bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(vinyl‐trans‐benzalacetophenone)
Authors: Unruh C. C. 
Published: April 2003

AbstractPolystyrene has been partially or completely modified to contain varying amounts of vinyl‐trans‐benzalacetophenone units in the polymer chain. Acetylation of polystyrene gave a pure poly(vinylacetophenone) which, when condensed with benzaldehyde, produced varying proportions of vinyl‐trans‐benzalacetophenone in the polymer. These styryl ketone polymers are very sensitive to ultraviolet radiation, thin layers becoming insoluble on brief exposure, yet can be stored in the dark for years without change.
Factors affecting viscose ripening
Authors: Easterwood Marie , Mueller W. A. 
Published: April 2003

AbstractRipening of spinnable viscoses has shown dexanthation rates to be constant for sulfate pulps; however, sulfite pulps appeared to ripen slightly faster than the sulfate pulps. The rate of dexanthation was unaffected by changes in alkalinity over relatively narrow ranges, and slightly affected by sulfur and cellulose content. Dilution of the viscose increased the dexanthation rate. A molar activation energy of 23 kcal. was calculated from a study of temperature effects on dexanthation of a high alpha sulfate pine pulp. Changes in salt index with respect to degree of substitution for all viscoses xanthated and dissolved at 25°C. followed the same linear function. For viscoses prepared at lower xanthation and/or dissolving temperatures, the ripening curves exhibited an initial rise suggesting two simultaneous changes: dexanthation and a randomizing of substitution. Split xanthation (the final xanthation step under essentially homogeneous conditions) yielded viscose having random substitution and exceptionally high salt index. As this solution ripened the salt index decreased linearly with respect to degree of substitution and eventually followed the same function as normally xanthated viscose, indicating that the final internal structures of the two solutions are similar.
Flexural deformation temperature of amine‐cured polyglycidyl and poly‐2,3‐epoxybutyl derivatives of phenol
Authors: Aelony David 
Published: April 2003

AbstractA number of polyglycidyl and poly‐2,3‐epoxybutyl derivatives of phenols were prepared. An attempt was made to correlate the flexural deformation temperatures of the amine cured polyepoxies with the following structural characteristics of the epoxy compounds: per cent oxirane, functionality, ring substituents other than epoxy (such as alkyl, alkenyl, aryl), and substitution of 2,3‐epoxybutyl for glycidyl group.
Polymer–diluent interactions. I. A new micromethod for determining polyvinyl chloride‐diluent interactions
Authors: Anagnostopoulos C. E. , Coran A. Y. , Gamrath H. R. 
Published: April 2003

AbstractThe changes that are observed under magnification when a single polyvinyl chloride particle is immersed in a drop of diluent and slowly heated have been explained on the basis of a three‐dimensional network system in which the polymer crystallites act as junction points for the network. The existence of a temperature at which a sharp gel‐to‐sol transformation is observed has been attributed to the melting of the polymer crystallites. The temperature at which this transformation occurs was found to be rate‐independent, reproducible, and characteristic for each polyvinyl chloride–diluent system. At this apparent melting temperature, the volume fraction of the diluent in the swollen particle was shown to approach unity. These findings made it possible, for the first time, to apply to polyvinyl chloride–diluent systems Flory's treatment of the effect of diluents on the crystal melting temperature of semicrystalline polymers. The apparent melting temperatures of polyvinyl chloride with 27 diluents were determined by the above method. The interaction parameter χ for each of the diluents used had been previously reported by Doty and Zable. A linear relationship was obtained when the reciprocal melting temperature was plotted against (1–χ)/V1 for all of the above polyvinyl chloride–diluent systems (V1 is the molar volume of the diluent at the melting temperature). From this plot the values for the extrapolated melting temperature of pure polyvinyl chloride and for the average heat of fusion were calculated and found to be 176°C. and 656 cal./mole, respectively. Based on these findings a micromethod has been developed which can be used to determine the parameter χ of a diluent with polyvinyl chloride from a single determination of this apparent melting temperature. This method also yields the value for the energy of interaction parameter B.
Polymerizable derivatives of long‐chain alcohols. II. Reactivity ratios for the copolymerization of some alkyl acrylates
Authors: Jordan Edmund F. , Doughty Kay M. , Port William S. 
Published: April 2003

AbstractMonomer reactivity ratios were determined for the copolymerization of some alkyl acrylate esters and, respectively, acrylonitrile and vinylidene chloride. For acrylonitrile (M1), the values found were: for butyl acrylate, r1 = 1.52 ± 0.03, r2 = 0.75 ± 0.18; for octyl acrylate, r1 = 1.93 ± 0.08, r2 = 0.83 ± 0.23; for octadecyl acrylate, r1 = 1.74 ± 0.04, r2 = 0.68 ± 0.18. If it is assumed that there is no change in the magnitude of the kinetic constants with chain length, a value for the generalized alkyl acrylate and acrylonitrile may be calculated and r1 = 1.61 ± 0.04, r2 = 0.50 ± 0.19. Values found with vinylidene chloride (M1) were: for butyl acrylate, r1 = 0.88 ± 0.10, r2 = 0.83 ± 0.02; for octyl acrylate, r1 = 0.87 ± 0.02, r2 = 0.70 ± 0.01; for octadecyl acrylate, r1 = 0.91 ± 0.05, r2 = 1.01 ± 0.01. For the generalized alkyl acrylate, the calculated values were r1 = 0.88 ± 0.04, r2 = 0.84 ± 0.01.
Problems in strain measurement in impact tests on textile materials
Authors: Backer Stanley , Krizik Jan G. 
Published: April 2003

AbstractThe limitations of conventional methods of measuring strain are discussed in light of the structural composition of textile materials. The difficulties introduced in static and impact testing by stress concentration and strain inhomogeneity are considered. The need for two‐point strain measurement in regions of homogeneous strain is emphasized. A low inertia strain‐measuring system utilizing magnetic tape is described as applied to tensile tests at jaw speeds of 1 to 100 ft./sec.
New high‐speed tensile tester for polymer films
Authors: Patterson Gordon D. , Miller Wilfred H. 
Published: April 2003

AbstractDesign characteristics are described of a rotating‐wheel tensile tester suitable for stressing a vertical specimen with a force of 115 kg. through a distance of 15 cm. in a velocity range of 10 to 730 m./min. with no more than 1% loss in velocity, thereby assuring constant speed of grip separation. Provision is made for specimens up to 7.5 cm. width in order to achieve multiaxial distributions of stresses which are important in bag failure and leading to the determination of critical strain rates. Instrumentation provides reliable triggering of stress and strain traces on a double‐beam oscilloscope. Straight‐line travel of the moveable specimen grip is assured by the use of tracks which restrain horizontal motions without hindering the desired vertical motion.
Use of the HLB system in selecting emulsifiers for emulsion polymerization
Authors: Greth Gerald G. , Wilson Joseph E. 
Published: April 2003

AbstractIn the present work a wide variety of nonionic emulsifiers and anionic/nonionic blends of emulsifiers were evaluated in the emulsion polymerization of vinyl acetate and styrene. It was found that the emulsion stability and other polymer emulsion properties are often dependent upon a certain property of the emulsifier known as the HLB value. It has been shown elsewhere that the HLB value can be correlated with a fundamental physical property of the system oil–water–emulsifier, namely, the spreading coefficient of the internal phase liquid on the surface of a 1% solution of the emulsifier in the external phase. In the emulsion polymerization of styrene, good emulsion stability coupled with adequate conversion rate was obtained in an emulsifier HLB range of 13 to 16. For certain emulsifier blends it was found that emulsion viscosity and emulsion particle size were strongly dependent on the HLB of the emulsifier. Similar comments apply to vinyl acetate polymerization, except that the most stable emulsions were obtained with emulsifiers in an HLB range from 14.5 to 17.5. These observations on preferred HLB range apply only to nonionic emulsifiers and anionic/nonionic emulsifier blends, which were the emulsifier types screened in the present investigation. For both styrene and vinyl acetate the most generally satisfactory emulsion properties were obtained in the present work by the use of an anionic/nonionic emulsifier blend (G‐3300/G‐3920).
A new synthetic elastomer based on a chlorophosphonated polyolefin
Authors: Leonard E. C. , Loeb W. E. , Mason J. H. , Wheelwright W. L. 
Published: April 2003

AbstractA new synthetic elastomer has been obtained based on an ethylene‐propylene copolymer prepared using an organometallic catalyst system. Reactive sites (phosphonyl dichloride groups) are placed on the copolymer chain by treating the polymer with phosphorus trichloride and oxygen. After hydrolysis or alcoholysis of the phosphonyl dichloride groups to phosphonic acid or phosphonic acid esters, vulcanization may be carried out by reaction with metallic oxides, particularly lead oxide. Vulcanizates of the polyolefin elastomer have outstanding resistance to heat, ozone, and oxygen, and have excellent electrical properties. This combination suggests the use of this material in high temperature electrical applications.
Changes in fine structure and mechanical properties induced by cyanoethylation of cotton yarns. II. Reacted without longitudinal shrinkage
Authors: Conrad Carl M. , Stanonis D. J. , Creely J. J. , Harbrink Pieter 
Published: April 2003

AbstractThe cellulose of cotton yarns was reacted with acrylonitrile under conditions preventing their longitudinal contraction. Changes taking place in the fine structure of the fiber were studied by means of optical microscopy, density measurements, x‐ray diffraction, and thermal stress behavior measurements. The results indicate that in spite of the strong tensions developed in the yarns, the reaction proceeds in both the accessible and the crystalline regions with considerable volume expansion and eventual disappearance of crystalline structure. Suggestions of a glass transition temperature appear at substitutions slightly above D.S. = 1. Annealing becomes possible at substitutions above D.S. = 2 with the development of the cyanoethyl cellulose crystal structure and over 40% increase in tensile strength. Changes in tenacity, ultimate elongation, energy of rupture, and immediate elastic recovery were also observed.
Radiation effects in polystyrene
Authors: Kline Donald E. 
Published: April 2003

AbstractAmorphous polystyrene was subjected to nuclear radiation in doses ranging from 1.2 × 1010 to 3.8 × 1011 ergs per gram. At low temperatures the internal friction of the highly irradiated polystyrene was greater than that of the unirradiated material, and beyond the glass transition, which begins near 370°K., the irradiated sample remained a solid and the internal friction decreased. Below 370°K. the dynamic modulus of the highly irradiated material scarcely differed from that of the unirradiated sample, while beyond 500°K. it was rather high (near 105 psi). At low irradiation doses crosslinking occurred sufficient for the formation of a nonliquefying, three‐dimensional network in the polystyrene, but no changes in the dynamic mechanical properties attributable to irradiation could be detected.
Properties of homopolymers of 2‐methyl‐5‐vinylpyridine
Authors: Gechele Giovanni B. , Convalle Giovanni 
Published: April 2003

AbstractThe physical and technological properties of the homopolymers of 2‐methyl‐5‐vinylpyridine (MVP) are reported. PMVP is rather similar in many mechanical and electrical properties to polystyrene. In addition, the pyridine nucleus imparts to the polymer a strong tendency to absorb water and great ease of quaternization with acids, halides, etc. This suggests applications of PMVP as a polyelectrolyte, a viscosity‐improving agent in aqueous acidic media, etc. However, the water absorption characteristic leads to poor outdoor durability and rapid deterioration of many properties after prolonged exposure to humidity.
Diisocyanate‐linked polymers. III. Relationships between the composition and ultimate tensile properties of some polyurethane elastomers
Authors: Smith Thor L. , Magnusson Alan B. 
Published: April 2003

AbstractThe ultimate tensile properties (tensile strength and elongation at rupture) of various series of polyurethane elastomers which apparently do not crystallize were studied. Elastomers which contained 0–20% isodecyl pelargonate were prepared from polyoxypropylene glycol 2025 (PPG), dipropylene glycol (DPG), trimethylolpropane (TMP), and toluene 2,4‐diisocyanate (TDI); the ratios of ingredients were varied so that all clastomers had approximately the same number of chains per unit volume v and tho same concentration of urethane groups [U]. Unplasticized elastomers were also prepared that were similar except that they were linked by hexamethylene 1,6‐diisocyanate, TDI, m‐phenylene diisocyanate, and naphthalene 1,5‐diisocyanate. Over a wide temperature range, the ultimate proper‐ ties of elastomers in both series were identical at equal values of T − Tg,. Series of elastomers were also preparcd from TMP, TDI, triethylme glycol, and two polyester diols: a 50/50 and an 80/20 copolymer of ε‐caprolactone and methyl ε‐caprolactone. In these series, v was held constant and [U] was varied. Within each series, the ultimate properties were identical at equal values of T − Tg, although the ultimate properties depended on the nature of the polyester diol and were different from those of similar elastomers prepared from PPG. To study the effect of the crosslinker type and the concentration, elastomers having a constant [U] were prepared from PPG, DPG, TUI, and six crosslinkers, three being trihydroxy and three being tetrahydroxy materials. At a given temperature, the tensile strength and ultimate elongation appeared to be inde‐ pendent of the crosslinker type and proportional to ve½ and 1/ve, respectively, the proportionality constants being temperature‐dependent. On these elastomers, equilibrium swelling ratios in benzene and rough values of the per cent sol were also measured and certain relations among these and the mechanical properties were observed.
The strain dependence of rubber viscoelasticity. Part III. Natural and butyl rubber at high extensions
Authors: Mason P. 
Published: April 2003

AbstractDynamic Young's moduli are derived from observations of wave propagation in stretched filaments of natural and butyl rubbers. Extensions up to about 700% are studied within a temperature range of −45 to +50°C. and a frequency range of 0.2 to 20 kycles/sec. At constant temperature and frequency both the real (E') and imaginary (E″) components increase with increasing extension. The loss factor (E″/E') decreases with increasing extension, but the decrease is more pronounced for the butyl rubber so that the large difference in damping between the two polymers in the unstrained state is greatly reduced at high extensions. Approximate relaxation spectra are derived for the strained materials on the basis of several assumptions regarding the applicability of the WLF equation. It is found that the spectra are displaced in the direction of longer times by increasing extension; this is equivalent to an increase in the monomeric friction coefficient with extension. The effect is more pronounced for the natural rubber than for the butyl, and consequently the ratio of the friction coefficients (butyl:natural) falls from several hundred unstrained state to approximately 3 at 550% extension.
Viscoelastic properties of the phenolic resin–polyvinyl butyral system
Authors: Takahashi Yūzō 
Published: April 2003

AbstractThe viscoelastic properties of the phenolic resin–polyvinyl butyral system were studied over a wide range of temperature by means of the vibrating reed method, at about 50 cycles/sec., and dielectrically, at 60 cycles/sec. Two mechanical loss peaks due to polyvinyl butyral in the mixed system, occurring at about 100 and 160°C., were readily observed. These peaks are influenced by the curing temperatures, being readily detected in specimens cured in the range 180–200°C. but not in those cured below 170°C. The effect of cure temperature on the appearance of a dielectric loss peak at about 100°C. for the system agrees in trend with the effect of cure temperature on the mechanical loss peak in the same temperature range. This result may lend some support to the hypothesis that the polar functional groups of the system play some important role in the appearance of a loss peak. The loss peak at about 100°C. coincides approximately with the maximum loss peak for polyvinyl butyral in the mixed system, and hence this peak may be due to the second‐order transition of the polyvinyl butyral which seems to be in a heterogeneous state in the specimen. Another peak, found at about 160°C., may be attributed to grafting or crosslinking between the phenolic resin and the polyvinyl butyral, resulting from chemical reaction between the two materials during the curing process, as was shown by results for the mixtures of the phenolic resin with PVB and with two PVB derivatives. A model of the state of dispersion of the two constituents in the system is proposed on the basis of these results. Finally, the loss peak occurring at about −42°C. for the system is clearly attributable to the phenolic resin alone. The molecular mechanism for this dispersion, on the basis of results of viscoelastic and dielectric measurements, may be the local movement of side chains, especially unreacted methylol and amino groups on the phenolic resin molecules, although there is no additional clear support for this conclusion.
Solution properties of diethylacetamide cellulose xanthate in dimethyl sulfoxide
Authors: Cornell R. H. , Swenson H. A. 
Published: April 2003

AbstractLight‐scattering and viscosity measurements were obtained for seven fractions of the diethylacetamide derivative of cellulose xanthate (DAX) in 90% dimethyl sulfoxide. The degree of substitution (D.S.) range represented by the samples was 0.4 to 1.22; the molecular weight range was 112,000 to 446,000. The following empirical equation between the intrinsic viscosity and D.P.w was found: [η] = (5.63 – 3.35 D.S.) × 10−3 D.P.w. As reflected by the km– D.S. plot, the Martin constants, and the configuration parameters, it was apparent that the low D.S. derivatives are considerably more extended in solution than high D.S. derivatives of the same chain length. Under such conditions, it is apparent that solvent‐polymer interaction has assumed an important role in determining the polymer configuration. The behavior of the DAX molecule in solution was found to be strikingly similar to that of other cellulose derivatives. Hydrodynamic considerations revealed that the behavior in solution appears to approach that of the more flexible synthetic polymers at D.S. levels above 0.9 and molecular weights above 400,000.
Viscoelastic properties of regenerated cellulose sheet
Authors: Wellisch Eric , Marker Leon , Sweeting Orville J. 
Published: April 2003

AbstractThe viscoelastic properties of regenerated cellulose containing several different softeners or water only were investigated. Measurements of creep and Young's modulus were made on the Instron tensile tester, and the creep curves were fitted to a mechanical model consisting of Voigt and Maxwell elements of springs and dashpots in series. The elastic and viscous parameters were determined for the various softened films and compared with each other and with measurements of Young's modulus. It was found that the elastic modulus is a function of the effective molar concentration of the softener in the film which is related to its ability to break hydrogen bonds. The inelastic deformation was found to be a linear function of the heat of vaporization of softener (including water) in the film which is related to hydrogen‐bonding energy. Thus, inelastic deformation requires breaking of interchain hydrogen bonds in contrast to pure elastic deformation which involves stretching of hydrogen bonds. A relationship of the Voigt unit and of the Maxwell unit on the composition of the cellulose‐softener system and on cellulose‐softener interaction has been demonstrated.
Inter‐ and intramolecular order in regenerated cellulose
Authors: Pennings A. J. , Prins W. , Hale R. D. , Rårnby B. G. 
Published: April 2003

AbstractCellulose was regenerated from technical viscose as bulk gels and thin films (never dried) and then conditioned by repeated swelling with sodium hydroxide solutions and steam treatments. These extraction and conditioning treatments of the gels increased the crystallinity and decreased the accessibility to water as measured by x‐ray, infrared, and density measurements. The density of the gels increased more during these treatments than one would expect from the increase in crystallinity as measured from x‐ray diffraction. Supported by the combined density, infrared, and D2O‐exchange data, this was taken as evidence that the conditioning also gives a closer packing or an increased order in the so‐called amorphous regions. Both steam‐conditioning and drying decreased the accessibility of thin films as measured by a combination of infrared analysis and swelling with sodium deuteroxide solutions in heavy water (NaOD in D2O). Reports in the literature that regenerated cellulose is completely accessible in dilute aqueous alkali solutions (about 1%) have not been verified. The intensity ratios of the different infrared absorption bands were measured during the gradual swelling and exchange with NaOD of increasing concentrations from 1 to 16% in D2O. The few data available now seem to indicate that hydroxyl groups assigned to intrachain hydrogen bonds in crystalline regions are more resistant to deuterium exchange than hydroxyl groups assigned to interchain hydrogen bonds. Based on these studies the concepts of crystallinity, order, and accessibility to water and swelling agents for regenerated cellulose are discussed.
Sur la dégradation thermique du chlorure de polyvinyle. I. Méthodes expérimentales d'etude cinétique
Authors: Guyot Alain , Benevise Jean‐Paul 
Published: April 2003

AbstractAn apparatus for polyvinyl chloride thermal degradation under isothermal conditions and in a controlled atmosphere is described with precision. Continuous measurement of loss of weight of the sample under degradation and, at the same time, continuous titration of hydrochloric acid evolved, can be carried out. The apparatus consists essentially of a magnetically equilibrated Ugine‐Eyraud balance, in which runs a purified gas stream that picks up volatile products in an argentimetric titration cell, coupled to a titrimeter and recorder. Total precision of simultaneous measurements is 1%. An example of the experimental results is given.
Adherend surface preparation
Authors: Thelen Edmund 
Published: April 2003

AbstractIf an adhesive joint is to be strong and permanent its adherend surfaces must be treated at least to remove oil, dirt, and dust. In addition, control of surface roughness, oxide formations, and sometimes adsorbed water is required. Deposition of chromium atoms or TiO2 is indicated for electron donor metals surfaces, and treatments may be useful to protect the adhesive from the adherend or vice versa, or to make their structures more congenial.