bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigations of the action of flame retardants in cellulose. II: Investigation of the flame‐retardant action of polyphosphonitride in cellulose
Authors: Choudhary Manjeet S. , Fink Johannes K. , Lederer Klaus , Krässig Hans A. 
Published: April 2003

AbstractPure regenerated cellulose fibers and those containing various amounts of phosphorus nitride were pyrolyzed under different conditions in the temperature range of 150–440°C. Easily volatile liquid pyrolysis products, the tar fraction of limited volatility, and the charred residue were determined gravimetrically. The liquid volatiles were analyzed by combined gas chromatography/mass spectrometry for their water content. The tarnfraction and the charred residue were inspected by infrared (IR) spectroscopy. The studies revealed that the phosphorus nitride flame retardant enhances the onset of the pyrolytic decomposition and the release of water at substantially lower temperatures as observed for pure cellulose. The water release favors the carbonization and its extent reduces the formation of levoglucosan as a precursor of easily flammable pyrolysis products. Thus phosphorous nitride must be classified into the water release favoring flame retardants.
Latex interpenetrating polymer networks based on acrylic polymers. IV. The influence on mechanical properties of the time of swelling the seed particles with the second monomer
Authors: Hourston D. J. , Satgurunathan R. , Varma H. C. 
Published: April 2003

AbstractTwo latex interpenetrating polymer networks, one based on a partially compatible pair and the other based on an incompatible pair of polymers, were prepared by a two‐stage emulsion polymerization. To investigate the effect of swelling the first formed polymer particles with the second monomer, the second stage of the synthesis was conducted after allowing the second monomer to be in contact with the seed latex for specified periods of time. Fabricated samples of these interpenetrating polymer networks were subjected to hardness, stress–strain, and dynamic mechanical measurements. The results showed an enhancement in mixing of the two networks in the case of the partially compatible pair and a detectable increase in the level of mixing for the incompatible pair.
Evaluation of adhesion characteristics of nylon‐6 tire cord to natural rubber
Authors: Mukherjee A. K. , Kulkarni S. G. , Chakravarty S. N. 
Published: April 2003

AbstractThe adhesion characteristics of Nylon‐6 cords to rubber matrix, using Resorcinol Formaldehyde Latex (RFL) solution, were evaluated at various conditions. The heat‐setting studies of RFL dipped cords in the temperature range of 180–210°C showed a loss in tensile properties. However, a minimum in the loss was observed when a pretension load was given to the cords. Percent shrinkage of RFL‐dipped cords increased with the increase in temperature of heat setting. Adhesion behavior of Nylon‐6 cords to rubber matrix showed some improvement under relaxed conditions in the entire temperature range studied. With the application of suitable tension to cord, adhesion behavior can be made constant. This has been attributed to the higher extent of shrinkage of cords under relaxed conditions providing greater cord surface area. This in turn, leads to increased cord to rubber matrix.
Preparation and properties of very thin films of syndiotacticity‐rich poly(vinyl alcohol)
Authors: Yamaura Kazuo , Ikeda Ken‐Ichi , Fujii Masaharu , Yamada Ryoji , Tanigami Tetsuya , Matsuzawa Shuji 
Published: April 2003

AbstractVery thin films of poly(vinyl alcohol) could be prepared by utilizing the adsorption of polymer molecules at air/water interface from the aqueous solutions of the poly(vinyl alcohol) derived from vinyl trifluoroacetate. The films prepared by the bubble method were thinner than those obtained by the frame method. The minimum thickness of the former films was 260 Å and that of the latter was 1800 Å. These very thin films resisted water at temperatures below 55°C. The maximum Young's modulus of the drawn/annealed films prepared from these samples was 30 GPa. The permeability of water, Jw/δP, was 2–6 × 10−3 cm · s−1 atm−1 (0–55°C) for the untreated film (thickness: 1800 Å) prepared by the frame method and 0.8–2.2 × 10−2cm · s−1 · atm−1 (5–55°C) for the untreated film (360 Å) prepared by the bubble method, and depended on the thickness of film.
Synthesis, crosslinking and degradation of some unsaturated polyester resins
Authors: Doss Ninette L. , Habib Samia , Nosseir Michael H. 
Published: April 2003

AbstractSome unsaturated polyester resins were prepared by the ester interchange between p‐carbethoxymaleananilic acid and p‐carbethoxysuccinanilic acid with saturated and unsaturated diols. Moreover, copolymers were also synthesized by the polyesterification of the aforementioned acids and maleic anhydride with the above‐mentioned glycols. The structure of both the unsaturated polyester resins and copolymer resins was established by IR, UV, and NMR spectroscopy. Also, viscosity measurements and molecular weight determinations were further tools for their structural elucidation. All the products were attempted to cure with styrene in the presence of benzoyl peroxide as initiator, and the produced network structures, in the form of films, were tested as surface coating materials for glass and metals. The structure of the cured products was established after their degradation, by physical and spectroscopical means.
Dynamic viscoelastic properties in the molten state for cellulose acylates and (cellulose oligo‐oxymethylene ether) acylates
Authors: Shiratsuchi Kentaro , Matsumoto Takayoshi , Yao Shigeru , Shiraishi Nobuo 
Published: April 2003

AbstractThe dynamic viscoelastic properties of cellulose acylates, its mixed acylates, and (cellulose oligo‐oxymethylene ether) acylates (COM acylates) have been meausured in the molten state over wide ranges of frequency and temperature. The log G′ vs. log ω curves as well as the similar curves for the loss modulus G′ at various temperatures for cellulose acylates could not be superposed into respective master curves by use of the time–temperature superposition principle. This is considered to be caused from the orientation of cellulose acylates main chain in the molten state. In the case of cellulose mixed acylates, rheological simplicity was found but this was only the case on selected combinations of acyl groups. Most cellulose acylates, which were introduced oxymethylene chains (OM chains) in between glucopyranose ring and the acyl group, behaved as thermorheologically simple materials in the molten state. When the acyl groups become large, however, it is necessary to introduce long OM chains in order to get thermorheologically simple COM acylates in their molten state. Several studies have been made concerning the behavior of side chains, both the OM and the acyl chains, of COM acylates in the molten state.
Effect of water on vapor phase photografting on cellulose and its derivatives
Authors: Kubota Hitoshi , Ogiwara Yoshitaka , Hinohara Sakae 
Published: April 2003

AbstractEffect of water on vapor phase photografting on cellulose was investigated at 60°C. An activated grafting of methyl methacrylate by water contained in the sample was observed in the experiment. The effect of water was commonly recorded irrespective of the type of cellulose derivatives such as cellulose acetate (degree of substitution, DS = 0.18 and 0.33), cellulose nitrate (DS = 0.35 and 0.75), and carboxymethl cellulose (DS = 0.19 and 0.74). Organic solvents can also be used in place of water, indicating that the percent grafting decreases in the order, water > methanol > acetone > cyclohexane. From ESR studies, water in the sample was found to contribute to the decay of cellulose radicals rather than to the radical formation. The decay was accelerated by organic solvents, and the magnitude of the effect was in the order, water ≈ methanol > acetone > cyclohexane. Based on the above investigation, it was presumed that water contained in the sample cannot contribute directly to the formation of cellulose radicals which may initiate grafting, but mostly promotes the penetration of monomer into cellulose fibers. Such penetration could lead cellulose radicals to an effective initiation of grafting.
Thermodynamic and structural properties of acrylonitrile–butadiene rubber/polyethylene blends
Authors: Frenkel R. , Ducháček V. , Kirillova T. , Kuzmin E. 
Published: April 2003

AbstractThermodynamics of interaction, adhesive properties, and the structure of acrylonitrile‐butadine rubber/low density polyethylene blends have been investigated. Enthalpy and entropy components of interaction parameters supporting an incompatibility of studied systems and a possibility of highly organized structure formation on the phase interface were determined by inversion gas chromatography. The formation of highly organized structures on the interface is made possible by a local diffusion of polybutadiene fragments into polyethylene phase. That is why acrylonitrile microblocks are oriented. By this manner adhesion between rubber and polyethylene phase is enforced and simultaneously a number of morphological changes take place.
Anomalies in the rheological behavior of polyethylene with very broad molecular weight distribution
Authors: Masson Patrick , Spitz Roger 
Published: April 2003

AbstractThe rheological behavior of high density polyethylenes with very broad molecular weight distribution is studied in the molten state starting from freshly synthesized powders. The complex viscosity increases slowly up to a limiting value as a function of ageing of the polymer and faster when the molten polymer is stirred. The phenomena are explained by an heterogeneous distribution of very high molecular weight nodules in the polymer arising from the synthesis and is proved by the preparation and characterization of polymers presenting the opposite heterogeneity and behavior (very low molecular weight nodules).
Hydrolysis and condensation mechanisms of a silane coupling agent studied by 13C and 29Si NMR
Authors: Nishiyama Norihiro , Horie Kozo , Asakura Tetsuo 
Published: April 2003

AbstractThe mechanisms of hydrolysis and condensation of a silane coupling agent, γ‐methacrylo‐xypropyltrimetoxysilane (γ‐MPTS) were investigated by the use of both 13C and 29Si nuclear magnetic resonance (NMR) spectroscopies. The NMR peaks of the hydrolyzed monomer and condensed polymer were assigned readily. The rate of hydrolysis and condensation of γ‐MPTS was dependent on water content. On the basis of the time‐dependent behavior of these peaks, the mechanisms of hydrolysis and condensation were clear.
A fourier analysis dynamic birefringence apparatus
Authors: Kumar Satish , Stein R. S. 
Published: April 2003

AbstractMolecular motion in a polymeric system can be studied using dynamic birefringence. Computer interfacing of the dynamic birefringence apparatus and the data treatment using Fourier analysis are reported in this paper. Experiments are done under sinusoidal strain; stress, strain and birefringence signals are monitored. Birefringence is measured using the optical transmission technique. An AIM‐65 microcomputer was interfaced with this apparatus for the purposes of data acquisition and data analysis. First‐order Fourier coefficients are used to determine the real and imaginary components of the modulus, the strain optical coefficient, and the stress optical coefficient. Higher order Fourier coefficients can be used to study the nonlinear viscoelastic behavior in the polymer.
Correlation of mechanical property, crosslink density and thermogravimetric behavior of castor oil polyurethane–polystyrene divinyl benzene simultaneous IPN networks
Authors: Kumar V. G. , Rao M. Rama , Guruprasad T. R. , Rao K. V. C. 
Published: April 2003

AbstractSeveral simultaneous interpenetrating networks (IPN) of castor oil polyurethane (COPUN) and polystyrene divinyl benzene (PSN) were synthesized under conditions where the free radical polymerization of styrene and the crosslinking reaction of castor oil and toluene diisocyanate progress at comparable rates. Comparison of the mechanical properties and crosslink density of the COPUN and COPUN/PSN‐IPNs indicates a marginal increase in tensile strength and crosslink density from COPUN to 60COPUN/40 PSN IPN. IPN samples prepared with further increased PSN content show steady decrease in the above properties. This reversal of the expected trend was attributed to the possible greater molecular interpenetration achieved due to similar gelation times with resultant extension of chains and increase in free volume between crosslinks. This was further confirmed from thermogravimetric data on the initial stages of decomposition of the IPNs.
Studies on the temperature dependence of extinction oxygen index values for cellulosic fabrics. I. Cotton
Authors: Horrocks A. R. , Price D. , Tunc M. 
Published: April 2003

AbstractThe concept of extinguishability as a measure of textile flammability is reviewed. Definition and determination of extinction oxygen index enables a parameter to be defined from which the effects of ignition time and fabric structure may be removed. This so‐called extinction oxygen index (EOI) and the derived value at zero ignition time [EOI]0 more exactly define the burning/nonburning fabric boundary than does the more widely used limiting oxygen index (LOI). This first paper reports the determination of EOI and [EOI]0 values for a series of cotton fabrics in the temperature range 20–200°C. The influence of the various fabric parameters of area density, air permeability, sample thickness, bulk density, and moisture content was investigated. The advantages of using the EOI rather than the LOI concept as a measure of textile flammability is indicated in the discussion of the results of this study with reference to previous work concerned with LOI data for cotton. In particular, the significance that environmental temperature has on EOI and related parameters reported here and previously reported LOI data is discussed in terms of various published models which define the burning/extinction threshold.
Retarding and antioxidant activity of 1‐cyclohexylthio‐2‐mercaptobenzimidazole in the vulcanization of NR accelerated by thiocarbamyl sulfenamide
Authors: Das Prasanta Kumar , Datta Rabindra Nath , Basu Dipak Kumar 
Published: April 2003

AbstractThe effect of 1‐cyclohexylthio‐2‐mercaptobenzimidazole (CMB) on the vulcanization of NR accelerated by N‐oxydiethylene thiocarbamyl‐N′‐oxydiethylene sulfenamide (OTOS) has been studied. It is found that CMB delays the onset of cure and generates 2‐mercaptobenzimidazole during vulcanization. The results indicate the retarding as well as antioxidant activity of CMB.
Dynamic compression characteristics of flexible foams. I. Similarity model, analysis, and experiments
Authors: Yossifon S. , Szanto M. 
Published: April 2003

AbstractA simple mathematical model is proposed, based on dimensional similarity parameters, to describe the characteristics of flexible plastic foams under impact conditions. The model assumes that the foam is rate‐dependent material, when the dynamic stress is a function of the strain and the strain rate. The similarity parameters include the geometric dimension of the foam, the mass of the absorbing body, and the drop height. By using this model, one can predict the maximum deformation, the maximum decelerations, and the time‐pulse period for a wide range of drop heights and masses, by conducting several drop tests. We verified the efficacy of this model by performing free‐fall drop tests with flexible polyurethane foam having a uniform density of 240 kg/m3.
Interpenetrating polymer networks from caster oil‐based‐polyurethanes and poly(ethyl acrylate). VII
Authors: Patel Mayur , Suthar Bhikhu 
Published: April 2003

AbstractLiquid prepolyurethanes were synthesized from castor oil and toluene‐2, 4‐diisocyanate (TDI) under different experimental conditions and varying NCO/OH ratios. All these prepolyurethanes were subsequently reacted with ethyl acrylate/ethylene glycol dimethacrylate mixtures by radical polymerization using benzoyl peroxide as initiator to obtain interpenetrating polymer networks (IPNs) by transfer molding. The novel polyurethane/poly(ethyl acrylate) IPNs are found to be tough films. These IPNs are characterized in terms of their resistance to chemical reagents, thermal behavior (DSC, TGA), mechanical behavior including tensile strength, Young's modulus, and elongation. The dielectric properties, namely electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε″), and loss tangent (tan δ) were computed. The mechanothermal behavior was analyzed by dynamic mechanical spectroscopy. The morphological behavior was studied by scanning electron microscopy.
Poly(phenylene oxide) composites containing crosslinked polystyrene microspheres. II. Dark crosses observed in microscope
Authors: Zhikuan Chai , Qipeng Guo 
Published: April 2003

AbstractExtinction phenomena observed between crossed polaroids in microscope were classified into three groups: (1) Poly(2, 6‐dimethyl‐1, 4‐phenylene oxide)/polystyrene composite with crosslinked polystyrene microspheres. Negative dark crosses were observed in the shells of the spheres, the cores of the spheres were completely extinct. The crosses disappeared at 170°C, which is 20°C above Tg of the matrix polymer. (2) Polycarbonate composite with glass beads. The dark crosses were positive and outside the glass beads. The crosses disappeared at 130°C, which is 20°C below Tg of the matrix polymer. (3) In situ polymerized composites with crosslinked polystyrene microspheres. The dark crosses were the same size of the spheres. They were negative in poly(methyl methacrylate) and poly(vinyl acetate) and positive in polystyrene. The disappearing temperatures of the crosses were 150, 110, and 285°C, respectively. The first two groups of phenomena are explained as the photoelastic effects caused by the thermally induced stresses. The last group is due to the inhomogeneous swelling or contracting of polystyrene networks in the matrices.
An analysis of the accuracy of determining molar‐mass averages of polymers by GPC with an on‐line light‐scattering detector
Authors: Procházka Ondřej , Kratochvíl Pavel 
Published: April 2003

AbstractThe effect of errors of concentration and molar‐mass detectors in GPC on the accuracy of determining molar‐mass averages Mn and Mw was analyzed. Model calculations show that by means of GPC with an on‐line low‐angle laser light‐scattering (LALLS) photometer only Mw can be determined with acceptable accuracy. Mn can be determined with acceptable accuracy only for polymers that have very small polydispersities. Mn can be determined with greater accuracy from data of a concentration detector and chromatographic‐column‐calibration data. The most suitable procedure for the determination of Mw seems to be a direct integration of the molar‐mass detector output, even if the error due to neglecting the second virial coefficient term is significant. Compared with the inaccuracy of detectors, axial dispersion appears not to be the main source of errors in GPC with an on‐line molar‐mass detector.
Copolymerization of vinyl chloride with 1‐olefins. III. An investigation of the copolymerization reaction of vinyl chloride with 1‐butene and 1‐pentene
Authors: Mrázek Z. , Jungwirt A. , Kolínský M. 
Published: April 2003

AbstractSeries of suspension copolymerization of vinyl chloride with various contents of 1‐butene and 1‐pentene (5–30 mass%) were carried out under the same reaction conditions. By applying a method which utilizes periodic sampling of heterogeneous reaction mixture from the reactor during the reaction and a gas chromatographic determination of unreacted vinyl chloride in the sample, the conversion curves of vinyl chloride were determined and the initial reaction rates were compared.
Separation and characterization of low‐conversion poly(styrene‐co‐methyl methacrylate) by liquid adsorption chromatography
Authors: Mori Sadao , Uno Yoshitaka 
Published: April 2003

AbstractPoly(styrene‐co‐methyl methacrylate) copolymers of narrow chemical composition distributions were separated according to composition by linear gradient elution at column temperatures between 10 and 80°C using silica gel as an adsorbent. The initial mobile phase was a mixture of chloroform and ethanol (99.0 : 1.0, v/v) and the final one (95.5 : 4.5). The relationship of retention volume and the composition of the copolymers was obtained. Higher column temperature (and/or less ethanol content in the mobile phase) is preferable for the separation of copolymers having less MMA and vice versa. Molecular weight dependence on retention volume was not observed. The chromatographed copolymers were still chemical heterogeneous: the compositional difference of the front and rear halves of an adsorption chromatogram of a copolymer was 2.1 %. The front half had a higher styrene content and lower molecular weight averages than those for the rear half of the peak. This separation method was reproducible and the relative standard deviation was about 0.6%. Recovery of fractions was 98.2% by isocratic elution and 96.4% by gradient elution.
Synthesis of new flame‐retarding epoxy resin based on 3′, 5′, 3″, 5″‐tetrabromophenolphthalein
Authors: Yang Chin‐Ping , Lee Tzong‐Ming 
Published: April 2003

AbstractNew flame‐retarding epoxy is synthesized by reacting 3′, 5′, 3Prime;, 5″‐tetrabromophenolphthalein (TBPP) with epichlorohydrin and characterized in comparison with commercially available tetrabromobisphenol‐A(TBBA) epoxy on their flame retardancy and thermostability. TBPP epoxy show better results in promoting flame resistance than TBBA epoxy. However, TBPP epoxy exhibits a greater effect on thermal decomposition temperature. The order of char yield at 800°C under nitrogen for the cured products is TBPP epoxy > phenolphthalein (PP) epoxy > TBBA epoxy. Meanwhile, there is a linear relationship between oxygen index and char yield for cured products of TBPP‐PP epoxy and TBBA‐BA epoxy systems.
Thin polymer films from fluidized electrode bed reactors
Authors: Teng F. S. , Mahalingam R. 
Published: April 2003

AbstractThe formation and deposition of a polymer as a thin, uniform solid film on a metal particle substrate is investigated in detail in a fluidized electrode bed reactor. Experiments were carried out in different designs of fluidized bed electrode cell reactor, using various metal particles and monomers. It was observed that diacetone acrylamide (DAA) monomer in 0.1N H2SO4 with aluminum particles (3530 μm) as cathode, in a concentric dual compartment cell, appeared to yield the best films. Infrared and elemental analyses were used to characterize the polymer film on the metal particles. Scanning electron microscopy (SEM) was employed to examine the surface and cross‐sectional profiles of the films. The potential profiles in both particulate and solution phases were measured and the importance of particulate electrical conductivity in the polymerization is thus explained. It was observed that the optimum particulate conductivity and hence the maximum yield occurs in the range of 10–20% bed expansion. The experimental product yields for various liquid superficial velocities (i.e., bed expansion) at different feeder current densities were compared to explain the possible controlling mechanism in packed and fluidized bed cells, noting that both chemical reaction and mass transfer control in the low bed expansion region while chemical reaction controls in the high bed expansion region. The current effciency decreases in the high current region due to side reactions at the fluidized bed electrode and due to pore diffusion in the polymer film.
Sorption of methylene chloride in polyethylene terephthalate
Authors: Liu C.‐P. Anthony , Neogi P. 
Published: April 2003

AbstractSorption of methylene chloride in polyethylene terephthalate has been performed at three different temperatures: 21, 34, and 48°C. The solubility data are explained through dual sorption. The diffusivities are more difficult to explain since some anomalous effects were present.