bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative chemical means of assessing polyethylene oxidizability
Authors: Meltzer Theodore H. , Goldey Richard N. 
Published: December 2004

AbstractThis paper compares results of four accelerated oxidation tests: the hot milling test, reaction with fuming nitric acid, absorption of oxygen gas at elevated temperature and the redox system—polyethylene—lead peroxide ignition test. The length of the induction period, is a product of antioxidant concentration but not of the inherent oxidizability of the resin. Discrepancies between induction periods as measured by oxygen absorption and hot milling differ because in the former the volume of pure oxygen absorbed is measured and in the latter the electrical consequences of air oxidation. In addition other polymeric degradation occur in milling. Nitric Acid treatment measures the effect of nitric acid upon the specific viscosity and is useful for chain scission comparisons. The ignition tests reflect both inherent oxidizability and presence of antioxidant. All four tests reflect oxidation parameters.
Novel phosphorus containing polymers
Authors: Kindley Lee M. , Podall Harold E. , Filipescu Nicolae 
Published: December 2004

AbstractTris‐hydroxymethylphosphine oxide (THPO) derived from commercially available tetrakishydroxy‐methylphosphonium chloride (THPC), was studied for its flame retardant properties in reactions with carboxylic acids, anhydrides, diisocyanates, urea, phenol, acyl and aroyl halides. Then the monobenzylated derivative of THPO referred to as BHPO was studied, which is more stable and more reactive with difunctional molecules.
Dynamic mechanical behavior during the thermosetting curing process
Authors: Lewis Armand F. 
Published: December 2004

AbstractThe application of a free vibration technique to the study of the cross‐linking of an epoxy resin by an amine is demonstrated. Curing curves are presented showing the changes in dynamic mechanical flexural modulus and damping during reaction. At room temperature, the glass transition point is reached after a conversion of about 65% of the epoxide groups. Comparisons of the dynamic mechanical and infrared curing curves indicate a lowering of the reaction rate after this point is reached. Finally, an activation energy for the epoxy‐amine cross‐linking reaction is calculated.
Impact behavior of a nitrile elastomer
Authors: Barkan P. , Sirkin M. F. 
Published: December 2004

AbstractThis investigation studies the behavior of several cylindrical specimens of a Buna‐N elastomer subjected to compression impact by a finite mass. Initial strain rates fall in the range between 40/sec and 400/sec, with maximum nominal strains up to 0.4. It is shown that values of nominal stress, true and nominal strain, energy dissipation and impact duration can be correlated with elastomer geometry and initial kinetic energy by means of two parameters derived from an analysis of a linear viscoelastic model. Other sources of variability of elastomer behavior are discussed.
Oxygen absorption studies on polypropylene
Authors: Bell G. W. , Heyd C. E. 
Published: December 2004

AbstractAn investigation of the effect of sample dimensions on the oxidation of polypropylene is described. The results are used to select testing conditions. Two examples of the utility of the method are presented. First, a control method for uninhibited polypropylene and, secondly, an investigation of the synergistic effect between 2,6‐di‐t‐butyl‐p‐cresol and dilaurylthiodipropionate.
Structure‐property modifications by fabrication operations
Authors: Maxwell B. , Gogos C. G. , Blyler L. L. , Mineo R. M. 
Published: December 2004

AbstractStudies of polymer morphology under ideal conditions approaching equilibrium structures have been shown to be valuable in the development of an understanding of the relationship of properties to structure. Practical fabrication operations do not permit the achievement of equilibrium structures in commercial products and its is therefore necessary to study the effects of processing on the actual structures that result. In addition, an understanding of the effects of processing variables on properties permits the development of fabrication operations which can be directed toward the improvement of properties. Topics covered include the effects of hydrostatic pressure during processing, effects of combinations of pressure and thermal history, relationships between thermal history and crystallization rates in isotactic polymers and the kinetic and morphological effects of flow deformation on crystallizable plastics.
Mechanical and dielectric relaxation of crystalline polymers in relation to degree of crystallinity and morphology
Authors: Passaglia E. 
Published: December 2004

AbstractMechanical and dielectric relaxation as related to the morphology of crystalline polymers is reviewed. The behavior with temperature of the imaginary part of the complex dielectric constant and the mechanical loss factor, tan δ, at constant frequency is discussed in detail for two typical crystalline polymers: poly(chlorotrifluoroethylene) and polypropylene. Three relaxations are typically observed: a low temperature relaxation occurring at temperatures below the dilatometric glass transition temperature; a glass temperature relaxation occurring near the glass transition temperature; and a high temperature relaxation occurring between the glass temperature and the melting point. The activation parameters are given for these relaxations, and the influence of morphology on them is discussed along with possible molecular interpretations.
Melt viscosity—temperature dependence of some low density polyethylenes
Authors: Mendelson R. A. 
Published: December 2004

AbstractThe melt viscosities of three low density polyethylenes of widely varying melt indices were studied as a function of temperature over a broad range of shear rates and shear stresses. Apparent viscosities at constant shear stress could be fitted adequately to a simple Arrhenius equation over the entire temperature range studied. However, pronounced curvature of the log ηa–1/T curves was observed for apparent viscosities at constant shear rate. The apparent activation energies for viscous flow at constant shear stress were found to decrease slowly with increasing shear stress and also to decrease with decreasing molecular weight. A temperature‐shear rate superposition was demonstrated to hold, and the shift factor dependence on temperature was determined.
The oxyluminescence of polymers III. Effects of oxidation and structure; Mechanisms involved
Authors: Schard M. P. 
Published: December 2004

AbstractStudies of polypropylene oxyluminescence show the luminous intensity to be dependent upon the degre of oxidation. The length of the low intensity level portion of the luninescence curve, or pseudo induction period, was found to be a measure of the useful stabilizer life, and the intensity of this portion indicative of the effectiveness of stabilization. The effect of peroxide decomposers was studied and results indicate that peroxide reactions are major producers of luminescence. Analysis of the accepted modes of polymer oxidation, in view of our luminescence findings, indicate that the rate of luminescence buildup should depend upon ease of R. formation and the luminous intensity should be dependent on peroxy radical concentration. The effect of tertiary‐carbon content on luminescence was also investigated, and luminous intensity was found to be dependent upon the amount of polymer branching. Model Compounds having slight structural variations were examined and were found to produce different intensity‐time curves during oxidation, which may be attributed to ease of formation of a reactive site and subsequent peroxy radical reactions.
Experimental investigations on fracture of polymers
Authors: Sharma M. G. , Lim C. K. 
Published: December 2004

AbstractThis article describes the experimental investigations on fracture of a polymeric material under various uniaxial and biaxial stress fields, at controlled rates of loading. The biaxial stress fields have been produced by subjecting tubular specimens to pure internal pressure, internal pressure combined with tension loading, pure torsion and torsion combined with tension loadings. The experimental arrangements developed for conducting the above tests have been described. Examination of fractured specimen subjected to various biaxial stress fields indicates that the fractured surface is mostly along the plane of maximum normal stress. However, the mode of fracture in the case of pure compression test resembles that of a brittle material. From the experimental fracture data, limiting failure curves for the material have been obtained corresponding to various maximum extension ratio rates. The experimental failure data were compared with various criteria of failure essentially developed for metals. It was found that none of the classical failure criteria applies to the material tested.
The effect of silane coupling agents in improving the properties of filled or reinforced thermoplastics
Authors: Sterman S. , Marsden J. G. 
Published: December 2004

AbstractThe application of silane coupling action produces significant improvements in physical properties in various thermpolastic resin systems. Both glass‐reinforced thermoplastics and the more conventional filled thermoplastic resin systems were studied. An order of specificity between resin and coupling agent exists for thermoplastic resins similar to that of thermosets. The interaction with thermosets is considered copolymerization, wereas that with thermoplastics is not yet clearly defined. The silanes are incorporated by pre‐treatment (best for glass reinforcement) or by addition during normal compounding. Fillers are added for a specific result, often with sacrifice of physical strength. Data presented show that silane addition upgrades filled thermoplastics to the level of clear resins and sometimes above. The effect of silanes on electrical properties of filled thermoplastics are also reported.
Fundamentals of plasticating extrusion. II. Experiments
Authors: Marshall D. I. , Klein I. 
Published: December 2004

AbstractExperiments were performed to develop quantitative information for designing plasticating extruders for low density polyethylene. Screw design variables explored included feed section length, compression section taper, and minimum channel depth. Operating variables included were screw speed, barrel temperature, and back pressure. A moving picture film illustrates temperature action and cross‐channel temperature distribution for some typical experiments using a new type of extruder screw for 2.5 inch and 8 inch diameter extrusion. The information gathered was used to obtain relations between performance and screw dimensions and revealed an optimum combination of feed section length and compression taper.
Bisphenol‐A bimodal epoxy resins. Part I: The dynamic mechanical characterization of a 6300 (340/22,500) weight average molecular weight system
Authors: Holmes Gale A. , Letton Alan 
Published: December 2004

AbstractBy using an advanced epoxy resin of 22,500 weight average molecular weight two bimodal systems of 6300 weight average molecular weights were prepared. By altering the curing procedure normally used to cure epoxy resins and high molecular weight resins we have succeeded in minimizing the difficulty associated with preparing bimodal epoxy resin systems. The ultimate Tg of these bimodal systems is associated with the phase morphology and controlled by the curing conditions employed. For the completely phase separated bimodal system a Tg of 473 K is reported and for the partially phase separated system a Tg of 466 K is reported. Equations were developed for predicting the equilibrium shear modulus of these bimodal systems. Theoretical predictions based on these equations were found to be consistent with experimental results.
Organosoluble, low‐dielectric‐constant fluorinated polyimides based on 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene
Authors: Yang Chin‐Ping , Hsiao Sheng‐Huei , Chung Cheng‐Lin 
Published: January 2005

AbstractA novel fluorinated bis(ether amine) monomer, 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy) naphthalene, was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 2,6‐dihydroxynaphthalene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel trifluoromethylated polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two‐stage process with thermal imidization of poly(amic acid) films. Most of the resulting polyimides were highly soluble in a variety of organic solvents and could afford transparent and tough films via solution casting. These polyimides exhibited moderately high glass transition temperatures (Tgs) of 249–311 °C, high thermal stability and good mechanical properties. Low moisture (0.19–0.85 %), low dielectric constants (2.49–3.59 at 10 kHz), and low color intensity were also observed. For a comparative study, a series of analogous polyimides based on 2,6‐bis(4‐aminophenoxy)naphthalene were also prepared and characterized. Copyright © 2005 Society of Chemical Industry
Versatile preparation of poly(1,4‐phenylenevinylene‐co‐1,4‐phenylene‐1,2‐ethanediyl) by CVD polymerization of p‐(methoxymethyl)benzyl chloride
Authors: Trinh Tung Ngo , Yu Young‐Jun , Kim Kyungkon , Joo Sung‐Hoon , Park Yongsup , Jin Jung‐Il 
Published: January 2005

AbstractIt was demonstrated that a series of copolymers consisting of 1,4‐phenylenevinylene (PV) and 1,4‐phenylene‐1,2‐ethanediyl (PE) units could be prepared from a single monomer, p‐(methoxymethyl)benzyl chloride, via the chemical vapor deposition polymerization (CVDP) method. The composition of the copolymers could be varied simply by altering the monomer activation temperature. The higher the temperature, the lower the content of the PV unit. The photo (PL)‐ and electroluminescence (EL) properties of the copolymers that revealed a blueshift when compared with PPV strongly depend on the amount of the PE units incorporated. The external quantum efficiencies of the electroluminescence devices having the configuration of ITO/PEDOT‐PSS/copolymer/Al‐Li were higher than that of PPV, which can be ascribed to the improved confinement of excitons. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 742–751, 2005
Analytical solutions to mathematical models of the surface and bulk erosion of solid polymers
Authors: Lyu Suping , Sparer Randall , Untereker Darrel 
Published: January 2005

AbstractThe process by which polymeric materials hydrolyze and disappear into their environments is often called erosion. Two types of erosion have been defined according to how the hydrolysis takes place. If hydrolysis occurs throughout the entire specimen at the same time, it is called bulk erosion. If the hydrolysis is mainly confined to a region near the surface of the specimen and the surface continuously degrades by moving inward, it is termed surface erosion. In this article, a kinetic relationship for bulk erosion is developed. This relationship provides a method for estimating the hydrolysis kinetic constants for bulk‐eroding polymers. This same relationship is also applicable to surface erosion at a microscopic level. Through its combination with a diffusion–reaction equation and the provision of moving boundary conditions, an analytical solution to the steady‐state surface‐erosion problem is obtained. The erosion rate, erosion front width, and induction time can all be expressed as simple functions of the rate of polymer bond hydrolysis, water diffusivity, and solubility, plus other parameters that can be experimentally determined. The erosion front width is the product of the induction time and the erosion rate. The ratio of the erosion front width to the polymer specimen thickness is a parameter that determines whether the specimen undergoes surface or bulk erosion. Theoretical results are compared with experimental observations from the literature, and agreement is found. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 383–397, 2005
Singularity of Crushing Behavior of Single Particles near Their Natural Period
Authors: Yashima Saburo , Hashimoto Hitoshi , Yashima Saburo 
Published: December 2004

AbstractWithin grinding machines the load acting on the particles and the loading rate are widely distributed. According to studies on the breakage mechanism of brittle materials, the mechanical properties which relate to breakage vary with the loading rate. In order to elucidate the grinding mechanism within the grinding machines, it is necessary to obtain the relationships between these properties and loading rate.In this study, the variation of strength, fracture energy, new surface area produced by fracture and fracture energy with the loading rate (ranging from 10−1 to 109 N/s) was investigated by means of compression tests on a large number of spherical specimens. As a result, a singularity of crushing behavior was observed under an impact loading corresponding to a duration of time of loading the same as the natural period of the spherical specimen. The crushing efficiency is especially at its maximum.
Asbestos Particle Characteristics Important for the Filter Cake Formation
Authors: Hraste Marin , Vidović Krunoslav 
Published: December 2004

AbstractTwo types of asbestos fiber, chrysotile and amosite, form filter cakes of different permeabilities while having a similar degree of dispersion.The filter cake resistance depends on the disperse phase characteristics and the conditions of cake formation. The main reason for the effects mentioned is different particle flexibility influenced by the specific structure of each type of asbestos particle.The flexible chrysotile fibers in the cake form dense and rigid, amosite, porous deposits. An increase in the velocity of the suspended chrysotile particles, caused by pressure difference and agitation, results in significant differences in filter cake resistance.
Über einige höhere Benzolhomologe
Authors: Halse O. M. 
Published: January 2005

AbstractIm ganzen sind in dieser Weise 14 tertiäre Benzolhomologe dargestellt worden. Dazu kommen noch die vier von Schreiner dargestellten. Es lassen sich noch weitere 14 voraussehen, deren Synthesen bald in Angriff genommen werden sollen. Es wird sich dann herausstellen, inwieweit Gesetzmäßigkeiten in bezug auf physikalische Konstanten und andere Eigenschaften beobachtet werden können. Mit dem bis jetzt vorliegenden Material lassen sich einstweilen solche nicht ermitteln.
Die Reduktionskatalyse ungesättigter Fette und Fettsäuren durch Nickeloxyde
Authors: Erdmann E. 
Published: January 2005

Abstract1. Durch die von Bedford und mir veröffentlichte Untersuchung über die Nickeloxyde als Reduktionskatalysatoren ist zum ersten Mal die unwiderleglich richtige Tatsache festgestellt worden, daß Nickeloxyde in besonders glatter Weise Wasserstoff auf ungesättigte Fette und Fettsäuren unter Atmosphärendruck zu übertragen vermögen.
Die Reindarstellung des Propylens
Authors: Trautz Max , Winkler Karl 
Published: January 2005

AbstractEine Anordnung zur katalytischen Darstellung des Propylens aus Propylalkohol oder besser Isopropylalkohol mit Graphittiegelmasse als Katalysator (nach Sabatier‐Senderens) und eine Anordnung zur Reinigung des Gases wird angegeben. Sein Siedepunkt wird zu −47,8° bei 750 mm, seine Dichte bei −79° zu 0,647, sein Brechungsindex für die gelbe He‐Linie (5876) zu 1,00102 bestimmt und festgestellt, daß die spezifischen Volumina von Propylen‐Trimethylengemischen bei −79° sich innerhalb der Fehlergrenze von etwa 7 v. T. additiv verhalten.
Berlinerblau und Turnbullsblau. V
Authors: Müller Erich 
Published: January 2005

AbstractDie potentiometrische Verfolgung der Bildung von Berlinerblau und Turnbullsblau bestätigt die Zusammensetzung, die ich früher auf Grund analytischer Daten über die Struktur dieser Körper geäußert habe, insonderheit lehrt sie, daß die bei den verschiedenen Mischungsverhältnissen gebildeten verschiedenen Verbindungen die Eigentümlichkeit besitzen, sich ineinander fest zu lösen.
Untersuchungen über die Darstellung des Nickelkatalysators und seine reduktionskatalytische Wirksamkeit
Authors: Lietz Ulrich 
Published: January 2005

AbstractDie Ergebnisse dieser Arbeit sind kurz zusammengefaßt die folgenden:1. Die Fällung der Nickelsulfatlösung mit Sodalösung ist mit Lösungen von Zimmertemperatur auszuführen. 2. Die Trocknung des Niederschlages hat in möglichst hohem Vakuum zu erfolgen. 3. Die Reduktionsdauer bei etwa 300° darf, wenn basisches Nickelcarbonat, welches nicht mehr als 0,5 g Nickel enthält, reduziert werden soll, 30 Minuten nicht überschreiten. 4. Die Annahme, daß das Nickelmetall das katalytisch Wirksame bei dieser Wasserstoffanlagerung ist, wird durch die Bildung von Nickelcarbonyl bei nur 24,5° C sehr wahrscheinlich. 5. Reines Kohlendioxyd übt keine Giftwirkung aus. 6. Die Änderung der Reaktionsgeschwindigkeit ist proportional der angewandten Katalysatormenge. 7. Die Änderung der Reaktionsgeschwindigkeit mit der Schüttelgeschwindigkeit ergab, daß die vorliegende Reaktionsgeschwindigkeit durch einen Diffusionsvorgang zu erklären ist. 8. Die Geschwindigkeit der Wasserstoffanlagerung an zimtsaures Natrium durch Nickel ist der Diffusionsgeschwindigkeit des Wasserstoffs zum Katalysator proportional, da die Änderung der Konzentration der Lösung von zimtsaurem Natrium keinen Einfluß auf Reaktionsgeschwindigkeit ausübt.
Effect of lower fatty acids on the solubilization of Butanol‐1 in aqueous solutions of sodium salts of fatty acids. I
Authors: Bose A. N. , Mehrotra K. N. 
Published: January 2005

AbstractEs wird über Arbeiten berichtet, die das Studium der Löslichkeitsbeeinflussung von Fettsäuren auf Butanol‐1 in Gegenwart von fettsauren Salzen beinhalten. Viskositätsmessungen an den Systemen sollen einen Hinweis auf die Flüssigkeitsstruktur geben.
Effect of lower fatty acids on the solubilization of Butanol‐1 in aqueous solutions of sodium salts of fatty acids. II
Authors: Bose A. N. , Mehrotra K. N. 
Published: January 2005

AbstractEs wird über Arbeiten berichtet, die das Studium der Löslichkeitsbeeinflussung von Fettsäuren auf Butanol‐1 in Gegenwart von fettsauren Salzen beinhalten. Viskositätsmessungen an den Systemen sollen einen Hinweis auf die Flüssigkeitsstruktur geben.
Beiträge zur Trennung der Seltenen Erden. IV. Weitere Untersuchungen über die Trennung Seltener Erden durch Komplexelution vom Kationenaustauscher mittels β‐Oxyäthyliminodiessigsäure
Authors: Wolf Leopold , Massonne Joachim 
Published: January 2005

AbstractMittels einer 2,0proz. Lösung von β‐Oxyäthyliminodiessigsäure als Elutionsmittel werden bei PH‐Werten von 7–8 lanthanreiche Ceriterdengemische getrennt. Die zweite Austauschersäule läßt sich hierbei in der H+‐Form verwenden. Das gegen Ende der Elution noch ausschließlich am Austauscher befindliche Lanthan kann durch Elutionsmittel höherer Konzentration rasch eluiert werden.Zum Zwecke der Trennung von Didymgemischen kann die zweite Austauscheräule anstatt mit Wasserstoffionen vorteilhaft auch mit Ionen der Yttererden beladen werden, wodurch neben der Trennung der Didym‐Komponenten eine bemerkenswerte Fraktionierung des in der zweiten Säle eingesetzten Yttererdengemischs erzielt werden kann.Mit Austauschersäulen von 2,2 cm Durchmesser und 130 cm Länge lassen sich etwa 20 g Seltenerdoxyde in 4 bis 5 Tagen trennen, so daß größere Anteile reiner Oxyde oder doch Fraktionen binärer Gemische anfallen, welche durch Wiederholung des Verfahrens in die reinen Komponenten aufgespalten werden.