bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of hydrolysis and denaturation of wheat gluten on adhesive bond strength of wood joints
Authors: D'Amico Stefano , Müller Ulrich , Berghofer Emmerich 
Published: January 2013

AbstractIn this study the adhesive bond strength of different wheat gluten modifications and the relationship between molecular weight and adhesive strength was examined. Guanidine hydrochloride and sodium hydroxide were used as denaturation and dispersing agent. Additionally wheat proteins were hydrolyzed by alkaline conditions and enzymes. Effects of different treatments were observed by viscosity measurements and gel electrophoresis. Wood lap joints were prepared with modified proteins and tensile shear strength was tested under dry and wet conditions. In situ hardening of different formulations was analyzed by means of DMA with two‐layered specimens in a three‐point bending test set‐up. Higher solubility had no positive effect on dry bonding strength and wet bonding strength was even reduced. Depending on the degree of hydrolysis, significant improvement of adhesive bond strength was observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Self‐healing supramolecular elastomers based on the multi‐hydrogen bonding of low‐molecular polydimethylsiloxanes: Synthesis and characterization
Authors: Zhang Anqiang , Yang Lin , Lin Yaling , Yan Lishan , Lu Hecheng , Wang Lianshi 
Published: January 2013

AbstractNovel self‐healing supramolecular elastomers based on polydimethylsiloxanes (SESi) were synthesized from a mixture of polydimethylsiloxanes derivers with single, di‐, or tri‐carboxylic acid groups (PDMS–COOHx, where x = 1, 2, and 3, respectively), diethylene triamine, and urea with a two‐stage procedure. The reactions and the final products were tracked, characterized, and confirmed by Fourier transform infrared spectroscopy, 1H‐NMR, differential scanning calorimetry, dynamic mechanical analysis, and gel permeation chromatography. Compared with a supramolecular rubber based on dimer acid (reported previously) with a similar synthesis procedure, the SESi showed a lower glass‐transition temperature of about −113°C for the softer chain of polydimethylsiloxane and showed real rubberlike elastic behavior and self‐healing properties at room temperature or even lower temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Tangible plasticization/filler effects of sodium salts of dimer acids on the mechanical properties of styrene ionomers
Authors: Ko Kwang‐Hwan , Park Hye Ryeon , Kim Joon‐Seop , Kim Young‐Wun 
Published: January 2013

AbstractThe effects of the presence of dimer acid (DA) molecules in Na‐sulfonated polystyrene (PSSNa) and poly(styrene‐co Na‐methacrylate) (PSMANa) ionomers on the ionomer properties were investigated using a dynamic mechanical analysis technique. The DA decreased the matrix and cluster Tgs of PSSNa ionomer without changing the ionic modulus, suggesting that the DA resided both in the matrix and cluster regions of PSSNa ionomer and acted mainly as a plasticizer. On the other hand, the DA decreased the cluster Tg of PSMANa ionomer, without changing the matrix Tg, and also increased the ionic modulus, implying that the DA behaved like plasticizer only for the cluster regions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Isothermal crystallization and spherulite growth behavior of stereo multiblock poly(lactic acid)s: Effects of block length
Authors: Rahaman Md. Hafezur , Tsuji Hideto 
Published: January 2013

AbstractStereo multiblock poly(lactic acid)s (PLA)s and stereo diblock poly(lactic acid) (DB) with a wide variety of block length of 15.4–61.9 lactyl units are synthesized, and the effects of block length sequence on crystallization and spherulite growth behavior are investigated at different crystallization temperatures, in comparison with neat poly(L‐lactide) (PLLA), poly(D‐lactide) (PDLA), and PLLA/PDLA blend. Only stereocomplex crystallites as crystalline species are formed in the stereo multiblock PLAs and DB, irrespective of block length and crystallization temperature. The maximum crystallinities (33–61%), maximum radial growth rate of spherulites (0.7–56.7 μm min−1), and equilibrium melting temperatures (182.0–216.5°C) increased with increasing block length but are less than those of PLLA/PDLA blend (67 %, 122.5 μm min−1, and 246.0°C). The spherulite growth rates and overall crystallization rates of the stereo multiblock PLAs and DB increased with increasing block length and are lower than that of PLLA/PDLA blend. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanical behavior, microstructure and thermooxidation properties of sequentially crosslinked ultrahigh molecular weight polyethylenes
Authors: Ríos Ricardo , Puértolas José Antonio , Martínez‐Nogués Vanesa , Martínez‐Morlanes María José , Pascual Francisco Javier , Cegoñino José , Medel Francisco Javier 
Published: January 2013

AbstractThe aim of this study was to explore the impact of the sequential irradiation and annealing process on the microstructure, thermooxidation behavior and mechanical properties of GUR 1050 ultrahigh molecular weight polyethylene (UHMWPE) with respect to the postirradiation annealed material. For this purpose, the effects of a variety of irradiation and annealing conditions on microstructure and mechanical properties were investigated. Differential scanning calorimetry was performed to characterize melting temperature, crystalline content and crystal thickness, whereas transmission electron microscopy provided additional insights into crystal morphology. Thermogravimetric experiments in air served to assess thermooxidation resistance and changes associated to radiation‐induced crosslinking. Fatigue properties were studied from three different approaches, namely short‐term cyclic stress–strain tests, long‐term fatigue experiments and crack propagation behavior. Likewise, three experimental techniques (uniaxial tensile test, impact experiments, and load to fracture of compact tension specimens) allowed evaluation of the fracture resistance. The present findings confirm sequentially crosslinked UHMWPE exhibited improved thermooxidation resistance and thermal stability compared to post‐irradiation annealed UHMWPE. Also, the mechanical behavior, including the fatigue and fracture resistance, of these materials was generally comparable regardless of the annealing strategy. Therefore, the sequential irradiation and annealing process might provide higher oxidation resistance, but not a significant improvement in mechanical properties compared to the single radiation dose and subsequent annealing procedure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and properties of a dispersing fluid loss additive based on humic acid graft copolymer suitable for cementing high temperature (200°C) oil wells
Authors: Salami Oyewole Taye , Plank Johann 
Published: January 2013

AbstractA humic acid graft copolymer possessing both water‐retention and dispersing properties in cement slurry was synthesized by grafting lateral chains of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS®), N,N‐dimethylacrylamide (NNDMA), and acrylic acid (AA) onto a backbone of humic acid using aqueous free radical polymerization. The graft copolymer is composed of 20 wt % humic acid backbone and 80 wt % graft chain (molar ratio AMPS/NNDMA/AA = 1 : 0.31 : 0.03), it exhibits a Mw of 323 kDa and is highly anionic in cement pore solution. The influence of this specific molecular design on cement flow properties is unraveled. When tested at 200°C, the graft copolymer achieved very low cement fluid loss values (∼50 mL) at low rheology. This behavior differentiates it from most common synthetic high temperature fluid loss additives which excessively viscosify cement slurries. The working mechanism of the graft copolymer was found to rely on adsorption onto the surface of hydrating cement. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanical and thermal enhancements of benzoxazine‐based GF composite laminated by in situ reaction with carboxyl functionalized CNTs
Authors: Xu Mingzhen , Hu Jinquan , Zou Xingqiang , Liu Mengdie , Dong Shihua , zou Yanke , Liu Xiaobo 
Published: January 2013

AbstractAn easy and efficient approach by using carboxyl functionalized CNTs (CNT‐COOH) as nano reinforcement was reported to develop advanced thermosetting composite laminates. Benzoxazine containing cyano groups (BA‐ph) grafted with CNTs (CNT‐g‐BA‐ph), obtained from the in situ reaction of BA‐ph and CNT‐COOH, was used as polymer matrix and processed into glass fiber (GF)‐reinforced laminates through hot‐pressed technology. FTIR study confirmed that CNT‐COOH was bonded to BA‐ph matrices. The flexural strength and modulus increased from 450 MPa and 26.4 GPa in BA‐ph laminate to 650 MPa and 28.4 GPa in CNT‐g‐BA‐ph/GF composite, leading to 44 and 7.5% increase, respectively. The SEM image observation indicated that the CNT‐COOH was distributed homogeneously in the matrix, and thus significantly eliminated the resin‐rich regions and free volumes. Besides, the obtained composite laminates showed excellent thermal and thermal‐oxidative stabilities with the onset degradation temperature up to 624°C in N2 and 522°C in air. This study demonstrated that CNT‐COOH grafted on thermosetting matrices through in situ reaction can lead to obvious mechanical and thermal increments, which provided a new and effective way to design and improve the properties of composite laminates. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Determination of optimum cure parameters of 977‐2A carbon/epoxy composites for quickstep processing
Authors: Khan Laraib A. , Iqbal Zafar , Hussain Syed Tajammul , Kausar Ayesha , Day Richard J. 
Published: January 2013

AbstractIn this study polymer‐matrix composite has been processed using autoclave and Quickstep techniques. A phenomenological approach was adopted for the optimization of cure cycle for Quickstep of an aerospace grade epoxy composite (Cycom 977‐2A carbon/epoxy prepregs). Though there are reports concerning the processing and properties of materials using Quickstep technique, little work has been reported on the design of optimized cure cycle for Quickstep processing based on rheology, ultrasonic testing, and mechanical characterization. A step by step account is provided in this study, describing the introduction, balancing and combination of isothermal dwell periods and temperature ramps in order to control the resin viscosity. All the panels manufactured were qualitatively assessed using ultrasonic C‐scan and afterwards fiber and void content, panel thickness, flexural strength, and interlaminar shear strength (ILSS) were assessed and compared with those obtained from traditional autoclave‐ and oven‐cured laminates. The Quickstep panel properties produced from optimized cure cycle was superior to oven curing and was comparable with autoclave. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation of chitosan modified talc and its application in high filler content paper
Authors: Yu Yang , Xue Guoxin , Gu Chunhong , Lou Jipan , Li Shizhen 
Published: January 2013

AbstractChitosan (CS) with different viscosity was investigated as a modifier of talc which was used to improve the strength properties and filler retention in high filler content papers. The particle size and morphology of the resulting modified talc were studied to confirm the successful modification. The zeta potential and coating amount of the CS modified talc were also investigated. It was found that CS viscosity was a critical factor for the filler modification and final paper properties. When high viscosity CS was applied, the resulting tensile strength of filled paper was 64% higher than that of unmodified talc at the filler content of 37% as well as maintained favorable optical properties. Furthermore, with the filler loading of 70% (based on the solid fiber weight), compared with that of unmodified talc, filler retention of modified talc was increased by 39%, while the drainage was little influenced. The field emission scanning electron microscopy images showed a better bonding capacity between modified talc and fibers than that of untreated talc. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Porous palygorskite‐polythiophene conductive composites for acrylic coatings
Authors: Zuo Shixiang , Yao Chao , Liu Wenjie , Li Xiazhang , Kong Yong , Liu Xiaoheng , Mao Huihui , Li Yingruo 
Published: January 2013

AbstractModified palygorskite‐polythiophene (MPA‐PTh) composites were prepared by chemical oxidative polymerization of palygorskite (PA) nucleartor with thiophene (Th) after the surface modification with γ‐(2,3‐epoxypropoxy) propytrimethoxysilane (KH‐560). The MPA‐PTh composites were doped in iodine vapor to create the porous palygorskite‐polythiophene (PMPA‐PTh) conductive composites. Fourier transform infrared spectra (FTIR), X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms using the Brunauer–Emmett–Teller method (BET) and electrochemical impedance spectrum (EIS) techniques were applied to characterize the modified PA and the prepared composites. According to FTIR and XPS, the KH‐560 was bound to the PA surface and the iodine ion (I3− and I5−) entered the PTh molecular chains. XRD, SEM, TEM, BET, and EIS analysis confirmed that the doping of iodine not only transform the core–shell MPA‐PTh into the PMPA‐PTh but also improve the electrical conductivity of composites. The PMPA‐PTh composites were fabricated that yield a volume resistivity of ∼2.44 × 102 Ω cm and a internal resistances of ∼100 Ω, and their BET surface area, BJH (Barrett–Joiner–Halenda) average pore size and BJH cumulative pore volume were improved in comparison with those of the MPA‐PTh composites. SEM images showed that the PMPA‐PTh composites could form consecutive space network and the PMPA‐PTh composites acrylic coating films had advisable conductivity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Carbazoles on same main chain for polymer solar cells
Authors: Qin Ruiping , Jiang Yurong , Ma Heng , Yang Le , Liu Hengzhi , Chang Fanggao 
Published: January 2013

AbstractPlanar conjugated 2,7‐linked carbazole blocks: Q1(2,7‐dibromo‐9‐octyl‐9H‐carbazole); Q2(7,7′‐dibromo‐9,9′‐dioctyl‐9H,9′H‐2,2′‐bicarbazole); Q3 (7‐bromo‐7′‐(7‐bromo‐9‐octyl‐9H‐carbazol‐2‐yl)‐9,9′‐dioctyl‐9H,9′H‐2,2′‐bicarbazole) were coupled with same acceptor (4,7‐di[2,5‐thiophene]‐5,6‐dioctyloxy‐2,1,3‐Benzothiadiazole) to prepare polymers HXS‐1, 2, 3 (Scheme 1). Bulk‐heterojunction polymer solar cells (BHJ PSCs) with these polymers were made. Power conversion efficiency of HXS‐1 was proved to be over 5.4%. It declined dramatically to 0.43% and 0.23% for HXS‐2 and 3 respectively. Their absorption and X‐ray diffraction pattern show the torsion angle in main chain increased when more carbazole units were added. More carbazoles will make polycondensation reaction more difficult to get high molecular weight polymers. The torsion angle was calculated using a semiempirical molecular orbital method. All the results pointed out that the coplanarity in the conjugated backbone was destroyed. Electron delocalization was disturbed because p‐orbital overlapping only occurs effectively in the parallel orbit so charge cannot move a longer distance. This study offers a useful and important insight to designing polymers for high performance PSCs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Investigation on high strength laser welds of polypropylene and high‐density polyethylene
Authors: Juhl Thomas Brokholm , Christiansen Jesper deClaville , Jensen Erik Appel 
Published: January 2013

AbstractMechanical strength in polymer weld interfaces in semi‐crystalline high density polyethylene (HDPE) and polypropylene (PP) is investigated. The welding method investigated is through transmission laser welding (TTLW). Utilizing the TTLW process with 0.4 wt % carbon black as absorber, a lap‐joint is formed which is tested for mechanical properties using an Instron tensile testing machine. In contrast to earlier investigations, the tensile tests conclude that 89% of the strength of a HDPE/HDPE weld was developed in a PP/HDPE weld with HDPE as the absorbing part. This high weld strength is explained from: (1) a relatively low reptation time being in the millisecond range for both HDPE and PP; (2) a polymer mesh size (tube diameter (a)) being similar to the equilibrium interpenetration depth, determined from Helfand's theory and the interaction parameter (χ); (3) The selected HDPE and PP were both metallocene catalyzed and constituted a similar crystallization temperature which is required for high crystallinity in/near the interface. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of drawing on the molecular orientation and polymorphism of melt‐spun polyvinylidene fluoride fibers: Toward the development of piezoelectric force sensors
Authors: Magniez Kevin , Krajewski Andrew , Neuenhofer Martin , Helmer Richard 
Published: January 2013

AbstractThin piezoelectric polyvinylidene fluoride fibers containing a high piezoelectric β‐phase content of up to 80% were developed in this work using a melt‐spinning process. After crystallization from the melt, the fibers were subsequently stretched unidirectionally at 120°C between 25 and 75% of their original length. The effects on the molecular orientation, polymorphism and tensile properties of the fibers were investigated. Polarized infra‐red spectroscopy and X‐ray diffraction results show that the conversion of α‐phase to β‐phase occurred during the stretching process as a result of molecular alignment and creation of a dipole induced by the CF2 groups normal to the fiber direction. These fibers were then integrated into various weave architectures in order to design flexible two‐dimensional textile‐based piezoelectric force sensors. The piezoelectric responsiveness of these materials, tested under impact (70 Newton force, 1 Hz frequency) was very promising, with a maximum output voltage of up to 6 V and an average sensitivity of up to 55 mV/N measured. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Orchestration of Inflammation and Adaptive Immunity in Borrelia burgdorferi–Induced Arthritis by Neutrophil‐Activating Protein A
Authors: Codolo Gaia , Bossi Fleur , Durigutto Paolo , Bella Chiara Della , Fischetti Fabio , Amedei Amedeo , Tedesco Francesco , D'Elios Sofia , Cimmino Marco , Micheletti Alessandra , Cassatella Marco A. , D'Elios Mario M. , de Bernard Marina 
Published: January 2013

AbstractObjectiveLyme arthritis (LA) is characterized by infiltration of inflammatory cells, mainly neutrophils (polymorphonuclear cells [PMNs]) and T cells, into the joints. This study was undertaken to evaluate the role of the neutrophil‐activating protein A (NapA) of Borrelia burgdorferi in eliciting inflammation and in driving the adaptive immune response.MethodsLevels of NapA, interferon‐γ (IFNγ), interleukin‐17 (IL‐17), and T cell–attracting chemokines were assessed by enzyme‐linked immunosorbent assay in synovial fluid from patients with LA. The profile of T cells recruited into the synovia of patients with LA was defined by fluorescence‐activated cell sorting analysis. NapA was intraarticularly injected into rat knees, and the cells recruited in synovia were characterized. The role of NapA in recruiting immune cells was confirmed by chemotaxis assays using a Transwell system.ResultsNapA, IFNγ, IL‐17, CCL2, CCL20, and CXCL10 accumulated in synovial fluid from patients with LA. Accordingly, T cells obtained from these patients produced IFNγ or IL‐17, but notably, some produced both cytokines. NapA promoted neutrophil and T lymphocyte recruitment both in vitro and in vivo. Interestingly, the infiltration of T cells not only resulted from the chemotactic activity of NapA but also relied on the chemokines produced by PMNs exposed to NapA.ConclusionWe provide evidence that NapA functions as one of the main bacterial products involved in the pathogenesis of LA. Accordingly, we show that, at very early stages of LA, NapA accumulates and, in turn, orchestrates the recruitment of inflammatory cells into the joint cavity. Thereafter, with the contribution of recruited cells, NapA promotes the infiltration of T cells producing IL‐17 and/or IFNγ.
Isolation and characterization of luciferase from Indian firefly, Luciola praeusta
Authors: Muthukumaran Thuraimony , KrishnaMurthy Nemani V , Sivaprasad Nagalingam , Sudhaharan Thankiah 
Published: January 2013

ABSTRACTLuciferase from Indian firefly Luciola praeusta (Coleoptera: Lampyridae: Luciolinae) was isolated and the properties compared with that of the North American firefly, Photinus pyralis. Luciola praeusta luciferase was purified using acetone extraction, gel‐filtration column chromatography, ammonium sulfate precipitation and anion exchange chromatography. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis indicates a homogeneous preparation and the molecular mass was slightly higher than that of Photinus pyralis. The effect of pH, buffer composition and metal ions on the spectral characteristics was studied. The maximum bioluminescence activity of luciferase was observed in ACES buffer at pH 6.5. The emission maximum of 562 nm (in crude extract) was red shifted to 570 nm in Tricine buffer at pH 7.8. In addition, the effect of bovine serum albumin on the storage stability of the protein was investigated. Based on the unique spectral characteristics observed, we propose that Luciola praeusta luciferase in the native form is suitable for the assay of biochemical metabolites in acidic pH. Copyright © 2013 John Wiley & Sons, Ltd.
A simple and rapid spectrofluorimetric method for determining the pharmacokinetics and metabolism of rhaponticin in rat plasma, feces and urine using a cerium probe
Authors: Sun Yang , Zhao Yingyong , Yang Xiaohui 
Published: January 2013

ABSTRACTRhaponticin (RH) demonstrates a variety of pharmacological activities, including antitumor, antithrombotic and antioxidant effects. It is essential to establish a simple, rapid and reliable analytical method for determining the pharmacokinetics of RH. A simple cerium ion (Ce3+) probe method was developed and validated to determine RH in rat plasma, feces and urine. The fluorescence intensities of the cerium ion (Ce3+) were quenched by addition of RH, along with a remarkable red shift. Spectral data revealed that fluorescence quenching of Ce3+ by RH was due to the formation of a Ce3+–RH complex. Using to the Stern–Volmer equation, the binding parameters for interactions between Ce3+ and RH were obtained. Based on these, a rapid and simple spectrofluorimetric method was developed to determine the metabolism and pharmacokinetics of RH using a Ce3+ probe. The assay was linear over the concentration range of 0.11–9.52, 0.25–8.87 and 0.18–9.10 μM for plasma, feces and urine, respectivelyand RH recoveries were found to be 98.24 ± 0.8, 97.78 ± 1.2 and 97.54 ± 0.8% for plasma, feces and urine, respectively. The relative standard deviations were < 9.5%. The spectrofluorimetric method was simple and rapid for quantitative determination of RH and its metabolism, and was affordable for most laboratories because of the fluorescence spectroscopy and low equipment cost. These pharmacokinetic, bioavailability and metabolism studies of RH will provide helpful information for the development of suitable dosage forms and clinical references on rational administration. Copyright © 2013 John Wiley & Sons, Ltd.