bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bending stress relaxation and recovery of wool, nylon 66, and terylene fibers
Authors: Chapman B. M. 
Published: April 2003

AbstractThe bending stress relaxation and subsequent recovery behavior were determined for merino wool, nylon, and Terylene fibers. The effect of four experimental parameters were investigated, viz., the level of bending strain (0.5–4%), the time of stress relaxation before release (1–1000 min), the relative humidity (0–85%), and the temperature (20°–60°C). For small strains the merino and nylon fibers displayed behavior characteristic of linear viscoelastic materials, while Terylene exhibited a degree of nonrecoverable set. It was possible to construct master recovery curves for fibers held bent for different times before release. These curves can be used as a more convenient means of presenting the results. A relationship was found, for each fiber type, between the percentage stress relaxation and the time taken to recover to a given level of set. This relationship appeared to be independent of the experimental conditions employed. Although the fibers were not linear viscoelastic under all conditions, recovery could be roughly predicted from their stress relaxation behavior at the particular test conditions using the Boltzmann superposition principle.
Determination of the diffusivity of n‐pentane in polystyrene bead foam
Authors: Fossey D. J. , Smith C. H. 
Published: April 2003

AbstractThe amount of residual n‐pentane in expandable polystyrene bead foam (PSBF) has an effect on the strength and dimensional stability of the foam. Data were needed to determine how fast the residual n‐pentane could be removed to enhance the properties of PSBF. An experiment was designed to determine the diffusivity of n‐pentane through PSBF at various temperatures. Mathematical models based on the appropriate diffusion differential equations were then used to predict n‐pentane concentrations in in cylinders of PSBF. The diffusivity of n‐pentane through PSBF was found to have a magnitude of 1×10‐8 to 1×10−6 cm2/sec and to vary with temperature, foam density, n‐pentane concentration, and foam structure.
Concerning the microstructure of dry‐RO membranes
Authors: Kesting R. E. 
Published: April 2003

AbstractThe microstructure of cellulose acetate reverse osmosis membranes which have been prepared by the Kesting dry process has been elucidated with the aid of scanning and transmission electron microscopy. The dry‐RO membranes consist of three layers: skin, transition layer, and substructure. The gel morphology of each of these layers originates in its sol precursors within the nascent membrane which manage to survive the sol → gel transition intact. The dense skin layer is composed of aggregates of tiny, slightly ellipsoidal nodules which are believed to be paracrystalline in nature. Immediately beneath the skin lies the transition layer, a narrow band of intermediate density consisting of widely separated closed cells. Below the latter lies the porous substructure which is composed of micrometer‐sized, open‐celled voids. Because of the size of their substructural voids, dry‐RO membranes are able to reversibly undergo wet–dry cycling without densification and loss of permeability.
The ferric hydroxide/hydrazine system as an initiator of vinyl polymerization
Authors: Brown C. W. , Longbottom H. M. 
Published: April 2003

AbstractThe reaction between ferric hydroxide and hydrazine was used to initiate the solution polymerization of methyl methacrylate. Polymerization occurs readily at pH > 6, over a wide range of iron concentration and of temperature. The initiation reaction appears to be of heterogeneous nature, like those in similar metal hydroxide/hydrazine systems.
The physical limits of grafting in two‐phase polymerization reactions
Authors: Rosen S. L. 
Published: April 2003

AbstractWhen rubber‐reinforced thermoplastics are produced, conversion of monomer to glassy polymer takes place in two thermodynamically incompatible phases. Regardless of the chemical nature of the grafting process, monomer which is converted in the glassy phase can never be grafted to rubber simply because it is never in contact with rubber. A simple model has been developed which describes quantitatively the upper limit of grafting arising from the physical nature of the process as a function of conversion and monomer‐to‐rubber ratio in the charge.
The chemistry of fast‐curing phenolic adhesives. II
Authors: Tiedeman G. T. , Sanclemente M. R. , Smith H. A. 
Published: April 2003

AbstractNovolak‐like materials have been prepared by reaction of phenol–formaldehyde resoles with aromatic amines. The hydroxymethyl groups present in resoles react with the ring carbons and the amino groups of the aromatic amine. Proportions of the two types of product vary with the amine used.
A new technique for thermal analysis of vapor‐producing reactions
Authors: McCarter R. J. 
Published: April 2003

AbstractAn apparatus was developed for measuring the rate at which vapors are evolved during the thermal degradation of materials and thereby deriving the kinetics of such reactions. Requisite to the operating scheme of the apparatus is the provision of a high‐temperature zone to convert condensable or tarry vapors into noncondensable form. The apparatus yields a direct measure of reaction velocity, rather than the integrated indication obtained with thermogravimetric analysis. This simplifies the identification and calculation of kinetic parameters. Increases in sensitivity and operating range are also achieved. Flexibility in operation is obtained that permits the separate recording of reactions that tend to overlap. Although the apparatus principally has been operated using a combustible gas indicator to meter the evolved vapors, a number of options are available for the latter function, including flowmeters and various continuous gas analyzers. The applicability of the method appears promising.
The stability of solutions in reactive monomers of crosslinkable polyesters containing bisacid A2
Authors: Lenk R. S. 
Published: April 2003

AbstractEarlier papers1–6 have dealt with the synthesis and purification of bisacid A2; the preparation of unsaturated polyesters by cocondensing bisacid A2 with maleic anhydride in varying proportions in the presence or absence of phthalic anhydride as a further modifying acid, using propylene glycol as the polyesterification diol; the hardness and the thermal and mechanical properties of cast, cured resins and glass fiber‐reinforced laminates; and the water and chemical resistance of the cured resins. This paper deals with the solution stability of the liquid resins prior to cure and, in particular, with the observed fact that solutions containing esters of bisacid A2 in sufficient quantity do not require the addition of stabilizers commonly needed for commercial polyesters in order to impart an acceptable shelf life to the liquid resins.
The determination of the amount of bound water within cellulosic gels by NMR spectroscopy
Authors: Carles J. E. , Scallan A. M. 
Published: April 2003

AbstractIt has been shown that the NMR spectrum of moist cellulose is consistent with the idea that part of the water within the gel is destructured and bound to the accessible surfaces. A method for calculating the amount of bound water is presented, but because of experimental difficulties in obtaining an exact value for the spin‐spin relaxation time of the protons in the bound water, only upper limits can at present be obtained for the amount of bound water. Accordingly, it is estimated that the amount of bound water does not exceed the following values: wood, 0.23 g/g; cotton, 0.15 g/g; two wood pulps, 0.30 and 0.33 g/g. The amount of bound water appears to approximate to a monomolecular layer upon all accessible surfaces, which suggests that the NMR technique might be used to determine the surface areas of the gels in the wet state.
The thermal degradation of model compounds of amine‐cured epoxide resins. I. The thermal degradation of 1‐(N‐ethylanilino)‐3‐phenoxypropan‐2‐ol
Authors: Paterson‐Jones J. C. , Percy V. A. , Giles R. G. F. , Stephen A. M. 
Published: April 2003

AbstractThe thermal degradations of 1‐(N‐ethylanilino)‐3‐phenoxypropan‐2‐ol in an inert atmosphere, in air, and over alumina were studied with the aim of investigating the thermal stability of the cure linkage in aromatic amine‐cured bisphenol A‐based epoxide resins. Degradation products were characterized. Possible degradation mechanisms are outlined and are related to the results of previous studies of the thermal degradation of these resins.
The thermal degradation of model compounds of amine‐cured epoxide resins. II. The thermal degradation of 1,3‐diphenoxypropan‐2‐ol and 1,3‐diphenoxypropene
Authors: Paterson‐Jones J. C. , Percy V. A. , Giles R. G. F. , Stephen A. M. 
Published: April 2003

AbstractThe thermal degradations in an inert atmosphere, in air, and over alumina of 1,3‐diphenoxypropan‐2‐ol and 1,3‐diphenoxypropene were studied with the aim of investigating the thermal stability of the glyceryl portion of bisphenol A‐based epoxide resins. Degradation products were characterized. The thermal stability of the glyceryl group relative to that of the cure linkage in aromatic amine‐cured epoxide resins is discussed.
Photochemical degradation of poly(ethylene terephthalate). IV. Surface changes
Authors: Blais P. , Day M. , Wiles D. M. 
Published: April 2003

AbstractThe chemical, physical, and mechanical changes in the surface properties of poly‐(ethylene terephthalate) film produced by ultraviolet light have been examined. Attenuated total reflection infrared spectroscopy has indicated that numerous chemical scission reactions occur in the front surface layer facing the source of irradiation, resulting in the formation of carboxylic acid endgroups. This preferential surface phtodegradation has been confirmed by examining the cross section of irradiated film by electron beam‐induced luminescence. Conventional electron microscopy revealed little changes in the surface appearance of irradiated film. However, indirect techniques were devised which indicated that changes do occur in the physical properties of the surface. These observed changes are believed to be responsible for the decrease in film tensile strength, which has been shown to be a surface phenomenon and not a bulk property.
Modification of oxidized lignins with styrene
Authors: Katuščák S. , Mahdalík M. , Hrivík A. , Minárik V. 
Published: April 2003

AbstractThe effect of original and ozonized lignins upon the polymerization of styrene was investigated. It was found that the unoxidized lignin prepared by hydrolysis of spruce wood meals with 42% HCl retards the thermal polymerization of styrene. The ozonization of HCl‐lignin leads to its chemical transformation during which two types of functional groups are formed: those inhibiting and those initiating the polymerization of styrene. Moreover, the polymerization of styrene in the presence of oxidized HCl‐lignin affords both homopolymer and grafted copolymer. The amount of the grafted copolymer depends upon the concentration of active oxygen in lignin formed during oxidation, upon the temperature of polymerization, and, finally, upon the kind and concentration of the solvent used in the polymerization system.
Preparation and copolymerization of divalent metal salts of ethylene glycol–methacrylate–phthalate
Authors: Matsuda Hideaki , Miyoshi Noriyuki 
Published: April 2003

AbstractDivalent metal salts of ethylene glycol–methacrylate–phthalate (EMP) were prepared by the reaction of EMP and divalent metal ions in aqueous solution. The divalent metal salts obtained, except for the Pb salt, have melting points which decrease in the order of Ca > Ba > Mg > Zn > Cd salt. The Zn and Cd salts are fairly soluble in most organic solvents. Therefore, the Zn salt and Cd salt were selected for the copolymerization with MMA, styrene (St), and hydroxyethyl methacrylate (HEMA). In the copolymerization, the rates of copolymerization increased markedly as the concentration of metal salts increased. Moreover, the systems containing MMA copolymerized more rapidly than those containing St. As for the physical properties of the copolymers obtained, compressive strength and Rockwell hardness were improved by introducing metal salts into the polymers; and heat distortion temperature and tensile and flexural strengths were also improved by selecting the most suitable concentration of metal salts according to the species of metal salts and vinyl monomers. The TGA and the boiling water resistance of the copolymers were also discussed.
Physical structure of phenolaniline–formaldehyde resol resin and its kaolin–filled phenoplasts
Authors: Bozveliev L. G. , Mihajlov M. G. 
Published: April 2003

AbstractAn investigation of the physical structure of samples of phenoaniline–formaldehyde resol resin in uncured and cured state, and of its phenoplasts containing different ratios of kaolin filler, was made with the aid of electron microscope pictures. The uncured and cured resin consists of microglobules of a size of 40–80 Å, which agglomerate to form larger‐sized globules of various dimensions. After a mathematical elaboration of the results of a large number of measurements, it was established that the diameters of the globules are casual values distributed in accordance with the normal (Gaussian) law. Both in the resin and in the kaolin‐filled phenoplasts (at a rate of 25 to 47 vol‐%), after curing at 170–180°C and a pressure of 300 kg/sq cm, the mean diameter of the observed globules was of a rather steady value and remained within the limits of 230–240 Å (with a standard deviation of 30–40 Å). A method was elaborated of determining the mean thickness of the adsorption coating of the resin on the filler particles. Calculations show that in the filling interval we have chosen, the thickness of the absorption coating is not below 1.8–0.6 times the mean thickness of the globules.
Factors influencing the market for tires and tire fibers
Authors: Sonnecken Edwin H. 
Published: April 2003

AbstractNot only technology, but domestic and international economic considerations, social developments, consumer lifestyles, and political pressures are the determinants of tomorrow's tire market. Tires for global markets are subject to international competition and world tire standards. Over‐the‐road highway tires—auto and truck—need improved technology to meet government safety regulations at affordable user costs. Grading and labeling implies substantial pressure on constructions and fibers. Vehicle design changes to meet demands of changing lifestyles bring other implications for tire and fiber markets. Cost per ton of freight hauled is becoming increasingly important. Earthmover tires of the future will be required to haul greater loads at higher speeds, meaning much larger vehicles, bigger tires, and higher ton miles per hour of payload.
Epoxy thermosetting systems: Dynamic mechanical analysis of the reactions of aromatic diamines with the diglycidyl ether of bisphenol A
Authors: Babayevsky P. G. , Gillham J. K. 
Published: April 2003

AbstractDynamic mechanical behavior during the reactions of four aromatic diamines (m‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenyl sulfone, and benzidine) with the diglycidyl ether of bisphenol A was studied by torsional braid analysis under isothermal conditions. Depending on the cure temperature, three types of behavior were observed: (I) below Tgg (the glass transition temperature of the reactive systems at the gel point); (II) between Tgg and Tg∞ (the glass transition temperature of the ultimately cured polymers); (III) above Tg∞. Overall activation energies and apparent overall rate constants of the cure reactions based on third‐order overall kinetics were determined before gelation, after gelation but before vitrification, and after vitrification, using gelation time, relative rigidity, and glass transition temperature Tg(t) of the polymers as kinetic terms. The influence of cure temperature and structure of the diamines on the kinetic parameters is discussed.
Modification of nylon 6 by organochlorosilanes. I. Chemical reaction
Authors: Varma I. K. , Mandal R. , Varma D. S. 
Published: April 2003

AbstractThe reaction of nylon 6 with dimethyldichlorosilane and vinylmethyldichlorosilane was investigated. Bright, 20‐denier monofilament, nylon 6 yarns with 12.83% nitrogen, 61.16% carbon, and 10.16% hydrogen content were taken. Benzene or toluene was used as solvent for the reagents. The extent of reaction was estimated from the increase in weight of the parent yarn. Reaction was carried in the presence of nitrogen or in atmospheric oxygen (air). The per cent weight gain increased with increase in concentration of reagents, time, and temperature of the reaction. Viscosity and dyeability of the modified samples were measured, and in some samples the percentage of carbon, hydrogen, and nitrogen was also determined.
Modification of nylon 6 with organochlorosilanes. II. Physical properties
Authors: Varma I. K. , Mandal R. , Varma D. S. 
Published: April 2003

AbstractThe physical properties of nylon 6 yarn treated with dimethyldichlorosilane (DMCS) and vinylmethyldichlorosilane (VMCS) in nitrogen atmosphere or air in the presence and absence of an amine have been compared with those of ether‐extracted parent yarn. Treatment with DMCS in nitrogen resulted in marginal improvement in breaking stress, considerable increase in breaking elongation, and elastic behavior, whereas initial modulus was decreased. A decrease in density, birefringence, and moisture regain with increase in per cent weight gain was observed. Mechanical damping was decreased considerably up to an optimum weight gain after which it was increased. Thermal properties were also determined, and results are discussed in relation to mechanical properties. The results indicate that the overall thermal stability has decreased in the chemically treated yarns. Treatment with organochlorosilanes in the presence of air results in a chain‐scission reaction and a decrease in mechanical properties.
Polymerization of laurinolactam. I. Impurities in industrial laurinolactam and their influence on anionic polymerization
Authors: Bukac̆ Z. , S̆ebenda J. 
Published: April 2003

AbstractFractions containing predominantly cyclododecanone (0.02%), C24 hydrocarbons (0.02%), and probably isomers of the mono‐ and diunsaturated 13‐membered lactam (0.05%) were isolated from industrial laurinolactam. Both the cyclic ketone and unsaturated lactams slow down the anionic polymerization of laurinolactam, but they exert only insignificant or no effects on the molecular weight of the resulting polymer if the polymerization has been activated with N,2‐disubstituted 3‐oxoamide. On the other hand, the molecular weight is greatly affected by the type of catalytic system. Of the purification techniques tested, the most effective and advantageous one was crystallization from 1,2‐dimethoxyethane.
Viscoelastic properties of epoxy resins. II. Antiplasticization in highly crosslinked epoxy system
Authors: Hata Naoaki , Yamauchi Ryo , Kumanotani Ju 
Published: April 2003

AbstractThe effect of the addition of certain low molecular weight compounds to highly crosslinked epoxy resins was investigated. The behavior which is known as antiplasticization, such as increases in modulus and yield strength and the elimination of β‐transition, was observed in the highly crosslinked system as well as in the reported cases of thermoplastics—poly(vinyl chloride), bisphenol A polycarbonate, and polysulfone. Chlorinated biphenyl was found to be one of the most effective antiplasticizers examined in the present paper. However, the remarkable reduction in compressive strain at break and impact strength was not recognized for the highly antiplasticized samples. These phenomena have been interpreted on the basis of free volume concept.
Sorption behavior of mercuric salts on chemically modified wools and polyamino acids
Authors: Friedman Mendel , Masri Merle Sid 
Published: April 2003

AbstractWool derivatives with sulfhydryl, thiosulfate, imidazole, pyrrolidone, or pyridine side chains were prepared and tested as potential scavengers for mercury salts in aqueous solution. More mercury is bound by these derivatives than by native wool or by certain commercial ion exchange resins under similar conditions. The presence of chloride ion, but not sulfate ion, in aqueous media decreased the extent of binding of mercuric chloride to both native and modified wools. The relative binding of mercuric chloride by various poly(amino acids) suggest that mercury is taken up by proteins by processes other than (or in addition to) specific combination with free functional groups. Two possibilities are suggested: the protein may act as a solid solvent for the mercurial, or the mercurial may form aggregated deposits within the protein after the specific binding sites have been occupied. These studies are intended to elucidate factors that govern mercury interaction with wool and other proteins and to develop improved scavengers for toxic metals.
Thermomechanical behavior of a polynorbornadiene
Authors: Roller M. B. , Gillham J. K. , Kennedy J. P. 
Published: April 2003

AbstractA high‐temperature linear amorphous hydrocarbon polymer synthesized cationically from 2,5‐norbornadiene (bicyclo[2.2.1]hepta‐2,5‐diene), was studied thermomechanically with respect to physical transitions and stability in nitrogen. The glass transition temperature was determined to be 320°C (at less than 1 cps), which is probably the highest known for a linear hydrocarbon addition polymer. The thermomechanical technique of torsional braid analysis, together with thermogravimetric analysis, differential thermal analysis, infrared analysis, and solubility studies, was used to investigate the sequential events of the glass transition and degradation. The polymer is of particular interest since it is a high‐temperature plastic which in the bulk form would probably need to be processed at high speeds in the vicinity of Tg in an inert atmosphere. The presence of tertiary hydrogen atoms should render it amenable to degradation by the earth's environment.
Fractionation of polypropylene by the rising temperature method
Authors: Ogawa Toshio , Hoshino Sadao 
Published: April 2003

AbstractPolypropylene having high isotacticity was fractionated by the rising temperature method. This method was then compared with the solvent gradient method through the characterization of fractions. It was found that the elution behavior in the rising temperature method was explainable by the equation of equilibrium between the polymer in dilute solution and the solid state polymer on the support, assuming that the heat of fusion and transition points for the deposited polymer were variable with polymer species.
Vinyl bromide polymerization with alkylboron and alkyl halide catalyst
Authors: Akimoto Akira 
Published: April 2003

AbstractTrialkylboron–alkyl halide catalyst systems were found to induce the polymerization of vinyl bromide and other vinyl monomers at low temperatures. Tri‐n‐butylboron is the most effective catalyst. Among alkyl halide, carbon tetrachloride gives the best yield of poly(vinyl bromide). The polymerization process can be controlled by adjusting the reaction conditions of the initiating components. The rate of polymerization varies depending on the diluent.