bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pyrolysis GC/MS studies on plasma‐polymerized pyrrole
Authors: Kojima Takakazu , Takaku Hideaki , Urata Yoshikiyo , Gotoh Kohji 
Published: April 2003

AbstractPyrolysis gas chromatography/mass spectrometry and infrared spectrometry have been carried out for plasma‐polymerized pyrrole (PPPy). The major thermal decomposition products have been identified as nitriles with less than four carbons and alkyl pyrroles. Evolution of only monosubstituted alkyl pyrroles, such as 2‐methylpyrrole and 2‐ethylpyrrole, suggests that PPPy consists of monosubstituted pyrrole rings. This is also supported by the result that the IR spectrum of PPPy differs from that of the electrochemically polymerized pyrrole, which consists of disubstituted pyrrole rings. Evolution of linear nitriles shows evidence that a PPPy molecule has the main chain containing nitrogen atoms. The mechanism of polymerization of pyrrole in the discharge is considered to be similar to that of aromatic hydrocarbons, which mechanism involves a process of production of acetylene. © 1993 John Wiley & Sons, Inc.
Thermoanalytical characteristics of durable press treated cotton fabrics
Authors: Trask‐Morrell Brenda J. , Kottes Andrews B. A. , Catalano E. A. 
Published: April 2003

AbstractThermoanalytical characteristics of chemically treated cotton fabric often appear similar to those of untreated cotton. The overwhelming amount of cotton cellulose versus the small quantities of finishing chemicals present can mask many features contributed by reactant. The current work is an initial attempt to detect and differentiate among a variety of durable press finishes. They include three N‐methylol reactants, and four polycarboxylic acids with two alkali metal salts of phosphorus‐containing acids used to catalyze their reaction with cellulose. Differential scanning calorimetric and thermogravimetric techniques were employed under dynamic nitrogen conditions. Changes in residue, rate of weight loss, peak intensity, and peak temperature were observed and varied with reactant, catalyst used, and washing. The ability to distinguish among polycarboxylic acids, catalysts, and/or other formaldehyde‐based reactants is of value to the textile chemist. With these preliminary results, we may soon offer a new means of finish identification. © 1993 John Wiley & Sons, Inc.This article is a US Goverment work and, as such, is in the public domain in the United States of America.
Mechanical and swelling properties of HTPB‐based copolyurethane networks
Authors: Jain S. R. , Sekkar V. , Krishnamurthy V. N. 
Published: April 2003

AbstractCopolyurethanes of hydroxy terminated polybutadiene (HTPB) and ISRO–Polyol (ISPO), an indigenously developed castor‐oil based polyol, have been prepared using toluene diiso‐cyanate and hexamethylenediisocyanate. The mechanical strength and swelling characteristics of the copolyurethanes cured with trimethylol propane and triethanolamine have been studied to evolve improved solid propellant binders. By varying the ratios of the two hydroxy pre‐polymers, chain extenders, and crosslinkers, copolyurethanes having a wide range of tensile strength and elongation could be obtained. Many of these systems are desirable for their use as propellant binders. The results have been explained in terms of the measured crosslink densities and other swelling properties. © 1993 John Wiley & Sons, Inc.
Studies on sequential interpenetrating polymer network (IPN) based on nitrile rubber and poly(vinyl acetate)
Authors: Patri M. , Samui A. B. , Deb P. C. 
Published: April 2003

AbstractSeveral elastomeric sequential interpenetrating polymer networks (IPNs) based on nitrile rubber (NBR) and poly(vinyl acetate) (PVA) have been synthesized. Cross‐linked NBR was swollen in vinyl acetate monomer containing benzoyl peroxide (BPO) as initiator and tetraethylene glycol dimethacrylate (TEGDM) as cross‐linker and then the swollen mass was polymerized. The composition of the IPNs could be varied by varying the swelling time and concentration of BPO and TEGDM. The properties of these IPNs were investigated by tensile test, differential scanning calorimetry (DSC), dynamic mechanical analysis, and swelling measurement. On increasing the PVA content as well as cross‐linking level, the tensile strength increased because of better mixing. DSC showed a single Tg value for all the individual IPNs, the Tg values changing regularly with composition. The tan δ peak for IPNs appeared at higher temperature compared to NBR and was found to be dependent on both the composition of IPNs as well as cross‐linking level. IPNs having 2 and 5% cross‐linker (TEGDM) showed splitting in the tan δ peak. On increasing the cross‐linker concentration to 9% and beyond, the splitting disappeared. The damping capability of the IPNs has been explained in terms of the magnitude of tan δ, area under the tan δ curve, and ½ peak width. The IPNs also showed better solvent‐resistance properties. © 1993 John Wiley & Sons, Inc.
Mechanical properties of honeycomb prepared from aromatic polyimide film
Authors: Ogawa Toshio , Okazaki Noriomi 
Published: April 2003

AbstractAromatic polyimides have many advantages such as low thermal expansion coefficient, good electrical insulation, and self‐extinguishing properties. We tried to use polyimide film for honeycomb structure. Polymide honeycomb core and sandwich panel were prepared from polyimide film, i.e., UPILEX R, and adhesive by the expansion method. Mechanical properties, i.e., compressive, crushed, shear, and flexural strengths, were evaluated for this core and panel. Compressive and crushed properties increased largely with the density of the honeycomb, whereas shear and midspan flexural properties did not vary so much with the density, because these failures occured in the adhered interface. Strong adhesion is required for improving the latter properties. © 1993 John Wiley & Sons, Inc.
Fumed silica as stabilizer of precursor emulsions used to prepare polymer latexes
Authors: Hong L. , Ruckenstein E. 
Published: April 2003

AbstractIntroducing small amounts of fumed silica into mixtures of organic liquids, which contain ethylene glycol dimethylacrylate (EGDMA), a hydrocarbon (such as decane), and one of the following monomers: allylchloride (AC), 3,4‐dichloro‐1‐butene (DCB), or methyl methacrylate (MMA), enabled their dispersion into an aqueous solution of surfactant with the generation of stable emulsions. Such emulsions cannot be generated in the absence of fumed silica. Functionalized polymer latexes of poly(AC–EGDMA), poly(DCB‐EGDMA), and poly(MMA–EGDMA) could, thus, be prepared through the polymerization of the emulsions. The chloride units in the poly(AC–EGDMA) or in the poly(DCB–EGDMA) were subsequently converted to quaternary ammonium salts. The resulted polymer‐supported quaternary ammonium salt together with RuCl3, 4‐N‐methylmorpholine N‐oxide (NMO) and ammonium persulfate were employed in the catalytic oxidation of toluene to benzoic acid. Furthermore, the presence of fumed silica in the emulsions enabled the preparation of latexes containing rather uniformly distributed inorganic particle clusters of submicrometer size. Polymer–inorganic blends of NaY zeolite–(SiOx)n/P (MMA–EGDMA), zeolite (4A)–(SiOx)n/P (MMA–EGDMA), TiO2–(SiOx)n/P (MMA–EGDMA), CuO–(SiOx)n/P (MMA–EGDMA), and Cu‐(SiOx)n/P (MMA–EGDMA) were thus obtained. © 1993 John Wiley & Sons, Inc.
Functional polymers for colloidal application. IX. The dispersing ability of anionic and zwitterionic aniline‐formaldehyde condensates to dyes
Authors: Kuo Ping‐Lin , Wey Bih‐Shiuh , Chen Wen‐Hsiang 
Published: April 2003

AbstractAnionic and zwitterionic aniline–formaldehyde condensates, N‐(3‐sodium propylsulfonate) aniline–formaldehyde condensates (PSAF), and N, N‐dimethyl‐N‐(3‐propylsulfonate) anilinium–formaldehyde condensates (DPSAF) are used as dispersants to disperse dyes (C. I. Navy Blue 79 and C. I. Brown 1), compared with the conventional dye dispersants–naphthalenesulfonate formaldehyde condensates (NSF). The dispersing properties of the condensates are assessed by the viscosity method, scanning electron microscopy (SEM), the final volume fraction after sedimentation, and adsorption behaviors. Compared to DPSAF, the PSAF and NSF with a lower molecular weight (PSAF‐L, NSF‐L) show significantly lower apparent viscosities of the paste of Navy Blue 79. Comparing the results of the viscosity method with those of SEM and the final volume fraction after sedimentation, it can be concluded that a better‐dispersed paste displayed by SEM shows a lower viscosity and a smaller final volume fraction. The amount of NSF‐L adsorbed on Navy Blue 79 is significantly higher than that of PSAF‐L and DPSAF‐H. However, the sulfonate on PSAF‐L can be extended more deeply toward the bulk phase compared to that on NSF‐L so that PSAF‐L can result in a high effective thickness. These adsorption phenomena are used to interpret the dispersing ability. For Brown 1, the anionic dispersants can reach a similar minimum viscosity independent of their molecular weight, but the PSAF with high molecular weight shows a remarkably low optimum concentration (ca. 3% compared to PSAF‐L 9%, NSFs 5%). © 1993 John Wiley & Sons, Inc.
Assessment of applicability of carreau, ellis, and cross models to the viscosity data of resin solutions
Authors: Raju K. V. S. N. , Krishna D. , Devi G. Rama , Reddy P. J. , Yaseen M. 
Published: April 2003

AbstractIn this study, three popular rheological models, which fit adequately well to viscosity data of polymeric materials, are chosen for making a comparative assessment of their applicability to practical data. The resulting nonlinear equations of the three models are solved by using Levenberg Marquardt's algorithm. The assessment of their applicability to practical viscosity data of 66 solutions of two resins in 11 solvent systems and reported data of other polymers has been analyzed. The Carreau and Ellis models have yielded unique global estimates for various rheological parameters, whereas the Cross model yielded local solutions. However, both Carreau and Cross models yielded parameter estimates with low overall residual error. The three models are found to have good applicability to viscosity data of resin solutions in good and moderate solvents; however, some deviation is observed when they are tested for solvents in which the resin has poor solubility. © 1993 John Wiley & Sons, Inc.
Undoping effect of electropolymerized polymer for two‐layer organic photovoltaic ceils based on polymer/dye junction
Authors: Uehara Kaku , Maekawa Akira 
Published: April 2003

AbstractThe undoping effects of electropolymerized poly(3‐methylthiophene) (PMeT) and poly(N‐methylpyrrole) (PMPy) on the open‐circuit photovoltage Voc and on short‐circuit pho‐tocurrent Jsc were investigated for two‐layer organic photovoltaic cells based on the PMeT or PMPy / vacuumevaporated rhodamine B (RB) under the electrochemical doping level between −3 and +3 V. The value of Voc of the undoped‐polymer / RB cell was larger than that of the doped‐polymer / RB cell. PMeT/RB and PMPy/RB cells gave the minimum value of Jsc at a doping level of 0 V. It was suggested that polarons and bipolarons states formed at a doping level of 0 V may work as a trap site for the carrier to decrease in Jsc. Undoping of the PMeT improved Voc and Jsc of the PMeT/RB two‐layer organic pho‐tovoltaic cell together with its durability. © 1993 John Wiley & Sons, Inc.
Physical characterization of wood and wood‐polymer composites: An update
Authors: Wright J. R. , Mathias L. J. 
Published: April 2003

AbstractNew and reliable test methods have been developed, and are under development, for the physical characterization of wood and whole wood‐polymer composites (WPC is used in this article to refer to polymer‐impregnated whole wood). The methods described here have been designed for smaller samples than are required for most ASTM tests. It should be stressed that, when comparing treated samples to untreated samples in any type of testing, the initial density or specific gravity (density before treatment) of the treated sample should be the same as the untreated control sample. If possible, measurements should be made on a given sample before and after treatment; on a split sample, half should be treated and compared with the untreated half. If there is much variation in density between samples within a group, the effectiveness of the treatment cannot be determined with an acceptable degree of accuracy, since whole wood varies greatly between specimens and density is a major factor contributing to property variability. For example, swelling (due to moisture uptake), modulus, toughness, surface hardness, and compressive strength of wood all increase dramatically with increasing density for both untreated whole wood and WPCs.Scanning electron microscopy, coupled with x‐ray energy analysis, indicated the presence or absence of good interaction between wood components and in situ formed polymer. For example, poly(EHMA) (the homopolymer of ethyl α‐hydroxymethylacrylate) and wood components were seen to be strongly bonded, and x‐ray activation elemental analysis confirmed the presence of poly(EHMA) and its copolymers within the wood cell walls. On the other hand, proton spin‐lattice relaxation in the rotating frame (T1p) measurements (by 13C solid‐state NMR) for balsa / EHMA WPCs gave two separate sets of relaxation times, one each for unique peaks corresponding to either the polymer or the wood components. It is probable that the region of interaction between poly(EHMA) and the wood component in the balsa / EHMA WPC (the interphase region) is small, as compared to the individual components, and is not observed. This result is consistent with a two‐parameter relaxation process for the peak at ca. 61 ppm, which includes overlapping peaks for the hydroxymethyl carbons of poly(EHMA) and cellulose. © 1993 John Wiley & Sons, Inc.
Polymer optical fiber for near infrared use
Authors: Takezawa Yoshitaka , Ohara Shuichi 
Published: April 2003

AbstractUsing the empirical simulation that we developed to estimate loss spectra of amorphous polymers, we predicted the intrinsic loss spectrum of fluorine‐containing polyarylate (FPAr) that should have a small attenuation loss in the near infrared region. Loss of FPAr is smaller than that of poly (methyl methacrylate), which is a typical optical polymer used as a core material in polymer optical fiber (POF), above 720 nm. FPAr was synthesized by phase transfer catalyzed polycondensation of 2,2‐bis (4‐hydroxyphenyl)‐1,1,1,3,3,3‐hexafluoropropane with isophthaloyl dichloride. Its glass‐transition temperature (Tg) by DSC is 163°C. This indicates that FPAr has higher heat resistance than polycarbonate (PC) by about 10°C. A film of 100μm thick has over 85% transmittance from 330 to 900 nm. Values from a tension test are similar to those of PC. As a result, FPAr is expected to be a good core polymer for POF, because of its highTg, good transparency, and good flexibility. Next, the POF made of FPAr was fabricated by a melt‐flow spinning method. It had larger attenuation loss than predicted. The difference from the simulation was extrinsic loss caused by the fabricating process. Therefore, when a more suitable fabricating process is developed, loss of FPAr‐POF can be decreased, so that it will be applicable to optical communications in the near infrared region. © 1993 John Wiley & Sons, Inc.
Effect of some sodium bisulfite adducts of different chain lengths on the course of the emulsion polymerization of vinyl acetate
Authors: Badran A. S. , Ramadan A. M. , Moustafa A. B. , Shaffel K. A. 
Published: April 2003

AbstractThe emulsion polymerization of vinyl acetate using some bisulfite adducts of different chain lengths with potassium persulfate as the redox initiation system, in the absence of emulsifier, was studied. The effects of such adducts, which contain the same weight equivalent of bisulfite anion, on the rate of polymerization, maximum conversion, and stability of the produced polymer lattices as well as the morphological characteristics including volume‐average diameters and the number of polymer particles per unit volume of water were investigated. The rate of polymerization was found to be dependent on the concentration of benzaldehyde, acetaldehyde, octyl aldehyde, methyl propyl ketone, and acetone sodium bisulfite adducts to the powers 0.54, 0.66, 0.95, 1.0, and 1.1, respectively. Also, it was found that increasing adduct chain lengths decreases the volume‐average diameter, increases the obtained lattice stability, and improves the morphology of the polymeric particles, where a spherical morphology and extra stability were obtained in the presence of the octyl aldehyde adduct. © 1993 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
The application of infrared microimaging for the determination of the distribution, penetration depth, and diffusion profile of methyl centralite and dibutyl phthalate deterrents in nitrocellulose monoperforated propellant
Authors: Louden J. D. , Duncan I. A. , Kelly J. , Speirs R. M. 
Published: April 2003

AbstractInfrared microspectroscopy was used to determine quantitatively and qualitatively methyl centralite (MC) and dibutyl phthalate (DBP) diffusion profiles in cross sections of nitro‐cellulose‐based monoperforated propellant grains. The absorbance values of the CO peak of DBP at 1717 cm −1 and the aromatic CC peak of MC at 1496 cm −1 were measured relative to the NO2 overtone peak of the nitrocellulose at 2555 cm−1 at 10 μm intervals from the outside edge inward (external profile) and the perforation edge inward (internal profile). Infrared microimaging was used to determine the distribution and penetration depth of the DBP and MC using the CO peak of DBP at 1717 cm−1 and the aromatic CC peak of MC at 1496 cm−1 as diagnostic of the two deterrents to obtain the contour and axonometric displays of the distribution. © 1993 John Wiley & Sons, Inc.
Synthetic pulp fiber ozonation: An ESCA and FTIR study
Authors: Chtourou H. , Riedl B. , Kokta B. V. , Adnot A. , Kaliaguine S. 
Published: April 2003

AbstractPolytheylen (PE) pulp fiber was treated by ozone for surface modification. Surface analysis was performed by using X‐ray photoelectron (ESCA) and IR (FTIR) spectroscopies. Carbon (C) and Oxygen (O) were the main atoms detected by ESCA (C1s, O1sregions) on the treated fiber. Analysis of the C1speaks (C1, C2, and C3) showed that the oxidation level changed with the ozonation time. O1speak components (O0, O1, and O2) were very useful to complete the surface analysis. FTIR spectra showed the presence of carbonyl groups (1740–1700 cm−1), even on nontreated fiber, which increased in intensity as treatment time increased. Ozone treatment went beyond the surface level to the bulk of the fiber. This was marked by a large increased of the intensity of the carbonyl band after 3 h of ozonation. Thermal analysis suggests structure and morphology changes of fiber when exceeding 2 h of ozonation. © 1993 John Wiley & Sons, Inc.
Hydrogenation of epoxidized natural rubber
Authors: Roy Sanjoy , Bhattacharjee S. , Gupta B. R. 
Published: April 2003

AbstractThe thermal properties of epoxidized natural rubber (ENR) have been found to improve upon hydrogenation in a solution phase, in the presence of a homogeneous catalyst, at 50°C. The hydrogenated ENR shows higher Tmax values in the DTG scan and, upon aging, the change in carbonyl concentration is less as compared to that of ENR, as detected by IR spectrophotometry. The hydrogenated product was characterized by IR and 1H–NMR spectroscopy. © 1993 John Wiley & Sons, Inc.
Thermotropic liquid crystalline copolyesters. I. Synthesis and thermal characterization of the copolyesters of terephthaloyl chloride, hydroquinone, and 1,4‐butane diol
Authors: Rath Asoke K. , Ponrathnam Surendra 
Published: April 2003

AbstractA new series of random thermotropic liquid crystalline polyesters (LCPs) was synthesized from terephthaloyl chloride, hydroquinone, and 1,4‐butane diol. The copolyester composition was varied by changing the relative mole ratio of hydroquinone and 1, 4‐butane diol in the feed. All the copolyesters displayed thermotropic liquid crystallinity at relatively low temperatures. Liquid crystalline behavior of the copolyesters has been characterized by polarizing light microscopy and by differential scanning calorimetry (DSC). The effect of co‐polyester composition on the temperature and thermodynamic parameters related to liquid crystalline transition is discussed. © 1993 John Wiley & Sons, Inc.
Flexural and impact properties of high‐density polyethylene/linear low‐density polythylene blend
Authors: Gupta A. K. , Rana S. K. , Deopura B. L. 
Published: April 2003

AbstractIn this article, a study of flexural and impact properties of binary blends of high‐density polyethylene (HDPE) and linear low‐density polyethylene (LLDPE), over a full range of blending ratios, is presented. The property distinctions in the three ranges of composition (viz., HDPE‐rich blend, LLDPE‐rich blend, and the middle region) are remarkable and consistent with the different effects of cocrystallization in the respective concentration ranges. Furthermore, the analysis of flexural yield properties data, in terms of the Ree‐Eyring equation, and the correlation of results with variation of x‐ray crystallinity are presented, which suggests the existence of two types (i.e., mobile and immobile) of segments in the amorphous phase of the blend. The relative variation of these two types of amorphous phase in the three different composition ranges of the blend are discussed. The impact strength variation of this blend is also found to correlate with the variation of the fraction of amorphous phase in the blend. © 1993 John Wiley & Sons, Inc.
Batch polymerization of methyl methacrylate in mini/macroemulsions
Authors: Fontenot K. , Schork F. J. 
Published: April 2003

AbstractThe kinetics of the isothermal batch macroemulsion and miniemulsion polymerizations of methyl methacrylate (MMA) at 50°C have been studied. Hexadecane was used as the cosurfactant or swelling agent. The nucleation mechanisms were observed to be different between macroemulsions and miniemulsions. The effect of surfactant, cosurfactant, initiator, shear, and hold time on droplet nucleation was studied. The miniemulsion particles were found to contain more radicals on average than the macroemulsion particles using certain recipes. This resulted in higher polymerization rates for the miniemulsions at identical particle numbers. The latex‐particle‐size distributions were similar even though the mini‐emulsion droplets start out with a high polydispersity of around 1.5. Miniemulsion latexes were found to be more stable under shear. Conductance of emulsions during polymerization was found to be a valuable on‐line tool for investigating particle nucleation and growth. © 1993 John Wiley & Sons, Inc.