bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas permeation related to the moisture sorption in films of glassy hydrophilic polymers
Authors: Laksmana F.L. , Kok P.J.A. Hartman , Frijlink H.W. , Vromans H. , Van Der Voort Maarschalk K. 
Published: February 2010

AbstractThe purpose of this article is to elucidate the effect of integral sorption of moisture on gas permeation in glassy hydrophilic polymers. The oxygen and the simultaneous moisture sorption into various hydroxypropyl methylcellulose (HPMC) films were measured under a wide range of relative humidities using sorption analyzer equipment. Correspondingly, the oxygen permeability at different ambient conditions was measured using an oxygen detector. The solubility of oxygen in the HPMC film was found to be affected by the amount of water and therefore by the water state. At low moisture content, the water molecules are present as bound water, which promotes the sorption of oxygen in the HPMC films. At moisture content higher than 5%, water clusters are rapidly formed, which increase the affinity of HPMC polymer towards water rather than towards oxygen molecules, resulting in a decrease of oxygen solubility in the polymer. This was found to be the governing factor for the reduction in the oxygen permeability in glassy HPMC films at high water activity. This proposes a specific interaction between moisture sorption and oxygen transport in coating films like HPMC, which is of important aspect in the coating design and formulation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of stoichiometric imbalances on the melt condensation polymerization of poly(dodecamethylene terephthalamide) studied by intrinsic viscosity and 13C‐NMR
Authors: Novitsky Theodore , Lange Christopher , Jarrett William , Mathias Lon , Osborn Scott , Ayotte Roger , Manning Steve 
Published: February 2010

AbstractPoly(dodecamethylene terephthalamide) (PA‐12,T) was synthesized by melt condensation polymerization of 12,T salt with 0, 1, 3, 5, or 10% molar excess of 1,12‐diaminododecane (DA), terephthalic acid (TA), or benzoic acid (BA). Intrinsic viscosities (IV) (0.5 g/dL in 96% H2SO4 at 25°C) were measured to determine relative molecular weight differences. IV was highest for reactions containing 1 and 3 mol % excess DA (1.36 and 1.31 dL/g, respectively), followed by the product of pure 1 : 1 salt (1.25 dL/g). For all concentrations of excess TA and BA, IV was decreased. 13C‐NMR chemical shifts for DA, TA, and BA end groups were identified and their concentrations determined by comparison with the intensity of main chain polymer peaks. A log–log plot of IV versus number average molecular weight calculated from 13C‐NMR data shows a linear trend with Mark‐Houwink constants of K = 55.8 × 10−5 dL/g and α = 0.81. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Comprehensive study of metal on the characteristic properties of epoxy resins
Authors: Mohan Pragyan 
Published: February 2010

AbstractA series of different type of epoxy resins containing metal(s) have been prepared by the using cobalt acrylate (CoA2), nickel acrylate(NiA2),bismuth acrylate (BiA3) during resinification. The values of epoxide equivalent weight, chlorine content increases whereas hydroxyl content, refractive index decreases in the presence of metal acrylate(s). The influence of complex formation of metal acrylate with ether linkage of epoxy resins were investigated by spectroscopy. Epoxy resins containing cobalt acrylate which was cured by p‐acetylbenzilidinetriphenylarsoniumylide (p‐ABTAY) shows better conducting properties in comparison to NiA2 and BiA3 containing epoxy resins. The dispersion of metal(s) in epoxy resins matrix was confirmed by scanning electron microscope (SEM). The glass transition temperature of epoxy resins containing CoA2 is lower than that of blank epoxy resins and epoxy resins containing bismuth and nickel acrylate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Modification of polypropylene composites containing potassium titanate whisker and talcum
Authors: Mao Shuangming , Wang Jikui , Qiu Chunchang , Guo Weihong , Wang Yaoxian 
Published: February 2010

AbstractModified polypropylene was prepared by blending with potassium titanate whisker (PTW) and 10 w/w% talc via Haake extruder followed by injection molding. Reinforced with both PTW and talc, the PP composites exhibited better mechanical properties. The tensile modulus and flexural modulus of PP composites tend to increase with the increasing of whisker concentrations. The talc plays a synergistic role in improving the mechanical properties of composites and reducing cost. Torque measurement shows the PP composites has a good processing condition due to lubrication of PTW. TGA test shows PP composites containing 20 w/w% PTW and 10 w/w% talc is useful for improving PP composite's thermo oxidative stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Palladium and platinum sorption on a thiocarbamoyl‐derivative of chitosan
Authors: Butewicz A. , Gavilan K. Campos , Pestov A. V. , Yatluk Y. , Trochimczuk A. W. , Guibal E. 
Published: February 2010

AbstractImmobilizing thiourea onto chitosan allowed using the polymer for the recovery of platinum groups metals (PGMs) in acidic solutions (up to 1–2M HCl concentrations). At low HCl concentration protonated amine groups may sorb chloroanionic metal species (electrostatic attraction mechanism); however, most of sorption proceeds through chelation on sulfur containing groups (less sensitive to acidic conditions). The bi‐site Langmuir equation was used for fitting sorption isotherms. The sorption of PGMs was weakly affected by the composition of the solution (presence of high concentration of anions and base metals). Maximum sorption capacities for Pd(II) and Pt(IV) ranged between 274 and 330 mg g−1 in 0.25M HCl solutions and decreased to 150–198 mg g−1 in 2M HCl solutions: Pd(II) sorption was systematically higher than Pt(IV) sorption. The pseudo‐second rate equation was used for modeling the uptake kinetics. Agitation speed hardly affected uptake kinetics indicating that external diffusion resistance is not the rate controlling step. Desorption yield higher than 85% were obtained using thiourea in 0.1M HCl solution. The adsorbents could be reused for at least three cycles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Semitransparent chitosan‐TiO2 nanotubes composite film for food package applications
Authors: Díaz‐Visurraga J. , Meléndrez M.F. , García A. , Paulraj M. , Cárdenas G. 
Published: February 2010

AbstractSemitransparent composite films were prepared made from TiO2 nanotubes in chitosan (CS) matrix. Hydrothermally synthesized titanium nanotubes (TiNTs) were dispersed in chitosan matrix in order to produce film‐forming solutions at 0.05 and 0.10% w/v. Structural, topological, optical and thermal properties of these films were evaluated. The antimicrobial activity of films against Salmonella
enterica serovar Typhimurium, Escherichia coli (Gram‐negatives) and Staphylococcus aureus (Gram‐positive) was also investigated. Fourier transform infrared (FTIR) spectra showed effective site‐selective interactions between chitosan and TiNTs. TiNTs prevented the degradation of films, avoiding the oxidization of the glucosamine ring. Characterizing techniques such as, Scanning electron microscopy–energy dispersive spectroscopy (SEM‐EDS) line profile and atomic force microscopy (AFM) were used to examine the TiNTs dispersion within the film. The morphological analysis indicated that the TiNTs were well dispersed and became clustered proportionally to the weight percentage of TiNTs used in the composites. The UV‐Vis spectra showed that TiNTs increased the film absorption in the UV region and the light barrier properties of films remained stable over the storage period. Photoacoustic spectroscopy (PAS) was used to study these films, nondestructively for their thermal effusivity (e). The films were effective in reducing the microbial concentration in the liquid culture for all bacteria tested. The effectiveness was found to dependent on the bacterial strain and TiNTs content. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Mechanical and morphological properties for sandwich composites of wood/PVC and glass fiber/PVC layers
Authors: Mongkollapkit Narudol , Kositchaiyong Apisit , Rosarpitak Vichai , Sombatsompop Narongrit 
Published: February 2010

AbstractThis work manufactured sandwich composites from glass fiber/poly(vinyl chloride) (GF/PVC) and wood/PVC layers, and their mechanical and morphological properties of the composites in three GF orientation angles were assessed. The effects of K value (or viscosity index) of PVC and Dioctyl phthalate (DOP) loading were of our interests. The GF/PVC was used as core layer whereas wood/PVC was the cover layers. The experimental results indicated that PVC with low K value was recommended for the GF/PVC core layer for fabrication of GF/WPVC sandwich composites. The improvement of PVC diffusion at the interface between the GF and the PVC core layer was obtained when using PVC with K value of 58. This was because it could prevent de‐lamination between composite layers which would lead to higher mechanical properties of the sandwich composites, except for the tensile modulus. The sandwich composites with 0° GF orientation possessed relatively much higher mechanical properties as compared with those with 45° and 90° GF orientations, especially for the impact strength. Low mechanical properties of the sandwich composites with 45° and 90° GF orientation angles could be overcome by incorporation of DOP plasticizer into the GF/PVC core layer with the recommended DOP loadings of 5–10 parts per hundred by weight of PVC components. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of nanoTiO2 addition on poly(methyl methacrylate): An exciting nanocomposite
Authors: Chatterjee Amit 
Published: February 2010

AbstractA systematic research has been conducted to investigate the matrix properties by introducing nanosize TiO2 (5 nm, 2.0–30% by weight) filler into a poly (methyl methacrylate) (PMMA) resin. A twin screw extraction process was developed to disperse the particles into the PMMA. The thermal, mechanical, and viscoelastic properties of the virgin PMMA and nanoTiO2‐PMMA composite were measured. The nanofiller infusion improves the thermal, mechanical and viscoelastic properties of the PMMA. Nanocomposite shows increase in storage modulus (∼ 60%), rubbery modulus (∼ 210%), glass transition temperature (∼ 27%), crosslink density (∼ 213%), initial decomposition temperature (∼ 83% at 1% wt. loss), and activation energy (∼ 141%). Mechanical performance and thermal stability of the nanoTiO2‐PMMA composites are depending on the dispersion state of the TiO2 in the PMMA matrix. Scanning electron microscopic study shows that the particles are well dispersed in the PMMA matrix. They are correlated with loading. Kinetics for thermal degradation analysis was studies. The integral procedural decomposition temperature (IPDT) is enhanced (∼ 117%). The nanocomposites of high activation energy possess high thermal stability. Interrelation of Tg, crosslink density, IPDT, storage modulus, activation energy, and TiO2 weight percent are established. Various reasons for these effects in terms of reinforcing mechanisms have been discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A novel thermoviscosifying water‐soluble polymer: Synthesis and aqueous solution properties
Authors: Wang Yu , Feng Yujun , Wang Biqing , Lu Zhiyong 
Published: February 2010

AbstractA novel thermoviscosifying water‐soluble polymer was synthesized by direct free radical copolymerization of acrylamide with a newly‐prepared macromonomer, and its aqueous solution viscosity behavior at different temperatures was preliminarily examined in both pure water and KCl brine in comparison with its homopolyacrylamide counterpart. Thermoviscosifying ability of the copolymer was clearly evidenced in both aqueous media, and the thermoassociative temperature of the copolymer decreased upon increasing KCl content in polymer solution. Under the same conditions, homopolyacrylamide shows only thermothinning behavior and viscosity loss in both pure water and KCl solution. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Kinetic analysis of solid‐state photodimerization reaction of photosensitive monomers and a polymer with cinnamoyl moieties
Authors: Jiao Yang , Guo Jinbao , Dong Xiaoming , Li Rui , Wei Jie 
Published: February 2010

AbstractThis work focused on the different kinetic behaviors in photodimerization between a low‐molecular‐weight molecule and a macromolecule, and the relationship between photodimerization and photo free radical polymerization. We have synthesized two monomers, one (M1) containing a cinnamoyl moiety and another (M2) containing both a cinnamoyl moiety and an acrylate moiety. Their chemical structures were confirmed by FTIR and 1H‐NMR spectral analysis. Polymer (P2) was obtained by free radical polymerization of acrylate moieties of M2. Real‐time FTIR (RT‐FTIR) was used to analyze the kinetic effects of photoreaction. The results strongly suggest that cinnamoyl moieties did not undergo free radical polymerization under exposure of ultraviolet (UV) light. Additionally, the photodimerization of M1 and P2 has been confirmed by RT‐FTIR spectra, UV absorption, and transmittance spectra; and photodimerization of M1 was also confirmed by solid‐state NMR spectra. The results show that this photoreaction of M1 is much faster than that of M2 and P2. Wide angle X‐ray diffraction patterns have demonstrated their different molecular arrangements, which may be responsible for the difference in photodimerization reaction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Rheological, mechanical, optical, and transport properties of blown films of polyamide 6/residual monomer/montmorillonite nanocomposites
Authors: Beatrice Cesar A. G. , Branciforti Marcia C. , Alves Rosa M. V. , Bretas Rosario E. S. 
Published: February 2010

AbstractExfoliated nanocomposites of polyamide 6 (PA6) with residual monomer and an organically treated montmorillonite (3 and 5 wt %) were produced by twin‐screw extrusion. The composites had their steady state, dynamic, and transient rheological properties measured by parallel‐plates rheometry; their exfoliation level was characterized by wide angle X‐rays diffraction (WAXD) and transmission electron microscopy (TEM). The characterization showed as follows: (i) the nanoclay's lamellas were well dispersed and distributed thru the PA6, (ii) the postpolymerization of the residual monomer produced more branched chains than linear ones in the pure PA6, (iii) the nanoclay's lamellas acted as entanglement points in the nanocomposites, and (iv) the molecular weight of the PA6 in the nanocomposites decreased. Blown films of the nanocomposites were produced by single screw extrusion; the die pressure during the film blowing of the nanocomposites strongly decreased. The tensile mechanical properties of the blown films were also measured. Along the machine direction (MD), the best mechanical properties were obtained with the 5 wt % nanocomposite, whereas along the transverse direction (TD), the 3 wt % nanocomposite had the best behavior. The glass transition temperature (Tg) of the blown films was measured by dynamic mechanical thermal analyses (DMTA). The 5 wt % nanocomposite had the highest Tg of all the films. The optical properties were measured by spectrophotometry; the nanoclay decreased the films' haze, but the level of transmittance was not affected. The water vapor and oxygen permeability rates of the nanocomposites films were found to be lower than in the pure PA6 blown film as a result of a tortuosity effect. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Flocculation by cationic polyelectrolytes: Relating efficiency with polyelectrolyte characteristics
Authors: Rasteiro M. G. , Garcia F. A. P. , Ferreira P. J. , Antunes E. , Hunkeler D. , Wandrey C. 
Published: February 2010

AbstractA series of acrylamide/dimethylaminoethylacrylate methyl chloride copolymers (AM‐co‐DMAEA) was evaluated as flocculants for model Precipitated Calcium Carbonate (PCC) in distilled water. These cationic polyelectrolytes (PEL) differed by their AM/DMAEA ratio, i.e., their charge density, chain architecture (linear and branched), their intrinsic viscosity (IV), and zeta potential of their aqueous solutions. The IV being directly related to the hydrodynamic volume of the PEL and the zeta potential reflecting the effective charges in suspension were selected for practically useful correlations with flocculation performance. The fractal dimension (dF) and the scattering exponent (SE) of the flocs, analyzed by the laser diffraction method, were taken as indication of primary particle and aggregate assembly. For the optimum PEL dosage, SE anddFvaried with the IV and zeta potential. It was observable that floc size, floc resistance, and floc reorganization correlate with the PEL characteristics. Copolymers with lower IV, which is here associated with PEL of similar molar mass but lower charge density, yielded larger and less resistant flocs. Copolymers with higher IV originated smaller more compact flocs being more resistant. In high shear situations, where floc breakage should be avoided, as it is the case in papermaking, polymers with high IV yielding large SE are advantageous. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Controllable surface modifications of polyamide by photo‐induced graft polymerization using immobilized photo‐initiators
Authors: Liu Ning , Sun Gang , Gaan Sabyasachi , Rupper Patrick 
Published: February 2010

AbstractA novel two‐step UV initiated grafting method has been developed and applied on surface modification of polyamide. Anthraquinone‐2‐sulfonate sodium, an acid dye, was chosen as the photo‐initiator. In the first step, photo‐initiators were ionically bonded onto polyamide through a normal acid dye dyeing process. Vinyl monomers such as acrylic acid were then grafted onto polyamide surface in the following step. During UVA irradiation, not only monomers were grafted onto polymer surface, photo‐initiator itself was also covalently bonded onto polymer. The grafted polymers were characterized by Fourier transform infrared spectrometer (FTIR), X‐ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM).The degree of photo‐grafting can be controlled by adjusting concentrations of photo‐initiator and monomer, as well as UVA exposure time. This process demonstrated the feasibility of efficiently modifying polymer surface under low UV intensity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of hydroxyvalerate composition of polyhydroxy butyrate valerate (PHBV) copolymer on bone cell viability and in vitro degradation
Authors: Liu Hui , Pancholi M. , Stubbs J. , Raghavan D. 
Published: February 2010

AbstractThe objective of this study was to elucidate the role of hydroxyvalerate (HV) composition in polyhydroxy butyrate valerate (PHBV) copolymer film on the degradation of copolymer and osteoblastic cell activity. Degradation was studied by monitoring time‐dependent changes in mass and chemical composition of the macroporous films. The mass loss of PHBV film upon 19 weeks of exposure to pH 7.4 phosphate buffer medium was found to range from 2.8% to 9.2% with a strong dependence on the original composition of the copolyester film and morphology. Tapping mode atomic force microscopy (TMAFM) was used to examine the roughness change of polyester films due to exposure to buffer medium. Chemical analysis of the degraded film was carried out using NMR to aid in the interpretation of the mass loss and TMAFM data. The NMR results showed a significant decrease in the mol % of HV content in the degraded PHBV film. Additionally, we established that UMR‐106 cell proliferation on macroporous PHBV matrix is minimally enhanced by the HV content of PHBV copolymer. Information provided by this study can be used in the selection of appropriate PHBV copolymer for clinical use where the biopolymer needs to remain physically intact and chemically unchanged during the intended period of biomedical application. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Experimental studies on electro‐conductive fabric prepared by in situ polymerization of thiophene onto polyester
Authors: Das Dipayan , Sen Kushal , Saraogi Aditya , Maity Syamal 
Published: February 2010

AbstractThis work deals with development, characterization, and performance of an electro‐conductive fabric prepared by in situ polymerization of thiophene onto polyester. An attempt was made to optimize the polymerization process to achieve highest level of electro‐conductivity of this fabric. The essential characteristics of this electro‐conductive fabric were examined and its electromagnetic shielding performance was evaluated. Polythiophene powder was also synthesized and analyzed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of electric field interference on double nozzles electrospinning
Authors: Yang Enlong , Shi Jingjing , Xue Yuan 
Published: February 2010

AbstractThe low production rate of electrospinning process may limit the industrial use of single needle system. To meet high yield requirement and uniform fibers, a bottom‐up multiple jets electrospinning nozzle was designed, each nozzle can emit 6–18 jets. The influence of electric field interference on jet path, membrane shape, and fiber morphology were investigated. Experiment finds that electrical field strength in the closer part of two nozzles is weakened because of electric field interference when the distance between two nozzles is 30 mm, making the jet hard to emit in this section, and closer part of electrospun fiber webs has fewer fibers. The spinning in far side part of two nozzles is similar to that of single nozzle. While in middle part of one nozzle, the jet path is short, elongation of jets smaller, the formed fibers thicker, solvent evaporation less sufficient. When the distance of two nozzles is increased to 50 mm, influence of electric field interference is weaker, the electrospun fiber web and average diameter of fibers are almost the same as that of single nozzle electrospinning. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structural characterization and antimicrobial activity of chitosan (CS‐40)/nisin complexes
Authors: Cai Jun , Yang Jianhong , Wang Changgao , Hu Ying , Lin Jianguo , Fan Lihong 
Published: February 2010

AbstractA complex of chitosan (CS‐40) and nisin (CS‐40/nisin) was prepared and characterized with Fourier transform infrared spectroscopy and thermal analysis (thermogravimetry, differential thermogravimetry, and differential scanning calorimetry). The results show that the complex formed mainly by electrostatic interaction between the protonated amino group in CS‐40 backbone with the carboxylate ion of nisin. Minimum inhibitory concentrations (MICs) were evaluated against Gram‐positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Bacillus stearothermophilus), Gram‐negative bacteria (Escherichia coli, Salmonella enteritidis, and Proteus vulgaris), and fungi (Fusarium oxysporum). The results show that the CS‐40/nisin solution did inhibit or even more strongly inhibited the growth of all the tested microorganisms, whereas CS‐40 did not inhibit the growth of F. oxysporum and nisin did not inhibit the growth of Gram‐negative bacteria (E. coli, S. enteritidis, and P. vulgaris). The relative inhibition times of CS‐40/nisin solutions with different concentrations and ratios of CS‐40 and nisin were also investigated against the seven microorganisms. The results showed that CS‐40/nisin solutions with CS‐40/nisin concentration ratios of 0.05/0.005, 0.05/0.0025, 0.05/0.00125, and 0.025/0.0001% had higher antimicrobial activity against all tested bacteria and fungi. The relationship between complex formation and antimicrobial activity is discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010