glass transition temperature (Tg) of SAN (Tg ≈ 107°C). However, the PTC trip temperature of SAN/SS (80 wt %) composites appeared at 94°C, well below the Tg of SAN. Addition of 1 phr of nanoclay increased the PTC trip temperature of SAN/CB (10 wt %) composites to 130°C, while SAN/SS (80 wt %)/clay (1 phr) nanocomposites showed the PTC trip at 101°C. We proposed that the mismatch in coefficient of thermal expansion (CTE) between SAN and SS played a key role that led to a disruption in continuous network structure of SS even at a temperature below the Tg of SAN. The dielectric properties study of SAN/SS (80 wt %) composites indicated possible use of the PTC composites as dielectric material. DMA results showed higher storage modulus of SAN/SS composites than the SAN/CB composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal, structural, and optical properties of γ‐irradiated poly(vinyl alcohol)/poly(ethylene glycol) thin film
Authors: Nouh S. A. , Nagla A. G. , Othman M. H. , Eman S. A. , Lotfi Z. I. 
Published: October 2011

AbstractPoly(vinyl alcohol)/poly(ethylene glycol) (PVA/PEG) copolymer was prepared using casting technique. The obtained PVA/PEG thin films have been irradiated with gamma rays with doses ranging from 1.5 to 20 Gy. The resultant effect of gamma irradiation on the thermal properties of PVA/PEG has been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The onset temperature of decomposition To and activation energy of thermal decomposition Ea were calculated, results indicating that the PVA/PEG thin film decomposes in one main weight loss stage. Also, the gamma irradiation in dose range 4–12 Gy led to a more compact structure of PVA/PEG copolymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. The variation of transition temperatures with gamma dose has been determined using DTA. The PVA/PEG thermograms were characterized by the appearance of an endothermic peak due to melting of crystalline phase. In addition, structural property studies using X‐ray diffraction and infrared spectroscopy were performed on both nonirradiated and irradiated samples. Furthermore, the transmission of the PVA/PEG samples and any color changes were studied. The color intensity (E was greatly increased with increasing the gamma dose and was accompanied by a significant increase in the blue and green color components. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal and insulating properties of epoxy/aluminum nitride composites used for thermal interface material
Authors: Yu Hui , Li Liangliang , Kido Teruo , Xi Guannan , Xu Guangchen , Guo Fu 
Published: October 2011

AbstractWe synthesized an epoxy matrix composite adhesive containing aluminum nitride (AlN) powder, which was used for thermal interface materials (TIM) in high power devices. The experimental results revealed that adding AlN fillers into epoxy resin was an effective way to boost thermal conductivity and maintain electrical insulation. We also discovered a proper coupling agent that reduced the viscosity of the epoxy‐AlN composite by AlN surface treatment and increased the solid loading to 60 vol %. For the TIM sample made with the composite adhesive, we obtained a thermal conductivity of 2.70 W/(m K), which was approximately 13 times larger than that of pure epoxy. The dielectric strength of the TIM was 10 to 11 kV/mm, which was large enough for applications in high power devices. Additionally, the thermal and insulating properties of the TIM did not degrade after thermal shock testing, indicating its reliability for use in power devices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Prompt modification of styrene‐butadiene rubber surface with trichloroisocyanuric acid by increasing chlorination temperature
Authors: Yin Long , Zhou Hongbing , Quan Yiwu , Fang Jianglin , Chen Qingmin 
Published: October 2011

AbstractIn this article, the surface of styrene‐butadiene rubber (SBR) was brushed with trichloroisocyanuric acid (TCI) (1 or 2 wt % in ethyl acetate) and then thermally treated under different conditions. The chemical modification was characterized by contact angle measurement and surface energy, ATR‐FTIR spectroscopy, scanning electron microscopy (SEM), and single‐lap shear test. The results revealed that the increase of the chlorination temperature was very effective for SBR surface modification by TCI, leading to enhanced surface wettability and shear strength within several minutes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Application of tin(IV) porphyrin complexes as novel catalysts for the synthesis of new copolyurethanes with cyclopeptide moiety
Authors: Rafiemanzelat Fatemeh , Abdollahi Elahe , Moghadam Majid , Mirkhani Valiollah , Tangestaninejad Shahram , Mohammadpoor‐Baltork Iraj 
Published: October 2011

AbstractNew electron deficient tin(IV) porphyrins were used as efficient catalysts for the reaction of 4,4′‐methylene‐bis‐(4‐phenylisocyanate) (MDI), with L‐leucine anhydride cyclodipeptide (LAC) and polyethyleneglycol‐400 (PEG‐400) and the results were compared with those obtained in the presence of a commercial catalyst, dibutyltin dilaurate (DBTDL). Molar ratio of catalysts to MDI, polymerization reaction time, viscosity, and yield of the resulting poly(ether‐urethane‐urea)s (PEUU) were compared in the presence of different catalysts. The rate of NCO conversion in the presence of each catalysts under the same reaction conditions was also compared and followed by FT‐IR NCO absorption band. FT‐IR, GPC, and viscosity studies have shown that tin(IV) porphyrins afford higher viscosity and reaction progress. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Fibrin as a scaffold for cardiac tissue engineering
Authors: Barsotti Maria Chiara , Felice Francesca , Balbarini Alberto , Di Stefano Rossella 
Published: October 2011

AbstractFibrin is a natural biopolymer with many interesting properties, such as biocompatibility, bioresorbability, ease of processing, ability to be tailored to modify the conditions of polymerization, and potential for incorporation of both cells and cell mediators. Moreover, the fibrin network has a nanometric fibrous structure, mimicking extracellular matrix, and it can also be used in autologous applications. Therefore, fibrin has found many applications in tissue engineering, combined with cells, growth factors, or drugs. Because a major limitation of cardiac cell therapy is low cell engraftment, the use of biodegradable scaffolds for specific homing and in situ cell retention is desirable. Thus, fibrin‐based injectable cardiac tissue engineering may enhance cell therapy efficacy. Fibrin‐based biomaterials can also be used for engineering heart valves or cardiac patches. The aim of this review is to show cardiac bioengineering uses of fibrin, both as a cell delivery vehicle and as an implantable biomaterial.
Ein Beitrag zu vereinfachten Berechnungsverfahren für die Heißbemessung von Stahlbetondruckgliedern
Authors: Held Markus , Gelien Marion 
Published: October 2011

AbstractKragstützen, ist ein aktuelles Thema, welches sowohl in der Praxis als auch in der Forschung tätige Ingenieure nach wie vor beschäftigt. Der Ansatz der Zonenmethode als einziges gemäß deutschem Nationalem Anwendungsdokument (NAD) zugelassenes, vereinfachtes Berechnungsverfahren wird fortlaufend erweitert und angepasst, um auch nichtlinearen Berechnungen zu genügen.Der vorliegende Beitrag beschäftigt sich zum einen mit der Frage, wie gut diese Anpassungen gelingen und zum anderen mit der Frage nach der Notwendigkeit einer weiteren Verifizierung dieser Methode.Contribution to the simplified calculation of fire resistance design of concrete columnsFire resistance design of concrete columns, especially cantilever columns, is a contemporary issue, which affects engineers in research and practice. The approach called zone method is continually upgraded and matched to answer nonlinear calculation methods. In the presented paper it is investigated wether the upgrading is successful. The necessity of further verification of the zone method is discussed.
Lynx: A user‐friendly computer application for simulating fatigue growth of planar cracks using FEM
Authors: Branco R. , Antunes F. V. , Costa J. D. 
Published: October 2011

AbstractPeople engaged in fracture mechanics education recognise the need to combine theory and effective practice in order to enhance students' skills in this field. Nevertheless, real experiments are not always possible for education purposes because they require too much time, involve specialised equipment and specimen preparation. In these circumstances, numerical simulation is a valid alternative to guarantee the link between theory and practice. In this article, a computer application capable of simulating the fatigue crack growth (FCG) of planar cracks under mode‐I cyclic loading is presented. This tool incorporates an extensive range of real significance problems found in the context of FCG. Besides, an intuitive and user‐friendly interface was provided in order to improve its functionality and to allow the user to define quickly and easily fundamental input data. Default values are proposed for less experienced users, seeking the minimum effort in numerical model definition. The use of this software in educational context is expected to provide a major insight into FCG phenomenon. © 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 22:529–540, 2014; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.10.1002/cae.20578