bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of acrylate processing aid‐based ionomer containing lanthanide (La(III)) ion on thermal stability, fusion, transparency and mechanical properties of rigid poly(vinyl chloride)
Authors: Zhu Xiaonan , Song Yihu , Chen Shaohui , Du Peihua , Zheng Qiang 
Published: May 2011

AbstractAn acrylate processing aid (ACR)‐based ionomer containing lanthanide (La(III)) ion was synthesized and the influences of the ionomer on thermal stability, fusion time, transparency and tensile properties of rigid poly(vinyl chloride) (PVC) were investigated. Results revealed that the ionomer with a suitable La(III) content behaved as a good stabilizer as well as processing aid to the rigid PVC product. The ionomer could accelerate fusion of PVC much more quickly than ACR because of the strong interaction between La(III) carboxylate and PVC. Moreover, it exhibited a stabilizing efficiency comparable to lanthanum and calcium stearates (LaSt3 and CaSt2). The composite stabilizer of ionomer/zinc stearate (ZnSt2) exhibited an ability to improve initial discoloration better than LaSt3/ZnSt2 and CaSt2/ZnSt2 because the ionomer could form a complex with ZnSt2 much more slowly than LaSt3 and CaSt2. The compounds stabilized using ionomer/ZnSt2 exhibited a transparency comparable to those stabilized using organotin or liquid barium/zinc stabilizers, which was much better than those stabilized using LaSt3/ZnSt2 and CaSt2/ZnSt2. Copyright © 2011 Society of Chemical Industry
Efficiency of 4,4′‐bis(N,N‐diethylamino) benzophenone for the polymerization of dimethacrylate resins in thick sections
Authors: Schroeder Walter F , Asmussen Silvana L , Cook Wayne D , Vallo Claudia I 
Published: May 2011

AbstractThe efficiency of 4,4′‐bis(N,N‐diethylamino)benzophenone (DEABP) for the polymerization of dimethacrylate monomers in thick sections (1–2 mm) was studied. DEABP (λmax = 365 nm) represents a complete initiating system as it contains both ketone and amine functional groups. During irradiation, DEABP photobleaches at a fast rate causing deeper penetration of light through the underlying layers, but the photoinitiation efficiency (rate of polymerization per photon absorption rate) is relatively poor. As a result, irradiation of methacrylate monomers at 365 nm results in a slow average polymerization rate and a reduced monomer conversion for thick sections due to the light attenuation caused by the high absorptivity of DEABP and photolysis products. These results highlight the inherent interlinking of light attenuation and photobleaching rate in polymerization of thick sections. Copyright © 2011 Society of Chemical Industry
Fast detection of hydrogen sulfide using a biodegradable colorimetric indicator system
Authors: Kato Edison T , Yoshida Cristiana MP , Reis Arlete B , Melo Itamar S , Franco Telma T 
Published: May 2011

AbstractA fast, colorimetric indicator system was developed by combining chitosan as a three‐dimensional biopolymer matrix and ferrous sulfate (FeSO4) as a colorimetric indicator of hydrogen sulfide (H2S) gas. Chitosan filmogenic suspensions (3.0% w/w) were obtained and FeSO4 was incorporated at 2.0 wt%. The colour parameters were measured using a colorimeter, after subjecting the system to various H2S exposure times. The novelty of this work is the biodegradability, a test performed in soil, which showed a weight loss of about 67% after 60 days, and the fast device formation indicating the presence of H2S gas. The chitosanFeSO4 system detected the presence of H2S in concentrations equal to or greater than 100 ppm within 30 s of exposure and produced a visual black colour as a response to the presence of H2S. Copyright © 2011 Society of Chemical Industry
Star poly(2‐ethyl‐2‐oxazoline)s—synthesis and thermosensitivity
Authors: Kowalczuk Agnieszka , Kronek Juraj , Bosowska Kornelia , Trzebicka Barbara , Dworak Andrzej 
Published: May 2011

AbstractA series of star‐shaped poly(2‐ethyl‐2‐oxazoline)s was prepared by cationic polymerization. The polymerization was initiated by dipentaerythrityl hexakis(4‐nitrobenzene sulfonate) and a tosylated hyperbranched polymer of glycidol. The polymerization proceeded in a controlled manner. The star structure of the products was determined by nuclear magnetic resonance. The molar mass distributions that were measured by gel permeation chromatography with multiangle laser light scattering were narrow, and the experimental values of the molar masses were close to those predicted. The very compact structure of the polymers obtained (compared with the linear counterparts) confirmed the star formation. The star poly(2‐ethyl‐2‐oxazoline)s show a phase transition temperature in the range 62–75 °C. Comparison of this phase transition temperature with that of the linear poly(2‐ethyl‐2‐oxazoline)s with the same molar masses indicates the influence of molar mass and topological structure of the macromolecule on temperature behavior. The prepared copolymers are spherical, which might be useful for the controlled transport and release of active compounds. Copyright © 2011 Society of Chemical Industry
Die Entdeckung verlorener Kunst. Kunstgeschichtliche Forschung mit Synchrotronstrahlung
Authors: Appel Karen , Alfeld Matthias , Dik Joris 
Published: May 2011

AbstractKunstwerke wurden oft von den Künstlern übermalt und gingen so der Kunstgeschichte verloren. Eine neue Methode der Röntgenfluoreszenzanalyse mit Synchrotronlicht ermöglicht die Rekonstruktion solcher übermalter Bilder. Durch eine Kombination der beim Durchleuchten erhaltenen Elementverteilungsbilder mit Informationen über die chemische Bindung der Elemente können die Bilder sogar koloriert werden. Diese Methode eignet sich auch zur Echtheitsprüfung. Mit ihr lassen sich zudem abgeschabte Schriften wieder sichtbar machen.
Naturkonstanten als solide Basis. Neudefinition der Einheit Kelvin
Authors: Fischer Joachim , Fellmuth Bernd , Gaiser Christof , Zandt Thorsten 
Published: May 2011

AbstractDie Entwicklung der sogenannten Primärthermometer macht erhebliche Fortschritte. Mit ihnen wird die Boltzmann‐Konstante in wenigen Jahren so exakt bestimmbar sein, dass die einmalige Festlegung ihres Zahlenwertes eine Neudefinition des Kelvins ermöglicht. Damit wird eine Naturkonstante anstelle einer Maßverkörperung zum Maßstab. Die wesentlichen Konsequenzen sind langfristiger Natur, denn das Maßsystem für die Temperatur wäre dann zeitlich unbegrenzt stabil. Dieses Ziel lohnt die weltweite Anstrengung.
Verschränkte Photonen auf Eis gelegt
Authors: Tittel Wolfgang , Sohler Wolfgang 
Published: May 2011

AbstractQuantennetzwerke und lange quantenoptische Übertragungsstrecken benötigen Quantenrepeater, deren wesentliche Komponenten Quantenspeicher sind. Sie erlauben, verschränkte Photonen (genauer: deren Quantenzustände) für eine gewisse Zeit zu speichern und kontrolliert wieder auszulesen. Die Kombination eines mit Thulium dotierten optischen Wellenleiters in Lithiumniobat als Speichermedium mit einem kürzlich entwickelten Quantenspeicherprotokoll und einer neuen, schmalbandigen Photonenpaarquelle hat es uns erstmalig ermöglicht, Quantenzustände reversibel von verschränkten Photonen auf einen Kristall zu übertragen. Ähnliche Ergebnisse, aber mit einem anderen Speichermedium, berichtete zeitgleich ein Forscherteam der Universität Genf.
Platzende Ballons – Retardierung in der Mechanik
Authors: Vollmer Michael , Möllmann Klaus‐Peter 
Published: May 2011

AbstractDie endliche Ausbreitungsgeschwindigkeit einer Störung führt zu einer verzögerten Wirkung. Dieses Phänomen nennt man in der Physik Retardierung. Am häufigsten werden retardierte elektromagnetische Felder oder Potentiale in der Elektrodynamik behandelt. Auch in der Mechanik sind solche Verzögerungseffekte bei der Schallausbreitung in Luft oder Gasen ohne weiteres wahrnehmbar, beispielsweise beim Echo. Deutlich schwieriger beobachtbar sind sie in der Mechanik nichtgasförmiger Materialien. Hochgeschwindigkeitskameras zeigen dieses Phänomen auf beeindruckende Weise.
Keine lange Leitung
Authors: Rolfs Claus 
Published: May 2011

AbstractEine schnelle Reaktion ist im Tierreich wichtig, sie kann über Leben und Tod entscheiden. Auch Pflanzen reagieren mitunter auf die Umwelt, nur meist erheblich langsamer als Tiere oder der Mensch. Physikalische Abschätzungen geben Auskunft über die Zeitskalen.
Gele mit Mundgefühl
Authors: Vilgis Thomas 
Published: May 2011

AbstractWarum sind Puddings so beliebt? Abgesehen von zahlreichen Geschmacksrichtungen bestimmt auch das Mundgefühl und damit die Essphysik die Liebe zu gelierten Produkten, deren Festigkeit und Schmelz gezielt gesteuert werden kann. Auch die Küche profitiert davon: Mit den Geliermitteln Agar‐Agar und Gelatine lassen sich interpenetrierende Netzwerke zu kulinarischen Köstlichkeiten heben.
“Clickable” polymers via a combination of RAFT polymerization and isocyanate chemistry
Authors: Moraes John , Maschmeyer Thomas , Perrier Sébastien 
Published: May 2011

AbstractWe describe a facile, one‐pot, two‐step polymerization towards synthesizing block co‐polymers bearing reactive isocyanate functional groups. Reversible addition fragmentation chain transfer (RAFT) polymerization is used to mediate the co‐polymerization of isocyanate‐bearing monomers dimethyl meta‐isopropenyl benzyl isocyanate (TMI) and 2‐isocyanatoethyl methacrylate (ICEMA) with styrene and methyl methacrylate (MMA), respectively. ICEMA was incorporated into the polymer at a faster rate than TMI and its unhindered isocyanate group was found to be more reactive than the hindered isocyanate group of TMI. Both the TMI/styrene and the MMA/ICEMA systems maintain the reactivity of the isocyanate functionality, which was exploited by attaching representative hydroxyl‐bearing small and large molecules as well as solid substrates to the block co‐polymers. Thus, we demonstrate the versatility of the block co‐polymer system as a basis for forming branched polymers or as grafts for a solid substrate. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Polyamide 6‐polycaprolactone multiblock copolymers: Synthesis, characterization, and degradation
Authors: Cakir Seda , Kierkels René , Koning Cor 
Published: May 2011

AbstractThis work describes the synthesis and characterization of polyamide 6 (PA 6)‐polycaprolactone (PCL) multiblock copolymers. Low molar mass, fully amine end‐capped PA 6 was prepared by the addition of a diamine monomer during ε‐caprolactam polymerization. A low molar mass PCL was selected to be incorporated as the biodegradable block and was fully end‐capped with toluene 2,4‐diisocyanate. End group analysis and molecular weight characterizations were performed for both end‐functionalized polymers by SEC, NMR and titration analysis. Incorporation of PCL into PA 6 was mainly achieved by solution mixing of the two end‐functional blocks and, was continued after the removal of the solvent with solid state polymerization (SSP) by gradual heating until about 40 °C below the melting temperature of the PA 6. Molecular weights started to grow immediately during solution mixing and only increased marginally during the SSP treatment. FTIR and SEC studies confirmed the reaction between the two components. DSC data, in combination with the enhanced molar mass during solution mixing pointed to a blocky microstructure, for which distinct melting and crystallization temperatures were observed for the PCL and the PA 6 blocks. Hydrolytic and enzymatic degradation studies were performed at 25 °C where the degree of degradation was followed by weight loss analysis, SEM and SEC. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and characterization of pH‐sensitive and thermosensitive double hydrophilic graft copolymers
Authors: Tu You‐Liang , Wang Cheng‐Chien , Chen Chuh‐Yung 
Published: May 2011

AbstractA series of poly(N‐isopropylacrylamide)‐co‐poly(Nε‐benzyloxycarbonyl‐L‐lysine) graft copolymers (PNIPAm‐co‐PZLLys) with different side chains (degree of polymerization, DP = 5∼40) and unit ratios (from 30 to 70 mol %) were prepared via free radical polymerization, followed by cleaving benzyloxycarbonyl groups (Z groups) to obtain the double hydrophilic graft copolymer, poly(N‐isopropylacrylamide)‐co‐poly(L‐lysine) (PNIPAm‐co‐PLLys). The pH‐ and temperature‐response properties of the graft copolymers in aqueous solution were studied. The experimental results indicate L15‐N30 and L15N‐70, that is, the PNIPAm‐co‐PLLys having the poly(L‐lysine) of DP = 15 as side chains as well as 30 and 70 mol %, respectively, of PNIPAm as backbone, have coil‐to‐helix transitions from pH 6 to pH 12 at room temperature and form uniform nanoscale micelle‐like dispersions in aqueous solution at pH 12. The graft copolymers also could form uniform and nanoscale micelle‐like structures at 50 °C in pH 6 buffer solution due to slightly polymer aggregation. With temperature and pH increased, both the deprotonated PLLys side chains and PNIPAm backbone become hydrophobic, leading to polymer precipitation. These results illustrate that a double tunable hydrophilic graft copolymer had been successfully synthesized via a simple radical polymerization, and could form micelles without serious polymer aggregation at a lower pH and a higher temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Efficient carbonyl hydrosilylation reaction: Toward EVA copolymer crosslinking
Authors: Bonnet Julien , Bounor‐Legaré Veronique , Boisson Fernande , Mélis Flavien , Cassagnau Philippe 
Published: May 2011

AbstractIn this article, the hydrosilylation reaction of carbonyl groups of acetate derivatives and SiH groups of hydride‐terminated polydimethylsiloxane at high temperature (100–130 °C) are described. Triruthenium dodecacarbonyl, Ru3(CO)12, was used as effective catalyst for hydrosilylation reaction. The hydrosilylation reactions with octyl acetate and 4‐heptyl acetate were investigated by multinuclear NMR spectroscopy (1H, 13C, and 29Si). This work provides evidence of the addition reaction of SiH groups onto carbonyl groups. The influence of the nature of the acetate structure on the reaction kinetics was shown and the slight contribution of side reactions at high temperature highlighted. Hydrosilylation reaction was extent to the crosslinking of ethylene‐vinyl acetate (EVA) copolymer in the same range of temperature. The formation of EVA chemical network was demonstrated by HR‐MAS NMR spectroscopy and by measuring the gel fraction of EVA chains in hot toluene. From Flory theory, the crosslinking density of elastic strand was calculated to be 80 mol m−3 in agreement with the measurements from swelling ratio (VA/SiH molar ratio: 11.8). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Poly(arylene ether)s with pendant diphenyl phosphoryl groups: Synthesis, characterization, and thermal properties
Authors: Tienda Kevin , Yu Zhenning , Constandinidis Fadwa , Fortney Andria , Feld William A. , Fossum Eric 
Published: May 2011

AbstractA series of poly(arylene ether)s, (PAEs), carrying a pendant diphenyl phosphoryl group were prepared via the nucleophilic aromatic substitution (NAS) reactions of 3,5‐difluorotriphenylphosphine oxide, 6. The difluoro monomer 6 was synthesized via two‐step reaction sequence and subsequently characterized by 1H, 13C, 19F, and 31P NMR spectroscopy, GC/MS, and elemental analysis. The reactivity of the electrophilic sites in 6, activated by only a diphenylphosphoryl group located in the meta‐position, in 6 was probed via NMR spectroscopy and model reactions and was determined to be sufficient to undergo typical NAS reactions. High molecular weight, amorphous, organic soluble poly(arylene ether)s, bearing a pendant diphenylphosphoryl group, were prepared via the reaction of 6 with a variety of bis‐phenols under typical NAS conditions. The poly(arylene ether)s were characterized for structure via the use of 1H, 13C, and 31P NMR spectroscopy while their thermal properties were evaluated using DSC and TGA analysis. The glass transition temperatures (Tg) of the synthesized PAEs ranged from 143 to 175 °C, while their 5% weight loss temperatures ranged from 467 to 510 °C under nitrogen and from 470 to 526 °C in air. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Structure and mechanical properties controlling of elastomer modified polypropylene by compounded β/α nucleating agents
Authors: Li Xiaoxi , Wu Haiyan , Dai Jian , Huang Ting , Wang Yong 
Published: May 2011

AbstractPrevious work showed that there was a synergistic effect of nucleating agent (NA) and elastomer in improving the fracture resistance of isotactic polypropylene (PP), relating to the formation of large amounts of β‐PP (β‐NA nucleated system) or the decrease of the spherulites diameters of α‐PP (α‐NA nucleated system). To find the direct relation between the synergistic efficiency of NA/elastomer and the microstructures of the materials, in this work, the ethylene‐propylene‐diene terpolymer (EPDM) modified PP blends with compounded NAs (β/α) were adopted and the changes of the microstructure and mechanical properties were investigated comparatively. The results showed that, with the adjustment of the mass fraction of compounded NAs, the microstructures of PP matrix including supermolecular structure and the relative fraction of β‐PP (Kβ) change accordingly. Specifically, the Kβ of β‐PP was successfully adjusted in the wide range of 0–78.9%. Consequently, the stiffness and the fracture resistance of the PP/EPDM blends were easily controlled in different degrees. It is believed that this work could provide a guide map for the design and preparation of certain polymer blends satisfying certain requirement. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Effect of molecular shape of diisocyanate units on the microscopic/macroscopic phase separation structure of polyurethanes
Authors: Park Kiho , Lim Wan Hee , Ko Eun‐A , Lee Han Sup 
Published: May 2011

AbstractThree diisocyanate units having different linearity and planarity on the basis of the arrangement of constituent aromatic rings are used to synthesize three polyurethanes (PUs) and the effects of the molecular structure of the diisocyanate units on phase separated morphologies of PUs have been studied. The linear and planar diisocyanate unit allows good packing of the hard segments in the hard domain by extensive intersegmental hydrogen bonding, and it forms a well ordered, long hard domain. However, the nonlinear and noncoplanar diisocyanate unit shows a lesser degree of hydrogen bonding in the short hard domain. Strong preferential orientation of the rigid/long hard domains inside a macroscopic grain boundary has been observed with the polarizing optical microscope especially for the PU based on the rigid diisocyanate. It was concluded that the molecular structure of the diisocyanate unit in PU plays an important role in determining the interchain interaction, the detailed phase‐separated domain structure, and local domain orientation in each grain boundary. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Fear of movement in cancer survivors: validation of the Modified Tampa Scale of Kinesiophobia—Fatigue
Authors: Velthuis Miranda J. , Van den Bussche Eva , May Anne M. , Gijsen Brigitte C. M. , Nijs Sara , Vlaeyen Johan W. S. 
Published: May 2011

AbstractObjective: To date, there is no validated questionnaire to assess fear of movement in cancer survivors. We aim to validate the Modified Tampa Scale of Kinesiophobia‐Fatigue (TSK‐F) in Dutch cancer survivors participating in a rehabilitation programme. We first select the optimal model for cancer survivors. Subsequently, stability, internal consistency, and construct validity of the optimal model is tested.Methods: A sample of 658 cancer survivors participating in a rehabilitation programme was included. Out of nine models derived in chronic pain and chronic fatigue patients, the optimal model of the TSK‐F was selected in a calibration sample (n1 = 329) using confirmatory factor analysis. Stability of the derived optimal model was confirmed in a validation sample (n2 = 329). Internal consistency and construct validity were assessed in the full sample.Results: The 11‐item two‐factor model of the TSK‐F was the best‐fitting model for cancer survivors and it seemed to be invariant for sex and cancer diagnosis. Internal consistency of the model was acceptable (Cronbach's alpha between 0.62 and 0.74). Construct validity was illustrated by significant associations between TSK‐F total and TSK‐F somatic focus with perceived global health status (EORTC‐QOL‐C30) and fatigue (FACT‐F) (p<0.001).Conclusions: The adjusted 11‐item TSK‐F consisting of two subscales ‘somatic focus’ and ‘activity avoidance’ seems to be a robust and valid tool in measuring fear of movement in cancer survivors with an acceptable internal consistency. Further psychometric testing of the TSK‐F in cancer survivors is recommended. In the future, TSK‐F scores may be used to customise rehabilitation programmes in cancer survivors.Copyright © 2011 John Wiley & Sons, Ltd.
Clinical validation of the EORTC QLQ‐OG25 questionnaire for the evaluation of health‐related quality of life in Mexican patients with esophagogastric cancers
Authors: Oñate‐Ocaña Luis F. , Velázquez‐Monroy Natalia , Vázquez Luis , Espinosa‐Mireles‐de‐Villafranca Pablo , Núñez‐Rosas Elvia , Ovando‐Lezama Maira , Vilar‐Compte Diana , García‐Hubard Gabriela , Carrillo José F. , Blazeby Jane M. , Aiello‐Crocifoglio Vincenzo 
Published: May 2011

AbstractBackground: Quality of life questionnaires (QLQ) QLQ‐STO22 and QLQ‐OES18 are currently available to measure Health‐related quality of life (HRQL) in patients with Esophageal (EC) or Gastric cancer (GC). The QLQ‐OG25 integrates questions from both questionnaires to be useful for EC, Esophagogastric junction carcinoma (EGJC), and GC. Our aim was to validate the Mexican‐Spanish version.Patients and Methods: The translation procedure followed European Organization for Research and Treatment of Cancer (EORTC) guidelines. QLQ‐C30 and QLQ‐OG25 instruments were completed by patients with EC, EGJC, and GC. Patients were divided into three groups: (1) palliative treatment; (2) treatment with curative intent, and (3) survivors. Reliability and validity tests were performed.Results: One‐hundred sixty‐three patients were included: 62 women and 101 men (mean age, 54.9 years; range, 22–82 years). Sixty‐nine, seventy‐three, and twenty‐one patients were allocated into groups 1, 2, and 3, respectively. Questionnaire compliance rates were high and were well accepted. Group 3 patients reported better functional HRQL scores and lower symptom scores than patients in groups 2 and 1. Scales in the QLQ‐C30 and QLQ‐OG25 distinguished among other clinically distinct groups of patients. Cronbach's α coefficients of all multi‐item scales of the QLQ‐OG25 instrument were >0.7 (range, 0.7–0.83). Multitrait scaling analysis demonstrated good convergent and discriminant validity, even adjusting by location. Test–retest scores were consistent.Conclusion: The Mexican‐Spanish version of the EORTC QLQ‐OG25 questionnaire is reliable and valid for HRQL measurement in patients with esophagogastric cancer and can be used in clinical trials in the Mexican community. Copyright © 2011 John Wiley & Sons, Ltd.