bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isobutylene copolymers of vinylbenzyl chloride and isopropenylbenzyl chloride
Authors: Jones Giffin D. , Runyon James R. , Ong Josephine 
Published: April 2003

AbstractThe styrene derivatives vinylbenzyl chloride and isopropenylbenzyl chloride were prepared and copolymerized with isobutylene and propylene in order to produce polymers with reactive halogens. Vinylbenzyl chloride and isobutylene have relative reactivities such that the copolymer is much richer in isobutylene than the starting mixture, while with isopropenylbenzyl chloride and isobutylene the difference in reactivities is less and is in the opposite direction. Copolymers containing small amounts of the reactive benzylic chlorine were vulcanized, either with amines or with a conventional butyl rubber cure. Permselective membranes were prepared from copolymers rich in benzylic chlorine.
Nonaqueous fluid xanthation of alkali cellulose
Authors: McDermott D. E. 
Published: April 2003

AbstractXanthation can be accomplished by slurrying the alkali cellulose in an organic liquid chosen to be miscible with carbon disulfide, immiscible with water, and a nonsolvent for sodium hydroxide, alkali cellulose, cellulose xanthate, and other components of viscose. Straight‐chain hydrocarbons, such as n‐hexane and n‐heptane, satisfy these requirements and function very well. A viscose preparation system using this method of xanthation would consist of a slurry step wherein the alkali cellulose and carbon disulfide are reacted in the selected organic liquid, a filtering step to remove the xanthate from the liquid, and a mixing operation to dissolve the xanthate in weak alkali to produce viscose. Because of the near‐perfect distribution of carbon disulfide throughout the reaction, this method of xanthation produces filterable viscoses a t very low degree of substitution. It is also possible to produce viscose of identical composition at widely different process conditions by various combinations of temperature, reaction time, and carbon disulfide concentration.
The resilience of chemically modified cottons. II. Reactions of cellulose with formaldehyde under acid conditions
Authors: Dusenbury J. H. , Pacsu E. , Teulings E. P. , Lobunez W. 
Published: April 2003

AbstractA study has been made of the reactions of cellulose with formaldehyde under acid conditions, where the fabrics are baked at elevated temperature. These treatments have involved cotton cellulose in a “dry” or relatively unswollen state and have resulted in the treated fabrics exhibiting improved crease rccovery both dry and wet. It has been found that boiling 1% acetic acid solution reduces the acetal contents of the treated fabrics and causes corresponding decreases in both dry and wet crease‐recovery improvement. The reproducibility of these treatments, with respect both to extents of formaldehyde incorporation and to dry and wet crease recovery, is found to be very good within a single treatment and, more importantly, tietween different treatments carried out under the same conditions. The rates of acetal removal by the boiling 1% acetic acid and the relationships between acetal content and crease‐recovery improvement have been found to be fairly complex. A study has also been made of the rates of acetal removal by boiling 1% acetic acid for samples of cotton card sliver treated with acid and subsequently heated in sealed tubes with paraformaldehyde. The rates of acetal removal in this case have been observed to be qualitatively similar to those observed for treated fabrics. The implications of these findings are discussed.
Treatment of teflon to promote bondability
Authors: Benderly Asaf A. 
Published: April 2003

AbstractVarious methods are reviewed whereby Teflon and other polyfluorocarbon resins can be surface treated in order to enhance their bondability with ordinary adhesives. The features of these methods are compared and some conclusions are drawn as to their relative usefulness. Particular emphasis is placed on the sodium‐naphthalene‐tetrahydrofuran treatment system and reference is made to a few military applications wherein sodium‐treated Teflon has been employed.
Some observations on the shrinkage of jute
Authors: Roy S. C. 
Published: April 2003

AbstractMeasurements have been made of the shrinkage in alkali and of the permanent contraction resulting from alkali treatment. The results supported by x‐ray evidence following the changes in orientation and degree of mercerization show that the shrinkage of jute is subject to a similar restraint as swelling, and the shrinkage behavior of jute compared to ramie is as that of a yarn compared to that of its constituent fibers. Unlike swelling, the shrinkage of jute at dilute alkali is less than that of ramie and the corresponding region of the shrinkage curve is conspicuous by the smoothness of swelling curve, indicating that the shrinkage refers primarily to the structural framework of the fiber, whereas an extrastructural material may contribute to swelling. Although the crystallinity of jute is comparable to that of rayon, no appreciable permanent contraction occurs in the fiber treated in dilute alkali, and this points to a restraint in the structure of jute similar to that exercised by the crystallites in ramie. Whereas the resistance in ramie is completely neutralized in mercerizing alkali and the whole of the alkali shrinkage remains as permanent contraction, the restraint still operates in jute, and the permanent contraction is in deficit of the alkali shrinkage. The respective disorientations are also of the same order. Both permanent contraction and crystalline disorientation continually increase on repeated alkali treatments of jute and ramie; the additional effect found in jute is its complete mercerization after a number of treatments. The shrinkage as indexed by its maximum value is strongly correlated with the oriented state of the fiber, and the disorientation produced in jute on dilute alkali treatment is followed by a lower maximum shrinkage. Incomplete disorientation of mercerized jute shows up in positive shrinkage and its proportion is the same as that of unconverted cellulose I residue. In spite of a very high degree of orientation, the reoriented fiber shows a considerably low maximum shrinkage compared to the native. This is suggested to have been due to the formation of some junction points when the freely swollen plasticized fiber is mechanically strained.
Anisotropy of swelling of jute
Authors: Roy S. C. 
Published: April 2003

AbstractThe use of swelling anisotropy as a means of determining the orientation of cellulose fibers has been critically reviewed, and it has been shown that the method should be suitable for highly oriented fibers within a certain range of orientation. The application of the method to untreated and variously treated jute fibers reveals certain structural differences with ramie, of which the following are noteworthy. Both noncrystalline and crystalline orientations of jute are influenced by treatments which can be regarded as being confined to the intercrystalline regions only and which do not affect ramie. As compared with ramie, the ultimate maximum disorientation, produced on mercerization treatment is markedly less in jute, and this holds for both the crystalline as well as the noncrystalline components of the fiber.
Role of hydrogen ion concentration in retrogradation of starch sols
Authors: Kalb A. Joseph , Sterling Clarence 
Published: April 2003

AbstractCornstarch sols were prepared with pH adjusted to various values both before and after gelatinization. Retrogradation was ascertained by measurement of crystallinity (x‐ray), enzymatic digestibility, and cold water solubility. When the starch was gelatinized after pH adjustment, maximum retrogradation was at a pH value of about 5, with diminishing retrogradation at higher and lower values. When the starch was gelatinized before pH adjustment, maximal retrogradation occurred at pH values 1–2, with diminishing retrogradation at higher values. After an initial period of rapid retrogradation, retrogradation at all pH values studied follows first‐order kinetics. The data are explained in terms of molecular size, role of pH in hydrogen bond rupture, the weakly acidic character of starch, and changes in the configurational entropy of starch molecules.
Anionic polymerization of epichlorhydrin
Authors: Zilkha Albert , Weinstein Meir 
Published: April 2003

AbstractThe anionic polymerization of epichlorhydrin with potassium hydroxide was studied at 110–120°C. in bulk and in solution. Large molar equivalent ratios of catalyst were needed for polymerization and even when using 150 mole‐% catalyst, the conversion was only about 50%. The polymers obtained were crosslinked and had a low chlorine content. Crosslinking may be due to attack of a propagating chain end on the partially positive carbon attached to the chlorine atom in a polymer, or on a terminal epoxide formed by an intramolecular elimination of chlorine. The water of hydration in the catalyst influenced the polymerization in that it was released on consumption of catalyst causing termination of the polymerization, relatively low conversion, and low chlorine content of the polymers. The polymers had infrared absorptions for both carbonyl and carbon double bonds and gave dinitrophenyl hydrazones that indicate the presence of aldehydes or ketones. Preliminary experiments showed that the crosslinked polyepichlorhydrins obtained can be converted to exchange resins by utilizing either the hydroxyl or the chlorine functions of the polymer. Thus sulfonation and phosphorylation of the polyhydroxy polymer obtained by alkaline hydrolysis of residual chlorine in the polyepichlorhydrin gave inorganic esters that had free acid groups and served as reversible cation‐exchange resins. Amination of the polymers with sodamide gave an anion‐exchange resin, while replacement of the chlorine with cysteine gave a resin that can be used as a chelating agent for heavy metals.
An X‐ray crystallinity index method with application to poly(ethylene terephthalate)
Authors: Statton W. O. 
Published: April 2003

AbstractWakelin's method of correlation analysis of x‐ray diffraction patterns was adapted for fibers, films, and polymer samples of poly(ethylene terephthalate). This method gives a number called a crystallinity index, which is a measure of how far an unknown sample is between the extremes of the most amorphous and most crystalline samples obtainable for a polymer species. By being relative, this index eliminates the controversial assumptions of absolute crystallinity determinations. It is especially suited for routine studies since the calculations are readily adapted to the use of a computer and since the total time needed to obtain an index is short. A study of the indices of a variety of poly(ethylene terephthalate) materials produced the following conclusions:(1) Maximum crystallization is achieved only by starting with an unoriented amorphous film. This is contrary to the view that orientation helps crystallization. Also, this shows that the act of spinning a fiber sets up an apparently strained state which will not crystallize to the same high level as a cast film. (2) Time of heating can be exchanged for temperature of heating, since the rate of crystallization is slow for this polymer. Thus, a longer time at a lower temperature is the equivalent of a shorter time at a higher temperature in producing equivalent crystallinities. (3) The crystallinity measured by density is not the same as the crystallinity measured by x‐rays. (4) A preordered state must exist in fibers in which segments of molecules have lost their complete randomness and are densely packed, yet the segments are not perfectly enough placed to produce x‐ray diffraction. Or, it can be concluded that spinning or drawing disrupts the fiber's perfect lattice so that less x‐ray diffraction is produced than the high density would indicate.
Acrylonitrile copolymerization with a NaClO3/Na2SO3 catalyst. Part I. Effect of 2‐methyl‐5‐vinylpyridine
Authors: Wishman M. , Detoro F. E. , Botty M. C. , Felton C. , Anderson R. E. 
Published: April 2003

AbstractBatch copolymers, made by polymerizing acrylonitrile, vinyl acetate, and 2‐methyl‐5‐vinylpyridine (MVP) with a chlorate‐sulfite redox catalyst, are fractionated with respect to MVP content when they are fractionated with respect to molecular weight or polymer grain size. Polymer fractions of lowest molecular weight or smallest grain size contain the most MVP. A mechanism is proposed to explain these facts. To test the proposed mechanism, both ultraviolet and electron microscopes are used to study polymer formed during the early stages of batch polymerization. The effects of adding MVP, and of total monomer concentration, on the particles formed are determined. Interpretations of the microscopical observations are compared with the chemical interpretation. When MVP is present, the initial particles formed are more soluble, form colloidal particles less readily, and stabilize the colloidal particles, if formed, due to the charges on the polymer Initial particles with highest MVP content form polymer of lowest molecular weight and aggregate into the smallest polymer grains.
Investigation of the catalyst in the cellulose–DMEU reaction. Part II. Physicochemical studies of the reaction
Authors: Ziifle Hilda M. , Berni Ralph J. , Benerito Ruth R. 
Published: April 2003

AbstractIn a continuation of a previously reported investigation into the effect of the catalyst in the cotton cellulose–DMEU reaction, experiments were performed in which the four inorganic salt catalysts originally studied, MgCl2, Mg(NO3)2, ZnCl2, and Zn(NO3)2, were employed at the higher metal ion concentration of 0.1M, and CuCl2and CdCl2were employed at 0.03Mconcentration. Data from infrared absorption spectra of the treated cotton products were in agreement with those obtained at the 0.03Mcatalyst concentration, again indicating that the catalyst entered into the reaction, forming a coordination complex through the formation of nitrogen‐to‐metal bonds between the catalyst and the DMEU molecule. Similarly, it was again indicated that reaction with DMEU takes place preferentially at the primary alcohol group of the anhydroglucose unit. Analyses of IR data indicated a higher degree of crosslinking, and thus fewer terminal OH or NH groups at the 0.03Mcatalyst than at the 0.1Mcatalyst concentration. Further evidence of complex formation was obtained from infrared spectra of the product of the CdCl2–DMEU reaction carried out in the absence of cellulose. Supplemental physical data obtained on products of reactions catalyzed with CdCl2and CuCl2at the 0.03Mlevel, when compared with those obtained on products catalyzed with MgCl2and ZnCl2, supported the earlier hypothesis that chlorine damage during heating was dependent upon the ability of the metallic complex to act as a free‐radical trap. Additional support for the free‐radical mechanism was obtained when treated cloth subjected to chlorination and exposed to ultraviolet radiation suffered the same discoloring and degradative effect as cloth chlorinated and subsequently scorched according to the usual AATCC method. Reaction rates of the cellulose–DMEU reaction at 45, 55, and 65°C. with each of the four catalysts at the 0.03Mconcentration were determined by following changes both in nitrogen and formaldehyde content as well as in crease recovery properties. The reaction was found to be pseudo first order when followed to 2/3 completion, and the catalysts, when ranked according to greatest to least effect upon the reaction rates, followed the order: Zn(NO3)2> ZnCl2> MgCl2= Mg(NO3)2. Enthalpies, entropies, and free energies of activation have confirmed the earlier hypothesis that the metal ion enters into the reaction, forming a transition state complex.
The mechanism of ozone cracking. I. Ozone cracking of plastic films
Authors: Salomon G. , Van Bloois F. 
Published: April 2003

AbstractStretched films from partly unsaturated natural rubber hydrochloride develop cracks and fracture in ozonized oxygen. Cracking occurs only above a minimum stress level of about 70 kg./cm.2. Ozone sensitivity increases exponentially with stress, but goes through a maximum near the yield point of the thermoplastic films. Contrary to rubbers, these high‐modulus materials do not undergo overall stress relaxation prior to fracturing induced by ozone. The rate of surface ozonization of an unstretched film is estimated gravimetrically and volumetrically; it is found to be similar to that of rubber surfaces. Physical and chemical changes of the ozonized surface are reported. Results are briefly compared with ozone attack on other (nonrubber) materials.
The fine structure of fibers and crystalline polymers. II. The growth of crystalline regions in fibers
Authors: Hearle J. W. S. 
Published: April 2003

AbstractThe ideas of spherulitic crystallization as found in bulk polymers are applied to crystal growth in a moving medium such as an extruded fiber. It is shown that the structure will depend on the velocity of motion and the crystalline growth and nucleation rates. If growth proceeds from a single nucleus a sector of a giant spherulite will form, growing at a front where the crystalline growth rate equals the velocity of motion but, if nucleation is predominant, then a structure of small spherulites or micelles will form. The effects of orientation and drawing are considered. A detailed mechanism of crystal formation in an oriented structure by means of a screw dislocation is discussed.
Failure criteria for some polyurethane propellants
Authors: Milloway Warren T. , Wiegand James H. 
Published: April 2003

AbstractExperimental and theoretical studies were made on failure criteria applicable to simple case‐bonded hollow cylindrical grains. The minimum strain at break at −75°F. for uniaxial tensile test was found to be at least twice the hoop strain at −75°F. of a thermally cycled, case‐bonded hollow cylinder of propellant when no failures were observed, whereas, when the minimum strain at break was equal to or less than the hoop strain of the cycled cylinder, the grain always cracked. For uniaxial tension, where the rate of elongation and temperature are controlled variables, the failure elongation varies from specimen to specimen and from batch to batch. A study of batch variability of the uniaxial test showed that a test at any test temperature from −40 to 180°F. could be used to characterize batch quality. The correlation of breaking strain at different rates and temperatures with the use of the WLF technique on one batch was found to be improved if an additional vertical shift factor was added to account for the lowering of the maximum failure elongation for temperatures below 0°F. However, by using a diagonal shift with rate, a graph of failure elongation versus temperature shows lower variability than does the WLF analysis.
Characterization of small gels in viscose
Authors: Sperling L. H. 
Published: April 2003

AbstractThe small gels present in cotton linters viscose, prehydrolyzed sulfate wood pulp viscose, and sulfite wood pulp viscose were examined by light scattering, electron microscopy, and chemical methods. In all cases a population of nearly monodisperse, spherical gels was found. The diameters are 0.3–0.6 μ by light scattering techniques, while the diameters of the dry gels by electron microscopy are near 0.1 μ. The difference is attributed to the swelling of the possibly crosslinked gels. The number of these inhomogeneities is very high, of the order of magnitude of 1011 gels/g. cellulose, yet they comprise less than 0.1% of the total mass involved. Chemically, the wood pulp viscose small gels appear to be about half cellulose II of a very low degree of substitution and about half of unknown composition. The cotton linters viscose gels contain xylan and some silica. These gels bear a striking resemblance to those studied in a previous acetate gel investigation, for both the cotton linters and the wood pulps. It is speculated that they may have a common origin.
Polymeric ligands. IV. Vinyltriacylmethanes
Authors: Degeiso R. C. , Donaruma L. G. , Tomic E. A. 
Published: April 2003

AbstractMethacrylylacetylacetone and acrylylacetylacetone were prepared by acylation of acetylacetone enolate salts with methacrylyl chloride and acrylyl chloride, respectively. Both monomers yielded poor homopolymers. Methacrylylacetylacetone formed copolymers with styrene and methyl methacrylate without difficulty.
Polystyrene modifications. III. Copolymers and terpolymers of 2,5‐dichlorostyrene and 3,4‐dichlorostyrene
Authors: Dunham K. R. , Vandenberghe J. , Faber J. W. H. , Fowler W. F. 
Published: April 2003

AbstractThermal properties and resistance to crazing of copolymers and terpolymers of 2,5‐dichlorostyrene and 3,4‐dichlorostyrene have been studied. Copolymers based on 2,5‐dichlorostyrene showed little or no improvement over polystyrene in craze resistance or glass transition temperature. Although copolymers of 3,4‐dichlorostyrene were generally brittle and crazed readily, poly(3,4‐dichlorostyrene‐co‐2‐ethylhexyl methacrylate) and poly(3,4‐dichlorostyrene‐co‐n‐hexyl methacrylate) crazed less readily than polystyrene.
Investigation of the protective ultraviolet absorbers in a space environment. III. Protective effectiveness
Authors: Schmitt Richard G. , Hirt Robert C. 
Published: April 2003

AbstractThe effectiveness of the ultraviolet absorbers in protecting organic coatings exposed to an extraterrestrial environment from photochemical degradation was studied for the commercially available absorbers and certain errocene derivatives. The change in solar absorptivity of the coatings was used as a measure of the degradation incurred, these data being obtained from the ultraviolet, visible, and near‐infrared absorption spectra of the polymers. Ultraviolet absorbers of the benzophenone and benzotriazole type used for terrestrial applications were found to be considerably less effective in a space environment. This was attributed to the strong ultraviolet absorption of the polymers at the shorter wavelengths, which competes with the absorber for the incident radiation. Certain benzoyl‐substituted ferrocene compounds were found to be extremely effective in protecting many types of polymeric coatings. The benzoylferrocenes are highly colored materials (red to orange) whose absorbing properties are extremely stable to ultraviolet radiation.
The use of tensile measurements in following cellophane degradation
Authors: Meltzer T. H. , Weiss E. , Garvin C. M. 
Published: April 2003

AbstractComparisons were made of changes in molecular weight and in tensile strength of regenerated cellulose after exposure to 40% KOH at 90°C., for varying lengths of time. In the absence of air, both parameters decreased in a fairly consistent manner. In the presence of air, an initial steeper drop was followed by an irregular up‐and‐down pattern. The theory is advanced that the increase in tensile strength was caused by increased crystallinity.
Some relationships between water vapor permeability and chemical/physical structure in rigid urethane foams
Authors: Hilado C. J. , Harding R. H. 
Published: April 2003

AbstractLow density rigid foams, reaction products of polyether polyols with tolylene diisocyanate, may transmit moisture vapor at rates from 0.3 to more than 8 perm‐inches at 23°C. Analysis of experimental data provided conservative design correlations showing that rate constants could be predicted only when a foam's polymer composition and physical structure were considered jointly. Among commercially acceptable rigid foam systems, cell structure and polymer aromaticity dominated the control of permeability levels. Permeabilities were lowest when transfer was directed perpendicular to the rise of highly orthotropic closed‐cell foams based on aromatic polyols of low equivalent weight. Permeabilities increased with effective cell diameter and also as foam density and closed‐cell content were reduced.