bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of arsenic agents by polyhydroxamic acid
Authors: Hosseini Seyyed Hossein 
Published: March 2011

AbstractArsenic agents are among the most destructive and fatal factors that exist in the environment, chemical agents, medicines, toxics, pesticides, etc., and working with these compounds is too limited and difficult due to their high toxicity. These deadly, dangerous, and weakening toxins are consumed for a large variety of purposes in the military industries. So measurement and identification of them are of great necessity. In this research work, acryl carbohydroxamic acid monomer was first prepared from acrylamide and then polymerized under radical conditions in the presence of azobisisobutyronitrile as an initiator. The produced polyhydroxamic acid (PHA) has antibacterial and anticancer properties as well as high complex‐forming properties with transition elements. By using the chelating properties of PHA, we took steps to identify arsenic agents such as trichloroarsine, dichloroethylarsine, and lewisites (I, II, III). This polymer, possessing unique properties, measures well the arsenic of low concentrations, lower than 10 ppm, existing in the samples within a very short time (a few seconds). We will also be able to perform qualitative assessments on it through instrumental methods or titration, if required. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
In situ grown titania composition for optimal performance and durability of Nafion® fuel cell membranes
Authors: Patil Yatin , Kulkarni Sunil , Mauritz Kenneth A. 
Published: March 2011

AbstractNafion® membranes were modified via in situ, catalyzed sol–gel reactions of titanium isopropoxide to form titania particles in the polar acid domains. FTIR spectroscopy showed successful intraparticle chemical bond formation with incomplete condensation of TiOH groups. Although such modification can lower membrane fuel cell performance, this study was aimed at reducing membrane degradation without significantly altering performance in the sense of material optimization. These incorporated particles did not change membrane equivalent weight and the water uptake was similar to that of the unmodified Nafion® membrane. Membrane dimensional stability, mechanical properties, and ability to withstand contractile stresses associated with humidity change at 80°C and 100% RH were improved. An open circuit voltage (OCV) accelerated degradation test showed the titania modification held voltage better than the unmodified membrane. Performance deterioration of Nafion® after the OCV test was much higher than that of the modified membrane and the fluoride emission of the latter was lower. The degraded Nafion® membrane failed when subjected to creep, whereas the modified membrane remained intact with significantly low deformation. This inorganic modification offers a simple way to enhance membrane durability by reducing both physical and chemical degradation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Optical characterization of plasma‐polymerized pyrrole‐N,N,3,5‐tetramethylaniline bilayer thin films
Authors: Kamal M. M. , Bhuiyan A. H. 
Published: March 2011

AbstractA capacitively coupled parallel‐plate reactor has been used to deposit plasma‐polymerized pyrrole (PPPy), plasma‐polymerized N,N,3,5‐tetramethylaniline (PPTMA), and plasma‐polymerized pyrrole‐N,N,3,5‐tetramethylaniline (PPPy‐PPTMA) bilayer thin films on to glass substrates at room temperature. To deposit the bilayer films, pyrrole monomer has been used as the mother material and N,N,3,5‐tetramethylaniline monomer has been deposited in different deposition time ratios after the pyrrole films were formed. Fourier transform infrared (FTIR) and ultraviolet–visible (UV–vis) spectroscopy techniques have been used to characterize the as‐grown thin films of about 500‐nm thick. The structural analyses by FTIR spectroscopy have indicated that the monomer has undergone the reorganization and the ring structure is retained during the plasma polymerization. From the UV–vis absorption spectra, allowed direct transition (Eqd) and allowed indirect transition (Eqi) energy gaps were determined. The Eqd for PPPy, PPTMA, and PPPy‐PPTMA bilayer films are found to be 3.30, 2.85, and 3.65 eV respectively. On the other hand, the Eqi for the same series are 2.25, 1.80, and 2.35 eV, respectively. From these results, it is seen that the energy gaps of the PPPy‐PPTMA bilayer films have been increased compared with the PPPy and PPTMA films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Comparative investigation of the formation of polytetrafluoroethylene nanoparticles on different solid substrates through the adsorption of tetrafluoroethylene
Authors: Garshasbi Ashkan , Mahdi Doroodmand Mohammad , Pooladi Reza , Safavi Afsaneh , Hossein Sheikhi Mohammad 
Published: March 2011

AbstractThe effects of different solid substrates, including carbon nanofibers (CNFs), activated carbon, alumina, silica, molecular sieves, and poly(N‐vinylpyrrolidione) (PVP), were compared for the high‐pressure synthesis of polytetrafluoroethylene [PTFE or (CF2)n] nanoparticles via the adsorption of thermally synthesized tetrafluoroethylene (C2F4) as the monomer. Scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA) were used for the characterization of the PTFE nanoparticles on different solid substrates. The results demonstrate that the average diameters of the PTFE nanoparticles were about 90 nm for the CNFs, 130 nm for PVP, 150 nm for alumina, and about 200 nm for silica. Also, TGA showed that the amounts of PTFE nanoparticles synthesized on each solid substrate were 3.53 ± 0.09% for CNFs, 2.31 ± 0.10% for PVP, 2.11 ± 0.12% for silica, and 0.97 ± 0.16% for alumina. Depending on the active surface area and the morphology of nanomaterials, such as CNFs, different capacities were evaluated for each solid support in the formation of the PTFE nanoparticles. The quantities and the size of the synthesized PTFE nanoparticles relied on the characteristics of the solid substrate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Interlaminar fracture toughness of woven fabric composite laminates with carbon nanotube/epoxy interleaf films
Authors: Sager Ryan J. , Klein Patrick J. , Davis Daniel C. , Lagoudas Dimitris C. , Warren Graham L. , Sue Hung‐Jue 
Published: March 2011

AbstractThe Mode I interlaminar fracture behavior of woven carbon fiber/epoxy composite laminates incorporating partially cured carbon nanotube/epoxy composite films has been investigated. Laminates with films containing carbon nanotubes (CNTs) in the as‐received state and functionalized with polyamidoamine were evaluated, as well as laminates with neat epoxy films. Double‐cantilever beam (DCB) specimens were used to measure GIc, the critical strain energy release rate (fracture toughness) versus crack length. Post‐fracture microscopic inspection of the fracture surfaces was performed. Results show that initial fracture toughness was improved with the amino‐functionalized CNT/epoxy interleaf films, but the important factor appears to be the polyamidoamine functionalization, not the CNTs. The initial fracture toughness remained relatively unaffected with the incorporation of neat epoxy and as‐received CNT/epoxy interleaf films. Plateau fracture toughness was unchanged with the use of functionalized CNT/epoxy interleaf films, and was reduced with the use of neat epoxy and as‐received CNT/epoxy interleaf films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Taxol‐loaded nanoparticles with methoxy poly(ethylene glycol)‐b‐poly(ε‐caprolactone) as a novel additive in the outer aqueous phase
Authors: Zhang Yanting , Hou Jingwen , Qian Changyun , Song Lei , Guo Shengrong 
Published: March 2011

AbstractTaxol‐loaded nanoparticles were prepared by solvent‐evaporation technique with methoxy‐added methoxy poly(ethylene glycol)‐b‐poly(ε‐caprolactone) (MPEG‐b‐PCL) (PEG wt % = 18.5%) as drug carrier and MPEG‐b‐PCL (PEG wt % = 86.8%) as the additive in the outer aqueous phase. The MPEG‐b‐PCL copolymers were synthesized via ring‐opening polymerization of ε‐caprolactone using Novozym 435 as biocatalyst. As a newly used additive in the outer aqueous phase, only 0.1% (w/v) MPEG‐b‐PCL with relatively high‐PEG content was needed. The effects of feed ratio of taxol to copolymer (w/w, 5–20%) on the characters of nanoparticles and in vitro drug release were investigated. The fabricated nanoparticles reached the highest encapsulation efficiency of 52.5% ± 3.9% when the feed ratio was 10%. The nanoparticles presented a core‐shell structure in aqueous solution, and their hydrodynamic diameter ranged from 75 to 105 nm. Transmission electron microscopy and atomic force microscope investigations exhibited that the nanoparticles had fine spherical shape and narrow particle size distribution. The size of nanoparticles did not change distinctly after incubation in pH 7.4 phosphate‐buffered solution (PBS) and pH 7.4 PBS with 10% fetal bovine serum at 37°C for 24 h. The nanoparticles with drug loading around 5% could achieve a sustained drug release for 7 days. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Utilization of starch and montmorrilonite for the preparation of superabsorbent nanocomposite
Authors: Zhou Ming , Zhao Jinzhou , Zhou Lizhi 
Published: March 2011

AbstractStarch and montmorrilonite (MMT) were used as raw materials for synthesizing starch‐graft‐poly[acrylamide (AM)–acrylic acid (AA)]/MMT superabsorbent nanocomposite by graft and intercalation copolymerization reaction of starch, AM, and AA in the presence of organic MMT micropowder in aqueous solution. Major factors affecting water absorbency such as weight ratio of monomers to starch, weight ratio of AM to AA, neutralization degree of AA, amount of crosslinker, initiator, and MMT were investigated. The superabsorbent nanocomposite synthesized under optimal synthesis conditions exhibits absorption of 1120 g H2O/g sample and 128 g H2O/g sample in deionized water and in 0.9 wt % NaCl solution, respectively. IR spectra showed that the graft copolymerization between OH groups on MMT and monomers took place during the reaction, and that crystal interlayer was pulled open in the superabsorbent nanocomposite. X‐ray diffraction analysis showed that the crystal interlayer of MMT was pulled open to 2.73 nm, and thus formed nanometer exfoliation composite material. Thermogravimetric analysis showed that starch‐graft‐poly (AM–AA) superabsorbent nanocomposite (8 wt % MMT) has good thermal stability. This superabsorbent nanocomposite with excellent water absorbency and water retention, being biodegradable in nature, economical and environment friendly, could be especially useful in industry, agricultural, and horticultural applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical and thermal properties of calcium carbonate‐filled PP/LLDPE composite
Authors: Ghalia Mustafa Abu , Hassan Azman , Yussuf Abdirahman 
Published: March 2011

AbstractPolymer blends typically are the most economical means to develop new resins for specific applications with the best cost/performance balance. In this paper, the mechanical properties, melting, glass transition, and crystallization behavoir of 80 phr polypropylene (PP) with varying weights of linear low density polyethylene (LLDPE) at 10, 20/ 20 wt % CaCO3, 30, 40, and 50 phr were studied. A variety of physical properties such as tensile strength, impact strength, and flexural strength of these blends were evaluated. The compatibility of these composite was examined by differential scanning calorimetry (DSC) to estimate Tm and Tc, and by dynamic mechanical analysis (DMA) to estimate Tg. The fractographic analysis of these blends was examined by scanning electron microscopy (SEM). It has been confirmed that increasing the LLDPE content trends to decreases the tensile strength and flexural strength. However, increasing the LLDPE content led to increases in the impact strength of PP/LLDPE blends. It was also found that up to 40 phr the corresponding melting point (Tm) was not effected with increasing LLDPE content. Each compound has more than one Tg, which was informed that there is a brittle‐ductile transition in fracture nature of these blends, the amount of material plastically deformed on the failure surface seems to increase with the increasing the LLDPE content. And PP/LLDPE blends at temperature (23°C) showed a ductile fracture mode characterized by the co‐existence of a shear yielding process; whereas at lower temperature (−20°C) the fractured surfaces of specimens appear completely brittle. The specimens broke into two pieces with no evidence of stress whitening, permanent macroscopic deformation or yielding. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Studies of organoclays with functionalized pillaring agents
Authors: Zhang Yongcheng , Pittman Charles U. , Arockiasamy Antonyraj , King Roger L. 
Published: March 2011

AbstractA series of clay pillaring agents with amino, olefin, and epoxy groups were synthesized. These pillaring agents were used to modify montmorillonite clay by ion‐exchange reactions. TGA studies showed that organoclays with imidazolium pillaring agents have a higher thermal stability than those with ammonium groups. The d‐spacings of organoclays were not affected by the pillaring agent functional groups and were sensitive to the size of pillaring agents. The dynamic‐mechanical properties of the resulting clay/epoxy composites determined by DMA were similar. The addition of these clays to this epoxy resin enhanced the Tg value of the resulting composites and greatly enhanced the storage moduli versus the pure epoxy resin by 1.6–1.8 times at 135°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Impact behavior and fracture morphology of acrylonitrile–butadiene–styrene resins toughened by linear random styrene–isoprene–butadiene rubber
Authors: Yang Juan , Wang Chao‐Xian , Yu Zhi‐Sheng , Li Yang , Yang Ke‐Ke , Wang Yu‐Zhong 
Published: March 2011

AbstractA novel toughening modifier, styrene–isoprene–butadiene rubber (SIBR), was used to improve the impact resistance and toughness of acrylonitrile–butadiene–styrene (ABS) resin via bulk polymerization. For comparison, two kinds of ABS samples were prepared: ABS‐1 was toughened by a conventional modifier (a low‐cis polybutadiene rubber/styrene–butadiene block copolymer), and ABS‐2 was toughened by SIBR. The mechanical properties, microstructures of the as‐prepared materials, and fracture surface morphology of the specimens after impact were studied by instrumented notched Izod impact tests and tensile tests, transmission electron microscopy, and scanning electron microscopy, respectively. The mechanical test results show that ABS‐2 had a much higher impact strength and elongation at break than ABS‐1. The microscopic results suggested that fracture resistance of ABS‐1 only depended on voids, shear yielding, and few crazing, which resulted in less ductile fracture behavior. Compared with ABS‐1, ABS toughened by linear random SIBR (ABS‐2) displayed the synergistic toughening effect of crazing and shear yielding, which could absorb and dissipate massive energy, and presented high ductile fracture behavior. These results were also confirmed by instrumented impact tests. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Intramolecular and intermolecular crosslinked poly(vinyl alcohol)–borate complexes for the sustained release of fertilizers and enzymes
Authors: Kale S. N. , Mona J. , Dhobale Sandip , Thite Trupti , Laware S. L. 
Published: March 2011

AbstractTherapeutic agents or agricultural fertilizers captured in polymer colloids (PCs) give rise to interesting applications, which are typically related to sustained release. We synthesized crosslinked polymer structures with poly(vinyl alcohol) (PVA) and borax precursors. Fourier transform infrared spectroscopy showed that a polymer–boron ion complex was formed with the crosslinking reaction at the OH site of PVA; thereby, PCs were formed. Field‐emission scanning electron microscopy showed that a uniform mesoporous two‐dimensional structure formed via intermolecular and intramolecular crosslinking. Trypsin enzyme and phosphate fertilizer were trapped in these PCs independently to study sustained release. Fertilizer‐incorporated PCs were mixed with soil samples, in which seeds of fenugreek were sown, and the plant growth was monitored a duration of 15 days. The fertilizer release, studied with UV–visible spectroscopy, showed a sustained signature of the fertilizer (at 690 nm) in the water extracts of soil, with much healthier plant growth compared to the control. For the trypsin‐incorporated PC samples, the released enzyme was made to interact with bovine serum albumin protein to monitor the released percentage with UV absorption spectroscopy. A systematic increase in the enzyme signature (at 280 nm) was observed for a duration of 60 min; this indicated the potential of PC for sustained drug release. The swelling calculations predicted that the mechanism involved was composed of pseudo‐swelling behavior. We envisaged that the hydroxyl groups of the PC broke in water and formed a complex with water. This complex slowly dissolved in water to release the entrapped molecules. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of porous poly(N‐isopropylacrylamide) hydrogels prepared in ethanol–water mixtures
Authors: Biswas Chandra Sekhar , Patel Vijay Kumar , Vishwakarma Niraj Kumar , Mishra Avnish Kumar , Ray Biswajit 
Published: March 2011

AbstractPoly(N‐isopropylacrylamide) (PNIPAM) hydrogels were prepared by free‐radical polymerization in different ethanol–water mixtures. A scanning electron microscopy study revealed that the resulting hydrogels were macroporous. The swelling ratios of the resultant hydrogels in water at 20°C followed this order: X0.34 ≈ X0.68 > X0.48 > X0.09 > X0.04 > X0, where Xa denotes a gel prepared in an ethanol–water solvent mixture with an ethanol molar fraction of a. Below the lower critical solution temperature, the swelling ratio values of all of the hydrogels gradually decreased with increasing temperature. The complete collapse of the PNIPAM chain of all of these gels occurred at about 38°C, whereas the same was observed at about 35°C for the conventional gel prepared in water. The swelling ratio values of all of the PNIPAM gels with different molar fractions of ethanol at 20°C passed through a minimum in the cononsolvency zone. The deswelling rates of the hydrogels decreased in the following order: X0.34 > X0.48 > X0.68 > X 0.09 > X0.04 > X0. The reswelling rates of these hydrogels decreased in the following order: X0 > X0.04 ≈ X0.48 > X0.09 ≈ X0.68 > X 0.34. The freeze‐drying process decreased the swelling ratios but increased the deswelling and reswelling properties of the PNIPAM gels. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of the solvent type on the formation and physical properties of polyacrylonitrile fibers via a solvent‐free coagulation bath
Authors: Mahmod D. S. A. , Ismail A. F. , Mustafa A. , Ng B. C. , Abdullah M. S. 
Published: March 2011

AbstractPolyacrylonitrile (PAN) fibers were fabricated via a dry‐jet wet‐spinning technique, and a solvent‐free coagulation bath system was adopted. The effects of different types of dope solvent on the formation and physical properties of the PAN fibers were investigated. Dimethylformamide and dimethyl sulfoxide (DMSO) were selected as the solvents and were added to a spinning solution consisting of 18 wt % PAN. The PAN fibers were examined with field emission scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. The field emission scanning electron micrographs revealed that the PAN fibers with the DMSO solvent exhibited a more circular shape and a smoother skin. The PAN fibers with the DMSO solvent had their glass‐transition temperature (Tg) at 121°C. This study indicated that the different types of dope solvent used in the dope preparation did not affect Tg of the PAN fibers because of the solvent‐free coagulation bath system; however, they significantly affected the physical formation of the PAN fibers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Emulsion copolymerization of tetrafluoroethylene with ω‐chlorotetrafluoroethyltrifluorovinyl ether and the synthesized copolymer properties
Authors: Allayarov S. R. , Ilyin A. N. , Olkhov Yu. A. , Allayarova U. Yu. , Dixon D. A. 
Published: March 2011

AbstractEmulsion copolymerization of ω‐chlorotetrafluoroethyltrifluorovinyl ether (Cl(CF2)2OCF = CF2 (FVE)) with tetrafluoroethylene (CF2 = CF2 (TFE)) was investigated at various monomer ratios. The copolymerization rate is below the rate of TFE homopolymerization and the copolymerization kinetics depends on the FVE content in the reaction medium. The copolymer composition is very similar if the FVE content in monomer mixture is ≤2.5 mol %. However, the percent amount of FVE in the copolymer, the copolymerization rate, and molecular mass of synthesized copolymers decrease noticeably with increase in the FVE content in the monomer mixture. The constants of copolymerization are r1= 2.8 (TFE) and r2 = 0.03 (FVE). The copolymer is a statistical polymer consisting of TFE blocks and individual FVE molecules between the blocks. The average molecular mass of copolymers is significantly less than that of the TFE homopolymer (PTFE) synthesized at the same conditions. The morphologies of PTFE and copolymer powders were investigated by thermomechanical analysis and are not similar. The copolymer has a completely amorphous diblock morphology depending on the FVE content. The introduction of FVE molecules into the copolymer macromolecules is accompanied by reduction of the crystalline portion of copolymer. If the FVE content in copolymer is ≥3.5 mol %, the copolymer macromolecules completely lose the ability to form crystalline portions as a result of their amorphicity. The introduction of up to 2.4 mol % FVE into the copolymer macromolecules yields a highly thermostable and meltable copolymer which can be processed by using the industrial processes used widely for thermoplastics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
The thermal conductivity of fir and beech wood heat treated at 170, 180, 190, 200, and 212°C
Authors: Kol Hamiyet Şahin , Sefil Yusuf 
Published: March 2011

AbstractHeat treatment changes the chemical, physical, and mechanical properties of wood. The properties of heat‐treated wood have been researched considerably, but the thermal conductivity of heat‐treated wood in various conditions has not been reported. In this study, the thermal conductivity of heat‐treated fir and beech wood at temperatures 170, 180, 190, and 212°C for 2 h with ThermoWood method were investigated. The results were compared with industrially kiln‐dried reference samples. The results show that heat treatment caused an important reduction on thermal conductivity of wood, the extend of which is depend upon temperature and wood species. Considering all heat treating temperatures, generally by increasing heat treatment temperature the thermal conductivity of wood decreased. The effect of heat treating temperature on thermal conductivity was identical for fir and beech wood. The highest decrease in thermal conductivity occurred at 212°C for both wood species. When compared with untreated wood, the decreases in thermal conductivity at 170°C, and 212°C for fir and beech wood were 2%, 9 and 2%, 16% respectively. Depending on heat treatment temperature, the decrease found out beech in high temperature is higher than that of fir. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011