bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cocontinuous cellulose acetate/polyurethane composite nanofiber fabricated through electrospinning
Authors: Tang Chunyi , Chen Pingping , Liu Haiqing 
Published: May 2008

AbstractCocontinuous cellulose acetate (CA)/polyurethane (PU) composite nanofibers were obtained through electrospinning of partially miscible CA and PU in 2:1 N,N‐dimethylacetamide (DMAc)/acetone mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were affected by component ratio in the binary mixtures. PU component not only facilitated the electrospinning of CA at CA concentration down to 12 wt%, but reinforced the tensile strength of CA/PU nanofibrous mats, while semirigid component CA in the composite nanofibers could greatly improve the rigidity and dimensional stability of CA/PU nanofibrous mats. In a series of nanofibrous mats with varied CA/PU composition ratios, CA/PU 20/80 showed excellent tensile strength and Young's modulus. The residual product after selective removal of any one of the components in CA/PU composite nanofibers by washing with proper solvent maintained the fiber structure but greatly reduced the fiber size, suggesting CA/PU composite fibers showed a cocontinuous nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Cell coalescence suppressed by crosslinking structure in polypropylene microcellular foaming
Authors: Zhai Wentao , Wang Hongying , Yu Jian , Dong Jinyong , He Jiasong 
Published: May 2008

AbstractA series of crosslinked polypropylene samples with increased melt strengths were prepared via a copolymerization reaction, followed by melt processing. These crosslinked PP samples (PP‐Cs) were foamed by a temperature rising process using supercritical CO2 as the physical blowing agent. The introduction of crosslinking structure resulted in PP‐Cs foams with well‐defined closed cell structure, decreased cell size, and increased cell density in comparison with a linear PP, which were attributed to the suppressed cell coalescence due to the significant increase in melt strength of PP‐Cs. Further increasing the crosslinking degree tended to enhance the suppression effect on the cell coalescence, and hence increase the cell density of PP foams under the same foaming conditions, especially at the longer foaming times. The well‐defined closed cell structure was observed at the foaming temperature of 170–250°C and saturation pressure of 12–20 MPa. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
A novel biobased resin‐epoxidized soybean oil modified cyanate ester
Authors: Zhan Guozhu , Zhao Lin , Hu Sheng , Gan Wenjun , Yu Yingfeng , Tang Xiaolin 
Published: May 2008

AbstractCyanate ester (CE) resin was modified with renewable resource, i.e. epoxidized soybean oil (ESO), and the effects of ESO content on the curing co‐reaction, morphologies, water absorption behaviors, thermal and mechanical properties of CE/ESO blends were studied. Differential scanning calorimeter (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA) were employed to characterize the ESO‐modified CE polymer networks. Homogeneous structures were observed for low‐content of ESO modified CE systems by SEM, while ESO‐rich particles were observed in the modified systems with ESO above 15 wt %. The blend of the CE and ESO resulted in an excellent combination as a new biobased thermoset material having relatively high mechanical properties with 15 and 20 wt % ESO as replacement of CE. Enhanced elongations at break were observed for the modified systems while the tensile strengths kept about the same level at the same time. The storage moduli and glass transition temperatures of the modified systems in the glassy state and rubber plateau were observed to be lower than those of neat CE with the increase of ESO weight percent. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Design of experiments applied to the study of the reaction between phenylphosphonic dichloride with bisphenol by inverse phase transfer catalysis method
Authors: Iliescu Smaranda , Grozav Ion , Plesu Nicoleta , Pascariu Aurelia , Ilia Gheorghe 
Published: May 2008

AbstractThe reaction of phenylphosphonic dichloride with bisphenol A (BA) by inverse phase transfer catalysis method was investigated. The design of experiments method was applied to establish the correlation between the simultaneous influence of the parameters (alkaline medium, reaction temperature, reagents molar ratio, and stirring speed) on yield and inherent viscosity, as well as for identifying the best reaction conditions. This method allows the simultaneous variation of control factors, thus decreasing the number of experiments in the polyphosphate synthesis. The process control factors used in this study were reagents' molar ratio, base concentration, and reaction temperature. The experimental results using 20 and 14 process runs, lead to an optimal synthesis procedure. The optimal values for yield and viscosity were obtained at molar ratio = 1, base concentration = 1.1 M, and reaction temperature = −12°C and have been experimentally verified with a series of four runs. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Effect of swelling agent on the molecular weight of poly(2,6‐dimethyl‐1,4‐phenylene oxide) synthesized in an aqueous medium
Authors: Liu Qun , Shentu Baoqing , Weng Zhixue 
Published: May 2008

AbstractThe effects of the species and content of a swelling agent on the molecular weight of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) synthesized in an aqueous medium were studied. It was found that the molecular weight of PPO increases after introducing a certain amount of the swelling agent during the oxidative polymerization of 2,6‐dimethylphenol (DMP). Tg of the PPO/swelling agent mixture decreases with the increase of the swelling agent content, and the relation between Tg of the PPO/swelling agent mixture and the swelling agent content obeys Fox equation. After the introduction of the swelling agent during the oxidative polymerization of DMP, the molecular weight of PPO is correlated with Tg of the PPO/swelling agent mixture and it was revealed that Tg plays an important role in the molecular weight of PPO synthesized in the aqueous medium. The same molecular weight of PPO can be obtained only if Tg of the PPO/swelling agent mixture is the same, no matter what kind of swelling agent is introduced during the oxidative polymerization of DMP. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Synthesis and solution properties of poly(vinyl ether)s with long alkyl chain, biphenyl, and cholesteryl pendants
Authors: Seno Ken‐Ichi , Date Akiko , Kanaoka Shokyoku , Aoshima Sadahito 
Published: May 2008

AbstractThe judicious choice of reaction conditions permitted living cationic polymerization of vinyl ethers with bulky and strongly interacting pendant groups, such as crystalline long alkyl chains and liquid crystalline mesogenic structures, using appropriate combinations of Lewis acids with added bases. Thus, well‐defined random and block copolymers with various pendants were also synthesized. Highly sensitive UCST‐type phase separation in various organic solvents was achieved employing crystallization of octadecyl pendants of homopolymers and random copolymers. This phase separation behavior is unusual for a polymer‐organic solvent system. Furthermore, thermally induced reversible physical gelation was conducted using this thermosensitive behavior. These specific pendants were very effective not only in organic media but also in water, in obtaining hydrogels with relatively low polymer concentrations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4392–4406, 2008
Improved properties of polyfluorenevinylenes by introduction of carbazole units
Authors: Jin Youngeup , Lee Minjung , Kim Sun Hee , Song Suhee , Goo Youngran , Woo Han Young , Lee Kwanghee , Suh Hongsuk 
Published: May 2008

AbstractNew electroluminescent polyfluorenevinylenes (PFV) copolymers with carbazole group, CzPFVs, have been synthesized by the GILCH polymerization. The carbazole groups were introduced as pendant to increase the electron rich ability of the copolymers. All CzPFVs exhibited absorption spectra with maximum peaks at around 417 nm. In the PL emission spectra of CzPFVs, maximum peaks around 463 nm and shoulder peaks around 490–500 nm were exhibited. By adjusting the feed ratios of carbazole groups in the CzPFVs, it is possible to have the higher current density and brightness, and the lower turn‐on voltage due to increasing hole injection ability. The maximum luminescence of CzPFV9 was 2003 cd/m2 at 7 V. The introduction of carbazole contents in PFVs can enhance the device performance to result in stable PL and EL spectra with high current density and brightness due to the increased hole injection ability and reduced interchain interaction between polymer backbones. Especially, the 1:1 mixture of CzPFV10 and PVK didn't show aggregation effect in PL spectra even after annealing the thin film at 80 °C up to 60 min, since the interchain interaction among polymer backbones with fluorenevinylene units was reduced. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4407–4419, 2008
Fabrication and characterization of poly(butylene succinate)‐grafted carbon fiber/poly(L‐lactide) nanocomposites
Authors: Moon Sungil , Iji Masatoshi 
Published: May 2008

AbstractA new poly(butylene succinate) (PBS)‐grafted vapor grown carbon fiber (VGCF)/poly(L‐lactide) (PLLA) nanocomposites were successfully prepared by an in situ condensation reaction between PBS (Mw = 6,000) and surface oxidized VGCF, followed by direct melt mixing technique, and their mechanical and thermal properties were evaluated. Fourier transform infrared spectroscopy and scanning electron microscopy studies indicate a chemical interaction between the PBS and the surface of VGCF. It was found that the maximum tensile strength and modulus of PBS‐grafted VGCF/PLLA nanocomposites were 135 MPa (27% increase relative to neat PLLA) and 4,400 MPa (29% increase relative to neat PLLA), respectively. The results indicate that significant improvement in the mechanical properties can be accomplished by optimizing the surface modification conditions for VGCF. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4433–4441, 2008
Synthesis and characterization of side‐chain liquid crystalline ABC triblock copolymers with p‐methoxyazobenzene moieties by atom transfer radical polymerization
Authors: He Xiaohua , Sun Wuqiong , Yan Deyue , Xie Meiran , Zhang Yiqun 
Published: May 2008

AbstractA series of novel side‐chain liquid crystalline ABC triblock copolymers composed of poly(ethylene oxide) (PEO), polystyrene (PS), and poly[6‐(4‐methoxy‐4′‐oxy‐azobenzene) hexyl methacrylate] (PMMAZO) were synthesized by atom transfer radical polymerization (ATRP) using CuBr/1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) as a catalyst system. First, the bromine‐terminated diblock copolymer poly(ethylene oxide)‐block‐polystyrene (PEO‐PS‐Br) was prepared by the ATRP of styrene initiated with the macro‐initiator PEO‐Br, which was obtained from the esterification of PEO and 2‐bromo‐2‐methylpropionyl bromide. An azobenzene‐containing block of PMMAZO with different molecular weights was then introduced into the diblock copolymer by a second ATRP to synthesize the novel side‐chain liquid crystalline ABC triblock copolymer poly(ethylene oxide)‐block‐polystyrene‐block‐poly[6‐(4‐methoxy‐4′‐oxy‐azobenzene) hexyl methacrylate] (PEO‐PS‐PMMAZO). These block copolymers were characterized using proton nuclear magnetic resonance (1H NMR) and gel permeation chromatograph (GPC). Their thermotropic phase behaviors were investigated using differential scanning calorimetry (DSC) and polarized optical microscope (POM). These triblock copolymers exhibited a smectic phase and a nematic phase over a relatively wide temperature range. At the same time, the photoresponsive properties of these triblock copolymers in chloroform solution were preliminarily studied. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4442–4450, 2008
Regio‐regular structure high molecular weight poly(propylene carbonate) by rare earth ternary catalyst and Lewis base cocatalyst
Authors: Tao Youhua , Wang Xianhong , Chen Xuesi , Zhao Xiaojiang , Wang Fosong 
Published: May 2008

AbstractLewis base modification strategy on rare earth ternary catalyst was disclosed to enhance nucleophilic ability of active center during copolymerization of carbon dioxide and propylene oxide (PO), poly(propylene carbonate) (PPC) with H‐T linkages over 83%, and number–average molecular weight (Mn) up to 100 kg/mol was synthesized at room temperature using Y(CCl3OO)3‐ZnEt2‐glycerine catalyst and 1,10‐phenanthroline (PHEN) cocatalyst. Coordination of PHEN with active Zinc center enhanced the nucleophilic ability of the metal carbonate, which became more regio‐specific in attacking carbon in PO, leading to PPC with improved H‐T linkages. Moreover, the binding of PHEN to active Zinc center also raised the carbonate content of PPC to over 99%, whereas the PPC from common rare earth ternary catalyst was about 96%. Unlike the highly regio‐regular structure PPC but with relatively low molecular weight recently reported in the literature, our high molecular weight regio‐regular PPC did show significant improvement in thermal and mechanical performances. PPC with H‐T linkages up to 83.2% showed glass transition temperature (Tg) of 43.3 °C, while Tg of PPC with H‐T linkages of 69.7% was only 36.1 °C. When H‐T connectivity was raised from 69.7 to 83.2%, the modulus of PPC showed a 78% increase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4451–4458, 2008
Kinetics of self‐condensing vinyl hyperbranched polymerization in three‐dimensional space
Authors: He Xuehao , Tang Jing 
Published: May 2008

AbstractSelf‐condensing vinyl hyperbranched polymerization (SCVP) with A‐B* type monomer is simulated applying Monte Carlo method using 3d bond fluctuation lattice model in three‐dimensional space. The kinetics of SCVP with zero active energy of reaction is studied in detail. It is found that the maximal number–average and weight–average polymerization degrees and the maximal molecular weight distribution, at varying the initial monomer concentration and double bond conversion, are about 52, 190, and 3.93, respectively, which are much lower than theoretical values. The maximal average fraction of branching points is about 0.27, obtained at full conversion at the initial monomer concentration of 0.75. The simulation demonstrated the importance of steric effects and intramolecular cyclization in self‐condensing vinyl hyperbranched polymerization. The results are also compared with experiments qualitatively and a good agreement is achieved. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4486–4494, 2008
The Cancer Communication Assessment Tool for Patients and Families (CCAT‐PF): a new measure
Authors: Siminoff Laura A. , Zyzanski Stephen J. , Rose Julia Hannum , Zhang Amy Y. 
Published: May 2008

AbstractObjectives: Caregivers and cancer patients frequently have conflicting and unmet communication needs. The Cancer Communication Assessment Tool for Patients and Families (CCAT‐PF) is a new instrument that assesses congruence in patient–family caregiver communication for both research and clinical purposes.Methods: The scale was developed using a sample of 190 lung cancer patient–caregiver pairs. Standard psychometric procedures were used to develop and test the scale including qualitative item pool development, item reduction and ascertainment of scale properties.Results: The multiple correlation of the 18‐item CCAT‐PF scale with the longer 30‐item scale was 0.94. All but three items had less than 20% variance accounted for when each item was regressed on the remaining 17, indicating that responses to an individual item were not readily predicted by the remaining items. Test re‐test reliability was 0.35 and Cronbach's alpha was 0.49 as the CCAT‐PF scale represents the sum of mostly independent items. Higher CCAT‐PF scores were significantly correlated with greater patient depression, greater patient perceived family conflict, lower patient–caregiver assessment and well‐being and less expressiveness and family cohesion. For both patients and caregivers, physical, functional and emotional well‐being were not associated with CCAT‐PF scores.Conclusion: The CCAT‐PF is a brief but reliable and valid tool. Although administering both family and patient versions is optimal, administering it to a patient or family caregiver only also produces reliable information. Copyright © 2008 John Wiley Sons, Ltd.
Predictors of breast cancer‐related distress following mammography screening in younger women on a family history breast screening programme
Authors: Brain K. , Henderson B. J. , Tyndel S. , Bankhead C. , Watson E. , Clements A. , Austoker J. ,   for the PIMMS Study Management Group
Published: May 2008

AbstractObjective: This longitudinal study investigated pre‐screening factors that predicted breast cancer‐specific distress among 1286 women who were undergoing annual mammography screening as part of a UK programme for younger women (i.e., under 50) with a family history of breast cancer.Methods: Women completed questionnaires one month prior to screening, and one and six months after receiving screening results. Factors measured were breast cancer worry, perceived risk, cognitive appraisals, coping, dispositional optimism, and background variables relating to screening history and family history.Results: Pre‐screening cancer worry was the most important predictor of subsequent worry, explaining 56/61% and 54/57% of the variance at one and six months follow‐up, respectively. Other salient pre‐screening predictors included high perceived risk of breast cancer, appraisals of high relevance and threat associated with the family history, and low perceived ability to cope emotionally. Women who had previously been part of the screening programme and those with a relative who had recently died from breast cancer were also vulnerable to longer‐term distress. A false positive screening result, pessimistic personality, and coping efforts relating to religion and substance use predicted outcomes of screening at one month follow‐up, but were not predictive in the longer‐term.Conclusion: Early intervention to ameliorate high levels of cancer‐related distress and negative appraisals would benefit some women as they progress through the familial breast screening programme. Copyright © 2008 John Wiley & Sons, Ltd.
Plasma‐Modified PTFE for Biological Applications: Correlation between Protein‐Resistant Properties and Surface Characteristics
Authors: Vandencasteele Nicolas , Nisol Bernard , Viville Pascal , Lazzaroni Roberto , Castner David G. , Reniers François 
Published: May 2008

AbstractPTFE samples were treated by low‐pressure O2 RF plasmas. The adsorption of BSA was used as a probe for the protein‐resistant properties. Exposure of PTFE to an O2 plasma leads to an increase in chamber pressure. OES reveals the presence of CO, CO2 and F in the gas phase, indicating a strong etching of the PTFE surface by the plasma. Furthermore, the high‐resolution C1s spectra show CF3, CF and CCF components. WCA as high as 160° were observed, indicating a super‐hydrophobic behavior. AFM images of surfaces treated at high plasma power showed an increase in roughness. Lower amounts of BSA adsorption were detected on high power, O2 plasma‐modified PTFE samples compared to low power, oxygen plasma‐modified ones.magnified image
Effects of Low‐Temperature Atmospheric Air Plasmas on the Activity and Function of Human Lymphocytes
Authors: Shi Xing‐Min , Zhang Guan‐Jun , Yuan Yu‐Kang , Ma Yue , Xu Gui‐Min , Yang Yun 
Published: May 2008

AbstractSamples of peripheral blood lymphocytes from 20 healthy adult volunteers were treated by using low‐temperature plasmas produced by DBD to investigate their activity and function change as a result of plasma exposure. When the lymphocytes were more than 5 cm away from the electrode center or when the treatment time was shorter than 5 s, their activity and function did not significantly change. When the lymphocytes were less than 5 cm away from the electrode center, and the treatment time was longer than 5 s, the activity and function was significantly reduced. Furthermore, plasma action resulted in the protein, nucleic acid and K+ leakage from lymphocytes, and therefore in the apoptosis of lymphocytes.magnified image
Plasma Modification of Solid and Porous Polyethylene
Authors: Walton Scott G. , Lock Evgeniya H. , Fernsler Richard F. 
Published: May 2008

AbstractThe use of electron beam generated plasmas to modify the surface of solid and porous polyethylene substrates is discussed. In both cases, the hydrophobicity of the material was increased by exposing the substrates to electron beam generated plasmas produced in Ar/SF6 mixtures. The solid material studies served as a basis for understanding the plasma‐induced changes at the substrate surface, while the porous material was treated using a system designed for two‐sided processing applications and proved to be the best way to maximize treatment. Plasma diagnostics were used to characterize the ion and neutral fluxes at the substrates and thereby obtain a better understanding of the plasma–polymer interaction.magnified image
Progress in permafrost hydrology in the new millennium
Authors: Woo Ming‐Ko , Kane Douglas L. , Carey Sean K. , Yang Daqing 
Published: May 2008

AbstractIncreased attention directed at the permafrost region has been prompted by resource development and climate change. This review surveys advances in permafrost hydrology since 2000. Data shortage and data quality remain serious concerns. Yet, there has been much progress in understanding fundamental hydrologic processes operating in a wide range of environments, from steep mountainous catchments, to the Precambrian Shield with moderate relief, to the low‐gradient terrain of plains, plateaus and wetlands. Much of the recent research has focused on surface water, although springs and groundwater contribution to streamflow have also been studied. A compendium of water‐balance research from 39 high‐latitude catchments reveals the strengths and limitations of the available results, most of which are restricted to only a few years of study at the small watershed scale. The response of streamflow to climate receives continued if not increasing attention, from the occurrence of extreme hydrologic events to the changing regimes of river flow at a regional scale. The effect of climate change and the role of permafrost on the changing discharge of large boreal rivers are major topics for further investigation. Extended field and modelling research on physical processes will improve knowledge of permafrost hydrology and enhance its relevance to societal needs. Copyright © 2008 John Wiley & Sons, Ltd.