bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relative inhibitory effect of various compounds on the rate of polymerization of methyl methacrylate
Authors: Georgieff K. K. 
Published: April 2003

AbstractThe relative inhibitory effect of the following compounds on the bulk polymerization of methyl methacrylate were measured: hydroquinone, p‐tert‐butylcatechol, p‐methoxyphenol, 2,4‐dichloro‐6‐nitrophenol, n‐propyl gallate, di‐tert‐butyl‐p‐cresol, 2,2'‐methylenebis(4‐methyl‐6‐tert‐butylphenol), 1‐amino‐7‐naphthol, p‐benzoquinone, 2,6‐dichloro‐p‐benzoquinone, 2‐amino‐1,4‐naphthoquinone, three aminoanthraquinones, diphenylamine, p‐nitrosodimethylaniline, α‐ and β‐naphthylamine, phenothiazine, N‐nitrosodimethylamine, hexamethylphosphoramide, n‐dodecyl mercaptan, benzenethiol, 2,2‐diphenyl‐1‐picrylhydrazyl, phenyl hydrazine, divinylacetylene, and various antimony and copper salts. Polymerization was carried out in a test tube in a bath at 101.2°C., benzoyl peroxide being used as initiator. Generally, phenols and naphthols were the strongest inhibitors, followed by quinones, aromatic amines, 2,2‐diphenyl‐1‐picrylhydrazyl, antimony pentachloride, phenyl hydrazine, divinylacetylene, and the thiols.
Polymerization of methyl methacrylate under ultrasonic irradiation
Authors: Osawa Zenjiro , Igarashi Nobuo 
Published: April 2003

AbstractPolymerization of methyl methacrylate with Grignard reagents and benzoyl peroxide under ultrasonic irradiation was carried out and the effect of the ultrasonic irradiation on the stereoregularity and the properties of the polymers obtained was studied. No effect of ultrasonic irradiation on the stereoregularity of the polymers was observed, but the yield and the intrinsic viscosity of the polymers were lower than those of polymers produced without ultrasonic irradiation. It is, therefore, assumed that the bonds at a propagating site between an active polymer end and a counterion are fairly strong and are not broken by the externally applied energy corresponding to an ultrasonic wave of 500 keycles/sec., even though carbon–carbon covalent bonds in the main chain are broken.
Some aspects of the degradation of epoxide resins
Authors: Stuart J. M. , Smith D. A. 
Published: April 2003

AbstractThis paper contains a description of the use of gas chromatography to examine the pyrolytic degradation of epoxide resins. The method depends on the pyrolysis of the material by use of an electrically heated filament, the difficulties of the method are examined and attempts to overcome them are described. The pyrolytic degradation of a resin based on the glycidyl ether of bisphenol‐A hardened with 1,2‐diaminoethane and also triethylenetetraamine, is described. An attempt has been made to explain, in terms of possible degradation reactions, the actual compounds detected in the pyrolytic breakdown.
Glass transition temperatures of poly(methyl methacrylate) plasticized with low concentrations of monomer and diethyl phthalate
Authors: Dudek Thomas J. , Lohr Jerome J. 
Published: April 2003

AbstractThe effect of low plasticizer concentrations on the glass transition temperature of poly(methyl methacrylate) (PMMA) has been studied experimentally for diethyl phthalate (DEP) and methyl methacrylate (MMA) as plasticizers. Volume dilatometry, differential thermal analysis, and a torsional pendulum were used to determine glass transition temperatures. The monomer‐plasticized PMMA samples were prepared by polymerizing MMA to a limiting conversion which was found to depend primarily on temperature. At temperatures slightly above the glass transition temperature of a MMA–PMMA system, a polymerization reaction occurred at a rate rapid enough to complicate the interpretation of the dilatometric and differential thermal analysis methods for determining the glass transition temperature. However, the torsional pendulum method could be used since it did not require measurements to be made at temperatures where polymerization could occur. The differential thermal analysis results showed that the temperature at which the polymerization reaction was first detectable was related to the glass transition temperature of the MMA–PMMA solution. The measured glass transition temperatures were compared with the predictions of the theories of Fox, Kelley, and Bueche, and Dimarioz and Gibbs on the effect of plasticizer concentration on the depression of the glass transition temperature.
Thermal characteristics of some rigid urethane foams
Authors: Smith Clifford H. 
Published: April 2003

AbstractThe thermal stability characteristics of three rigid urethane foams prepared from various formulations, to give a wide range of molecular structure, were investigated by means of TGA, DTA, and long‐term heat aging. Compressive strength values over a temperature range of −73°C to +232°C were also determined for these foams. Based on all tests performed, a toluene diisocyanate foam displayed the poorest thermal stability characteristics of the three foams studied. A combination toluene diisocyanate–polymethylene polyphenylisocyanate foam showed intermediate elevated temperature properties, whereas, a foam employing only polymethylene polyphenylisocyanate demonstrated the best over‐all high temperature stability.
Polarization colors of nitrocellulose
Authors: Kohlbeck J. A. , Bolleter W. T. 
Published: April 2003

AbstractThe polarization colors of nitrocellulose (NC) fibers show an orderly progression from gray‐white at 11.0% nitrogen (N) through first‐order whites, yellows, and reds to second‐order blue at 12.6% N. At higher levels of nitration, the polarization colors revert back to first orders with fibers containing 13.1% N showing gray changing to intense white at 13.5% N. The length‐positive and length‐negative character of NC fibers also changes with the degree of nitration. Fibers nitrated to about 12.4% N are optically neutral and become increasingly positive with a decrease in the level of nitration and increasingly negative as the level of nitration increases. This optical property and the polarization colors of NC provide much information about the level and range of nitration of NC fibers.
An infrared technique for the quick analysis of cotton–polyester blends
Authors: Iyer P. Bhama , Iyer K. R. Krishna , Patil N. B. 
Published: April 2003

AbstractThe details of an infrared technique standardized to analyze cotton–polyester blends of different compositions are reported. It is observed that particle size plays a very important role in the peak intensity of the 1725 cm−1 band (CO stretching) in polyester, the absorption band recommended for analysis of cotton–polyester blends. However, the product of the band width and peak intensity is found to be dependent on particle size to a lesser extent and hence is a more reliable parameter in the measurement of percentage composition. It has further been shown that the method of sample preparation can affect the band width and hence the results. A suitable sample preparation procedure is, therefore, described whereby an accuracy of ±3% in the estimation of polyester content in a given blend can be achieved.
Modification of poly(vinyl alcohol) fibers by hexamethylene diisocyanate
Authors: Varma D. S. , Nedungadi Chandran 
Published: April 2003

AbstractPoly(vinyl alcohol) multifilament yarn was modified by reaction with hexamethylene diisocyanate. The effects of reaction variables such as time, temperature, concentration of reagents, solvent, and atomosphere were studied. The role of solvent appears to be very important in the reaction. Dimethylformamide, on account of its swelling power, proved better than the solvents benzene, toluene, and dioxane. Physical properties of modified fibers were compared with those of the parent. Moisture regain of the modified samples decreased with increasing add‐on percent. The elastic recovery was not improved, and there was little effect of the HMDI treatment on mechanical properties. The thermal stability of poly(vinyl alcohol) modified with diisocyanate with small add‐on was slightly improved.
The effect of red phosphorus on the flammability of poly(ethylene terephthalate)
Authors: Granzow A. , Cannelongo J. F. 
Published: April 2003

AbstractAddition of red phosphorus in concentrations of about 4% to poly(ethylene terephthalate) (PET) reduces the flammability of that polymer. The rates of flame propagation and the ignitability are reduced, while the oxygen index (O.I.) is increased. The surface temperature of burning PET amounts to TS ≈ 380°C; addition of 4% red phosphorus raises this value to TS ≈ 450°C. An increase of the environmental temperature TE enhances the flammability of PET and PET + phosphorus samples; the O.I. decreases and the rate of flame propagation increases with temperature. The flame‐retardant effectiveness of red phosphorus is reduced if the sample is burned in a N2O atmosphere. This indicates that part of the flame retardancy imparted by phosphorus involves gas‐phase inhibition. The major flame‐retardant action does, however, occur in the condensed phase, since the rate of pyrolysis of PET is affected by the presence of red phosphorus.
Azeotropic graft polymerizations of dienes and acrylonitrile onto poly(propylene oxide)
Authors: Fall H. H. 
Published: April 2003

AbstractGraft copolymerizations of isoprene or butadiene with acrylonitrile in an approximately 2:1 weight ratio onto poly(propylene oxide) are azeotropic. These products, when vulcanized with sulfur, yield elastomers with excellent tensile properties.
Structure–property relationships in crosslinked networks from cis‐1,4‐polybutadiene and methacrylic acid. Swelling behavior
Authors: De Candia F. , Taglialatela A. , Vittoria V. 
Published: April 2003

AbstractIn the present paper, we report results obtained analyzing the swelling behavior of a composite system prepared from vulcanizing mixtures of cis‐polybutadiene and methacrylic acid with different amounts of acid. Two solvents were used as swelling agents, decalin and the N,N‐dimethylformamide. The structural data, given by low‐angle x‐ray diffusion spectra, were used to interpret the mechanical behavior described in terms of the Mooney‐Rivlin equation and hysteresis loops. Structural and mechanical data give information about the swelling mechanism of the solvents and about the problem of the experimental deviations from the Gaussian theory of rubber elasticity.
Analysis of cotton fiber maturity. II. Glycerol retention value of cotton
Authors: Kulshreshtha A. K. , Chudasama V. P. , Dweltz N. E. 
Published: April 2003

AbstractThe imbibition of glycerol by cotton has been used as a measure of fiber porosity which includes a major contribution from the fiber lumen. Cotton is swollen in glycerol to saturation and subjected to centrifugation until constant weight is attained. The glycerol retention value (GRV) is calculated from the increase in weight of cotton after swelling and centrifugation. This method is applied to determine GRVs and pore space of 12 American cottons which have different wall thicknesses but more or less the same fiber perimeter. A high negative correlation is obtained between GRV and the percentage of mature fibers for various raw and extracted cottons. Effect of fiber wax content of GRV was studied. It has been shown how the average lumen area in swollen state can be calculated from GRV and gravimetric fineness. The significance of pore space is discussed.
Thermal degradation of polystyrene
Authors: Kishore K. , Verneker V. R. Pai , Nair M. N. R. 
Published: April 2003

AbstractThe importance of the study of thermal degradation of polymeric fuels arises from their role in the combustion of solid propellants. Estimation of the condensed‐phase heat release during combustion can be facilitated by the knowledge of the enthalpy change associated with the polymer degradation process. Differential scanning calorimetry has been used to obtain enthalpy data. Kinetic studies on the polymeric degradation process have been carried out with the following objectives. The literature values of activation energies are quite diverse and differ from author to author. The present study has tried to locate possible reasons for the divergence in the reported activation energy values. A value of 30 kcal has been obtained and found to be independent of the technique employed. The present data on the kinetics support to chain‐end initiation and unzipping process. The activation energies are further found to be independent of the atmosphere in which the degradation of polymer fuel is carried out. The degradation in air, N2, and O2 all yield a value of 30 kcal/mole for the activation energies.
Highly accessible or decrystallized cotton by chemical methods
Authors: Tsuji Waichiro , Hirai Asako , Hosono Masao 
Published: April 2003

AbstractTo obtain highly accessible cotton by cyanoethylation with acrylonitrile after pretreatment with swelling agents, the effect of various swelling agents was examined. Swelling agents such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ethylamine, triethylamine, ethylenediamine, piperazine, benzyltrimethylammonium hydroside (BTMOH), urea, dimethyl sulfoxide, dimethylformamide, zinc chloride, and liquid ammonia were examined. It was found that the sodium hydroxide pretreatment or the dual pretreatment with either potassium hydroxide, ethylenediamine, or BTMOH, and sodium hydroxide prior to acrylonitrile treatment gave modified cottons having moisture regain as high as 14%. In such cases, maximum values of moisture regain were observed at the degrees of cyanoethylation of 5–8%.
Molecular stiffness and thermal properties of polymers
Authors: Aharoni Shaul M. 
Published: April 2003

AbstractBecause it merely reflects rotational hindrance, the parameter σ alone does not convey a measure of chain stiffness. Stiffness can arise from short links joined by rigid joints, or from long, stiff links with flexible joints. Flexibility results from the absence of rigid joints and stiff, long links. The slope of the product σΔT versus TR indicates stiffness; the higher the slope, the stiffer the chain. The polymers whose thermal data are presented in this paper are divisible into two major groups. Those whose d(σΔT)/dTR = 1.37 are flexible, and those whose d(σΔT)/dTR = 3.44 are stiff. The indication is that there exists a direct relationship between the polymer expansivity above Tg and the stiffness parameter of the chain.
Grafting of ethyl α‐cyanacrylate on poly(vinyl alcohol)
Authors: Huczkowski Pawel , Kapko Jerzy , Polaczek Jerzy 
Published: April 2003

AbstractBecause hydrophilic copolymers containing cyanacrylate elements should be useful as components of adhesives in surgery, the conditions of grafting of ethyl α‐cyanacrylate on poly(vinyl alcohol) were studied. Two anthraquinone derivatives were applied as sensitizers in UV‐initiated grafting; 2,6‐disulfoanthraquinone sodium salt proved to be especially efficient. IR spectra and derivatograms of poly(vinyl alcohol‐g‐ethyl α‐cyanacrylate) are described.
Formation of particles in the preparation of carboxylated polystyrene latexes
Authors: Sakota Kazuyuki , Okaya Takuji 
Published: April 2003

AbstractCarboxylated polystyrene latexes have been prepared by copolymerizing acrylic acid at the appropriate degree of neutralization in the absence or presence of sodium dodecyl sulfate (SDS), and the particle formation process was investigated from the number and uniformity of particles. In the absence of SDS or in a concentration range of SDS lower than 6.41 mmole/l., the formation of particles can predominantly be attributed to the precipitation of growing radicals formed in the aqueous phase; whereas in a concentration range of SDS higher than 6.41 mmole/l., the formation of particles can predominantly be attributed to the initiation of polymerization in the interior of SDS micelles containing solubilized styrene by the collision of growing radicals formed in the aqueous phase. In the former range, the number of particles increases linearly with increasing concentration of SDS below the critical concentration of 1.60 mmole/l., which is sufficient to stabilize particles formed by the precipitation of growing radicals, and remains constant above the critical concentration. The effect of initiator concentration as well as amount of styrene on the formation of particles also supports the particle formation process described above.
Method for correcting molecular weight from gel permeation chromatography. II. Long‐chain branching correction of low‐density polyethylenes
Authors: Nakano Seikou , Goto Yukitaka 
Published: April 2003

AbstractDirect measurement of intrinsic viscosity on gel permeation chromatography effluent was performed with use of an automatic viscometer in order to determine molecular characteristics of branched polymers. In analyzing the viscosity data, the instrumental spreading was considered. Results obtained from three low‐density and one high‐density polyethylene were compared with those obtained by such other methods as osmometer, light scattering, and column elution fractionation.
The structure and physical properties of copolymers of lactams
Authors: Šimůnková E. , Zelinger J. , Kubánek V. , Králíček J. 
Published: April 2003

AbstractCopolymers of caprolactam with caprylolactam and laurolactam were prepared by activated anionic copolymerization under adiabatic conditions, at an initial polymerization temperature of T0 = 130°C. The drop of the crystalline phase content and changes of the copolymer morphological structure depending on the content of comonomers result in increasing toughness and deformability due to enhanced yielding ability. The dependences of the copolymer structure and properties on the concentration of comonomers are different for the two series of copolymers. This results from different courses of the polymerization and crystallization history as a consequence of a large difference between polymerization rates of caprylolactam and laurolactam.
Bimodal character of polyester–solvent interactions. I. Evaluation of the solubility parameters of the aromatic and the aliphatic ester residues of poly(ethylene terephthalate)
Authors: Knox B. H. 
Published: April 2003

AbstractThe Hildebrand and the Hansen solubility parameters of the aromatic and the aliphatic ester residues of poly(ethylene terephthalate), PET, are evaluated and compared to those determined experimentally. The interactions of nonaqueous solvents with the aromatic and aliphatic ester residues of PET are also described in terms of their relative basicity and acidity in the Lewis sense, where the aromatic residue may be taken as a Lewis acid and the aliphatic ester residue may be taken as a Lewis base.
Ion movements in cellulose acetate membranes
Authors: Horigome Shinkichi , Taniguchi Yoshio 
Published: April 2003

AbstractThe behavior of ions in a cellulose acetate membrane was discussed from the standpoint of mobilities obtained from the membrane potentials. The mobilities of univalent ions larger in radius or divalent ions relative to Na+ ion mobility in the membrane are much different from those in aqueous solutions. The order of the mobilities of ions in the membrane is shown quantitatively. The mobilities of the ions with radii larger than a certain value in the membrane decrease with increase in their size. This could be explained by the physical friction between the ion and the membrane wall. This friction is of importance as the ionic radius comes close to the intermolecular gaps between polymer chains. The mobilities of Na+ anyd 1− ions in the membrane are (2–3) × 10−7 cm2/sec‐V and are about three to four orders of magnitude less than those in aqueous solutions.
Effects of atmospheric pollutants at high temperature on the adhesion of RFL‐coated tire cords to rubber
Authors: Hartz R. E. , Adams H. T. 
Published: April 2003

AbstractThe examination of treating oven pollutant effects on the adhesion of RFL‐coated polyester and nylon tire cord to rubber was conducted using a hot strip adhesion test. Ozone, ultraviolet light, and ozone–ultraviolet light were examined at 140°F. Nitrogen oxides, sulfur dioxide, and air were tested at 320°F. Ozone and ozone–UV (singlet molecular oxygen) systems were many orders of magnitude greater degradants than the other pollutants known to exist in the ovens. The remaining pollutants tested were ranked in order of degradation effect with NO2 > NO ≫ SO2 ≡ air ≡ heat alone. The mechanism for adhesion loss involves addition to the olefinic double bonds to reduce unsaturation sites for cure.
DSC evaluation of epoxy and polyimide‐impregnated laminates (prepregs)
Authors: Pappalardo L. T. 
Published: April 2003

AbstractDifferential scanning calorimetry has been applied to the study of epoxy–glass and Kerimid 601 (polyimide–glass) prepregs used in making multilayer printed wiring boards. The data generated through thermal analysis are thermodynamic and kinetic. Thermodynamic properties of B‐stage prepregs obtained are endothermal and exothermal peak temperatures, glass transition temperatures, and heats of residual cure. They were obtained from thermograms made at fixed scanning rates. Kinetic information obtained from isothermal cure scans gave rates of residual cure, cure times, and energies of activations. This information gives the process engineer useful information for controlling the processing of multilayer printed wiring boards.
Crystallinity in jute fiber as revealed by multipeak resolution
Authors: Ray P. K. , Montague P. E. 
Published: April 2003

AbstractA method of multipeak resolution and computation of background scatter in x‐ray diffraction from fiber has been applied to jute fibers. While crystallinity as determined by this method in raw and delignified jute fibers remains unchanged, perfection of the crystalline regions improves on delignification.
Torsional braid analyzer measurements of polymer damping factors
Authors: Hartmann Bruce , Lee G. F. 
Published: April 2003

AbstractMeasurements were made in a torsional braid analyzer (TBA) and a torsional pendulum (TP) on a diglycidyl ether of bisphenol A cured with methaphenylenediamine over a broad temperature range that included the γ transition of this polymer. Based on a comparison of the results from the two instruments, we conclude that (1) the relative shear modulus measured in the TBA differs from the absolute modulus measured in the TP by a multiplicative constant that is independent of temperature in the glassy state; (2) the damping factor measured in the TBA is, at least approximately, equal to the damping factor measured in the TP, contrary to the usual assumption that only relative values are obtained from the TBA; and (3) as a result of (1) and (2), the TBA can be used to determine not only the temperature of a transition but also its activation energy.
Crosslinked poly(vinyl alcohol) hydrogels as swollen elastic networks
Authors: Peppas Nikolaos A. , Merrill Edward W. 
Published: April 2003

AbstractTransparent crosslinked PVA hydrogels were prepared by electron beam irradiation of aqueous solutions under nitrogen. These weak hydrogels, upon swelling at 30°C in water, showed low elastic moduli (up to 50 psi), low ultimate tensile strength (up to 4 psi), and low extensibility to break (not higher than 85%). Values of the molecular weight between crosslinks Mc were calculated from swelling and from tensile experiments. In fact, two values of Mc were calculated for each swelling experiment, (a) allowing for observed variation in the polymer–solvent interaction parameter χ1 with concentration, and (b) fixing χ1 = 0.494 according to literature data. The correlation of the Mc obtained from tensile data with the Mc obtained from swelling data, by (a) or (b), was approximately linear and gave the same per cent agreement.