bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterization of nanoparticle‐filled, mixed‐matrix membranes for the pervaporation dehydration of isopropyl alcohol
Authors: Prasad C. Venkata , Yeriswamy B. , Sudhakar H. , Sudhakara P. , Subha M. C. S. , Song J. I. , Rao K.Chowdoji 
Published: February 2012

AbstractNovel polymeric mixed‐matrix membranes (MMMs) were prepared by the incorporation of different amounts of 13X zeolite into a sodium carboxymethylcellulose (NaCMC)/poly(vinyl alcohol) (PVA) blend matrix. The resulting MMMs were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy to analyze the possible chemical reactions between NaCMC, PVA, zeolites, and glutaraldehyde. Scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and X‐ray diffraction were used to analyze the surface morphology, thermal stability, and crystallinity, respectively, of the membranes. Swellings studies were performed at 35°C, and we found that membranes containing 20 wt % zeolite showed higher values (960 kg m−2 h−1) at 17.5 wt % water in an isopropyl alcohol (IPA)/water mixture. Pervaporation (PV) experiments were also performed to evaluate the membrane performance in different compositions of the IPA/water mixture at 35°C. The mechanical properties were also tested, and we found that the optimum mechanical strength and percentage elongation at break were 42.24 N/mm2 and 3.38, respectively, for the membrane containing 15 wt % zeolite. The experimental results show that both the flux and selectivity increased with increasing zeolite content. The membrane containing 20 wt % zeolite showed the highest separation selectivity (5118) with a substantial flux of 0.121 kg m−2 h−1 at 35°C and with 10 wt % water in the feed; this suggested that the membranes could be used effectively to break the azeotropic point of the water–IPA mixture, so as to remove a small amount of water from IPA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synergistic effect of hindered amine light stabilizers/ultraviolet absorbers on the plasticized PVC during photo‐irradiation
Authors: Chai Ruidan , Chen Shuangjun , Zhang Jun 
Published: February 2012

AbstractTwo kinds of piperidine derivatives including a low‐molecular weight (Wt. 481, T770) and a high‐molecular weight (Wt. 2000–3100, C944) hindered amine light stabilizers (HALS) are added singly or with ultraviolet absorbers (UVA) in combination to plasticized poly(vinyl chloride) (PVC) samples. Digital photos, color changes, attenuated total refection‐Fourier transform infrared spectra (ATR‐FTIR), and mechanical properties are obtained to investigate the photostable effect of the light stabilizers on the plasticized PVC after artificial aging. PVC samples with HALS perform well at the first 400 h of irradiation in color change, FTIR, and mechanical properties, but at the last 400 h the photostability decreases. Besides, C944 performs better than T770, because C944 is a high‐molecular weight UV stabilizer and has good extraction resistance. Plasticized PVC samples with UVA resist discoloring and photooxidation from the photo‐irradiation. Excellent synergism is observed between the combination of HALS and UVA. PVC with HALS/UVA performs better than PVC with HALS and PVC with UVA in color differences, FTIR, and mechanical properties. The synergism is due to the different stages of functions between HALS and UVA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Influences of exfoliated graphite on structures, thermal stability, mechanical modulus, and electrical resistivity of poly(butylene terephthalate)
Authors: Li Meilu , Jeong Young Gyu 
Published: February 2012

AbstractWe report structural features and multifunctional properties of nanocomposites based on poly(butylene terephthalate) (PBT) and exfoliated graphite (EG), which are manufactured by melt‐compounding technique. Scanning electron microscope and X‐ray diffraction data exhibit that graphene platelets of EG are well dispersed and exfoliated in the PBT matrix even at high EG content of 7.0 wt %. Raman spectra support that graphene platelets of EG are interacted specifically with phenyl rings of PBT chains at nanocomposite interfaces. DSC cooling and following heating thermograms of the nanocomposites demonstrate that graphene platelets of EG play a role as effective nucleating agents for PBT α‐phase crystals and thus lead to accelerating the overall crystallization of the nanocomposites. Thermal stability of PBT/EG nanocomposites is improved substantially due to the gas barrier effect of graphene platelets of EG dispersed in the PBT matrix, especially at the active oxygen gas condition. Dynamic mechanical modulus of the nanocomposites is also enhanced significantly with increasing the EG content. The electrical volume resistivity of the nanocomposites is decreased dramatically from ∼ 1018 to ∼ 106 Ω cm by forming the electrical conduction path at a certain EG content between 3 and 5 wt %. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Fluoro‐functionalized PLA polymers as potential water‐repellent coating materials for protection of stone
Authors: Giuntoli Giulia , Rosi Luca , Frediani Marco , Sacchi Barbara , Frediani Piero 
Published: February 2012

AbstractA series of sixteen fluoro‐functionalized poly(lactic acid)s were synthesised using two commercial fluorinated alcohols [3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluoro‐1‐octanol and 4‐(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl)benzyl alcohol] as co‐initiators in the ring‐opening polymerization of L‐lactide and rac‐lactide (the racemic mixture of L‐ and D‐lactide) catalyzed by Tin(II) 2‐ethylhexanoate. The polymers were characterized by NMR, IR, GPC, DSC and tested as potential protective coating for stone. The performances were comparatively evaluated in terms of water protection efficacy and colour changes of the treated stone. Furthermore, the photo‐stability of nine selected polymers under Solar Box condition was also investigated. It has been shown that the presence of fluorine makes the stone more water‐repellent. The polymers showed also interesting photo‐stability and some of them provided a behavior close to PLA‐FLK‐PLA block copolymers recently reported in the literature, in spite of their lower fluorine content © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electrical conductivity of polymer blends of poly(3,4‐ethylenedioxythiophene): Poly(styrenesulfonate): N‐methyl‐2‐pyrrolidinone and polyvinyl alcohol
Authors: Chen Chang‐hsiu , LaRue John C. , Nelson Richard D. , Kulinsky Lawrence , Madou Marc J. 
Published: February 2012

AbstractThe goal of this study is to determine the electrically conductivity of the polymers poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate): N‐methyl‐2‐pyrrolidinone (PEDOT: PSS: NMP) and PEDOT: PSS when blended with polyvinyl alcohol (PVA). While the conducting polymers have high conductivity when not blended with PVA, they are brittle and difficult to spin‐coat. Thus, the motivation for this study is to develop blends of these two conducting polymers with PVA to produce a material with optimized mechanical properties and that can also be spin‐coated. The blends are produced using aqueous preparations of these materials. Mixtures of various weight percentages (wt %) of PEDOT: PSS: NMP and PEDOT: PSS are prepared and spin‐coated on glass slides to form thin films. In the blends, the film conductivity increases with increasing content of either PEDOT: PSS: NMP or PEDOT: PSS. For example, 100 wt % of PEDOT: PSS: NMP and 60 wt % of PEDOT: PSS: NMP blended with PVA exhibit conductivities of, respectively, 10 and 4.02 S/cm. In contrast, conductivities of only 0.0525 and 0.000506 S/cm are observed, respectively, for 100 wt % of PEDOT: PSS and 60 wt % of PEDOT: PSS content in the PEDOT: PSS/PVA blends (No NMP). The addition of the NMP enhances the electrical conductivity by two to five orders of magnitude (depending on the amount of PVA in the blend) due to conformational change of PEDOT chains. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and characterization of novolak phenol formaldehyde resin from liquefied brown‐rotted wood
Authors: Li Gai‐Yun , Hse Chung‐Yun , Qin Te‐Fu 
Published: February 2012

AbstractThe brown‐rotted wood was liquefied in phenol with phosphoric acid as catalyst and the resulting liquefied products were condensed with formaldehyde to yield novolak liquefied wood‐based phenol formaldehyde resin (LWPF). The results showed that brown‐rotted wood could be more easily liquefied than sound wood in phenol. The residue content of liquefied wood decreased continually with the progress of brown‐rot decay. Both water wash and neutralization and water wash slightly improved the thermofluidity and curing properties of LWPF with a small reduction of LWPF yield. An increase in phenol to wood (P/W) ratio from 2 to 3 slightly improved the flow property of LWPF, but with an accompanied by 20% deduction in the product yield. Increased liquefaction time from 30 min to 60 min showed no significant influence on the resulting LWPF. The moldings fabricated from LWPF yielded higher charpy impact, flexural and flexural modulus strength but yielded lower temperature deflection under load than that of the commercial novolak resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical properties and nanostructure correlation of condensation‐type poly(dimethyl siloxane)/layered silicate hybrids
Authors: Vasilakos S. P. , Tarantili P. A. 
Published: February 2012

AbstractComposites of silicone rubber reinforced with organomontmorillonite (OMMT) nanoparticles were prepared by direct mixing and characterized in terms of morphology, in correlation with mechanical performance. Two grades of commercial montmorillonite (MMT) with different types of organic modification were studied, namely Cloisite® 20A and Cloisite® 30B. Low, medium, and higher molecular weight PDMS were used as matrices. Using X‐ray diffraction analysis, it was shown that OMMT loadings at a weight ratio to resin ranging from 5 to 10 parts per hundred (phr) can produce delamination hybrids. Mechanical testing showed that for OMMT loadings up to 8 phr, the prepared nanocomposites present higher tensile strength, stiffness, and tear resistance with respect to the neat silicone. Improvement of the solvent resistance was also recorded by swelling experiments in toluene, and this behavior of the nanocomposites is consistent with their mechanical properties. The results showed that processing characteristics, as well as the overall reinforcing efficiency of nanofillers, are greatly dependent on the initial molecular weight of the elastomer, because this parameter controls the resulting network density and concentration of polar end groups. The content of organic modification of MMT was also found as an important characteristic for proper filler dispersion. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Heredity and difference of multiple‐scale microstructures in PAN‐based carbon fibers and their precursor fibers
Authors: Yu Meijie , Xu Yong , Wang Chengguo , Hu Xiuying , Zhu Bo , Qiao Kun , Yuan Hua 
Published: February 2012

AbstractMultiple‐scale microstructures, including skin‐core structure, fibril structure, lamellar structure, crystal/amorphous structure, were found co‐present in the fibers during the whole production process of polyacrylonitrile (PAN)‐based carbon fibers. The structural heredity and difference among them were systematically investigated for the first time by scanning electron microscope, optical microscope, transmission electron microscope, and X‐ray diffraction. The relations between the four kinds of structures and their formation mechanisms were analyzed. The skin‐core structure is contributed to inhomogeneous distribution of composition and chemical structure along the radial direction in oxidative stabilized fibers, which is proved different in PAN precursor fibers and carbon fibers. Fibrils are successively separated from low‐temperature oxidative stabilized fibers by ultrasonic etching in dimethylsulfoxide solution. The separation of individual fibril becomes harder and even impossible in those fibers prepared at temperatures higher than 245°C. This suggests a stronger bonding force between fibrils in high‐temperature oxidative stabilized fibers and carbon fibers. The lamellar structures within fibrils are observed in all of these fibers but with thicker lamella width with increasing temperature. They are unlikely due to the alternatively alignment of crystal regions and amorphous regions as reported by many previous literature, because the oxidative stabilized fibers are amorphous but have lamellar structures. The (002) diffraction arc gives the evidence that the lamellar structure in carbon fibers is not strictly perpendicular to the fiber axis, but have an angle of about 45° with it. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and characterization of isocyanate‐functionalized PVA‐based polymers with applications as new additives in lubricant formulations
Authors: Moreno G. , de Paz M. V. , Valencia C. , Franco J. M. 
Published: February 2012

AbstractThis work deals with the incorporation of reactive isocyanate groups into polymer additives, which could be potentially used to modify the rheological properties of lubricating greases by reinforcing the role of traditional thickening agents. Thus, a batch of partially protected poly(vinylalcohol) (PVA) copolymers was successfully synthesized. Some of their OH groups were blocked as tetrahydropyranyl (THP) ethers (PVA–THP), while the spare hydroxyl groups were further functionalized with NCO pendant groups by reaction with 1,6‐hexamethylene diisocyanate, leading to several isocyanate‐functionalized PVA‐based polymers (PVA–THP–NCO), which were tested as rheology modifiers of lithium lubricating greases. The highest protection degree of hydroxyl groups achieved as THP‐ether was 58.5% and the recovered polymers were isolated with excellent yields (close to 90% in most cases). NCO‐functionalized PVA‐based polymers (PVA–THP–NCO) exerted a significant rheological modification in lithium 12‐hydroxystearate lubricating greases, increasing the values of the linear viscoelastic functions. The influence of the degree of protection and later functionalization of PVA on the rheological properties of PVA–THP–NCO‐additivated lubricating greases is discussed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal, magnetic, and optical characteristics of ABS‐Fe2O3 nanocomposites
Authors: Nabiyouni Gholamreza , Ghanbari Davood 
Published: February 2012

AbstractUniform monodisperse FeOOH and hematite (Fe2O3) nanoparticles were synthesized at room temperature via a facile sonochemical reaction between FeCl3 and NaOH. Fe2O3 nanoparticles were then added to acrylonitrile–butadiene‐styrene (ABS) polymer. Nanoparticles and nanocomposites were characterized using X‐ray diffraction, scanning electron microscopy, Fourier transform infrared, and photoluminescence (PL) spectroscopy techniques. The effect of the presence of FeOOH and Fe2O3 nanoparticles in the polymer matrix on the thermal properties was studied using thermogravimetric analysis and derivative thermogravimetric analysis, in both air and nitrogen atmospheres. The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer. We found that the Fe2O3 nanoparticles exhibit a ferromagnetic behavior with a saturation magnetization of 0.869 emu/g and a coercivity of 191 Oe at room temperature. The coercivity of ABS/ Fe2O3 (5%) nanocomposites is found to be 252 Oe, higher than 226 Oe which is obtained for ABS/Fe2O3 (20%). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Infrared spectroscopy study of photodegradation of polymer modified asphalt binder
Authors: Araujo Maria de Fátima A. de S. , Lins Vanessa de F. C. , Pasa Vânya M. D. , Fonseca Cíntia Gonçalves 
Published: February 2012

AbstractThe effect of solar radiation in the aging of the asphalt binder can be considered relevant in several countries due to the high level of insulation. This article deals with the comparative aging of a conventional asphalt binder and styrene‐butadiene‐styrene modified asphalt binder samples under the effect of weathering. The samples were exposed to cycles of xenon radiation, moisture, and temperature. The degradation of binders was analyzed by using the technique of Fourier transform infrared spectroscopy. The CH/CO ratio decreased 92.5% for the conventional asphalt cement and 74% for the polymer modified asphalt after 150 h of exposure in a weathering chamber. The oxidation resistance of styrene‐butadiene‐styrene modified asphalt binder was higher than the conventional asphalt cement evaluated by using the weathering test and infrared spectroscopy analysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electrolyte effects of poly(3‐methylthiophene) via PET/ITO and synthesis of 5‐(3,6‐di(thiophene‐2‐yl)‐9H‐carbazole‐9‐yl) pentanitrile on electrochemical impedance spectroscopy
Authors: Ates Murat , Karazehir Tolga , Uludag Nesimi 
Published: February 2012

AbstractIn this article, 3‐methylthiophene (3MTh) and 5‐(3,6‐di(thiophene‐2‐yl)‐9H‐carbazole‐9‐yl) pentanitrile (ThCzpN) comonomer were electrochemically deposited on poly(ethylene terephthalate)/indium tin oxide (PET/ITO) electrode and carbon fiber micro electrode (CFME) in sodium perchlorate (NaClO4)/acetonitrile (ACN), respectively. ThCzpN comonomer was characterized by 1H‐nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy (FTIR) analysis. Poly(ThCzpN)/CFME is characterized by cyclic voltammetry (CV), Scanning electron microscopy‐energy dispersive X‐ray analysis (SEM‐EDX), and electrochemical impedance spectroscopy (EIS). The detailed characterization of the resulting electrocoated poly(3MTh) on PET/ITO thin films was studied by different techniques, i.e., CV and EIS. The effects of electrolytes after electrocoated of modified electrodes were examined by EIS technique in various electrolytes medium (sodium perchlorate (NaClO4), lithium perchlorate (LiClO4), tetraethyl ammonium tetrafluoroborate (TEABF4), and tetrabutyl ammonium tetrafluoroborate (TBABF4)/acetonitrile (ACN) solution). Capacitive behaviors of modified PET/ITO electrode were defined via Nyquist, Bode‐magnitude, Bode‐Phase, and admittance plots. Variation of capacitance values by various electrolytes and low‐frequency capacitance (CLF) values are presented. CLF value electrocoated polymer thin film by CV method in the 0.1M NaClO4 electrolyte with a charge of 7.898 mC was obtained about 59.1 mF cm−2. The highest low‐frequency capacitance (CLF) was obtained from the Nyquist plot with [ThCzpN]0 = 3 mM as 0.070 mF cm−2. Equivalent circuit model [R(QR(CR)(RW))(CR)] was suggested for poly(3MTh) on PET/ITO in four different electrolytes medium. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The preparation, structures, and properties of poly(vinylidene fluoride)/multiwall carbon nanotubes nanocomposites
Authors: Tang Xue‐Gang , Hou Meng , Ge Lei , Zou Jin , Truss Rowan , Yang Wei , Yang Ming‐Bo , Zhu Zhong‐Hua , Bao Rui‐Ying 
Published: February 2012

AbstractPoly(vinylidene fluoride) (PVDF)/multiwall carbon nanotubes (MWCNTs) were prepared by a phase inversion technique. Long chain macromolecules, maleic anhydride grafted PVDF (PVDF‐MAH) were used to fine tune the interface. Transmission electron microscopy (TEM) images revealed that the MWCNTs are quasi‐homogeneously dispersed in the PVDF matrix. The results of differential scanning calorimetry (DSC) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) showed that the addition of MWCNTs induced β‐phase PVDF, and both the melting behavior and crystal structures of PVDF did not change obviously by the addition of MWCNTs. However, the addition of long chain macromolecules PVDF‐MAH did not alter the crystal structure according to the ATR‐FTIR test, but significantly changed the melting behavior as evidenced by a multiple melting behavior detected by DSC. Dynamic mechanical analysis (DMA) tests showed that both the addition of MWCNTs and PVDF‐MAH increased the storage modulus and the improvement of nanocomposites was better at low temperature regions than high temperature regions. In addition, no significant change of the Tg was observed with the addition of MWCNTs and PVDF‐MAH. Tensile tests showed that the addition of MWCNTs and PVDF‐MAH increased the modulus and tensile strength. Creep test showed that the addition of MWCNTs can increase the creep stability. However, the interfacial modification here was not enough to change the creep behavior significantly. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A ratiometric fluorescent probe for bisulphite anion, employing intramolecular charge transfer
Authors: Wang Gang , Qi Haiping , Yang Xiao‐Feng 
Published: February 2012

ABSTRACT4‐(1H‐benzimidazol‐2‐yl)benzaldehyde (1) has been developed as a new ratiometric fluorescent probe for bisulphite, based on the modulation of intramolecular charge transfer (ICT). Upon mixing with bisulphite in aqueous ethanol, an aldehyde–bisulphite adduct was formed and the ICT of the probe was switched off, which resulted in a ratiometric fluorescence response with an enhancement of the ratios of emission intensities at 368 and 498 nm. The detection range of the probe for bisulphite is in the 2.0–200 µmol/L concentration range and the detection limit is 0.4 µmol/L. Probe 1 produces a ratiometric fluorescent response to bisulphite with a marked emission wavelength shift (130 nm) and displays high selectivity for bisulphite over other anions. Copyright © 2012 John Wiley & Sons, Ltd.
Review of HPLC methods and HPLC methods with mass spectrometric detection for direct determination of aspirin with its metabolite(s) in various biological matrices
Authors: Mullangi Ramesh , Sharma Kuldeep , Srinivas Nuggehally R. 
Published: February 2012

ABSTRACTAspirin, the most widely used drug in the world, has been known to mankind for over a century. It is not only the pharmacologically active entity, but is also biotransformed into a major metabolite, i.e. salicylic acid, which also exhibits similar pharmacologic/pharmacodynamic properties. Hence it is necessary to quantitate aspirin along with its metabolite(s) in various biological matrices accurately and precisely to correlate with pharmacological/pharmacodynamic activity. This paper provides a comprehensive overview of various bioanalytical methods (HPLC and LC‐MS/MS) that have been reported for direct quantitation of aspirin along with its metabolite(s). The review also provides general information on sample collection, sample processing, internal standard selection, conditions for chromatographic separation, succinct validation data and applicable conclusions for reported assays in a structured manner. Copyright © 2012 John Wiley & Sons, Ltd.