bluuebunny/crossref_metadata_2025 huggingface dataset:
The 2004 Indian Ocean tsunami: Tsunami source model from satellite altimetry
Authors: Hirata Kenji , Satake Kenji , Tanioka Yuichiro , Kuragano Tsurane , Hasegawa Yohei , Hayashi Yutaka , Hamada Nobuo
Published: August 2014

Satellite altimetry measurements of sea surface heights for the first-time captured the Indian Ocean tsunami generated from the December 2004 great Sumatra earthquake. Analysis of the sea surface height profile suggests that the tsunami source, or the seafloor deformation, of the great earthquake propagated to the north at an extremely slow speed of less than 1 km/sec on average for the entire 1300-km-long segment along the northern Sumatra-Nicobar-Andaman Trench. The extremely slow propagation speed produces a very long duration of tens minutes, longer than earthquake source duration estimated (480–500 sec) from short-periodP-wave radiation. The satellite altimetry data requires a total seismic moment of 9.86 × 1022Nm (Mw=9.3). This estimate is approximately 2.5 times larger than the value from long-period surface wave analysis but nearly the same as that from the ultra-long-period normal mode study. The maximum amount of slip (∼30 m) is identified in an offshore region closest to the northern most part of Sumatra where the largest tsunami run-up heights were observed.
The Great Tsunami of 26 December 2004: A description based on tide-gauge data from the Indian subcontinent and surrounding areas
Authors: Nagarajan B. , Suresh I. , Sundar D. , Sharma R. , Lal A. K. , Neetu S. , Shenoi S. S. C. , Shetye S. R. , Shankar D.
Published: August 2014

The Great Tsunami of 26 December 2004 is described using data from seven tide gauges in India and others from surrounding areas in the Indian Ocean. The tsunami struck the Indian east coast around 0330 UTC. The amplitude was 2 m above the tide at Chennai, Paradip, and Colombo. The east coast of India (and of Sri Lanka) was hit shortly after high tide; Tuticorin and Colombo, however, were hit shortly after low tide. The tsunami wave propagated northward along the Indian west coast. All these gauges are to the west of the earthquake zone and the detided sea levels show first a rise in sea level with the arrival of the tsunami, and then a sharp decrease. Spectral and wavelet analysis of the detided series show that the maximum amplitude was at a period of 35–45 minutes, with another maximum around 20 minutes. Along the Indian east coast, however, there is another broad peak between 1–2 hours within the first few hours after the first tsunami wave.
Tsunami heights and damage along the Myanmar coast from the December 2004 Sumatra-Andaman earthquake
Authors: Satake Kenji , Aung Than Tin , Sawai Yuki , Okamura Yukinobu , Win Kyaw Soe , Swe Win , Swe Chit , Swe Tint Lwin , Tun Soe Thura , Soe Maung Maung , Oo Thant Zin , Zaw Saw Htwe
Published: August 2014

The tsunami heights from the 2004 Sumatra-Andaman earthquake were between 0.4 and 2.9 m along the Myanmar coast, according to our post tsunami survey at 22 sites in Ayeyarwaddy Delta and the Taninthayi coast. Interviews to coastal residents indicate that the tsunami heights were lower than high tide level in rainy season, probably by storm surge. They also testified that the arrival times were between 2 and 5.5 hours after the earthquake but the reliability may be low because nobody felt ground shaking. Much smaller tsunami than the neighboring Thai coast, where the tsunami heights were 5 to 20 m, explains relatively slighter tsunami damage in Myanmar; the casualties were reported as 71, compared to about 8300 in Thailand. The smaller tsunami was probably due to the fact that the main tsunami source did not extend to Andaman Islands. The tsunami travel times and maximum heights computed from a 700 km long source are basically consistent with the observations. For a nearby tsunami source, the tsunami hazard would be more significant in Myanmar, because coastal houses are unprotected for tsunamis and no infrastructure exists to disseminate tsunami warning information.
Lipocalin 2 is a Regulator Of Macrophage Polarization and NF-κB/STAT3 Pathway Activation
Authors: Guo Hong , Jin Daozhong , Chen Xiaoli
Published: August 2014

Lipocalin 2 (Lcn2) has been previously characterized as an adipokine/cytokine and implicated in obesity and inflammation. Herein, we investigated the role and potential mechanism of Lcn2 in the regulation of macrophage polarization in obesity-associated inflammation. We observed that Lcn2−/− mice displayed an up-regulation of expression of M1 macrophage marker Cd11c but a down-regulation of M2 marker arginase 1 in adipose tissue and liver of mice upon a high-fat diet feeding. Lcn2-deficient bone marrow–derived macrophages (BMDMs) were more sensitive to lipopolysaccharide (LPS) stimulation, leading to a more profound up-regulation of expression of pro-inflammatory markers than wild-type (WT) BMDMs. Accordingly, LPS stimulation elicited an increase in the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), c-Jun, and STAT3 signaling pathways as well as an up-regualtion of expression of NF-κB and STAT3 target genes such as IL-1β, IL-6, iNOS, and MCP-1 in Lcn2−/− BMDMs compared with WT controls. Pre-treatment of recombinant Lcn2 attenuated LPS-stimulated degradation of IκBα and STAT3 phosphorylation as well as LPS-induced gene expression of IL-6 and iNOS in Lcn2−/− BMDMs. Moreover, the NFκB inhibitor markedly blocked LPS-stimulated STAT3 phosphorylation in Lcn2−/− BMDMs. These results together with the time course of Lcn2 secretion, NFκB and STAT3 phosphorylation in response to LPS stimulation, suggest that Lcn2 plays a role as an anti-inflammatory regulator in macrophage activation via modulating a feed-forward activation of NFκB-STAT3 loop.
The Quality of life of patients with morbid obesity before and after gastric banding and gastric bypass
Authors: Egiev V , Majorova J , Leont’yeva M , Meleshko A
Published: August 2014

In order to estimate the quality of life in bariatric surgery patients usually two scales are used: GIQLI (gastrointestinal Quality of life index) and BAROS (Bariatric analysis and reporting outcome system). In our work we used the original estimation of the quality of life, based on the questionnaire GIQLI. This questionnaire consists of two parts: universal and specific. For the estimation of the level of morbid obesity two main scores are utilized: overweight and the Body Mass Index (BMI). We estimated the quality of life of patients with morbid obesity before the operation (25 patients), after gastric banding (25 patients) and gastric bypass (25 patients). For the control group we show the answers for the same questionnaire of 26 volunteers without any chronic diseases, including morbid obesity. Gastric bypass was performed in patients with BMI more than 40 kg/m2, gastric banding was performed in patients with BMI less than 40 kg/m2. The median periods of supervising the patients after gastric bypass and gastric banding were 3±1,9 years and 4,3±1,7 years for each. After the surgery the percentage of reduction of the overweight was significantly higher in the patients after the gastric bypass. It means that the weight loss is more effective after gastric bypass than gastric banding. The index of the quality of life of the patients with the morbid obesity was much lower than in the control group (р0,05). After the surgical treatment all the scores increased in the group of the patients being operated on, than in the group of the patients with obesity before the operations (р0,05). While comparatively estimating the two operations we got practically the same results after gastric bypass and gastric banding. For gastric banding a very important index of the improvement of the quality of life is the level of the weight loss, but after the gastric bypass there were no such outcome.
Syndrome of hypogonadism in males
Authors: Rozhivanov R V
Published: August 2014

Hypogonadism in men - a clinical and laboratory syndrome caused by decreased secretion of testosterone by the testes. Depending on the level of destruction of the hypothalamic-pituitary-gonadal axis we distinguish two main forms of hypogonadism: hypergonadotrophic or primary hypogonadism and hypogonadotropic or secondary hypogonadism, clinical manifestations, diagnosis and treatment of which are presented in this clinical lecture. Keywords: hypogonadism, testosterone, hypergonadotrophic hypogonadism, hypogonadotropic hypogonadism, treatment.
Innere und äußere Kreise
Authors: Siems Renke
Published: August 2014

Der Beitrag rekonstruiert prominente bibliothekspolitische Beiträge der 1980er Jahre vor dem Hintergrund des unmittelbar danach einsetzenden digitalen Wandels und fragt danach, wie die seinerzeit kritisierten Strukturen und Mentalitäten bis heute aktuelle Problemlagen konturieren und die Rolle von Bibliotheken in digitalen Informationsumwelten (mit-)bestimmen.
Agenda 2020 für die Wildauer Hochschulbibliothek
Authors: Seeliger Frank
Published: August 2014

Die Wildauer Hochschulbibliothek hatte sich 2013 trotz guter „Bilanzen“ entschlossen, wegen der auf sie kommenden Unwägbarkeiten und Herausforderungen ein strategisches wie machbares Konzept zu erarbeiten. Dieses soll bis zum Jahr 2020 umgesetzt sein und die Entscheider im Umfeld der Hochschulbibliothek über ihre Ziele und Meilensteine verständigen. Die Stakeholder sollen über die schriftliche Fixierung ebenfalls dafür gewonnen und begeistert werden. Das ambitionierte Werk, die Agenda 2020, startete damit, dass das Bibliotheksteam fern vom Alltag an einem ungewöhnlichen, aber inspirierenden Ort in Klausur ging. Ein Segeltörn zu Pfingsten 2013 gab den Start für die Agenda 2020. Sieben Themenfelder konnten identifiziert und mit konkreten Vorhaben formuliert werden.
Die elektronische Ausleihe – rechtliche Rahmenbedingungen für minderjährige Bibliotheksbenutzer
Authors: Katzenberger Ruth , Kieselstein Jana
Published: August 2014

Verschiedene Anbieter eröffnen Bibliotheken die Möglichkeit der digitalen Ausleihe: Bibliotheksnutzer können im Rahmen der elektronischen Ausleihe über ein Internetportal ihrer Bibliothek elektronische Medien wie E-Books, E-Music oder E-Papers „ausleihen“. Analog zur Ausleihe eines Printmediums können die Nutzer für eine bestimmte Frist das elektronische Medium downloaden, sich für ausgeliehene Titel vormerken etc. Dieser Beitrag skizziert die Probleme, die sich ergeben können, sobald ein minderjähriger Bibliotheksnutzer aktiv an der elektronischen Ausleihe partizipieren möchte.
Museen, Archiv und Bibliothek – Provenienzforschung in der Klassik Stiftung Weimar
Authors: Haufe Rüdiger , Krokowski Heike , Prölß Peter
Published: August 2014

Die Klassik Stiftung Weimar überprüft ihre Bestände auf NS-verfolgungsbedingt entzogenes Kulturgut. Hierzu gehören die Sammlungen der Museen, die Bestände des Goethe- und Schiller-Archivs und der Herzogin Anna Amalia Bibliothek. Die Provenienzforscher müssen nicht nur die Spezifika der unterschiedlichen Objektarten, wie Gemälde, Grafiken, Autographen oder Bücher berücksichtigen, sondern auch die heterogene Vorgeschichte der Einrichtungen.
An additional marine fungal lineage in the Diatrypaceae, Xylariales: Pedumispora rhizophorae
Authors: Klaysuban Anupong , Sakayaroj Jariya , Jones E.B. Gareth
Published: August 2014

Pedumispora rhizophorae, a marine ascomycete reported only from mangrove habitats, was referred to the Diaporthales on the basis of morphological characteristics. To clarify the phylogenetic classification of P. rhizophorae, we re-examined the morphological features of a recent collection of this fungus and evaluated its taxonomic position at the molecular level. Phylogenetic analyses revealed that P. rhizophorae is distantly placed from the Diaporthales, and groups in the Diatrypaceae, Xylariales with strong support. Pedumispora rhizophorae shares many features with members of the Diatrypaceae, including its saprobic habit on decaying plant material, ascomata embedded in a pseudostroma, the presence of paraphyses and pigmented ascospores. However, P. rhizophorae differs from other members of the Diatrypaceae in that this species has apically truncate asci without an apical apparatus, which deliquesce at maturity, whereas diatrypaceous species have persistent long-stalked asci with a more or less truncate apex. Within the Diatrypaceae, the ascospores of most species are allantoid in shape and unicellular, whereas P. rhizophorae possesses septate, filiform ascospores with apical cells lacking cytoplasm. Filiform ascospores and deliquescing asci are common in many unitunicate marine ascomycetes and are regarded as an adaptation to aquatic environment.
Comparison of Improvacuter™ tubes with BD Vacutainer™ tubes for various hormones in the aspects of stability and influence of gel separators
Authors: Zungun Cevdet , Yılmaz Fatma MeriÇ , Boru Elif Guney , Topcuoglu Canan
Published: August 2014

Validation of blood collection tubes are important to determine the role of different collection tubes which influence the assurance of laboratory results. We compared two different tubes (Improvacuter

We compared the results of nine immunoassays performed on UniCel

Estradiol and testosterone concentrations obtained from Improvacuter Gel and Clot Activator tubes and BD Vacutainer SST II Advance tubes remained below the lower limits of analytical range for the same analytes while they were within the limits in BD Vacutainer Clot Activator tubes and Improvacuter tubes. Statistical significance of stability was not clinically significant for the hormone parameters we tested in all four tubes.

Gel containing tubes (both BD and Improve) gave comparable results with the tubes which do not contain gel except for estradiol and testosterone. The use of gel containing tubes for estradiol and testosterone are not recommended on UniCel
Key criteria for the design of polymeric stabilizers for aqueous titanium dioxide dispersions of high solid content
Authors: Creutz Serge , Jérôme Robert
Published: August 2014

Amphiphilic copolymers consisting of an aminated hydrophobic block and a hydrophilic poly(sodium methacrylate) one have been synthesized with different structures and tested as stabilizers for aqueous dispersions of alumina coated titanium dioxide (80 wt.-% solid). The dispersion stability is ruled by the strength of the anchoring of the aminated block onto the pigment and by the dynamics of the micelles formed by the copolymer. Any decrease in the anchoring strength, for example as a result of higher steric hindrance for the adsorbing block or of random rather than blocky distribution of the aminated co-units, is detrimental to the dispersion stability and makes this stability more dependent on the copolymer composition. Indeed, the position and dynamics of the unimers ⇄ micelles equilibrium then control the adsorption of the copolymer on the pigment during the grinding process.
Grafting of living poly(tetrahydrofuran) onto aminodendrimers
Authors: Tanghe Leen M. , Goethals Eric J.
Published: August 2014

Hybrid polymers consisting of poly(propyleneimine) dendrimers (AstramolTM) and linear poly(tetrahydrofuran) (polyTHF) were obtained by grafting living cationic polyTHF onto the dendrimer. By varying the mole ratio of polyTHF to dendrimer, either modified dendrimers, containing only a few linear polymer chains, or ‘superstar’ polymers, i.e. dendrimers containing a large number of polyTHF chains, were obtained. The average number of grafted chains per dendrimer unit, the grafting degree, could be estimated by means of 1H NMR spectroscopy. For polyTHF with molar mass of 2000 g/mol or lower, all primary amino functions of the dendrimers up to the 5th generation (32 primary amino functions) could be grafted. For polyTHF with molar mass of 4000 g/mol, the maximum grafting degree was lower than the number of primary amino groups available and decreased with increasing dendrimer generation.
Copolymerization of ethylene and 4-vinylcyclohexene by various metallocenes in the presence of Al(iBu)3/[Ph3C][B(C6F5)4]
Authors: Kim Il , Kim Young-tae
Published: August 2014

Copolymerizations of ethylene and 4-vinylcyclohexene (VCH) were carried out with isospecific rac-1,2-ethylenebis(1-indenyl)Zr(N(CH3)2)2 [rac-(EBI)Zr(NMe2)2] and syndiospecific isopropylidene(cyclopentadienyl)(9- fluorenyl)ZrMe2 [iPr(Cp)(Flu)ZrMe2] compounds combined with Al(iBu)3/ [Ph3C][B(C6F5)4] as a cocatalyst system. VCH was regioselectively inserted into the copolymer through the vinyl double bond, leaving the endocyclic double bond unreacted. rac-(EBI)Zr(NMe2)2 catalyst showed a higher polymerization rate but lower VCH reactivity than the iPr(Cp)(Flu)ZrMe2 catalyst. The calculation of copolymerization parameters according to Kelen-Tüdös resulted in rE = 131.49 and rVCH = 0.02 for the iPr(Cp)(Flu)ZrMe2 catalyst. When [VCH] in feed was 90.5 mol-%, [VCH] in polymer was 1.88 and 8.04 mol-% for rac-(EBI)Zr(NMe2)2 and iPr(Cp)(Flu)ZrMe2 catalysts, respectively. The resulting copolymers were characterized using NMR, Raman and intrinsic viscosity measurements.
Synthesis and structure-property relationships of novel poly(p-xylylene)s with aromatic substituents
Authors: Ishaque Michael , Wombacher Ralf , Wendorff Joachim H. , Greiner Andreas
Published: August 2014

Two step synthesis of educts for the synthesis of poly(p-xylylene)s was accomplished by Grignard-type coupling reaction of 4-bromotoluene and different aldehydes or p-tolylaldehyde and different aryl bromides followed by conversion of alcohols into corresponding chlorides. Derivatives of poly(p-xylylene) (PPX) were obtained by vapor phase pyrolysis/chemical vapor deposition (CVD) or Gilch-type polymerization of these chlorides. Functional groups along the PPX main chain were introduced by substituted phenyl rings in a-position. The resulting PPXs are soluble under ambient conditions and are amorphous in the solid state. The glass transition temperatures varied only slightly with substituents on the phenyl ring in a-position. Significant enhancement by substituents was found for the thermal stability under nitrogen and a considerable decrease of the surface energies by fluorinated substituents.
PVC/poly(norbornene ester) blends: mixtures of flexible and rigid random coils
Authors: Raubacher Florian , Roth Mark D. , Wendorff Joachim H.
Published: August 2014

Considered are blends of the flexible coil-shaped poly(vinyl chloride) (PVC) and rigid coil-shaped polymers, poly(norbornene ester)s, characterized by strong rotational constraints. The unexpected finding is that the stepwise increase of the specific heat at the glass transition Tg as well as the relaxation of the enthalpy in a temperature interval below Tg (physical aging) vanish as the concentration of poly(norbornene ester)s increases in blends with PVC. The interpretation is that the very specific nature of the glass transition of the rotationally confined poly(norbornene ester) - cooperative librations within the minima of the rotational potential - controls the relaxation properties of the blends. The composition vs. glass transition temperature relation is strongly curved for the blends due to the very small increase of the specific heat of the poly(norbornene ester)s at the glass transition.
Quasi-one-dimensional platinum compound/polymer composites
Authors: Bremi Juliane , Caseri Walter , Smith Paul
Published: August 2014

Films of polymers comprising the quasi-one-dimensional compounds K2[Pt(CN)4]Br0.3, [Pt(NH3)4][PtCl4] (Magnus’ green salt), or [Pt(NH2Oc)4][PtCl4] (Oc = octyl) were prepared from homogeneous solutions followed by solvent evaporation. Above a percolation threshold of ca. 8 - 10% v/v, the composites adopted the semiconductor behavior of K2[Pt(CN)4]Br0.3 or Magnus’ green salt, respectively. In the case of Pt(NH2Oc)4][PtCl4], a network established in the gel state in organic solvents was retained in the composites. Upon orientation of the composites by drawing, dichroism of the materials comprising Magnus’ green salt and polarized light emission with K2[Pt(CN)4]Br0.3 was observed.
Complex formation and selective hydrogen bonding in poly(4-vinylphenol-co-methyl methacrylate)- poly(N-vinylpyrrolidone-co-vinyl acetate) systems
Authors: Akiba Isamu , Seki Takehiro , Akiyama Saburo
Published: August 2014

Poly(4-vinylphenol-co-methyl methacrylate) (P(VPh-MMA)) and poly(Nvinylpyrrolidone- co-vinyl acetate) (P(VPr-VAc)) form hydrogen bonding complexes with approx. 1:1 stoichiometry between the VPh unit of P(VPh-MMA) and the VPr unit of P(VPr-VAc) in methanol. These complexes show much higher glass transition temperatures than average polymer blends, suggesting the presence of extremely strong hydrogen bonds. FTIR measurements revealed selective hydrogen bonds between the hydroxy group of VPh units in P(VPh-MMA) and the carbonyl group of VPr units in P(VPr-VAc).
Nanocomposite materials: from lab-scale experiments to prototypes
Authors: Dortmans Ardi , Batenburg Lawrence F. , Koster Theodorus P. M , Nelissen Roel G. , Fischer Hartmut
Published: August 2014

A porous PMMA material has been reinforced by clay particles, and properties of the resulting material were evaluated. The clay has been intercalated in a first step by melt-extrusion with a suitable block copolymer. A radical polymerisation reaction after swelling of the intercalated clay with monomer leads in a subsequent step to a nanocomposite material with improved mechanical properties. The optimum load of modified clay was determined to be about 3 to 4 wt.-%. A separation of the reinforcing mineral into single sheets and a subsequent homogeneous incorporation of these sheets into the polymer matrix material increased different mechanical properties by approximately 60%. The lifetime of porous polymer moulds used for pressure casting of sanitary ware has been analysed, modelled and increased. The mechanical behaviour of the existing porous PMMA mould material was analysed using mechanical tests to assess the lifetime under cyclic loading. The relevant stress levels were obtained through in situ strain gauge measurements on a polymer mould for the production of a washing basin. These results were confirmed by means of finite element stress analyses. The lifetime of the washing basin mould under the relevant production conditions was predicted from these data and found to be in good agreement with practical experience. A method to improve the limited lifetime under higher pressures was developed by applying nanodispersed clay as reinforcement. The improved material shows an increase in lifetime under cycling loading by about 1000% in mechanical tests. This improvement is confirmed for a pressure casting mould made of the improved material when used in the actual production process.
Poly(styrene/acrolein) and poly(styrene/α-tert-butoxy-ω- vinylbenzyl-polyglycidol) microspheres. Similarities and differences
Authors: Basinska Teresa
Published: August 2014

Properties of two types of polystyrene microspheres with polyacrolein and polyglycidol components in their surface layers are compared. Microspheres were prepared in batch radical emulsifier-free emulsion copolymerizations of styrene with acrolein and/or α-tert-butoxy-ω-vinylbenzyl-polyglycidol macromonomer ( Mn̅ = 2700). Polymerizations were initiated with potassium peroxodisulfate, and the ratio of initial concentrations of styrene and initiator was constant. Number average diameters of poly(styrene/acrolein) (P(S/A)) and of poly(styrene/polyglycidol) (P(S/PGL)) particles were in the range of 200 - 650 nm and decreased with increasing concentration of acrolein and/or polyglycidol in the polymerizing mixtures. The diameter polydispersity of synthesized particles ( Dw ̅ /Dn̅) was usually lower than 1.02. X-ray photoelectron spectroscopy for P(S/A) and P(S/PGL) microspheres showed that surface layers of particles were significantly enriched in polyacrolein or polyglycidol segments, surface fractions of which increased with increasing concentration of the more hydrophilic comonomer in the polymerizing mixture. In the case of P(S/A) particles, the maximal fraction of polyacrolein approached 80 mol-%, whereas for P(S/PGL) particles the maximal surface fraction of PGL was 42 mol-%. Human serum albumin was used as a model protein for studies of attachment onto P(S/A) and P(S/PGL) microspheres. It has been found that for both kinds of particles, the maximal surface concentration of attached (adsorbed and/or covalently immobilized) protein decreased with increasing fraction of hydrophilic component in the particle surface layer (polyacrolein or polyglycidol units). In the case of P(S/A) particles, adsorption always accompanied covalent immobilization of proteins. To the contrary, covalent immobilization of proteins onto the P(S/PGL) microspheres proceeded without adsorption of proteins.
Orientation behaviour of AB and ABC block copolymers under large amplitude oscillatory shear flow in bulk and in concentrated solution
Authors: Stangler Stefan , Abetz Volker
Published: August 2014

Flow alignment in a large amplitude oscillatory shear field of lamellar AB and ABC block copolymers has been studied in bulk and in solution. Flow birefringence and 2D small-angle X-ray scattering were used to monitor the orientation. Qualitatively similar orientation behaviour was found for the diluted and the bulk AB block copolymer. While in AB diblock copolymers there is only one interface between the different blocks which may influence the orientation behaviour, in ABC triblock copolymers there are two interfaces within the macromolecule. It will be shown that the introduction of a third block leads to a quite different orientation behaviour in comparison to the AB system. In the lamellar diluted ABC system always the parallel orientation dominates, but it occurs in coexistence with the perpendicular and transverse orientations.
Kinetics of the anionic polymerization of 2-(tertbutyldimethylsilyloxy) ethyl methacrylate
Authors: Breiner Thomas , Schmidt Hans-Werner , Müller Axel H. E.
Published: August 2014

The kinetics and the extent of side reactions of the anionic polymerization of silyl-protected 2-hydroxyethyl methacrylate, 2-(tert-butyldimethylsilyloxy)ethyl methacrylate (TBDMS-HEMA), in tetrahydrofuran (THF) were studied as a function of polymerization temperature. Lithium chloride was added in order to achieve a controlled polymerization. The results of polymerizations at various temperatures are compared with reported data for methyl methacrylate and tert-butyl methacrylate in THF. The activation energy for the studied monomer is lower compared to the other methacrylates. Gel permeation chromatography-viscosity studies show that poly(TBDMS-HEMA) exhibits a more wormlike structure in THF than other polymethacrylates, as indicated by a higher Mark-Houwink exponent, α = 1.025.
Dynamic mechanical properties of crystalline polymer blends. The influence of interface and orientation
Authors: Galeski Andrzej
Published: August 2014

Modification of the interface changes the viscoelastic response of crystalline polymer blends. For incompatible systems, usually one or more additional tan δ (mechanical loss) peaks appear which reflect the embrittlement of the material. Upon proper compatibilization, the additional peaks disappear and the material becomes tougher. The associated phenomena are explained and illustrated by a number of examples including polypropylene filled with calcium carbonate, polyethylene (PE) and polystyrene compatibilized blends, compatibilized blends of poly(ethylene terephthalate) (PET) with polyethylene as well as polyamide 6/polypropylene- graft-acrylic acid blends. Modes of deformation producing cavitation and cavity free deformation were applied to polymer blends in order to study the influence of molecular orientation and the presence of cavities. It is concluded that interfaces between blend components are weak elements of the blends even in the presence of a compatibilizer. Dynamic mechanical analysis (DMTA) evidenced the occurrence of interactions of the compatibilizer with blend components through temperature shift and intensity change of α, β and γ relaxation processes of polymer components. In oriented films of PET/high-density PE compatibilized blends, the chain segments in the amorphous phase of PET are oriented along machine direction. However, there is a significant anisotropy of chain packing in the plane perpendicular to the drawing direction - the pseudohexagonal packing of chain fragments being in register over the whole film. The PET amorphous phase exhibits anisotropy: DMTA studies show that the glass transition occurs at different temperatures while bending the film in different directions. The source of the ‘anisotropy’ in glass transition is the anisotropy of the amorphous phase: the pseudohexagonal packing and the orientation of chain segments. It is evident that the free volume and frozen fraction of the amorphous phase exhibit some degree of anisotropy. In highly compressed samples free of cavities, the glass transition temperature is shifted to higher temperature as compared to undeformed or drawn and cavitated blends. The shift is the result of high molecular orientation of the amorphous phase of matrix polymer and of the stabilization effect of unbroken interfaces in compressed samples.
Labile hyperbranched poly(triazene ester)s – decomposition behavior and their use as porogens in thermally stable matrix polymers
Authors: Eigner Markus , Voit Brigitte , Estel Katrin , Bartha Johann W.
Published: August 2014

Hyperbranched polyesters containing labile triazene units in the main chain have been characterized according to their photochemically and thermally induced decomposition behavior. Irradiation with UV light results in a first order decomposition behavior with half-time of 6 to 48 min depending on the structure of the repeating unit. Thermal decomposition starts at about 160°C, and about 50% mass loss are achieved after 15 min at 250°C. Homogeneous incorporation of these globular, functional polymers in thermostable polymer matrices (polyimides and benzocyclobutane-based polymers) was possible. Smooth films from blends of thermostable matrix and up to 50% hyperbranched polymers could be prepared. The hyperbranched component could be destroyed selectively, and the resulting porous matrix has been studied as insulating material for microelectronic multilayer applications.
pH Dependence of the morphology of aqueous micelles formed by polystyrene-block-poly(2-vinylpyridine)-blockpoly( ethylene oxide) copolymers
Authors: Gohy Jean-François , Willet Nicolas , Varshney Sunil K. , Zhang Jian-Xin , Jérôme Robert
Published: August 2014

The morphology of micelles formed by two polystyrene-block-poly(2- vinylpyridine)-block-poly(ethylene oxide) (PS-b-P2VP-b-PEO) copolymers was studied in water by dynamic light scattering and transmission electron microscopy. Spherical micelles were observed that consist of a PS core, a P2VP shell and a PEO corona. The characteristic size of core, shell and corona depends on the copolymer composition. An important increase in micellar size occurs at pH < 5 as a result of P2VP block protonation. The reversibility of this pH effect depends on copolymer composition, too. The conformation of the PEO block plays an important role in this pH driven morphological transition.
Low voltage scanning electron microscopy and atomic force microscopy: state-of-the-art microscopy techniques for investigations of polymer single crystals
Authors: Loos Joachim , Tian Mingwen
Published: August 2014

Recent studies on organization and reorganization of polymer single crystals have contributed to the actual discussion on novel approaches towards understanding polymer crystallization and melting. In this context, low voltage scanning electron microscopy (LVSEM) and atomic force microscopy (AFM) demonstrate their importance for the investigation of polymer crystals. Both techniques are able to visualize the morphology of individual single crystals, which have a thickness in the order of 10 to 30 nm and a lateral size of a few micrometers, respectively, without any additional sample treatment such as coating or etching. Main advantage of LVSEM is its large range of observation: LVSEM is suited for fast screening and sample quality evaluation on the millimeter or micrometer level, and at the same time it has the prospect for detection of morphological details with nanometer resolution. The main strength of AFM is twofold: first, its excellent ability for precise quantitative thickness determination of the crystals, and second, using non-contact mode it can act as a non-destructive investigation technique, which allows in situ investigation of dynamic processes during sample treatment. By presenting some results of our studies, e.g., time dependent growth or temperature dependent annealing behavior of individual single crystals, we like to point out the specific advantages of the two techniques for fundamental studies on individual crystals, or ultra-thin polymer layers in general.
Morphological basis for the complex melting behaviour of isotactic polystyrene
Authors: Al-Hussein Mahmoud , Strobl Gert
Published: August 2014

Temperature-dependent small-angle X-ray scattering spectroscopy of isothermally cold crystallized isotactic polystyrene revealed considerable morphological reorganization during subsequent heating to the melt. Both the crystalline thickness and the long period increased continuously with increasing temperature before the samples finally melted. The temperature dependence of these changes correlated very well with the melting behaviour observed with differential scanning calorimetry. As the temperature increased during a heating scan, the initial lamellae that formed during isothermal crystallization showed only little reorganization until they started to melt. Then, the molten material recrystallized continuously into increasingly thicker lamellae at increasing temperature until they finally melted. As the crystallization temperature approached the final melting temperature of the recrystallized lamellae, the initial lamellae melted without further recrystallization and no morphological changes were seen in this case.
Change of modulus and yielding properties of syndiotactic polypropylene with the glass transition
Authors: Men Yongfeng , Strobl Gert , Wette Patrick
Published: August 2014

Semi-crystalline polymers like syndiotactic polypropylene pass during tensile deformation different stages with cross-overs at four critical points. Temperature variation above ambient changes the stresses at the critical points, but leaves the strains constant. Cooling down to the glass transition leads to the following changes: Fracture occurs before the onset of strain hardening. Yield point strain shifts to lower values. Young’s modulus increases by a factor on the order of the inverse of the crystallinity, as can be expected when the amorphous regions also contribute to the transmission of forces.
Simulation of size exclusion chromatography for branched polymers formed by simultaneous long-chain branching and random scission
Authors: Tobita Hidetaka , Kawai Hideki
Published: August 2014

In free-radical olefin polymerization, polymer transfer reactions can lead to chain scission as well as to the formation of long-chain branches. The dimensions of branched polymers so formed are investigated theoretically, by focusing our attention on the effects of scission frequency that is often difficult to determine. Scission reactions decrease the weight-average molecular weight significantly. When the polymer molecules are fractionated by the degree of polymerization (DP), however, the averages of branching density P ρ ̅and the mean-square radius of gyration of polymers with DP = P, P, are essentially unchanged, as long as the scission frequency is not very large. In a simple relationship between the ratios g and g’ of radii of gyration and hydrodynamic radii, g’ = gb, the value of b may change as a function of DP, and a simplified model function b = A log P + B was used to investigate the elution curve of size exclusion chromatography (SEC). It is shown that, although the molecular weight distribution (MWD) calibrated relative to standard linear polymers in SEC is much narrower than the true MWD, the use of a light scattering photometer to determine the absolute weight-average molecular weight within the elution volume makes the obtained MWD very close to the true one. On the basis of the P vs. P relationship, the calibrated MWD can be converted reasonably well to the true MWD. This simplified transformation method can be applied without knowing the scission frequency or the DP dependence of b. Once the true MWD is successfully estimated, a reliable parameter for the scission reaction can be determined.
Miscibility in blends of poly(ethylene-co-vinyl nitrate) and poly(vinyl methyl ketone)
Authors: Kondo Masashi , Akiba Isamu , Akiyama Saburo
Published: August 2014

The miscibility and interactions of poly(vinyl nitrate) (PVN) / poly(vinyl methyl ketone) (PVMK) and poly(ethylene-co-vinyl nitrate) (EVN) / PVMK blends were investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). PVN/PVMK blends were found to be miscible in the entire composition and temperature range. In addition, the compositional dependence of the glass transition temperature showed a positive deviation from the linear additivity rule, a phenomenon normally associated with compounds having attractive interactions. However, in this case, no attractive interactions between PVN and PVMK were identified by FTIR analyses. On the other hand, EVN/PVMK blends were found to be immiscible for most copolymer compositions, blend compositions and temperature ranges. Furthermore, intramolecular repulsive interactions of EVN were not apparent despite strong contrary expectations. Therefore, the phase behaviour in these blends was explained by a miscibility mechanism different from that of conventional polymer blends containing random copolymers.
Liquid crystalline vinylcyclopropane derivatives bearing cholesteryl side groups: synthesis, characterization and polymerization
Authors: Alupei Valentina , Ritter Helmut
Published: August 2014

New optically active 1,1-disubstituted 2-vinylcyclopropanes ,3a, b were synthesized by esterification of the corresponding 1-ethoxycarbonyl-2-vinylcyclopropane- 1-carboxylic acid 2a,b with cholesterol and characterized by 1H NMR and IR spectroscopy. The liquid crystalline properties of the obtained monomers are reported. The effect of the structure of the 2-vinylcyclopropane monomers on the phase transition of the mesogen was investigated. Radical polymerization of the asymmetrically substituted monomers 3a,b in solution and in bulk resulted in liquidcrystalline polymers with 1,5-opened units, as evidenced by 1H NMR spectroscopy.
Self-organized structures of hydrogen bonded poly(4-vinylphenol) - tertiary amino lipid mixtures
Authors: Akiba Isamu , Sakurai Kazuo
Published: August 2014

Mesomorphic structures of hydrogen bridged poly(4-vinylphenol) - N,N-dimethyl- n-octadecylamine (PVPh-NDOA) and PVPh - N,N-dioctadecylmethylamine (PVPh-DOMA) mixtures were investigated by means of wide angle X-ray diffraction, small angle X-ray scattering, and IR spectroscopy. Octadecyl chains of the PVPh-NDOA and PVPh-DOMA mixtures showed hexagonal αH and orthorhombic βO packing, respectively. In addition, PVPh-NDOA and PVPh-DOMA formed lamellar structures with periods of 3.5 and 2.5 nm, respectively.
Preparation of cellulose acetate films with controlled porosity
Authors: Estrada Rodolfo-Fabian , Alvarez-Gayosso Carlos , Castaño Victor M.
Published: August 2014

Porous polymeric films were obtained by immersing a solution of cellulose acetate and high molecular weight poly(acrylic acid) into an ice-water mixture. The films, the porosity of which can be controlled (reversibly) by immersion into hot water for varying periods of time, were characterized by IR spectroscopy and lowvacuum scanning electron microscopy.
Kinetic parameter estimation using an adiabatic reaction, with validation using NIR spectroscopy, 1 Application to a macrodiol / isocyanate polyurethane formulation
Authors: Dupuy Jérôme , Maazouz Abderahim , Benali Samira
Published: August 2014

A kinetic model of the cure of a polyurethane formulation is determined by the evolution of the conversion calculated during adiabatic experiments. The identified kinetic parameters are validated with two different methods: i) by comparing the simulated and measured evolutions of the conversion rates during these adiabatic reactions, ii) by comparing the simulated and measured (using NIR spectroscopy) evolution of the conversion into a mould during a RIM process.
Degradation of chitosan in the presence of poly(vinyl alcohol) and poly(acrylic acid) by a crude enzyme complex from Trichoderma viride
Authors: Paneva Dilyana , Mincheva Rosica , Stoilova Olya , Manolova Nevena , Rashkov Iliya
Published: August 2014

The degradation of chitosan in the presence of poly(vinyl alcohol) (PVA) or poly(acrylic acid) (PAA) by a crude enzyme complex from Trichoderma viride was studied. It was found that neither PVA nor PAA suppress chitosan hydrolysis. By varying the experimental conditions, the optimal conditions for chitosan degradation in the presence of PVA (37°C, pH 6) or PAA (37°C, pH 4) were found. The biocontrol agent T. viride was embedded in films of chitosan, PVA, chitosan/PVA and chitosan/PAA. Microbiological tests showed that T. viride retained its ability to develop and reproduce in all studied film types. The obtained results imply that the prepared systems are appropriate carriers of biocontrol agents and might be used as novel agropharmaceuticals.
Convenient synthesis of a surface-active alkoxyamineinitiator from styrene oxide Living/free-radical polymerization of styrene and n-butyl acrylate
Authors: Beyou Emmanuel , Humbert Julien , Chaumont Philippe
Published: August 2014

A novel alkoxyamine based on N-tert-butyl-1-diethylphosphono-2,2- dimethylpropyl nitroxide (DEPN) has been designed with a functional group, which promotes the chemisorption of free silanols from silicon surface and organicinorganic hybrid materials by a sol-gel process. This alkoxyamine has been synthesized in high yield from styrene oxide and has been employed for the nitroxide-mediated polymerization of styrene and n-butyl acrylate. The resulting alkoxysilane-containing homo- and copolymer precursors have been shown to have narrow molecular weight distributions.
Polyolefin structural control using phenoxy-imine ligated group 4 transition metal complex catalysts
Authors: Matsukawa Naoto , Ishii Sei-ichi , Furuyama Rieko , Saito Junji , Mitani Makoto , Makio Haruyuki , Tanaka Hidetsugu , Fujita Terunori
Published: August 2014

This paper describes the structural control of polyolefins achieved by using group 4 transition metal complex catalysts featuring a pair of phenoxy-imine chelate ligands (named FI catalysts). FI catalysts can produce very low to ultrahigh molecular weight polymers. For example, a Zr-FI catalyst bearing a cycloalkyl group on the imine-nitrogen with methylaluminoxane (MAO) activation is capable of selectively forming vinyl-terminated low molecular weight polyethylenes (Mw < 5000) whereas a Zr-FI catalyst with a triethylsilyl group ortho to the phenoxyoxygen can generate ethylene/propylene amorphous copolymers with ultra-high molecular weights (Mw > 10 000 000) when treated with iBu3Al / Ph3CB(C6F5)4. In addition, a Ti-FI catalyst, possessing an o-phenoxytrimethylsilyl group, with MAO can form highly syndiotactic polypropylenes ([rrrr] = 84%, Tm = 140°C) via a chainend control mechanism. Conversely, upon activation with iBu3Al / Ph3CB(C6F5)4, a Hf-FI catalyst with a tert-butyl group ortho to the phenoxy-oxygen is able to produce high molecular weight isotactic polypropylenes ([mm] = 69%, Tm = 124°C, Mw = 412 000) via a site control mechanism. Therefore, FI catalysts have shown the ability to create various polyolefin architectures by simple variation of the central metal, the ligand structure and the co-catalyst.
Morphology and mechanical properties of transcrystalline isotactic polypropylene
Authors: Nitta Koh-hei , Yamamoto Yoshikazu
Published: August 2014

We examined mechanical and morphological properties of fully transcrystalline polypropylene grown from the surface of poly(tetrafluoroethylene) sheets. Comparison of mechanical properties between transcrystalline and spherulitic polypropylenes demonstrated that Young’s modulus is dependent on the crystallinity and independent of the supermolecular structure. On the other hand, the mechanical yielding process was predominantly affected by the supermolecular structure, and the mechanical energy required for yielding of transcrystalline sheets was greater than that of the spherulitic morphology. In addition, it was found that mechanical necking is required for the alignment of lamellae in the stretching direction. This means that the unfolding process of lamellae orienting in the stretching direction is associated with necking and ductility.
Viscometric investigations on the intrinsic viscosity of polyvinylpyrrolidone affected by polymer-polymer interactions in solution
Authors: Al-Azhar Omar Melad
Published: August 2014

The intrinsic viscosity of polyvinylpyrrolidone (PVP) and various added polymers was investigated by the polymer-solvent method. It has been found that both polymer-polymer interactions and the concentration of the added polymer affect the intrinsic viscosity of PVP. In the ‘polymer-solvent’ system poly(methyl methacrylate) + dimethylformamide (PMMA+DMF), the intrinsic viscosity of PVP decreases as the concentration of PMMA increases, showing that the repulsive interaction between PVP and PMMA originates from the contraction of PVP coils in solution due to the intermolecular excluded volume. However, in the polymersolvent systems poly(vinyl chloride) (PVC) + DMF or poly(vinylidene fluoride) (PVDF) + DMF, the attractive interactions between PVP and PVC or PVDF cause an expansion of PVP coils in solution at high concentrations of PVC or PVDF. The polymer-solvent method allows estimating the compatibility of the used polymers.
Synthesis and characterization of poly(ethyl glyoxylate) – a new potentially biodegradable polymer
Authors: Burel Fabrice , Rossignol Laetitia , Pontvianne Pascale , Hartman Jonas , Couesnon Nicole , Bunel Claude
Published: August 2014

Poly(ethyl glyoxylate) (PEtG), a new polyacetal, was synthesized via anionic polymerization in CH2Cl2. End-capping was achieved using phenyl isocyanate. Average molecular weights in the range of 9000 - 216 000 were obtained. 1H and 13C NMR characterization highlight the non-stereoregularity of PEtG. The polymer is quasi-atactic and the polymerization almost followed a Bernoulli process. Compared to its homologue poly(methyl glyoxylate), PEtG exhibits enhanced thermal stability (>200°C) and a lower glass transition temperature, Tg. Molecular weight influences Tg, but does not affect thermal stability.
Kinetics of non-isothermal melting and crystallization of gamma-irradiated isotactic polypropylene
Authors: Nedkov Emanuel , Dobreva Tatyana
Published: August 2014

The non-isothermal kinetics of melting and crystallization of gamma-irradiated isotactic polypropylene were investigated by differential scanning calorimetry. At constant temperature the melting rate increased with the dose. During the melting, the average lamellar thickness, the free surface energy and the transport energy through the phase boundary reduced with increasing the dose. The crystallization rate decreased with increasing dose at constant temperature. Mixed α-γ spherulites were grown during crystallization. The non-isothermal crystallization rate expressed, in fact, the rate of secondary nucleation of the lamellae in the spherulites and their growth. Raising the irradiation doses led to a decrease of the crystallization temperature. A critical dose of irradiation of about 200 kGy was found, where the dependences of the calculated kinetic parameters underwent an important change. This change could be successfully connected with the effect of radiation annealing and melting.