bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of neutron irradiation on the structural, mechanical, and thermal properties of jute fiber
Authors: Sinha E. , Rout S. K. 
Published: July 2008

AbstractThis article describes the effect of neutron irradiation on jute fiber (Corchorus olitorius). The jute fibers (4.0 tex) were irradiated by fast neutrons with an energy of 4.44 MeV at different fluences ranging from 2 × 109 to 2 × 1013 n/cm2. An important aspect of neutron irradiation is that the fast neutrons can produce dense ionization at deep levels in the materials. Structural analysis of the raw and irradiated fibers were studied by small‐angle X‐ray scattering (SAXS), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy. Thermal analysis carried out on the raw and irradiated fibers showed that the thermal stability of the fibers decreased after irradiation. The mechanical properties of the jute fibers were found to decrease after irradiation. The SAXS study showed that the average periodicity transverse to the layer decreased after irradiation, which may have been due to the shrinkage of cellulosic particles constituting the fiber. The residual compressive stress developed in the fiber after irradiation resulted in a decrease in crystallite size as supported by our XRD analysis. Observation with SEM did not indicate any change produced in the surface morphology of the fiber due to irradiation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of poly(N‐vinyl‐2‐pyrrolidone) grafted sodium alginate hydrogel beads for the controlled release of indomethacin
Authors: Işıklan Nuran , İnal Murat , Yiğitoğlu Mustafa 
Published: July 2008

AbstractGraft copolymers of sodium alginate (NaAlg) with N‐vinyl‐2‐pyrrolidone were prepared using azobisisobutyronitrile as initiator. The graft copolymers (NaAlg‐g‐PVP) were characterized with Fourier transform infrared spectroscopy, elemental analysis, and differential scanning calorimetry. Polymeric hydrogel beads of NaAlg and NaAlg‐g‐PVP were prepared by crosslinking method using glutaraldehyde (GA) as a crosslinker in the hydrochloric acid catalyst (HCl) and these beads were used to deliver anti‐inflammatory drug, indomethacin (IM). Chemical stability of the IM after encapsulation into beads was confirmed by FTIR. Preparation conditions of the NaAlg‐g‐PVP beads were optimized by considering the percentage entrapment efficiency, particle size, swelling capacity and their release data. In vitro release studies were performed in simulated gastric fluid (pH 1.2) for the initial 2 h, followed by simulated intestinal fluid (pH 7.4) for 4 h. Effects of GA concentration, exposure time to GA, drug/polymer (d/p) ratio, and concentration of HCl on the release of IM were discussed. It was observed that IM release from the beads decreased with increasing GA concentration and exposure time. IM release also decreases with increasing d/p ratio and HCl concentration. The highest IM release was obtained to be 77% for beads crosslinked with 0.027M GA. Swelling experiments were also performed to compute molecular mass between crosslinks of the beads. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Formation of a bicontinuous structure membrane of polyvinylidene fluoride in diphenyl ketone diluent via thermally induced phase separation
Authors: Yang J. , Li D. W. , Lin Y. K. , Wang X. L. , Tian F. , Wang Z. 
Published: July 2008

AbstractThe polyvinylidene fluoride (PVDF)‐diphenyl ketone (DPK) mixture was studied as a new system to prepare PVDF membranes via thermally induced phase separation (TIPS). The phenomena of liquid–liquid phase separation was found in this mixture when the temperature of mixture was decreasing and the PVDF concentration was less than 30 wt %. Using DPK as diluent, PVDF membrane with bicontinuous structure was obtained without necessity to add a nonsolvent or a stretching process further. The phase diagram of PVDF‐DPK system was also constructed to help investigate the effect of PVDF concentration and coarsening temperature on morphology of resulting membrane. The experiments showed that high coarsening temperatures and low PVDF concentrations resulted in the formation of the large pore size membrane. The strength of the wet membrane was decreasing with decreasing PVDF concentration. On condition that the PVDF concentration was larger than 30 wt %, thermally induced solid–liquid separation occurred and bicontinuous structure disappeared. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Study on radiation‐induced grafting of hydrophilic monomers onto chitosan
Authors: Dergunov Sergey A. , Nam Irina K. , Maimakov Tauzhan P. , Nurkeeva Zauresh S. , Shaikhutdinov Erengaip M. , Mun Grigoriy A. 
Published: July 2008

AbstractThe graft polymerization of 2‐Hydroxyethyl acrylate, 2‐Hydroxyethyl methacrylate, and N‐vinylpyrrolidone onto chitosan in aqueous solution initiated by γ‐ray irradiation was carried out. The effect of various conditions such as the absorbed dose, concentration of monomer, and solvent on grafting was investigated. The grafting yield increased with the increase in absorbed dose. The degree of grafting increased with increase in the radiation dose. The obtained graft copolymers showed the solubility in water in wide pH interval. The interactions between grafted chitosan copolymers with sodium dodecyl sulfate (SDS) were studied in an aqueous solution. It was found that there is a narrow molar ratio of SDS/cation (∼ 0.40–0.70) depending on different grafted copolymers, at which the turbidity of SDS‐grafted chitosan complex has a maximum due to the formation of water insoluble interpolymer aggregates via the SDS attached on the polymer chain. The turbidity falls sharply with the further addition of excessive SDS, which forms micelle in the solution and causes the de‐aggregation of the interpolymer aggregates and also because of the precipitation of complexes and returns to the original level. The morphologic properties of thin films of SDS‐ grafted chitosan complex were investigated. It was observed that upon heating the insoluble complex of SDS and grafted chitosan in water, superstructures were formed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation, characterization, and cellular interactions of collagen‐immobilized PDMS surfaces
Authors: Keranov I. , Vladkova T. , Minchev M. , Kostadinova A. , Altankov G. 
Published: July 2008

AbstractMultistep procedure to biofunctionalization of (poly)dimethylsiloxane (PDMS) surfaces is present here, including plasma‐based Ar+ beam treatment; acrylic acid grafting; and flexible PEG spacer coupling prior to the collagen immobilization by peptide synthesis reaction. The success of any step of the surface modification is controlled by XPS analysis, contact angle measurements, SEM, and AFM observations. To evaluate the effect of PEG chain length, three diNH2PEGs (2000, 6000, and 20,000 D) of relative long polymer chain were employed as a spacer, expecting that a long flexible spacer could provide more conformational freedom for the collagen molecules and fibroblast reorganization to further cellular matrix formation. Human fibroblast cells were used as a model to evaluate the biological response of the collagen‐immobilized PDMS surfaces. It is found that the earlier described biofunctionalization is one more road to improvement of the cellular interaction of PDMS, the last one being the best when PEG spacer with moderate chain length, namely of 6000 D, is used. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of novel polyphenol species derived from bis(4‐aminophenyl)ether: Substituent effects on thermal behavior, electrical conductivity, solubility, and optical band gap
Authors: Kaya İsmet , Yıldırım Mehmet 
Published: July 2008

AbstractIn this study, four different Schiff bases namely 4,4′‐oxybis[N‐(2‐hydroxybenzilidene)aniline] (2‐HBA), 4,4′‐oxybis[N‐(4‐hydroxybenzilidene)aniline] (4‐HBA), 4,4′‐oxybis[N‐(3,4‐dihydroxybenzilidene)aniline] (3,4‐HBA), and 4,4′‐oxybis[N‐(4‐hydroxy‐3‐methoxybenzilidene)aniline] (HMBA) were synthesized. These Schiff bases were converted to their polymers that have generate names of poly‐4,4′‐oxybis[N‐(2‐hydroxybenzilidene)aniline] (P‐2‐HBA), poly‐4,4′‐oxybis[N‐(4‐hydroxybenzilidene)aniline] (P‐4‐HBA), poly‐4,4′‐oxybis[N‐(3,4‐dihydroxybenzilidene)aniline] (P‐3,4‐HBA), and poly‐4,4′‐oxybis[N‐(4‐hydroxy‐3‐methoxybenzilidene)aniline] (PHMBA) via oxidative polycondensation reaction by using NaOCl as the oxidant. Four different metal complexes were also synthesized from 2‐HBA and P‐2‐HBA. The structures of the compounds were confirmed by FTIR, UV‐vis, 1H and 13C NMR analyses. According to 1H NMR spectra, the polymerization of the 2‐HBA and 4‐HBA largely maintained with COC coupling, whereas the polymerization of the 3,4‐HBA and HMBA largely maintained with CC coupling. The characterization was made by TG‐DTA, size exclusion chromatography and solubility tests. Also, electrical conductivity of the polymers and the metal complex compounds were measured, showing that the synthesized polymers are semiconductors and their conductivities can be increased highly via doping with iodine ions (except PHMBA). According to UV–vis measurements, the optical band gaps (Eg) were found to be 3.15, 2.06, 3.23, 3.02, 2.61, 2.47, 2.64, 2.42, 2.83, 2.77, 2.78, and 2.78 for 2‐HBA, P‐2‐HBA, 4‐HBA, P‐4‐HBA, 3,4‐HBA, P‐3,4‐HBA, HMBA, PHMBA, 2‐HBA‐Cu, 2‐HBA‐Co, P‐2‐HBA‐Cu, and P‐2‐HBA‐Co, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Biodegradable polymeric micro‐nanofibers by electrospinning of polyester/polyether block copolymers
Authors: Detta N. , El‐Fattah A. A. , Chiellini E. , Walkenström P. , Gatenholm P. 
Published: July 2008

AbstractTwo block copolymers consisting of biodegradable segments of poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL) with slight different lengths of soft hydrophilic segments (PEG) and molecular weight were produced. The copolymer with shorter PEG segments and higher molecular weight was named copolymer A, while the other copolymer B. Both copolymers were dissolved in dichloromethane at the same concentration (5% w/v) and electrospun. Different combinations of spinning voltage (SV) and distance needle to collector were used. Electrospun A copolymer showed curly and uniform fibers with an average diameter of 2 μm, while B copolymer fibers were straight, uneven, and much thinner (submicrometric). In the latter case, fiber bundles and beads were also present. Viscosity measurements on the solutions before spinning showed a viscosity of 13.0 mPa s for A copolymer solution and 5.5 mPa s for B copolymer. The mechanical properties on dog‐bone shaped samples from the electrospun material evidenced that A copolymer had much higher stress and elongation at break but approximately the same elastic modulus as compared to B copolymer. Fiber morphology and mechanical properties of electrospun block copolymers are deeply influenced by different amount and length of soft and hard segments, and block copolymers can be the best suited systems to fit several applications because of the broad range of properties they show upon changing the composition ratio and molecular weight of components. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of surface modification on the dispersion of nanoscale α‐Al2O3 particles in a thermoplastic polyurethane matrix
Authors: Chen Cheng‐Ho , Mao Ching‐Feng , Tsai Ming‐Shyong , Yen Fu‐Su , Lin Jian‐Min , Tseng Ching‐Hui , Chen Heng‐Yi 
Published: July 2008

AbstractIn this study, two types of nanoscale α‐Al2O3 particles were used for preparation of α‐Al2O3/thermoplastic polyurethane (TPU) composites. These α‐Al2O3 particles were either coated or uncoated with stearic acid. For the uncoated α‐Al2O3/TPU composite, the results of field‐emission scanning electron microscopy (FE‐SEM) and energy dispersive X‐ray spectrometry indicate that uncoated α‐Al2O3 particles are significantly aggregated together. This aggregation is due to the poor compatibility between the inorganic filler (α‐Al2O3) and the organic matrix (TPU). The size of clusters is in the range from 5 to 20 μm. For the coated α‐Al2O3/TPU composite, FE‐SEM results indicate that most coated α‐Al2O3 particles are well dispersed in the TPU matrix. This phenomenon results from the effect of surface modifier (i.e., stearic acid) on α‐Al2O3 particles. Stearic acid can act as a compatibilizer to bridge the boundary between the TPU matrix and the α‐Al2O3 particle. Stearic acid is not only a suitable surface modifier for the nanoscale α‐Al2O3 particle, but also a good dispersant for the dispersion of nanoscale α‐Al2O3 particles in the TPU matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Crystallization, orientation morphology, and mechanical properties of biaxially oriented starch/polyvinyl alcohol films
Authors: Wang Jing , Lu Yafei , Yuan Huilin , Dou Peng 
Published: July 2008

AbstractBiaxially oriented starch/polyvinyl alcohol (PVA) films were prepared by stretching starch/PVA blend precursor films that were fabricated by extrusion casting via a twin‐screw extruder. Investigations on crystallization, orientation morphology, and mechanical properties of extrusion cast and stretched starch/PVA films were carried out by using differential scanning calorimetry, scanning electron microscope, wide angle X‐ray diffraction (WAXD), and tensile testing. The fresh extrusion‐cast starch/PVA films, which were almost amorphous, can crystallize spontaneously when aged at room condition. A good compatibility between starch and PVA was obtained by extrusion‐casting technology. The well‐developed molecular orientation, which did not occur along the machine direction during the extruding process, was observed in stretched film samples. Stretching unaged films can induce crystallization and the orientation of crystalline structures during stretching, resulting in the changes in diffraction peaks of WAXD patterns. The effect of stretch ratio and the orientation distribution in the plane of the film on mechanical properties of stretched films was studied, and the equal biaxially oriented films were found to exhibit in‐plane isotropy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Compatibilization of poly(vinyl chloride) and polystyrene blends with poly(styrene‐co‐n‐methylolacrylamide)
Authors: Escobar D. , Mendizabal E. , González‐Núñez R. 
Published: July 2008

AbstractIn this work, the compatibilization of blends of plasticized polyvinyl chloride (PVC) and polystyrene (PS) with poly(styrene‐co‐n‐methylolacrylamide) (PSnMA) was investigated. The PSnMA was synthesized by emulsion polymerization with different amounts of n‐methylolacrylamide (nMA). Particle size and phase behavior was determined by scanning electron microscopy, and mechanical properties were determined in an Universal Testing Machine. Micrographs revealed that an appreciable size reduction of the dispersed phase was achieved when small amounts of PSnMA were added to the blend, and as the amount of nMA was increased, particle size decreased. When the (PVC/PS/PSnMA) blend was subjected to solvent extraction to remove PS and unreacted PVC, the residue showed a single Tg. Tensile modulus and the ultimate strength of the blends increased with PSnMA content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Enhancement of PVC/ENR blend properties by poly(methyl acrylate) grafted oil palm empty fruit bunch fiber
Authors: Raju Gunasunderi , Ratnam Chantara Thevy , Ibrahim Nor Azowa , Rahman Mohammad Zaki Ab. , Yunus Wan Md Zin Wan 
Published: July 2008

AbstractEffect of oil palm empty fruit bunch (OPEFB) fiber and poly(methyl acrylate) grafted OPEFB on several mechanical properties of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blends using HAKEE Rheomixer at the rotor speed of 50 rpm, mixing temperature 150°C, and mixing period of 20 min. The fiber loadings were varied from 0 to 30% and the effect of fiber content in the composites on their ultimate tensile strength (UTS), Young's modulus, elongation at break, flexural modulus, hardness, and impact strength were determined. An increasing trend was observed in the Young's modulus, flexural modulus, and hardness with the addition of grafted and ungrafted fiber to the PVC/ENR blends. However the impact strength, UTS, and elongation at break of the composites were found to decrease with the increase in fiber loading. An increase in elongation at break and UTS and decrease in the flexural and Young's modulus was observed with the addition of PMA‐g‐OPEFB fiber compared to ungrafted fiber. This observation indicates that grafting of PMA onto OPEFB impart some flexibility to the blend. The morphology of cryogenically fractured and tensile fracture surfaces of the composites, examined by a scanning electron microscope shows that the adhesion between the fiber and the matrix is improved upon grafting of the OPEFB fiber. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
In situ development of Zn/Cd‐incorporated poly(esteramide‐urethane) from sustainable resource
Authors: Zafar Fahmina , Ashraf S. M. , Ahmad Sharif 
Published: July 2008

AbstractIt was for the first time we attempted to develop zinc and cadmium incorporated linseed oil based poly(esteramide‐urethane) [Zn/Cd‐LPEAUr], and investigated their structure, mechanism, and properties. The resin was synthesized in situ by the reaction of linseed oil derived fatty amide diol [HELA], divalent zinc/cadmium acetate and toluylene‐2, 4 (6), diisocyanate [TDI; 2–12 wt %] with minimal solvent. The structural elucidation of Zn/Cd‐LPEAUr was carried out by FTIR, 1H‐NMR, and 13C‐NMR spectral techniques. TGA and DSC techniques were used to measure the thermal stability and curing behavior of these resins, respectively. The physicomechanical and chemical/corrosion resistance properties were investigated by standard laboratory methods. The performance of Zn/Cd‐LPEAUr coating was compared with reported oil based polyesteramide. Antibacterial test of the resins were performed by agar diffusion method against E. coli and S. aureus, and compared with those of petroleum‐based metal containing polyurethanes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
LiClO4 doped cellulose acetate as biodegradable polymer electrolyte for supercapacitors
Authors: Selvakumar M. , Bhat D. Krishna 
Published: July 2008

AbstractThe possibility of producing a biodegradable polymer electrolyte based on cellulose acetate (CA) with varied concentration of LiClO4 for use in supercapacitors has been investigated. The successful doping of the CA films has been analyzed by FTIR and DSC measurements of the LiClO4 doped CA films. The ionic conductivity of the films increased with increase in salt content and the maximum ionic conductivity obtained for the solid polymer electrolyte at room temperature was 4.9 × 10−3 Ω−1 for CA with 16% LiClO4. The biodegradation of the solid polymer electrolyte films have been tested by soil burial, degradation in activated sludge, and degradation in buffer medium methods. The extent of biodegradation in the films has been measured by AC Impedance spectroscopy and weight loss calculations. The study indicated sufficient biodegradability of the materials. A p/p polypyrrole supercapacitor has been fabricated and its electrochemical characteristics and performance have been studied. The supercapacitor showed a fairly good specific capacitance of 90 F g−1 and a time constant of 1 s. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Electrospun self‐assembled nanofiber yarns
Authors: Mondal Abhijit , Borah Ritutapan , Mukherjee Avishek , Basu Sandip , Jassal Manjeet , Agrawal Ashwini K. 
Published: July 2008

AbstractA technique for making self‐assembled electrospun (E‐spun) nanofiber yarns from poly(acrylonitrile) in a single step is described. The process involved formation of the nanofiber yarn directly within the electrospinning zone and its removal before it can reach the counter‐electrode. The yarn is presumably formed due to splitting of the main jet into numerous nanojets and their reassembly into a single entity midway between the two electrodes. The process was found to occur at a particular field strength, which varied considerably with the concentration of the polymer dope. The gross morphology of yarns and the alignment of nanofibers in the yarn were evaluated by scanning electron microscopy (SEM). The rationale behind the formation of the yarn like structure has been explained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Polypropylene/clay nanocomposites prepared by in situ grafting‐melt intercalation with a novel cointercalating monomer
Authors: Song Pingan , Tong Lifang , Fang Zhengping 
Published: July 2008

AbstractPolypropylene (PP)/clay nanocomposites were prepared by melt‐compounding PP with organomontmorillonite (OMT), using maleic anhydride grafted polypropylene (PP‐g‐MA) as the primary compatibilizer and N‐imidazol‐O‐(bicyclo pentaerythritol phosphate)‐O‐(ethyl methacrylate) phosphate (PEBI) as the cointercalating monomer. X‐ray diffraction patterns indicated that the larger interlayer spacing of OMT in PP was obtained due to the cointercalation monomer having a large steric volume and the d‐spacing further increased with the addition of PP‐g‐MA, as evidenced by transmission electron microscopy. Thermogravimetric analysis revealed that the PEBI‐containing PP nanocomposites exhibited better thermal stability than PEBI‐free PP composites. Dynamic mechanical analysis demonstrated that the storage modulus was significantly enhanced, and the glass transition temperature (Tg) shifted slightly to low temperature with the incorporation of clay for PP/OMT hybrids. PEBI‐containing PP/OMT composites gave a lower Tg value because of the strong internal plasticization effect of PEBI in the system. Cone calorimetry showed that the flame‐retardancy properties of PP nanocomposites were highly improved with the incorporation of PEBI. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of composites of polyethylene with polypyrrole‐coated wollastonite
Authors: Ong Chu Kuen , Ray Sudip , Cooney Ralph P. , Edmonds Neil R. , Easteal Allan J. 
Published: July 2008

AbstractComposite sheets of polyethylene and polypyrrole‐coated wollastonite were prepared by extrusion and compression molding. Four compatibilizers were also evaluated, poly(ethylene‐co‐methyl acrylate) (EMA), maleated polyethylene (MAPE), poly(ethylene‐co‐vinyl alcohol) (EVOH), and poly(vinyl alcohol) (PVOH). The composite materials were characterized using X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy (SEM), Raman spectroscopy, and mechanical properties determined by tensile tests. SEM micrographs showed that significantly improved interactions occurred between the PE matrix and polypyrrole‐coated wollastonite particles in the presence of EMA, MAPE, and EVOH. Raman spectroscopy confirmed that the polypyrrole coating on the wollastonite particles was not thermally degraded during melt processing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008