bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment degradation of natural rubber by moving die processability test and FTIR spectroscopy
Authors: Narathichat M. , Sahakaro K. , Nakason C.
Published: October 2009

Thermal and mechanical degradation of natural rubber (NR) mixed with N‐(1,3‐dimethylbutyl)‐N′‐phenyl‐p‐phenylenediamine (6PPD), polymerized 1,2‐dihydro‐2,2,4‐trimethyl‐quinoline (TMQ), and 50/50 weight basis mixture under high temperature and shearing conditions were investigated using a moving die processability test and FTIR spectroscopy. Relationship between dynamic properties in terms of tan δ value and chemical changes of NR molecules during degradation were correlated. The results indicated that the NR mixed with antioxidants caused decreased level of chain scission and oxidative degradation. The 6PPD provided better protection of NR against degradation at elevated temperature than TMQ. Furthermore, it was found that a prolonged mixing time caused more pronounced oxidative degradation on NR molecules than increased mixing temperature. The antioxidative capability of those antioxidants on NR was ordered based on their effectiveness as follows: 6PPD > 6PPD mixed with TMQ > TMQ. It was also found that the moving die processability test and FTIR spectroscopy are efficient routes to estimate the oxidative degradation of NR molecules. Therefore, the techniques could be applied to assess or compare antioxidative capability of various types and amounts of antioxidants used in the rubber formulation within a reasonable testing time. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Aggregation phenomena of amphiphilic UVB absorptive oligoesters containing p‐alkoxycinnamate and poly(ethylene oxide) blocks
Authors: Changhin P. , Wanichwecharungruang S. P. , Luadthong C. , Sritana‐Anant Y.
Published: October 2009

The synthesis of new amphiphilic oligoesters containing a hydrophobic block based on p‐alkoxycinnamate and hydrophilic poly(ethylene oxide) is reported. Two hydrophobic monomers, 1,2‐(bis(4‐(2‐carboxyvinyl)phenoxy))ethane (M2) and 1,12‐(bis(4‐(2‐carboxyvinyl) phenoxy))dodecane (M12), were synthesized. Four oligoesters, poly((1,2‐(bis(4‐(2‐carboxyvinyl)phenoxy))ethane) ‐co‐(poly(ethylene oxide)200)) (P2‐200), poly((1,2‐(bis(4‐(2‐carboxyvinyl)phenoxy))ethane)‐co‐(poly(ethylene oxide) 400)) (P2‐400), poly((1,12‐(bis(4‐(2‐carboxyvinyl)phenoxy)) dodecane)‐co‐(poly(ethylene oxide)400)) (P12‐400), and poly((1,12‐(bis(4‐(2‐carboxyvinyl)phenoxy))dodecane)‐co‐ (poly(ethylene oxide)1000)) (P12‐1000) were then constructed by reacting the M2 or M12 with poly(ethylene oxide) (PEO) with lengths of ∼ 4 (PEO 200), ∼ 10 (PEO 400), or ∼ 23 (PEO1000) units using multiple esterifications. These oligoesters possess UVB absorption properties and show good solubility in various organic solvents. Self‐assembly of the oligoesters into aqueous spherical colloids could be induced through an acetone to water solvent displacement technique. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Alternating tangent approach for the optimal vulcanization of 2D‐3D EPM/EPDM thick elements
Authors: Milani G. , Milani F.
Published: October 2009

The main problem in industrial practice when dealing with the curing process of thick EPM/EPDM elements is constituted by the different temperatures, which undergo internal (cooler) and external regions. Indeed, while internal layers remain essentially under‐vulcanized, external coating is always over‐vulcanized, resulting in an overall average tensile strength insufficient to permit the utilization of the items in several applications where it is required a certain level of performance. A possibility to improve rubber output mechanical properties is the utilization of mixtures of at least two peroxides, the first highly active at high temperatures (i.e., for external layers), the second at low temperatures (internal regions). In this framework, in this article, a simple numerical procedure for the optimization of final mechanical properties of vulcanized 2D and 3D thick rubber items is presented. In particular, a so called alternating tangent approach (AT) for the determination of the optimal input parameters to use during the production of complex 2D/3D thick items is presented. Vulcanization external temperature Tc and rubber exposition time t are assumed as input production parameters, whereas output mechanical property to optimize is represented by the average tensile strength of the item. In the algorithm, a sufficiently large interval of exposition times at fixed Tc (or curing temperatures at fixed exposition times) is chosen at the initial iteration, namely evaluating rubber tensile strength at a very under‐vulcanized and at a very over‐vulcanized exposition time. For each extreme of the interval, first derivatives of final tensile strength with respect to exposition time (or curing temperature) are evaluated numerically. At the successive iteration, search exposition interval is reduced to one‐half through bisection, selecting the right or left semi‐interval basing the choice on first derivative sign evaluated at the middle point. The approach proposed converges very quickly to the optimal solution, competing favorably both with a very expensive method based on the subdivision of the domain in a refined grid of points and with recently presented GA approaches. Two meaningful examples of engineering interest, consisting of an high voltage electric cable and a 3D thick rubber docks bumper are illustrated. When dealing with the 3D item, due to its thickness, different mixtures of two peroxides (50%‐50%, 25%‐75% and 75%‐25% molar ratios) are also used to improve drastically final mechanical properties. Optimal production Tc and t parameters are obtained for all the cases analyzed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Retracted: Electrospinning instabilities in the drop formation and jet ejection at various concentrations of polyvinyl alcohol polymer solution
Authors: Kong C. S. , Lee S. H. , Lee K. Y. , Jo N. K. , Kim H. S.
Published: October 2009

This article has been retracted because of prior acceptance by another publication. The publisher regrets any inconvenience this may have caused.
Effect of chlorine dioxide gas on physical, thermal, mechanical, and barrier properties of polymeric packaging materials
Authors: Rubino Maria , Netramai Siriyupa , Auras Rafael , Annous Bassam A.
Published: October 2009

The effects of gaseous chlorine dioxide (ClO2) on properties and performance of 10 selected polymeric packaging materials, including polyethylene (PE), biaxially oriented poly(propylene), polystyrene, poly(vinyl chloride), poly(ethylene terephthalate) (PET), poly(lactic acid), nylon, and a multilayer structure of ethylene vinyl acetate (EVA)/ethylene vinyl alcohol (EVOH), were evaluated. Physical, mechanical, barrier, and color properties as well as infrared (IR) spectra were assessed before and after polymer samples were exposed to 3600 ppmV ClO2 gas at 23°C for 24, 168, and 336 h. The IR spectra of the ClO2‐treated samples revealed many changes in their chemical characteristics, such as the formation of polar groups in the polyolefin, changes in functional groups, main chain scission degradation, and possible chlorination of several materials. The ClO2‐treated PE samples showed a decrease in tensile properties compared with the untreated (control) films. Decreases in moisture, oxygen, and/or carbon dioxide barrier properties were observed in the treated PE, PET, and multilayer EVA/EVOH/EVA samples. A significant increase (P < 0.05) in the barrier to O2 was observed in the ClO2‐treated nylon, possibly the result of molecular reordering, which was found through an increase in the crystallinity of the material. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of PMMA/SiO2 nanocomposites by in situ suspension polymerization
Authors: Zheng Junping , Zhu Ran , He Zhihui , Cheng Gang , Wang Hongyan , Yao Kangde
Published: October 2009

Poly(methyl methacrylate) (PMMA)/SiO2 nanocomposites were prepared by in situ suspension polymerization. Two types of modified methods were used to modify nano‐SiO2: one was modification by γ‐methacyloxypropyl trimethoxy silane (KH570) and lauryl alcohol (12COH) while the other was grafting PMMA onto the surface of KH570 treated SiO2. Transmission electron microscopy (TEM) and Fourier transformed infrared (FTIR) were used to characterize the structures of the nanocomposites. The influence of synthetic conditions, for instance, surface modification, initial SiO2 contents and reaction temperature, on the microsphere's size and molecular weight of the extracted PMMA were studied by gel permeation chromatograph (GPC) and optical microscopy (OM) in details. Thermal property of the nanocomposites was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicate that the presence and content of SiO2 have a vital effect on the shape and size of the nanocomposite microspheres, as well as molecular weight of the extracted PMMA. Grafting polymer to the surface of SiO2 is an effective way for the purpose of effective in situ suspension polymerization. Compared to pure PMMA, the thermal properties of the nanocomposites were improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Impact of the steric position of phosphonate groups in poly(N,N‐dimethylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonate‐co‐2‐X‐phosphonate) on its adsorbed conformation on cement: Comparison of vinylphosphonic acid and 2‐acrylamido‐2‐methylpropanephosphonate modified terpolymers
Authors: Plank Johann , Dugonjić‐Bilić Fatima , Lummer Nils Recalde
Published: October 2009

For phosphonated copolymers, the effect of distance of the phosphonate group from the polymer backbone on the Ca2+ chelating capability and the adsorption behavior on cement was studied. For this purpose, 2‐acrylamido‐2‐methylpropane phosphonic acid (AMPPA) and vinyl phosphonic acid (VPA), respectively, were reacted in an aqueous free‐radical polymerization with N,N‐dimethylacrylamide (NNDMA) and 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS®) to give poly(N,N‐dimethylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonate‐co‐2‐acrylamido‐2‐methylpropanephosphonate) (CaAMPS®‐co‐NND MA‐co‐CaAMPPA) and poly(N,N‐dimethylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonate‐co‐vinylphosphonate) (CaAMPS‐co‐NNDMA‐co‐CaVPA), respectively. Adsorption behavior and thus performance of the terpolymers strongly depend on their calcium binding capacity. Ca2+ selective conductivity measurements show that the AMPPA modified terpolymer chelates less calcium than the VPA polymer. Therefore, it interacts less with surfaces containing calcium atoms/ions. To investigate the consequences for practical applications adsorbed amounts on cement surface and effectiveness as water retention agent (fluid loss additive, FLA) in oil well cement slurries with and without acetone‐formaldehyde‐sulfite (AFS) dispersant were determined. CaAMPS‐co‐NNDMA‐co‐CaAMPPA and AFS adsorb simultaneously whereas CaAMPS‐co‐NNDMA‐co‐CaVPA does not allow dispersant adsorption. The reason is that affinity of phosphonate functions towards Ca2+ ions is reduced with increasing distance from the polymer backbone. Thus, AMPPA is a weaker anchor group than VPA. Zeta potential measurements indicate that the increased length of the side chain holding the phosphonate function decreases the anionic charge density of the polymer. Accordingly, CaAMPS‐co‐NNDMA‐co‐CaAMPPA appears to develop weaker bonds with the cement surface. Upon addition of AFS, the AMPPA modified FLA can change its adsorbed conformation from “train” to “loop” or “tail” mode and thus provide space for the dispersant to adsorb as well. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of iron(III) complex of an amino‐functionalized polyacrylamide‐grafted lignocellulosics and its application as adsorbent for chromium(VI) removal from aqueous media
Authors: Anirudhan Thayyath S. , Rijith Sreenivasan , Suchithra Padmajan S.
Published: October 2009

This study concerns with the development of a new adsorbent, iron(III) complex of an amino‐functionalized polyacrylamide‐grafted coconut coir pith (CP), a lignocellulosic residue, for Cr(VI) in water and industry effluents. The adsorbent (AM‐Fe‐PGCP) was characterized by FTIR, EDS, Mössbauer, surface area analyzer, TG/DTG, and potentiometric titration. The effects of contact time, initial sorbate concentration, pH, dose of adsorbent, and temperature on Cr(VI) adsorption were studied to optimize the conditions for maximum adsorption. The kinetics of sorption was investigated using pseudo‐first‐order and pseudo‐second‐order rate equations with the later giving a better fit to the experimental data. The mechanism of sorption was found to be film diffusion controlled. The Langmuir isotherm model yields a much better fit than the Freundlich and Dubinin–Radushkevich models with maximum adsorption capacity of 142.76 mg/g at 30°C. Simulated industry wastewater sample was treated with AM‐Fe‐PGCP to demonstrate its efficiency in removing Cr(VI) from wastewater. The alkali treatment (0.1M NaOH) and re‐introduction of Fe3+ lead to a reactivation of the spent adsorbent and can be reused through many cycles of water treatment and regeneration without any loss in the adsorption capacity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Predicting the effect of dissolved carbon dioxide on the glass transition temperature of poly(acrylic acid)
Authors: Cao Gui‐Ping , Liu Tao , Roberts George W.
Published: October 2009

The morphology and size of poly(acrylic acid) (PAA) particles produced by precipitation polymerization in supercritical CO2 (scCO2) depends on the glass transition temperature (Tg) of the polymer at reaction conditions. In this study, the use of the Sanchez–Lacombe equation of state (SL‐EOS), in conjunction with Chow's equation, to predict the effect of CO2 pressure on the Tg of PAA was evaluated. Characteristic parameters for PAA were determined by fitting density data. Characteristic parameters for CO2 were determined by fitting density data in the supercritical region. When the SL‐EOS was used in a purely predictive mode, with a binary interaction parameter (ψ) of 1, the solubility of CO2 in PAA was underestimated and Tg was overestimated, although the trend of Tg with CO2 pressure was captured. When was determined by fitting the SL‐EOS to the measured sorption of scCO2 in PAA, the calculated Tg's agreed very well with measured values. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Anionic polymerization of 1,3‐cyclohexadiene: Addition of poly(1,3‐cyclohexadienyl)lithium to fullerene‐C60
Authors: Natori Itaru , Natori Shizue
Published: October 2009

The addition of poly(1,3‐cyclohexadiene) (PCHD) carbanion to fullerene‐C60 (C60) was examined using poly(1,3‐cyclohexadienyl)lithium (PCHDLi), PCHDLi/1,4‐diazabicyclo[2,2,2]octane (DABCO), and PCHDLi/N,N,N′,N′‐tetramethylethylenediamine (TMEDA). The reactivity of PCHD carbanions was in the order of PCHDLi > PCHDLi/DABCO > PCHDLi/TMEDA, regardless of the polymer main chain structure. PCHDLi, PCHDLi/DABCO, and PCHDLi/TMEDA in toluene formed σ‐structures, σ‐ and π‐structures, and π‐structures, respectively. The degree of localization on the terminal carbanion was a main factor for control of this addition reaction. In addition, all 1,2‐cyclohexadiene (1,2‐CHD) unit sequences contributed to preventing the addition reaction. That is, large steric hindrance of the polymer main chain was another important factor to control the addition reaction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nanostructures and thermomechanical properties of epoxy thermosets containing reactive diblock copolymer
Authors: Xu Zhiguang , Hameed Nishar , Guo Qipeng , Mai Yiu‐Wing
Published: October 2009

Polystyrene‐block‐poly(glycidyl methacrylate) reactive diblock copolymer (PS‐b‐PGMA) was synthesized via atom transfer radical polymerization (ATRP). The diblock copolymer was characterized using nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The cured epoxy thermosets with 10–20 nm PS particles were prepared by blending the diblock copolymer with epoxy resin. The nanostructures were examined by means of transmission electronic microscopy (TEM) and small angle X‐ray scattering (SAXS). The formation of the nanostructures was caused by the reaction‐induced microphase separation mechanism. It is significant that the glass transition temperatures (Tgs) of these epoxy thermosets were increased by the addition of PS‐b‐PGMA reactive block copolymer as revealed by both differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Incorporating amylopectin in poly(lactic acid) by melt blending using poly(ethylene‐co‐vinyl alcohol) as a thermoplastic carrier. (I) morphological characterization
Authors: Nordqvist D. , Sanchez‐García Maria D. , Hedenqvist Mikael S. , Lagaron Jose M.
Published: October 2009

In this study, the possibility of using a biodegradable grade of thermoplastic poly(ethylene‐co‐vinyl alcohol) with high (71 mol %) vinyl alcohol (EVOH‐29), as a carrier to incorporate the renewable and biodegradable component amylopectin (AP) into poly(lactic acid) (PLA) through melt blending, was investigated. The effect of using a plasticizer/compatibilizer (glycerol) in the blend systems was also investigated. In a first step, the EVOH/AP blends were produced and thereafter, in a second step, these were mixed with PLA. In this first study, the blend morphology was investigated using optical microscopy, scanning electron microscopy and Raman imaging spectroscopy and the thermal properties were measured by differential scanning calorimetry. Despite the fact that EVOH and AP are both highly polar, their blends were immiscible. Still, the blends exhibited an excellent phase dispersion on a micron level, which was enhanced further by the addition of glycerol. A good phase dispersion was finally observed by incorporation of the latter blends in the PLA matrix, suggesting that the proposed blending route can be successfully applied for these systems. Finally, the Differential scanning calorimetry (DSC) data showed that the melting point of EVOH dropped in the EVOH/AP blends, but the properties of the PLA phase was still relatively unaffected as a result of blending with the above components. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The fracture mechanism of polylactic acid resin and the improving mechanism of its toughness by addition of acrylic modifier
Authors: Ito Masakazu , Abe Satomi , Ishikawa Masaru
Published: October 2009

The fracture mechanism of polylactic acid (PLA) resin and the improving mechanism of its toughness by addition of an acrylic modifier were examined. Plane strain compression testing of PLA clearly showed strong softening after yielding. Because the stress for craze nucleation of PLA was close to the yield stress, brittle fractures resulted. The addition of an acrylic modifier to the PLA significantly lowered the yield stress and formed many voids. The release of the strain constraint because of the formation of many voids and the decrease of yield stress resulted in the relaxation of stress concentration, and the toughness was improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Vinylester resin‐clay hybrids using various intercalating agents
Authors: Agag Tarek , Akelah Ahmed , Abdelwahab Mohamed , Takeichi Tsutomu , Muto Hiroyuki
Published: October 2009

Vinylester resin‐clay hybrids were prepared by the mixing different types of organically‐modified montmorillonite (OMMT) with vinylester resin (VER) prepolymer, followed by thermal polymerization. VER prepolymer was synthesized from the reaction of diglycidylether of bisphenol‐A (DGEBA) with acrylic acid. Various types of organic ammonium salts have been used as intercalating agents for montmorillonite, including N,N‐dimethyl‐N‐(4‐vinylbenzyl)stearyl ammonium chloride (VSA), N‐allyl‐N,N‐dimethyl‐stearyl ammonium chloride (ASA) and N,N‐dimethyl‐stearyl ammonium chloride (SA). The dispersion of OMMT into VER matrix was studied by XRD, which indicates the dependence of the morphology mainly on the OMMT content. UV–vis spectra of the hybrids were used to give a quantitative value of the effect of OMMT content on the transparency of VER/OMMT hybrid films. Also, the Vickers test has been performed to study the effect of OMMT content on the surface hardness of the hybrid films. In addition, the thermal properties of the hybrids have been characterized by measuring the softening points and thermogravimetric analyses of the hybrids in comparison with the pure resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
New generation polymeric nanospheres for lysozyme adsorption
Authors: Akgöl Sinan , Öztürk Nevra , Denizli Adil
Published: October 2009

Novel hydrophobic nanospheres with an average size of 100 nm utilizing N‐methacryloyl‐(l)‐tryptophan methyl ester (MAT) as a hydrophobic monomer were prepared by surfactant free emulsion polymerization of 2‐hydroxyethyl methacrylate (HEMA) and MAT. MAT was synthesized using methacryloyl chloride and l‐tryptophan methyl ester. Specific surface area of the nonporous nanospheres was found to be 1914 m2/g. Poly(HEMA–MAT) nanospheres were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Average particle size, size distribution, and surface charge measurements were also performed. Elemental analysis of MAT for nitrogen was estimated as 1.95 mmol/g polymer. Then, poly(HEMA–MAT) nanospheres were used in the adsorption of lysozyme in batch system. Using an optimized adsorption protocol, a very high loading of 1075 mg lysozyme/g nanosphere was obtained. The adsorption phenomena appeared to follow a typical Langmuir isotherm. It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption amount or enzyme activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of stimuli‐responsive star‐like copolymer H20‐PNIPAm‐r‐PEGMA via the ATRP copolymerization technique and its micellization in aqueous solution
Authors: Di Chunfeng , Jiang Xuesong , Yin Jie
Published: October 2009

A series of novel star‐like copolymers H20‐poly(N‐isopropylacrylamide)‐random‐poly(poly(ethylene glycol) methyl ether methacrylate) (H20‐PNIPAm‐r‐PEGMA), which could respond to both temperature and ionic strength stimuli in aqueous solution were synthesized by atom transfer radical polymerization. Stimuli‐response of these copolymers in aqueous solution was characterized by dynamic laser scattering (DLS), 1H‐NMR and turbidity. In aqueous solution, these star‐like copolymers exhibited response to temperature and ionic strength with tunable low‐critical solution temperature (LCST) from 32 to 100°C. The LCST values of copolymers increased with increasing PEGMA contents, while decreased with increasing ionic strength. An interesting phenomenon, which should be a unique character of star‐like copolymer, was observed by the turbidity test of copolymer 1160. The addition of sodium chloride and increase of concentration can let copolymer 1160 behave normally, which was further confirmed by atomic force microscopy and DLS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on the influence of thermal characteristics of hyperbranched polyurethane phase change materials for energy storage
Authors: Cao Qi , Liao Li , Xu Haili
Published: October 2009

A series of hyperbranched polyurethane (HB‐PU) phase change induced energy storage materials were prepared by polyethylene glycol (PEG), methylene diphenyl 4,4′‐diisocyanate (MDI), and hyperbranched polyester polyalcohol via a two‐step process. The influence of thermal characteristics of HB‐PU was investigated using differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXD). It has been found that the thermal characteristics of HB‐PU are affected by some factors. Such as the molecular weight and content of soft segment, once the Mn of PEG soft segments is larger than the critical Mn (2000 g/mol), both the phase change enthalpy and temperature increase as Mn of PEG soft segment and soft segment content (SSC) increase. The influence of the microstructure of hard segment originates from diisocyanate and hyperbranched polyester polyalcohol, HB‐PUs with regular microstructure and lower generation of hyperbranched polyester polyalcohol have high energy storage capability. Furthermore, the conditions of measurement affect the thermal characteristics of materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reactive compatibilization of polymer blends by γ‐irradiation: Influence of the order of processing steps
Authors: Sonnier Rodolphe , Massardier Valérie , Clerc Laurent , Lopez‐Cuesta Jose Marie , Bergeret Anne
Published: October 2009

Results concerning γ‐irradiation of polymer blends such as HDPE/ground tire rubber (GTR) and PP/HDPE are reported in this article with a special emphasis on the order of processing steps. Irradiation dose varied in the range 0–100 kGy. The two first polymers (HDPE and rubber) are preferentially crosslinked under γ irradiation while PP undergoes chain scission. Mechanical tests and differential scanning calorimetry (DSC) analysis show that the efficiency of the reactive compatibilization by γ irradiation depends greatly on the chronology of γ‐irradiation and injection‐molding steps. Electron spin resonance (ESR) results reveal that numerous radicals remain trapped in the materials after γ‐irradiation even after a long time. Then the effect of irradiation on material properties is different if polymers are melted after irradiation or not. Crosslinking and chain scission are not affected in an equivalent way by the order of processing steps. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on thermal enhancement mechanism of POSS‐containing hybrid nanocomposites and relationship between thermal properties and their molecular structure
Authors: Feng Yan , Jia Yong , Guang Shanyi , Xu Hongyao
Published: October 2009

In this study, a series of poly(4‐acetoxystyrene) (PAS)‐octavinyl polyhedral oligomeric silsesquioxane (POSS) blends and the polystyrene (PS)‐octavinyl POSS blends were prepared by the solution‐blending method and characterized with Fourier transform infrared (FTIR), X‐ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) techniques. The results show that the glass‐transition temperature (Tg) of the PAS‐POSS blends increases at a relatively low POSS content and then decreases at a relatively high POSS content. POSS can effectively improve the thermal stability of the PAS‐POSS blends at low POSS content, and Tg of PAS‐POSS blends decreases with the increase in POSS content at relatively high POSS content. However, the Tg of the PS‐POSS blends persistently decreases even at very low POSS content. Tg change mechanism was investigated in detail by XRD, TEM, and FTIR spectra. The influence mechanism of POSS content and dispersion in composites, and parent polymer structure on thermal properties of the blends was investigated in detail. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Enhanced corrosion protective coating based on conducting polyaniline/zinc nanocomposite
Authors: Olad Ali , Rasouli Haleh
Published: October 2009

Conducting polyaniline (PANI) is being explored as promising material for protection of metals against corrosion. It has the possibility of making smart coatings on metals, which can prevent corrosion even in scratched areas where bare metal surface is exposed to the aggressive environment. However, PANI coatings have poor barrier and mechanical properties. The barrier property of coatings can be enhanced by the addition of appropriate filler particles. Also it has been demonstrated that nanoparticulate fillers give much better barrier properties even at lower concentrations. In this study, the effect of zinc nanoparticles on the anticorrosive property of PANI coating on iron samples has been investigated. The PANI/Zn nanocomposite was synthesized by in situ polymerization of aniline in the presence of Zn nanoparticles. The nanocomposite was characterized by using FTIR, conductivity measurement, cyclic voltammetry, and AFM techniques. Results showed that PANI/Zn nanocomposite coating has improved corrosion protection effect when compared with pure PANI coating. The corrosion current of PANI/Zn coated samples were found to be much lower than that of pure PANI coated samples. The results were referred to the good barrier properties of Zn nanoparticles and improvement in electrochemical corrosion protection of PANI coating in the presence of Zn nanoparticles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and electrochemical capacitance of poly(pyrrole‐co‐aniline)
Authors: Zhang Ai‐Qin , Wang Li‐Zhen , Zhang Lin‐Sen , Zhang Yong
Published: October 2009

The copolymer of pyrrole and aniline, poly(pyrrole‐co‐aniline), has been prepared by chemical oxidation of corresponding monomer mixtures with ammonium peroxysulfate. Techniques of FTIR, SEM‐EDS, and BET surface area measurement were used to characterize the structure and morphology of the copolymer. The electrochemical properties of the copolymer were investigated by cyclic voltammetry, galvanostatic charge‐discharge, and electrochemical impedance spectroscopy. The results indicated that poly(pyrrole‐co‐aniline) was about 100–300 nm in diameter and showed better electrochemical capacitive performance than polypyrrole and polyaniline. The specific capacitance of the copolymer electrode was 827 F/g at a current of 8 mA/cm2 in 1 mol/L Na2SO4 electrolyte. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of poly(butylene succinate‐co‐butylene terephthalate) (PBST) copolyesters with high molecular weights via direct esterification and polycondensation
Authors: Luo Shengli , Li Faxue , Yu Jianyong , Cao Amin
Published: October 2009

In this article, biodegradable poly(butylene succinate‐co‐butylene terephthalate) (PBST) copolyesters with high molecular weights were synthesized by direct esterification and polycondensation route. The reaction conditions and catalytic systems were investigated in detail. Through balancing the reaction efficiency and the costs of reactants, the proper molar ratio of diol to diacid was determined. Titanium tetraisopropoxide (TTiPO) was found to be an effective catalyst both in esterification and polycondensation reaction, and its content was optimized based on the esterification ratio and amount of formed by‐products. The complex reaction was determined to be the dominant catalytic reaction mechanism. By importing the additives of metal oxides coupled with TTiPO, the weight‐average molecular weights of PBST increased sharply from 8.51 × 104 to 14.38 × 104, manifesting the additives promoted the polymerization reaction greatly. The enhancement of carbonyl polarization and provision of suitable reaction space arose from the metal oxides were the reasons for promoting the polymerization reaction. With respect to thermal properties, the same melting point and heat of fusion were found, while thermal stability increased with the import of additives. The result was prone to be interpreted by the higher molecular weights of PBST in the presence of additives. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The mechanical properties and thermal performances of polypropylene with a novel intumescent flame retardant
Authors: Zhang Qingbo , Xing Haitao , Sun Caiying , Xiang Haiwang , Jiang Dawei , Qin Linlin
Published: October 2009

A novel intumescent flame retardant: tetra‐spirophosphoryl‐benzoguanamine (TSPB) containing three constituents was used as a new flame retardant for polypropylene to prepare flame‐retardant materials, whose flammability and thermal behavior were studied by the limited oxygen index (LOI), thermogravimetric analysis (TGA), in addition whose mechanical properties were investigated in this work. It was found that when the addition of TSPB was 25 wt %, the LOI value of the PP could achieve to 29.5 and pass the UL‐94 V‐0 rating test. The TGA data showed that TSPB could enhance the thermal stability of PP and effectively increase the char residue formation. The mechanical performance test showed that the addition of TSPB improve the mechanical performances of PP to some extent. Thus, the trinity intumescent flame retardant TSPB is good to modify PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Patterned conductive polyaniline films fabricated using lithography and in situ polymerization
Authors: Liu Cheng‐Dar , Wu Sheng‐Yen , Han Jin‐Lin , Hsieh Kuo‐Huang
Published: October 2009

In this article, we describe a novel bottom‐up technique for the preparation of transparent conductive films of polyaniline (PANI). A UV‐curable photoresist was formulated containing an acrylate‐endcapped urethane oligomer [UA(PPG400)], acrylic acid, a photoinitiator, and a reactive diluent (tripropylene glycol diacrylate), and the lithography techniques were used to pattern the structure with line widths/spaces of 100 μm/100 μm, 10 μm/10 μm, and 5 μm/5 μm on a polyethylene terephthalate substrate. The carboxylic acid units on the surface of the patterned photoresist interacted with the aniline monomer units to form anilinium complexes; using ammonium persulfate as a chemical oxidant, we then synthesized a layer of conductive PANI on the surface of the patterned resist through in situ polymerization. The optimal conductivity of the PANI conductive film was ca. 10 S/cm. The thin film was characterized, and its physical properties investigated using Fourier transform infrared spectroscopy, UV–Vis spectroscopy, differential scanning calorimetry, optical and atomic force microscopy, and four‐point probe conductivity measurements. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Dyeing and deodorizing properties of cotton, silk, wool fabrics dyed with Amur Corktree, Dryopteris crassirhizoma, Chrysanthemum boreale, Artemisia extracts
Authors: Lee Young‐Hee , Hwang Eun‐Kyung , Jung Young–Jin , Do Seong‐Kook , Kim Han‐Do
Published: October 2009

This study used four kinds of natural colorant solutions extracted from Amur Corktree, Dryopteris crassirhizoma, Chrysanthemum boreale, Artemisia using water at 90°C for 90 min with a liquor ratio (solid natural colorant material/solvent water, weight ratio) of 1/10. The dyeing, color fastness, deodorizing properties of cotton, silk, wool fabrics dyed with natural colorant extracts were compared. These properties were found to be significantly dependent on the extract concentration, colorant structure, fabric type. Color fastness (light, water, perspiration fastness) ranged between second and fifth grades and deodorizing performance of fabrics dyed with various natural colorant extracts between 34 and 99%. It is worth noting that the use of natural colorants notably enhanced the deodorizing performance. Wool fabrics showed the highest performance increase at 98–99%, followed by silk and cotton. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A novel soluble PANI/TPU composite doped with inorganic and organic compound acid
Authors: Wang Jiliang , Yang Wanqing , Tong Pengcheng , Lei Jingxin
Published: October 2009

A series of novel soluble and thermoplastic polyurethane/polyaniline (TPU/PANI) composites doped with a compound acid, which was composed of an organic acid (p‐toluene sulfonic acid) and an inorganic acid (phosphoric acid), were successfully prepared by in situ polymerization. The effect of aniline (ANI) content, ratio of organic acid/inorganic acid, and different preparation methods on the conductivity of the TPU/PANI composites were investigated by using conductivity measurement. Lithium bisoxalato borate (LiBOB) was added to the prepared in situ TPU/PANI to coordinate with the ether oxygen groups originating from the soft molecular chains of TPU, and thus the conductivity of the composites was further enhanced. The molecular structure, thermal properties, and morphology of the TPU/PANI composites were studied by UV–visible spectroscopy, differential scanning calorimetry, and scanning electron microscopy, respectively. The results show that the in situ TPU/PANI composites doped with the compound acid can be easily dissolved in normal solvents such as dimethylformamide (DMF) and 1,4‐dioxane. The conductivity of the TPU/PANI composites increases with the increase of the ANI content, in the ANI content range of 0–20 wt %; however, the conductivity of the composites reduces with further increment of ANI content. The conductivity of the TPU/PANI composites prepared by in situ polymerization is about two orders of magnitude higher than that prepared by solution blending method. LiBOB can endow the in situ TPU/PANI composites with an ionic conductivity. The dependence of the conductivity on temperature is in good accordance with the Arrhenius equation in the temperature range of 20–80°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nonwetting, nonrolling, stain resistant polyhedral oligomeric silsesquioxane coated textiles
Authors: Misra Rahul , Cook Robert D. , Morgan Sarah E.
Published: October 2009

Cotton/polyester fabric surfaces were modified using nanostructured organic‐inorganic polyhedral oligomeric silsesquioxane (POSS) molecules via solution dip coating. Surface wetting characteristics of coatings prepared from two chemically and structurally different POSS molecules, a closed cage fluorinated dodecatrifluoropropyl POSS (FL‐POSS) and an open cage nonfluorinated trisilanolphenyl POSS (Tsp‐POSS), were evaluated with time and compared with Teflon. Surface analysis, including Atomic Force Microscopy, SEM/EDAX, and NMR revealed the presence of POSS aggregates on the fabric surface leading to a spiky topography, high roughness, and hysteresis. POSS coated fabrics showed complete reversal of surface wetting characteristics with contact angles higher than the benchmark Teflon surface. Water contact angle measured as a function of time showed equivalent or better performance for POSS‐coated surfaces in comparison to Teflon. Furthermore, FL‐POSS coated fabric exhibited exceptional stain and acid resistance along with a 38% reduction in relative surface friction. Additionally, “nonsliding” and high surface adhesion behavior of water droplets on the FL‐POSS coated fabric are reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Simultaneous determination of itraconazole and hydroxyitraconazole in human plasma by liquid chromatography–isotope dilution tandem mass spectrometry method
Authors: Jia Jing‐ying , Lu Chuan , Liu Gang‐yi , Zhang Meng‐qi , Liu Yan‐mei , Wang Wei , Weng Li‐ping , Li Shui‐jun , Yu Chen
Published: October 2009

A rapid and sensitive liquid chromatography–isotope dilution tandem mass spectrometry method was developed and validated for quantification of itraconazole (ITZ) and its active metabolite hydroxyitraconazole (OH‐ITZ ) in human plasma. The plasma samples were extracted with tert‐butyl methyl ether and two isotope‐labeled internal standards (D5‐itraconazole and D5‐hydroxyitraconazole) were used. The chromatographic separation was performed on a Capcell Pak C18 MG III (100 × 2 mm, 5 µm, Shiseido). The protonated ions of analytes were detected in positive ionization in multiple reaction monitoring mode. The plasma method has a lower limit of quantification of 1 ng/mL with a linearity range of 1–500 ng/mL for ITZ and OH‐ITZ using 100 µL of plasma. The recoveries of the method were found to be 69.47–71.98% for ITZ and 75.68–82.52% for OH‐ITZ. The intra‐ and inter‐batch precision was less than 11% for all quality control samples at concentrations of 2.5, 200 and 400 ng/mL. These results indicate that the method was efficient with a short run time (4.5 min) and acceptable accuracy, precision and sensitivity.The validated method was successfully applied to analysis of human plasma samples in pharmacokinetics study. Copyright © 2009 John Wiley & Sons, Ltd.
Quantum Tunnelling in Enzyme‐Catalysed Reactions. Edited by Rudolf K. Allemann and Nigel S. Scrutton.
Authors: Wymore Troy
Published: October 2009

RSC, Cambridge 2009, XXV+385 pp., hardcover £ 119.95.—ISBN 978‐0‐85404‐122‐0
Bacterial Polysaccharides: Current Innovations and Future Trends. Edited by Matthias Ullrich.
Authors: Ling Chang‐Chun
Published: October 2009

Caister, Norwich 2009, XII+358 pp., hardcover £ 150.00.—ISBN 978‐1‐904455‐45‐5
Application of Aqueous Two‐Phase Systems for the Potential Extractive Fermentation of Cyanobacterial Products
Authors: Chavez‐Santoscoy A. , Benavides J. , Vermaas W. , Rito‐Palomares M.
Published: October 2009

The potential use of aqueous two‐phase systems (ATPS) to establish a viable protocol for the in situ recovery of cyanobacterial products was evaluated. The evaluation of system parameters such as poly (ethylene glycol) (PEG) molecular mass, concentration of PEG and salt was carried out to determine the conditions under which Synechocystis sp. PCC 6803 cell and cyanobacterial products, i.e., β‐carotene and lutein, become concentrated in opposite phases. PEG‐phosphate ATPS proved to be unsuitable for the recovery of cyanobacterial products due to the negative effect of the salt upon the cell growth. The use of ATPS PEG‐dextran (6.6 % w/w PEG 3350, 8.4 % w/w dextran 66900, TLL 17.3 % w/w, VR 1.0, pH 7) and (4.22 % w/w PEG 8000, 9.77 % w/w dextran 66900, TLL 18 % w/w, VR 1.0, pH 7) resulted in the growth of cyanobacteria (Synechocystis sp. PCC 6803) and the concentration of lutein in opposite phases. However, β‐carotene was seen to concentrate in the top phase together with the biomass. The results reported here demonstrate the potential application of ATPS to establish the conditions for an extractive fermentation prototype process for the recovery of cyanobacterial products.
Brønsted Acid Catalyzed Morita–Baylis–Hillman Reaction: A New Mechanistic View for Thioureas Revealed by ESI‐MS(/MS) Monitoring and DFT Calculations
Authors: Amarante Giovanni W. , Benassi Mario , Milagre Humberto M. S. , Braga Ataualpa A. C. , Maseras Feliu , Eberlin Marcos N. , Coelho Fernando
Published: October 2009

A Morita–Baylis–Hillman (MBH) reaction catalyzed by thiourea was monitored by ESI‐MS(/MS) and key intermediates were intercepted and characterized. These intermediates suggest that thiourea acts as an organocatalyst in all steps of the MBH reaction cycle, including the rate‐limiting proton‐transfer step. DFT calculations, performed for a model MBH reaction between formaldehyde and acrolein with trimethylamine as base and in the presence or the absence of thiourea, suggest that thiourea accelerates MBH reactions by decreasing the transition‐state (TS) energies through bidentate hydrogen bonding throughout the whole catalytic cycle. In the rate‐limiting proton‐transfer step, the thiourea acts not as a proton shuttle, but as a Brønsted acid stabilizing the basic oxygen center that is formed in the TS.
Dötz Benzannulation Reactions: Heteroatom and Substituent Effects in Chromium Fischer Carbene Complexes
Authors: Jimenez‐Halla J. Oscar C. , Solà Miquel
Published: October 2009

We have carried out a theoretical investigation of the Dötz reaction between acetylene and a series of chromium Fischer‐type carbenes [(CO)5CrC(X)R] with different representative substituents (R=CHCH2, Ph) and heteroatom ligands (X=OH, NH2, OCH3, N(CH3)2) by using density functional theory with the B3LYP functional. We have studied the Dötz and chromahexatriene mechanisms of benzannulation and also the reaction mechanism leading to cyclopentannulation. For the benzannulation, it was found that the most likely mechanism in the case of vinylcarbenes is the chromahexatriene route, whereas for phenylcarbenes, the Dötz route via a ketene intermediate is clearly the most favorable. The reactions leading to the cyclopentannulated and benzannulated products are more exothermic with vinylcarbenes than with phenylcarbenes and also more exothermic with alkoxycarbenes than with aminocarbenes. The relative stability of the cyclopentannulated products as compared with the benzannulated products increases for bulkier X substituents and on going from alkoxy‐ to aminocarbenes. The kinetic data concurs with the experimental product distribution found for vinylcarbenes, by which mainly benzannulated products are obtained, and dimethylaminophenylcarbenes, which lead exclusively to cyclopentannulated adducts.
Effect of Mitral Regurgitation on Cerebrovascular Accidents in Patients with Atrial Fibrillation and Left Atrial Thrombus
Authors: Nair Chandra K. , Aronow Wilbert S. , Shen Xuedong , Anand Kishlay , Holmberg Mark J. , Esterbrooks Dennis J
Published: October 2009

Background

The effect of mitral regurgitation (MR) on the incidence of new cerebrovascular accidents (CVA) and mortality in patients with atrial fibrillation (AF) and left atrial thrombus (LAT) is unknown.

Objective

To investigate the effect of MR in patients with AF and LAT on new CVA and mortality.

Methods

Eighty nine consecutive patients, mean age 71 years, with AF and LAT documented by transesophageal echocardiography were investigated to determine the prevalence and severity of MR and the association of the severity of MR with new cerebrovascular accidents (CVA) and mortality at 34‐mo follow‐up.

Results

Of 89 patients, 1 + MR was present in 23 patients (26%), 2 + MR in 44 patients (50%), 3 + MR in 17 patients (19%), and 4 + MR in 3 patients (4%). Mean follow‐up was 34 ± 28 mo. The Cox proportional hazards model showed that the severity of increased MR did not significantly increase new CVA or mortality at 34‐mo follow‐up. The only variable predictive of mortality was left ventricular ejection fraction (LVEF), and with every unit increase in LVEF, the risk decreased by 3%.

Conclusion

MR occurred in 87 of 89 patients (98%) with AF and LAT. There was no association between the severity of MR and the incidence of CVA or mortality. Copyright © 2009 Wiley Periodicals, Inc.
Outcome and prognostic features in pediatric gliomas
Authors: Qaddoumi Ibrahim , Sultan Iyad , Gajjar Amar
Published: October 2009

BACKGROUND:

Pediatric gliomas are rare and heterogeneous tumors. The Surveillance, Epidemiology, and End Results (SEER) database allows a large‐scale analysis of the clinical characteristics and prognostic features of these tumors.

METHODS:

The authors analyzed available SEER data on 6212 patients younger than 20 years at diagnosis of glioma (1973‐2005), according to 4 age categories: <1 year, 1‐3 years, 3‐5 years, and 5‐20 years.

RESULTS:

The overall 5‐ and 10‐year survival estimates were 71% ± 0.62% (standard error) and 68% ± 0.67%, respectively. Forty‐one percent of gliomas were cerebral; the frequency of cerebellar tumors (22%‐32% of gliomas) increased sharply after the first year of life. Of the tumors for which grade was available, 77% were low grade (grade I or II). Tumor grade emerged as the most significant independent prognostic factor in all age groups except the youngest age group, in which extent of resection was most significant. Surgery other than gross total resection was an adverse prognostic factor (hazard ratio, 2.18; 95% confidence interval, 1.78‐2.67). Age <3 years predicted a greater likelihood of survival in patients with high‐grade gliomas and brainstem tumors. Conversely, age <3 years predicted a lower likelihood of survival in patients with low‐grade gliomas. Children aged <1 year received less radiotherapy than older patients (P < .0001) and were less likely to undergo gross total resection (P < .0001).

CONCLUSIONS:

The survival of children with gliomas is influenced by histologic subtype, age, and extent of resection. Despite its limitations, the SEER database provides a useful tool for studies of rare tumors such as pediatric gliomas. Cancer 2009. © 2009 American Cancer Society.