bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption, desorption, resorption, redesorption, and diffusion of haloalkanes into polymeric blend of ethylene–propylene random copolymer and isotactic polypropylene
Authors: Aminabhavi Tejraj M. , Phayde Hemant T. S. 
Published: April 2003

AbstractMolecular transport of haloalkanes into sheets of a polymeric blend of an ethylene–propylene random copolymer and isotactic polypropylene has been studied by a sorption gravimetric technique in the temperature interval of 25–70°C. For all liquids, equilibrium sorption, desorption, resorption, redesorption, and degree of penetrant overshoot have been influenced by the nature of the liquid and the temperature. Diffusion coefficients were calculated from the sorption–desorption kinetic curves using Fick's mathematical relations. The values of diffusion coefficients followed the Arrhenius‐type behavior. The temperature‐dependent sorption data were analyzed using the van't Hoff relation. The activation parameters for diffusion and heat of sorption data were discussed in terms of the molecular interactions between liquids and the polymer chain segments. The experimental and calculated results are discussed on the basis of the chemical nature of liquids. © 1995 John Wiley & Sons, Inc.
Studies on natural rubber bound para‐phenylenediamine antioxidants in NBR
Authors: Avirah Shanti A. , Joseph Rani 
Published: April 2003

AbstractPara‐phenylenediamine (PD) was chemically attached to depolymerized natural rubber by a photochemical reaction. The rubber bound PD was characterized by TLC, 1H‐NMR, IR, and TGA. The efficiency and permanence of the bound PD were compared with conventional antioxidants in NBR vulcanizates. The rubber bound PD was found to be less volatile and more resistant to water and oil extraction. The vulcanizates showed improved aging resistance in comparison to vulcanizates containing conventional antioxidants. The liquid rubber bound antioxidant reduces the amount of plasticizer required for compounding. © 1995 John Wiley & Sons, Inc.
Structure development in processing of polypropylene films with additives
Authors: Radhakrishnan S. , Kane K. , Kadu A. , Natu H. P. 
Published: April 2003

AbstractThe crystallization behavior, modification of crystalline form, and orientation in polypropylene processed by blow film extrusion was studied as a function of processing parameters as well as different types of additives. The isothermal crystallization rate was greatly enhanced in the presence of certain additives, especially CaCO3. The crystalline form was predominantly α type in both compression molded or blow extruded films. However, there was an unusually large intensity of the α040 peak in the X‐ray diffraction of the latter case films. The variation of the peak intensities and the increase of birefringence with increase of take‐up speed has been explained on the basis of orientation induced by uniaxial stress in the machine direction. This orientation contained two components, namely the orientation of the b axis of the crystallites and the orientation of loosely bound polymer chains in the amorphous regions. © 1995 John Wiley & Sons, Inc.
Solvent crazing as a stress‐induced surface adsorption and bulk plasticization effect
Authors: Kefalas V. A. 
Published: April 2003

AbstractIn solids with low bulk modulus, like polymer glasses, concentration of stress due to surface defects and other kinds of inhomogeneities can induce substantial surface tension reduction and bulk plasticization in extremely localized regions. This effect becomes important in the presence of organic liquids. As a liquid comes into contact with the polymer surface and as stress is applied, a point is reached when the work to draw new surface area becomes minimal. In addition, at least up to a diffusion limited extent, bulk solvation can also take place locally. At this point, solvent crazing initiates in the presence of a triaxial stress field, and craze fibrils are easily drawn with additional deformation. For van der Waals (WL) interactions between polymer and solvent, two different expressions for solvent craze initiation have been derived. The first is derived assuming interfacial tension reduction (ITR) is the dominant mechanism for solvent craze initiation. The second is derived assuming that flaw tip bulk plasticization (BP) is the main mechanism for solvent craze initiation. Existing experimental data on six different glassy polymers was also examined with respect to the above two expressions. A relatively good functional relation (straight line passing near the origin) was found for a wide spectrum of glassy polymers and apolar (WL) liquids, for both the (ITR) and (BP) cases. Additional assumptions made in this analysis, especially about the stress concentration factor and the bulk modulus of the materials, indicate a better correlation with interfacial tension reduction data, in the case of (WL) liquids. However, better controlled experiments would be necessary to properly identify the mechanisms of environmental crazing, even in the case of (WL) liquids. © 1995 John Wiley & Sons, Inc.
Morphology and properties of blends of polyethylene with a semiflexible liquid crystalline polymer
Authors: Mantia F. P. La , Geraci C. , Vinci M. , Pedretti U. , Roggero A. , Minkova L. I. , Magagnini P. L. 
Published: April 2003

AbstractBlends of three polyethylene (PE) samples (two HDPE grades and LLDPE) with an experimental sample of a semiflexible liquid crystalline polymer (SBH 1:1:2 by Eniricerche) have been prepared in a Brabender compounder. The processing‐aid effect of the LCP has been demonstrated by the decreased energy required for extruding the blends, as compared to that needed for neat PE. The thermal properties, as studied by differential scanning calorimetry (DSC), have shown that the two components of the blends are immiscible. However, the dispersed SBH phase has been found to act as a nucleating agent for the crystallization of LLDPE, whereas no such effect was observed for HDPE. This has been taken as an indication that the phase interactions of SBH with LLDPE are more pronounced than with HDPE. The morphological study of the blends, done by scanning electron microscopy (SEM), has confirmed this conclusion. In fact, the SBH particles show a much better dispersion and a narrower size distribution in the LLDPE/SBH blends. The mechanical properties of the blends have been studied on compression‐molded specimens. The results indicate that the reinforcing effect of SBH is practically none for both HDPE grades. In fact, the elongation at break decreases to very low values, and the tensile strength is also reduced, when the LCP concentration increases beyond 5–10%, whereas the tensile modulus does not vary appreciably, over the whole (0–20%) LCP range investigated. On the contrary, the tensile modulus of the LLDPE/SBH blends increases up to ca. 50%, and the elongation at break decreases more smoothly, on increasing the SBH content up to 20%. © 1995 John Wiley & Sons, Inc.
Characterization of KEVLAR fibers using selected probes
Authors: Rebouillat S. , Escoubes M. , Gauthier R. , Vigier A. 
Published: April 2003

AbstractThe characterization of KEVLAR‐29 fibers has been performed by studying their interactions with three model compounds in gaseous form. Water, aniline, and epoxystyrene were used for this purpose. The effects on the nature of these interactions of two types of surface engineering, namely the coating with an epoxy resin and a reactive plasma treatment, were also studied. The results obtained from the three analytical techniques used in this work provide a more fundamental understanding of the fiber bulk properties vs. their surface characteristics. The diffusion, condensation, plasticization, and adsorption mechanisms involved during the interactions between the probes and the KEVLAR fibers are evidenced and discussed. © 1995 John Wiley & Sons, Inc.
Partial specific volume and thermal expansion coefficient of poly(N‐vinylimidazole)
Authors: Morales E. , Gómez‐antón M. R. , Piérola I. F. 
Published: April 2003

AbstractThe density of poly(N‐vinylimidazole) dilute solutions in methanol, triethylene glycol, dimethyl sulfoxide, and N,N‐dimethylformamide as well as in an aqueous neutral (with and without ionic strength) and acid solution have been measured at several temperatures. The specific volume of the polymer in bulk has been determined experimentally and theoretically, following the group aditivity method, and both values were coincident. Partial specific volume and thermal expansion coefficient were found to be solvent‐dependent. These results were interpreted in terms of the different types of solvation or the interaction of polymer‐solvent. © 1995 John Wiley & Sons, Inc.
Hydropolysilanes as precursors to silicon carbide
Authors: Shieh Yeong‐Tarng , Sawan Samuel P. 
Published: April 2003

AbstractA systematic study of the roles of three different types of monomers and their compositions in hydropolysilane homo‐, co‐, and terpolymers on their pyrolytic yields to silicon carbides was performed. The diorganodichlorosilane monomer, serving to increase molecular weights of the polymers, is not a significant factor in pyrolytic yields. The organotrichlorosilane monomer, leading to branched structures of the polymers, is helpful in obtaining high pyrolytic yields. The monoorganodichlorosilane monomer, providing crosslinking sites for the polymers, is useful in retarding decomposition during pyrolysis. The precursor‐to‐ceramic conversion chemistry was studied using thermogravimetry, infrared spectroscopy, X‐ray powder diffraction, and Rutherford backscattering spectrometry. The pyrolytic yields were not pyrolysis‐time‐dependent but decreased as the pyrolysis temperature increased. The apparent crystalline size increased as both the pyrolysis time and temperature increased. For a 30 min pyrolysis, the pyrolysis temperature must be over 1000–1200°C to provide a crystalline pyrolytic residue. © 1995 John Wiley & Sons, Inc.
Polymer encapsulation of arsenic‐containing waste
Authors: Carter M. , Baker N. , Burford R. P. 
Published: April 2003

AbstractThe potential for encapsulation of arsenic waste by combination with two commodity polymers was evaluated. Initial studies employed nontoxic substitutes, these being gypsum and calcium carbonate, with host polymers being predominately a recycled grade of polyethylene (PE) and a synthetic elastomer. The latter was used at low processing temperatures with rather volatile arsenic compounds. The gypsum caused processing difficulties due to evolved water, but the CaCO3 was able to be readily combined at high volumes. Arsenic trioxide was able to be incorporated at modest levels in PE and was less successfully combined with the rubber. However, the higher processing temperatures needed for PE caused the As2O3 to sublime. Less volatile calcium arsenite, readily prepared from As2O3, was able to be mixed at high volume ratios with the rubber, although processing with PE was less successful. These results may be used in conjunction with other methods for stabilization and would be applicable to other forms of medium‐ to high‐level waste. © 1995 John Wiley & Sons, Inc.
Liquid chlorine as chlorinating agent for preparation of chlorinated natural and synthetic rubbers
Authors: Cataldo Franco 
Published: April 2003

AbstractIn order to overcome the use of solvents like carbon tetrachloride (during the industrial preparation of chlorinated natural rubber or chlorowaxes) which are suspected of damaging the layer of atmospheric ozone, I proposed the use of liquid Cl2 as both chlorinating agent and solvent. It is shown that natural rubber or synthetic cis‐1,4‐polyisoprene can be swelled by liquid chlorine at −40°C. By equilibrating to room temperature, the rubber is chlorinated by the expansion of the chlorine trapped in the rubber granules in a process resembling popcorn formation. Chlorine uptake was found to be 56.5% and the chlorinated rubber obtained was studied by FT‐IR spectroscopy. Cis‐1,4‐polybutadiene, when chlorinated with liquid chlorine, gives a hard insoluble product with chlorine content of 36%. © 1995 John Wiley & Sons, Inc.
Diffusion‐controlled sorption of dye by cylindrical fibers: Matching empirical and theoretical models
Authors: Etters J. Nolan 
Published: April 2003

AbstractUnder quite specific, limiting assumptions, sorption of molecular probes by cylindrical fibers can be described by use of the conventional diffusion equation solutions of Hill, Newman, Wilson, Crank, Carman–Haul, or Urbanik. In addition, sorption also may be described by use of relatively simple empirical equations. Statistical analysis reveals which one of three empirical, exponential equations best fits theoretical data generated by use of formal solutions to the diffusion equation, and the selected equation is then applied to real data. © 1995 John Wiley & Sons, Inc.
Preferred collagen fiber orientation in the human mid‐shaft femur
Authors: Goldman Haviva M. , Bromage Timothy G. , Thomas C. David L. , Clement John G. 
Published: April 2003

AbstractCollagen fiber orientation is one aspect of the microstructure of bone that influences its mechanical properties. While the spatial distribution of preferentially oriented collagen is hypothesized to reflect the effects of loading during the process of aging, its variability in a modern human sample is essentially unknown. In a large sample (n = 67) of autopsied adults, the variability of collagen fiber orientation in the mid‐shaft femur was examined in relation to age and sex. Montaged images of entire 100 μm thick cross‐sections were obtained using circularly polarized light microscopy (CPLM) under standardized illuminating conditions. An automated image‐analyzing routine divided images into 48 segments according to anatomical position. Average gray values (varying with orientation) were quantified for each segment, and one‐way ANOVA with Tukey HSD post hoc tests were applied to assess differences between segments. Collagen fiber orientation appeared to be nonrandomly distributed across the mid‐shaft femur sample; however, no single “human” pattern was identified. Individual variation, unexplainable by age, sex, or body size, exceeded population‐level trends. Differences between age and sex groups suggest there is a strong correspondence between collagen fiber orientation and tissue‐type distributions. The minimal consistencies demonstrated here may reflect mechanical forces induced at the femoral mid‐shaft. However, the myriad of other factors that may influence collagen fiber orientation patterning, including growth trajectories, metabolic and nutritional status, and disease states, must be explored further. Only then, in conjunction with studies of other structural and material properties of bone, will we be able to elucidate the linkages between microstructure and functional adaptation in the human mid‐shaft femur. Anat Rec Part A 272A:434–445, 2003. © 2003 Wiley‐Liss, Inc.
Global analysis of cell type‐specific gene expression
Authors: Galbraith David W. 
Published: April 2003

AbstractThe tissues and organs of multicellular eukaryotes are frequently observed to comprise complex three‐dimensional interspersions of different cell types. It is a reasonable assumption that different global patterns of gene expression are found within these different cell types. This review outlines general experimental strategies designed to characterize these global gene expression patterns, based on a combination of methods of transgenic fluorescent protein (FP) expression and targeting, of flow cytometry and sorting and of high‐throughput gene expression analysis. Copyright © 2003 John Wiley & Sons, Ltd.
MetNet: software to build and model the biogenetic lattice of Arabidopsis
Authors: Wurtele Eve Syrkin , Li Jie , Diao Lixia , Zhang Hailong , Foster Carol M. , Fatland Beth , Dickerson Julie , Brown Andrew , Cox Zach , Cook Dianne , Lee Eun‐Kyung , Hofmann Heike 
Published: April 2003

AbstractMetNet (http://www.botany.iastate.edu/∼mash/metnetex/metabolicnetex.html) is publicly available software in development for analysis of genome‐wide RNA, protein and metabolite profiling data. The software is designed to enable the biologist to visualize, statistically analyse and model a metabolic and regulatory network map of Arabidopsis, combined with gene expression profiling data. It contains a JAVA interface to an interactions database (MetNetDB) containing information on regulatory and metabolic interactions derived from a combination of web databases (TAIR, KEGG, BRENDA) and input from biologists in their area of expertise. FCModeler captures input from MetNetDB in a graphical form. Sub‐networks can be identified and interpreted using simple fuzzy cognitive maps. FCModeler is intended to develop and evaluate hypotheses, and provide a modelling framework for assessing the large amounts of data captured by high‐throughput gene expression experiments. FCModeler and MetNetDB are currently being extended to three‐dimensional virtual reality display. The MetNet map, together with gene expression data, can be viewed using multivariate graphics tools in GGobi linked with the data analytic tools in R. Users can highlight different parts of the metabolic network and see the relevant expression data highlighted in other data plots. Multi‐dimensional expression data can be rotated through different dimensions. Statistical analysis can be computed alongside the visual. MetNet is designed to provide a framework for the formulation of testable hypotheses regarding the function of specific genes, and in the long term provide the basis for identification of metabolic and regulatory networks that control plant composition and development. Copyright © 2003 John Wiley & Sons, Ltd.
Overexpression of Skp2 in carcinoma of the cervix does not correlate inversely with p27 expression
Authors: Dowen S. E. , Scott A. , Mukherjee G. , Stanley M. A. 
Published: April 2003

AbstractS‐phase kinase associated protein 2 (Skp2) is a member of the F‐box family of substrate recognition subunits of SCF‐ubiquitin ligase complexes and controls progression from G1‐S‐phase by targeting cell cycle regulators such as p21 and p27. Its locus is at 5p13, a region of frequent amplification in several cancers including carcinoma of the cervix (CaCx). Overexpression of Skp2 has been observed in many cancers of an advanced stage. We examine the expression of Skp2 in 42 invasive CaCx and its correlation with tumour differentiation state and p27 expression. Using immunohistochemistry we found increased nuclear expression of Skp2 in 55% of invasive CaCx cases analysed. It is significant that poorly differentiated tumours invariably exhibit high Skp2 expression (>40% positive nuclei), whereas well‐differentiated tumours express Skp2 at a lower level (<20% positive nuclei). Skp2 expression in normal cervical epithelia is <10% (positive nuclei). Increased Skp2 protein levels did not correlate inversely with p27 expression. Our data suggest that Skp2 may contribute to the progression of CaCx, however, unlike non‐human papillomavirus (HPV) containing tumours, p27 is unlikely to be the major target protein contributing to malignant progression. The high prevalence of HPV types in CaCx may circumvent the need for Skp2 to eliminate p27. © 2003 Wiley‐Liss, Inc.
Über polyester der acetylendicarbonsäure. XI, mitteilung über polyester
Authors: Batzer von H. , Weißnberger G. 
Published: April 2003

AbstractEs wird die Synthese von Polyestern der Acetylendicarbonsäure beschrieben. Die Acetylenbindung wird durch polymeranaloge Hydrierung nachgewiesen; die so erhaltenen Bernsteinsäure‐Polyester sind mit den früber hergestellten Polyestern identisch. Die Hydriergeschwindigkeit ist vom Molekulargewicht abhängig.Der Zusammenhang zwischen Viskositätszahl und Kettengliederzahl der Polyester der Acetylendicarbonsäure entspricht der bekannten Potenzgleichung; für die untersuchten Lösungsmittel ergab sich jeweils ein niedrigerer Exponent als für die Polyester aus entsprechenden gesättigten Monomeren.Die Polyester der Acetylendicarbonsäure sind plastische Harze ohne Faserbildungseigenschaften.
Gang und gleichgewicht der caprolactampolymerisation (Weiterentwicklung)
Authors: Matthes von A. 
Published: April 2003

AbstractDie bereits früher (Makromolekulare Chemie V (1950) 197) in mathematische Formulierung gebrachte Kinetik der ϵ‐Caprolactampolymerisation kann, völlig unverändert, auch dahin interpretiert werden, daß die Reaktion über ein konzentrationsmäßig nicht in Erscheinung tretendes Instabiles Iäuft, welches vermutlich mit der Aminocapronsäure identisch ist. Nur eine solche Instabilen‐Kondensation, nicht aber eine einfache, unkomplizierte Kondensation steht mit den Erscheinungen im Einklang.Die nach den allgemeinen Regeln ableitbaren Formeln für das Kettenlängengleich gewicht werden auch unter extremen Bedingungen erfüllt bei Benutzung einer viskosimetrischen Polymerisationsgradformel.

für das Perlon.
tert‐Butyl peresters as initiators in vinyl polymerizations. I.
Authors: Misra G. S. , Mathur V. R. B. 
Published: April 2003

AbstractPeresters dissociate thermally to alkoxy and acyloxy radicals. The acyloxy radical may dissociate further into an aryl radical and carbon dioxide. Alternatively they may break into these products in a single stage reaction. The decomposition of tert‐butyl perbenzoate has been studied and it has been shown that the primary products of the dissociation of this ester are alkoxy and acyloxy radicals.The polymerization of styrene, using tert‐butyl perbenzoate, tert‐butyl percinnamate and tert‐butyl percrotonate has been studied at 120 ± 1°C. It has been shown that the rate of polymerization is proportional to the square root of the initiator concentration and the 3/2 power of the monomer concentration.
Polycondensation‐addition. IV. Polysulfonamide‐ureas from isocyanatobenzenesulfonyl chlorides and diamines
Authors: Iwakura Yoshio , Hayashi Katsumi , Inagaki Koichi 
Published: April 2003

Abstractp‐Isocyanatobenzenesulfonyl chloride (I) and m‐isocyanatobenzenesulfonyl chloride (II) were prepared by treating the corresponding aminobenzenesulfonic acids with phosgene and phosphorous pentachloride in dioxane. Tha compounds I and II were subjected to polycondensation‐addition with several diamines to obtain polysulfonamide‐ureas. Some of the polymers obtained were high molecular, film‐forming materials.
Über polystyrol‐phenyl‐disulfimid. Umsetzungen an hochpolymeren in einer dreiphasenreaktion
Authors: Koch Von Ursula , Wolf Friedrich , Schult Willi 
Published: April 2003

AbstractPolystyrolsulfonamid läßt sich in einer „Dreiphasenreaktion”︁ mit Benzolsulfochlorid zu Polystyrol‐phenyl‐disulfimid umsetzen. Durch Ionenaustausch wurden 11 verschiedene Salze daraus hergestellt und deren thermische Stabilität geprüft.
Neue copolymerisate und polymergemische des vinylchlorids
Authors: Trautvetter Von W. 
Published: April 2003

AbstractSterisch geordnetes PVC entsteht bei der radikalischen Polymerisation von VC bei genügend tiefen Temperaturen. Sein Verzweigungsgrad, wahrscheinlich auch die Anzahl der 2,2‐Verknüpfungen und die Molekulargewichtsverteilung unterscheiden sich vom konventionellen PVC.Kälte‐PVC läßt sich bei etwas höheren Temperaturen als normales PVC zu einem Material verarbeiten, das höhere Wärmeformbeständigkeit, höhere Zugfestigkeit, aber etwas schlechtere Schlagzähigkeit als normales PVC besitzt.Es wird der Einfluß der Verarbeitungsparameter auf die mechanischen Werte von Mischungen aus PVC und Kälte‐PVC mit einem Copolymerisat aus Äthylen und Vinylacetat dargelegt. Verarbeitungstemperatur und ‐dauer spielen zur Erhaltung optimaler Eigenschaften eine entscheidende Rolle.Die Eigenschaften von chloriertem Kälte‐PVC werden mit denen von chloriertem PVC verglichen. In Blends geht der Vorteil höherer Wärmeformbeständigkeit und Zugfestigkeit von chloriertem Kälte‐PVC verloren.