bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipases improve the grafting of poly(ethylene terephthalate) fabrics with acrylic acid
Authors: Dadashian F. , Montazer M. , Ferdowsi S. 
Published: December 2009

AbstractIn this study, poly(ethylene terephthalate) (PET) fabrics were modified with two types of commercial lipases, namely, Lipex and Lipolase, and grafted with acrylic acid (AA) to improve their absorption properties. The effects of the enzyme concentration, reaction temperature, time, and pH on the grafting of AA onto PET were investigated. The pretreatment of PET with lipases increased the amount of AA that was introduced to the PET fibers, whereas AA grafting onto the untreated PET fabrics led to lower graft yields. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the AA‐grafted pretreated polyester fabrics. A new band appearing at 1546 cm−1 in the Fourier transform infrared spectrum implied that AA was introduced onto the PET fabrics. The surfaces of the fabric fibers presented in scanning electron microscopy micrographs clearly indicated the formation of a layer of grafted poly (acrylic acid). The results show that the density of surface grafting was improved by the lipase pretreatment. The increase in grafting was higher for Lipex than for Lipolase. The highest graft yield was obtained with 1% Lipex and Lipolase for 30 min at pH values of 7 and 5, respectively. There were no significant changes in the tenacity or weight reduction of the fabrics. The moisture content of the samples increased linearly with increasing graft yield. This was higher for the pretreated fabrics grafted with Lipex. A higher color strength was obtained for grafted PET samples that were pretreated with Lipex when they were dyed in alkaline aqueous solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ethylene–propylene–diene terpolymer/silica compound modification with organosilane [bis(triethoxysilylpropyl)disulfide] and improved processability and mechanical properties
Authors: Kim Kwang‐Jea 
Published: December 2009

AbstractBifunctional silane [bis(triethoxysilylpropyl)disulfide (TESPD)] was added to a silica‐containing ethylene–propylene–diene terpolymer mold compound, and its effects with respect to the vulcanization properties, processability, and physical properties were investigated. The addition of TESPD caused reduced heat generation during mixing, low minimum torque, low drop temperature, and low extrusion pressure buildup in the extruder. It also caused a high vulcanization torque, high torque rise, high torque maximum, and high elongational modulus. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Deposition of silicon oxide hard coatings by low‐temperature radio‐frequency plasmas
Authors: Huang Chun , Yu Qingsong 
Published: December 2009

AbstractIn this study, the deposition of silicon oxide (SiOx) hard coatings on polycarbonate (PC) substrates was attempted with low‐temperature radio‐frequency (RF) plasmas from tetramethyldisiloxane (TMDSO) with the addition of oxygen. The coating uniformity and deposition rate were investigated in terms of substrate size, glow uniformity, and RF power input. The hardness of the resulting SiOx plasma coatings was examined by the ASTM pencil hardness test method. The hardness of the resulting SiOx plasma coatings was mainly determined by the TMDSO–O2 ratio in the plasma gas mixture. Ultraviolet–visible transmission spectra showed that these plasma coatings were transparent in the visible light region. Fourier transform infrared–attenuated total reflection analysis results indicated that the resulting SiOx plasma coatings were inorganic in nature. The interfacial adhesion, which is a common problem in the deposition of hard protective coatings on polymeric substrates, was also significantly improved by the deposition of an ultrathin plasma polymer interlayer from TMDSO before the deposition of the SiOx plasma coatings on the PC substrates. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(9‐vinylcarbazole)/silver composite nanotubes and networks formed at the air–water interface
Authors: Wang Chang‐Wei , Xin Guo‐Qing , Lee Yong‐Ill , Hao Jingcheng , Jiang Jianzhuang , Liu Hong‐Guo 
Published: December 2009

AbstractSilver‐nanoparticle‐doped poly(9‐vinylcarbazole) (PVK) nanocomposites were prepared via the reduction of Ag+ ions and the self‐assembly of PVK on AgNO3 aqueous solution surfaces. The formed composite nanostructures depended strongly on the experimental temperature. Thick round disks of PVK surrounded by discrete Ag nanoparticles and/or with irregular holes formed at room temperature; nanotubes and micronetworks doped with Ag nanoparticles formed at about 30–40°C, and networks formed at higher temperature. Further investigation revealed that the nanotubes were transformed from thin round disks. The length of the PVK/Ag composite nanotubes were longer than 10 μm, and the average size of the embedded Ag nanoparticles was found to be about 3.5 nm. The composite networks were composed of round pores with diameters of several hundred nanometers and fine silver nanoparticles embedded in the thin polymer films that covered the pores. The formation of the nanotubes was a very interesting self‐assembly phenomenon of the polymer at the air–water interface that has not been reported before. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fabrication and characterization of TiO2/poly(dimethyl siloxane) composite fibers with thermal and mechanical stability
Authors: Kim Young Bum , Cho Donghwan , Park Won Ho 
Published: December 2009

AbstractThe mechanical stability of titania (TiO2) nanofibers was improved by fabricating TiO2/poly(dimethyl siloxane) (PDMS) composite fibers using a combination of hybrid electrospinning and sol‐gel methods, followed by heat treatment at 250°C for 3 h. The compositions (90/10, 80/20, and 70/30, w/w) of the TiO2/PDMS composite fibers were varied by adjusting the flow rate of the PDMS sol with the flow rate of TiO2 sol fixed. There was no significant change in morphology and average diameter of the as‐spun TiO2/PDMS fibers after heat treatment. Both the tensile strength and modulus of the TiO2/PDMS composite fibers increased gradually with increasing PDMS content up to 30 wt %. In addition, from the photo‐degradation reaction of methylene blue, the photocatalytic activity of TiO2/PDMS composite fibers was strongly dependent on the TiO2 content (%) in the composite fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Rigid‐rod polybenzoxazoles containing perylene bisimide: Synthesis, structures and photophysical properties
Authors: Xu Xiao‐Hui , Liu Xiao‐Yun , Zhuang Qi‐Xin , Han Zhe‐Wen 
Published: December 2009

AbstractA novel perylene bisimide dye bearing carboxylphenylene substituents on the imide N atoms was synthesized and four conjugated copolymers containing different contents of perylene bisimide dye were synthesized via PPA/P2O5 copolymerization method. The structures of the four copolymers were characterized by FTIR, elementary analysis, 1H‐NMR and XRD. The copolymers showed good thermal stabilities but poor solubilities due to the high rigidity of the backbone. The photophysical characteristics of the copolymers were investigated by UV‐Vis and PL spectra in solutions and films. Because of the conformational change of perylene bisimide chromophore, the absorptions of perylene bisimide core in copolymers showed a large blue‐shift (56 nm) compared to that of the perylene monomer. In PL experiments, when exciting the benzoxazole, an obvious fluorescent quenching was observed in all copolymers, which can be attributed to the energy transfer from benzoxazole units to perylene bisimide fragments and fluorescence quenching. With increasing perylene content, the copolymers turned to layered and friable. The XRD test showed that the interchain distances increased slightly with increasing perylene content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Viscosity effects in the photopolymerization of two‐monomer systems
Authors: Marcinkowska Agnieszka , Andrzejewska Ewa 
Published: December 2009

AbstractPhotopolymerization kinetics and viscosity behavior of five different two‐monomer systems forming hydrogen bonds and composed of mixtures of a high viscosity monomer (HVM) and a low viscosity monomer (LVM) at various molar ratios were investigated at six polymerization temperatures. The monomers used were mono‐ or dimethacrylates. Detailed viscosity measurements of the monomer mixtures showed significant negative deviations from the theoretical values (characterized by excess logarithm viscosities) indicating that interactions between the molecules of the same type (in individual monomers) are stronger than those between two molecules of different types (HVM and LVM). The photopolymerization kinetics were analyzed from the point of view of the appearance, viscosity and temperature behavior of the most reactive composition (MRC), the one showing the highest value of the maximum polymerization rate within a range of the HVM: LVM ratios. It was found that MRC appearance is determined mainly by the initial viscosity of the two‐monomer system, whereas the functionality of the monomers (and network formation) is much less important (MRC is observed even in linear systems). The initial viscosity of all the monomer mixtures showing MRC lay in the range of 0.06–2 Pa s, which is narrow compared to the range of viscosities of the monomers (approximately 10−3–103 Pa s). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of regenerated Antheraea yamamai silk fibroin film and controlled‐molecular conformation changes by aqueous ethanol treatment
Authors: Zheng Zhonghou , Wei Yanqiong , Yan Shuqin , Li Mingzhong 
Published: December 2009

AbstractThe methods of dissolving Antheraea yamamai (A. yamamai) silk fibroin fibers and preparing the regenerated silk fibroin were studied. The molecular conformations of A. yamamai silk fibroin film treated by different concentration ethanol solution were investigated by XRD, FTIR, and Raman spectra. The results indicated that A. yamamai silk fibroin fibers could be completely dissolved in dense lithium thiocyanate solution at about 35°C for 1 h. The initial regenerated film consisted of α‐helix and random coil components. The aqueous ethanol treatment of the film resulted in significant increase in β‐sheet component and improvement of water resistance of the film. This effect was strongly dependent on ethanol concentration, and 60–80% (w/w) ethanol was most effective. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Imidazolium salts as liquid coupling agents for the preparation of polypropylene‐silica composites
Authors: Donato Ricardo K. , Benvegnú Moisés A. , Furlan Luciano G. , Mauler Raquel S. , Schrekker Henri S. 
Published: December 2009

AbstractThis article describes the application of ionic liquid 1‐decyl‐3‐methylimidazolium tetrafluoroborate in the preparation of polypropylene‐silica composites. The sol‐gel technology was used to prepare xerogel silica‐ionic liquid hybrid S1, which was obtained as a free flowing powder of aggregated spherical particles. Ionic liquid free silica S2 was obtained by extraction and calcination of S1. Melt blending of isotactic polypropylene with S1 and S2 afforded the composites C1 (with ionic liquid) and C2 (without ionic liquid), respectively. The presence of ionic liquid on the S1 silica surface promoted significantly improved silica dispersion in the polymer matrix and prevented compression of the silica particles. Furthermore, the crystallization temperature of composite C1 was significantly higher, which indicated that silica‐ionic liquid filler S1 acted as nucleating agent. The resistance to thermal decomposition of both composites was increased, but this was higher in the presence of ionic liquid. These results show that liquid salts can function as coupling agents and compatibalizers for the preparation of polymeric composites with differentiated properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Rapid and efficient removal of heavy metal ions from aqueous media using cysteine‐modified polymer nanowires
Authors: Tolani Sagar , Mugweru Amos , Craig Michael , Wanekaya Adam K. 
Published: December 2009

AbstractWe report the development of a novel, simple, and highly effective polymeric material with nanoscale dimensions for use in removal of heavy metal ions from aqueous media. The nanomaterial was ∼ 200 nm in diameter and several microns long and was fabricated in the form of nanowires via template‐directed electrochemical polymerization. The nanowires were covalently modified by cysteine, a nonessential amino acid with very high binding constants for selected toxic heavy metal ions, such as, As3+, Cd2+, Pb2+, and Cu2+. We demonstrated rapid and efficient removal of As3+, Cd2+, Pb2+, and Cu2+ ions from natural water samples. The arsenic removal capacity was found to be ∼ 160 mg As3+ per gram of the material, a substantially greater removal capacity than other materials reported to date. The removal capacity of other heavy metals ions was also rapid and effective, their concentrations becoming undetectable in a matter of minutes after treatment with the nanowires. These nanowires have demonstrated potential that could lead to a low cost, novel, and highly effective technique for use in treatment of drinking water and for other environmental remediation purposes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of polymer–nanoclay conductive nanocomposites
Authors: Ahmad Irfan , Hussain Manwar , Seo Keum‐Suk , Choa Yong‐Ho 
Published: December 2009

AbstractPolymer–clay nanocomposites based on poly(3,4‐ethylenedioxythiophene)/polystyrene sulfonate (PEDOT) : PSS and nanoclay montmorillonite were synthesized and characterized. The doping of PEDOT with polystyrene sulfonate made it water dispersible (PEDOT–PSS). Sodium dodecyl benzene sulfonate (SDBS) and ionic liquid were used to increase the interlayer spacing and the conductivity of the nanocomposites, respectively. The nanocomposite was characterized by various techniques, such as X‐ray diffraction (XRD), TEM, surface resistivity, and thermogravimetric measurement analysis. Interlayer spacing increased as a result of the addition of SDBS, and this was confirmed by the 2θ shift observed via XRD analysis. The surface morphology of the conductive coated clay was examined by TEM analysis. Good electrical surface conductivity, interlayer spacing, and polymer coating were observed for the material prepared using the surfactant and conductive ionic liquid. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
In‐process ultrasonic measurements of orientation and disorientation relaxation of high‐density polyethylene/polyamide‐6 composites with compatibilizer
Authors: Lin Congmei , Sun Huimin , Wang Shan , Huang Jian , Li Jiang , Guo Shaoyun 
Published: December 2009

AbstractThe relaxation processes of orientation and disorientation of melts of high‐density polyethylene (HDPE) and polyamide‐6 (PA6) blends compatibilized with a compatibilizer precursor (CP) of HDPE‐grafted maleic anhydride (HDPE‐g‐MAH) were investigated in a restricted channel using real‐time ultrasonic technique. The experimental results showed that the evolution of ultrasonic velocity of HDPE/PA6 blends during the orientation or disorientation processes could be described by the exponential equation from which the maximum orientation degree and relaxation time could be obtained. Subsequently, the effects of CP on the relaxation processes of orientation and disorientation were studied. In addition, the relations of the CP content and the morphology and viscosity were investigated by scanning electron microscope analysis and rheological tests. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Emulsion polymerization of isoprene. Estimation of the branching exponent with the help of a mathematical model
Authors: Minari Roque J. , Rodriguez Virginia I. , Estenoz Diana A. , Vega Jorge R. , Meira Gregorio R. , Gugliotta Luis M. 
Published: December 2009

AbstractThis work investigates a batch and unseeded emulsion polymerization of isoprene at 10°C with n‐dodecylmercaptan as chain transfer agent (CTA). The obtained polyisoprene (PI) was analyzed by size exclusion chromatography (SEC) with on‐line viscometry. A global polymerization model was adjusted to the measurements of conversion, average particle size, and average molecular weights. The CTA concentration strongly affects the average molecular weights but has a negligible effect on conversion, average particle diameter, and average branching. Due to the combined effects of chain transfers to the polymer and to the CTA, the final molar mass distributions exhibited dispersity indexes higher than 10. The polymerization model predictions on the average degree of branching was combined with an ideal SEC model for adjusting the branching exponent of PI in tetrahydrofuran at 25°C that resulted ε = 2.5. A sensitivity analysis showed that +20% errors in $\overline{M}$w induced variations in ε lower than −10%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Sustained release of tetracycline from polymeric periodontal inserts prepared by extrusion
Authors: Obaidat Aiman A. , Hammad Mohammad M. 
Published: December 2009

AbstractThe specific aim of this study was to prepare polymeric inserts containing tetracycline that are intended for intraperiodontal pocket application. The inserts were prepared by a simple extrusion method and based on mixtures of polyvinyl alcohol, glyceryl behenate, xanthan gum, carrageenan, hydroxypropyl methylcellulose, and hyaluronic acid in addition to tetracycline HCL. The inserts were characterized regarding average weight, diameter, water content, and average tetracycline content. Zero‐order release kinetics of tetracycline were observed in case of three of the four batches of the prepared inserts with release profiles that were essentially similar. The release of the drug was incomplete in all cases. This was due, as shown by the equilibrium dialysis tests, to tetracycline binding by the polymers. However, the inserts performed more than 7 days drug sustained release which indicates promising results for local delivery of tetracycline for treatment of periodontal disease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effect of process parameters on the size and morphology of poly(D,L‐lactide‐co‐glycolide) micro/nanoparticles prepared by an oil in oil emulsion/solvent evaporation technique
Authors: Mahdavi Hamid , Mirzadeh Hamid , Hamishehkar Hamed , Jamshidi Ahmad , Fakhari Amir , Emami Jaber , Najafabadi Abdolhossien Rouholamini , Gilani Kambiz , Minaiyan Mohsen , Najafi Mahnaz , Tajarod Maryam , Nokhodchi Ali 
Published: December 2009

AbstractFor the past few decades, there has been a considerable research interest in the area of biodegradable polymeric micro‐ and nanoparticles for tissue engineering, regenerative medicine, implants, stents, medical devices, and drug delivery systems. Poly(D,L‐lactide‐co‐glycolide) (PLGA) is well‐known by its safety in biomedical preparations which has been approved for human use by the FDA. The goal of this study was to evaluate the influence of process parameters on size characteristics of PLGA microparticles prepared by oil in oil (o/o) solvent evaporation technique. This method has been introduced as one of the most appropriate methods for hydrophilic agents. Scanning electron microscopy showed that prepared particles were spherical with smooth surface without aggregation. Particle size varied from 570 nm to 29 μm in different experimental conditions. Stirring speed, polymer concentration, impeller type, and dropping size had a significant effect on the particle size. The polydispersity index of particles showed a strong relationship with the surfactant concentration, impeller type, and dropping size. It was concluded that increasing in temperature up to 50°C or changing in dropping rate has a little effect on reducing the size of PLGA particles. The residual solvent content in the final suspension was less than 0.1 ppm that is in appropriate range for biomedical application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Chemical modification of olive pomace by various esters and silane
Authors: Rabouhi Aida , Boukerrou Amar , Kaci Mustapha , Djidjelli Hocine , Martinez‐Vega J. J. 
Published: December 2009

AbstractThe olive pomace was modified chemically to improve the interface between the polymer matrix and the cellulosic fillers. The modification was done using various ester types having the same nature, however, with different chain lengths and one silane. Before the surface treatment, the olive pomace was extracted with acetone to remove contaminants on the surface, using Soxhlet apparatus. The transesterification of olive pomace with the different ester components, i.e., vinyl acetate, vinyl propanoate, and vinyl butanoate, and the condensation reaction with dichlorodimethylsilane was confirmed by Fourier transform infrared (FTIR) analysis. Moreover, the treatment of olive pomace with vinyl acetate improves the thermal stability and the sample records higher onset temperature of degradation as measured by thermogravimetric analysis (TGA). The results obtained indicated also that the reaction between the hydroxyl groups of waste flour and the acetyl, propionyl, pivalyl, and silane groups have occurred. The modified wood flours exhibited a decrease in the hydrophilicity as supported by the lower moisture content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Flexural properties of phenolic resin reinforced with glass powder: Preliminary results
Authors: Ku H. , Trade M. , Nixon R. , Wong P. 
Published: December 2009

AbstractPhenol formaldehyde was filled with glass powder to increase its flexural strength for civil and structural applications by a research centre on composites, University of Southern Queensland (USQ). To reduce costs, the centre wishes to fill in as much glass powder as possible subject to maintaining sufficient strength of the composites in structural applications. This project varies the percentage by weight of the glass powder in the composites from 5 to 30%. The specimens were then subjected to flexural tests. The results show that composite with 17.5% by weight of the glass hollow spheres produces the highest flexural strength and flexural modulus combined with a very good fluidity for casting. The maximum flexural strain was achieved with pure resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
New polymers from plant oil derivatives and styrene‐maleic anhydride copolymers
Authors: Öztürk Cem , Küsefoğlu Selim H. 
Published: December 2009

AbstractIn this study, styrene maleic anhydride copolymer (SMA2000, Styrene : Maleic Anhydride 2 : 1) is grafted and/or crosslinked with epoxidized methyl oleate, epoxidized soybean oil, methyl ricinoleate (MR), castor oil (CO), and soybean oil diglyceride. Base catalyzed epoxy‐anhydride and alcohol‐anhydride polyesters were synthesized by using the anhydride on SMA, the epoxy or secondary alcohol groups on the triglyceride based monomers. The characterizations of the products were done by DMA, TGA, and IR spectroscopy. SMA‐epoxidized soy oil and SMA‐CO polymers are crosslinked rigid infusible polymers. SMA‐epoxidized soy oil and SMA‐CO showed Tg's at 70 and 66°C, respectively. Dynamic moduli of the two polymers were 11.73 and 3.34 Mpa respectively. SMA‐epoxidized methyl oleate, poly[styrene‐co‐(maleic anhydride)]‐graft‐(methyl ricinoleate), and SMA‐soy oil diglyceride polymers were soluble and thermoplastic polymers and were characterized by TGA, GPC, DSC, NMR, and IR spectroscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010