bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of a Mark‐Houwink type relationship for poly‐N‐tert‐butylacrylamide in methanol
Authors: Cavell E. A. S. , Gilson I. T. , Jennings B. R. , Jerrard H. G. 
Published: April 2003

AbstractViscosity and light‐scattering measurements have been made on five samples of poly‐N‐tert‐butylacrylamide in methanol, for which brief preparative details are given. Specific viscosities ηsp have been determined at 25°C. with two U‐tube viscometers, No. 0 and No. 1, over a range of concentrations c. The mean flow gradients lie in the range 360–750 sec.−1 for No. 0 and 535–940 sec.−1 for No. 1. Graphs of ηsp/C against c are linear for concentrations between 0.18 and 1.0 g./dl. at all gradients less than about 640 sec.−1 with samples having weight‐average molecular weights of 24.5, 5.46, 4.04, 3.79, and 1.65 × 105. At lower concentrations, which give correspondingly higher gradients, the linear relation ceases. Possible reasons for this are suggested. By extrapolation of the linear portions of the appropriate curves to zero concentration, apparent limiting viscosity numbers \documentclass{article}\pagestyle{empty}\begin{document}$[\eta ]_{\begin{array}{*{20}c} {c = 0} \\ {G = 760} \\ \end{array}} $\end{document} have been obtained, where the value G = 760 sec.−1 is the gradient for pure methanol. Light‐scattering data have been employed to obtain the molecular weights of the samples using the Zimm technique. Depolarization ratios, determined for different concentrations at wavelengths 4358 and 5461 A. and extrapolated to zero concentration, were negligible. The constants k1 and α in the expression \documentclass{article}\pagestyle{empty}\begin{document}$[\eta ]_{\begin{array}{*{20}c} {c = 0} \\ {G = 760} \\ \end{array}} $\end{document} =k1Mwα have the values 8.87 ± 0.44 × 10−4 and 0.525 ± 0.026, respectively.
CH2 rocking vibrations of polyethylene oxybenzoate
Authors: Ishibashi Matahumi 
Published: April 2003

AbstractInfrared spectra of poly(p‐ethylene oxybenzoate) and four of its diol oligomer series (from monomer to tetramer) have been obtained in the range of 400–4000 cm.−1. An assignment of the CH2 rocking vibrations has been made on the basis of analysis of spectra of ethylene glycol and its derivatives, and with the help of data from related compounds containing OCH2CH2OH endgroups linked to a phenyl and/or to a benzoyl residue and containing a OCH2CH2Ogroup between a phenyl and a benzoyl residue. This assignment suggests that the OCH2CH2O groups of poly(p‐ethylene oxybenzoate) are in the trans conformation. The similarity between the noncrystalline and the crystalline phase spectra of poly(p‐ethylene oxybenzoate) suggests that the OCH2CH2O groups exist in essentially the same (trans) conformation in both phases.
Elastic effects and extrudate distortions in capillary flow of molten polyethylene resins
Authors: Schott Hans 
Published: April 2003

AbstractDuring the flow of polymer melts, distortions of the emerging stream begin at well defined critical shear conditions and increase in severity at higher shear. End‐corrected critical shear stresses in the capillary extrusion of molten polyethylene are independent of the length/radius ratio of the capillary but increase somewhat with rising temperature. The recoverable shear strain reaches its maximum value at the critical conditions, where it was calculated as the elastic component of the end effects and by applying Hooke's law in shear. Critical recoverable shear strain as well as the derived quantities shear modulus and normal force increase with increasing temperature. Linear polyethylene has higher values for these three parameters than two branched resins. Relaxation times calculated as the ratio viscosity/shear modulus agree rather well with values determined by other means.
Synthesis and polymerization of 1‐(perfluoroacyl)aziridines
Authors: Pittman A. G. , Lundin R. E. 
Published: April 2003

AbstractThe preparation and polymerization of representative 1‐(perfluoroacyl)aziridines were examined. Polymerization of the aziridines was induced by heat, by certain inorganic nucleophiles such as cyanide, fluoride, and chloride, and by organic bases. Certain other inorganic nucleophilic reagents such as KI and KBr effected the rearrangement of the 1‐(perfluoroacyl)aziridines to the isomeric 2‐perfluoroalkyl‐2‐oxazolines. A possible reaction mechanism involving anionic polymerization in competition with oxazoline formation was discussed.
Polymer deformation. II. Drawing of polyethylene single crystals
Authors: Geil P. H. 
Published: April 2003

AbstractThe effect of molecular weight average and distribution, defect type, fold plane type and orientation, and the presence of fold domain boundaries on the deformation characteristics of polyethylene single crystals drawn on a Mylar substrate has been investigated. Defect content is suggested to have a bigger effect than either molecular weight or distribution. Fold plans of the {100} type are shown to deform in a different fashion than those of the {110} type. Boundaries between {100} and {110} fold domains are greatly susceptible to failure whereas those between neighboring {110} fold domains are not. Clear evidence for deformation through {110} twinning and a crystal transformation is shown. Plastic deformation without molecular unfolding or fracture occurs in many polyethylene crystals for elongation up to at least 150%.
Polyquinoxalines
Authors: Stille J. K. , Williamson J. R. 
Published: April 2003

AbstractThe reaction of stoichiometric amounts of 1,4‐diglyoxalylbenzene with 3,3′‐diaminobenzidine affords nearly quantitative yields of a polyquinoxaline. Reaction of the monomers in the absence of solvent and heating to 250°C. or reaction of the monomers in a solvent to form a prepolymer and heating of the prepolymer to 250°C. provides soluble polymer with nearly identical properties. Heating the polymer to 375°C. under reduced pressure increase the molecular weight. A study of model compounds and reactions indicates that the polymer is predominately poly[2,2′‐(1,4‐phenylene)‐6,6′‐diquinoxaline] instead of the 2,3′‐ or 3,3′‐isomers. These polymers are stable in air to 500°C. and under nitrogen lose only 20% of their weight at 800°C.
Polymerization in liquid sulfur dioxide. Part XIX. Effects of aniline and its derivatives on the radical polymerization of acrylonitrile in liquid sulfur dioxide
Authors: Matsuda Minoru , Abe Susumu , Tokura Niichiro 
Published: April 2003

AbstractRadical polymerization of acrylonitrile in liquid sulfur dioxide was carried out at 50°C. with α,α‐azobisisobutylonitrile as an initiator. When aniline (An), dimethylaniline (DMA), dimethyl‐o‐toluidine (DMoT), and diethylaniline (DEA) were added to this system, it was found that each base acted as a retarder for the polymerization. When the chain transfer constant was calculated for each base, the values were 1.0 (An), 1.5 (DMA), 3.0 (DMoT), and 9.3 (DEA). The Alfrey‐Price etr values calculated from these values were −2.79 (An), −3.14 (DMA), −3.72 (DMoT), and −4.66 (DEA). On plotting these values against pKa of each base, a linear relationship was found.
Studies in condensed phosphates. Part VI. Paper chromatographic studies of condensed phosphates
Authors: Mehrotra R. C. , Gupta V. S. 
Published: April 2003

AbstractPaper chromatographic analysis of the complex polymetaphosphates, i.e., (Nax‐M(1−x)2PO3)n, where M is Ca, Ba, or Cu and x = 1/3 reveals that the observed values of Rf and Rg for the above derivatives are similar to those for the simple sodium polymetaphosphate (NaPO3)n, but are different from those of the phosphate anions viz., orthophosphate, pyrophosphate and trimetaphosphates.
Cyclo‐ and cyclized diene polymers. II. Infrared study of the cyclization of cis‐1,4, trans‐1,4, and 3,4‐polyisoprenes
Authors: Štolka M. , Vodehnal J. , Kössler I. 
Published: April 2003

AbstractCyclization of cis‐1,4, trans‐1,4‐, and 3,4‐polyisoprene was carried out in toluenesolution with sulfuric acid. With 1% H2SO4, calculated on polymer, a stationary state of cyclization was reached in which 33% of the original unsaturation and about 50% of the total unsaturation remained in cyclized trans‐1,4‐ and 3,4‐polyisoprene. The rate of cyclization of cis‐1,4‐polyisoprene was very small, and the limiting value was not reached even after 100 hr. at 80°C. Infrared spectra of cyclized polymers show decreased absorption intensity of the bands characteristic of groups in the linear polymer. With 10% H2SO4 calculated on polymer (a heterogeneous mixture), all three polyisoprenes cyclize to give polymer with none of the original unsaturation in the chain. Infrared spectra of cyclized trans‐1,4‐and cis‐1,4‐polyisoprene are identical. The spectrum of cyclized 3,4‐polyisoprene differs only by two peaks, at 1385 and 1370 cm.−1. The spectra of all three cyclized isomers show new bands in infrared spectrum at 2870, 1265, 1200, 1040, and 810 cm.−1. A comparison has been made of the infrared spectra of cyclopolymers of isoprene, butadiene, and chloroprene prepared from monomers by use of Ziegler‐Natta catalysts with spectra of cyclized polyisoprene. The spectra are very similar, which indicates that both types of polymer have the same polycyclic structure.
Degradation of poly‐3,3‐bis(chloromethyl)oxacyclobutane (penton)
Authors: Golden J. H. , Hazell E. A. 
Published: April 2003

AbstractThe degradation of Penton [poly‐3,3‐bis(chloromethyl)oxacyclobutane] by electron irradiation in vacuum has been investigated. Viscometric measurements on the irradiated material showed that the polymer underwent random chain scission without crosslinking. The chemical changes responsible for the fairly rapid breakdown of the polymer were examined by infrared analysis and by analysis of the gases, predominantly hydrogen, hydrogen chloride, and carbon monoxide, evolved during irradiation. The chain scission of Penton is accompanied by formation of terminal unsaturation and allylic chlorine groups. The effects of radiation on the flexural and tensile properties of Penton were examined, and it was shown that the pattern of behavior in flexure was closely similar to that in tension. The form of the tensile strength curves obtained for irradiated Penton at various rates of straining was examined and related to that of hypothetical brittle strength curves. Some effects of radiation, rate of testing and temperature on the brittle strength of the polymer have been determined. The viscometric and tensile results obtained were compared with those obtained for the structurally related polyoxymethylene (Delrin) which was much less resistant to radiation.
Analysis of copolymers by means of density gradient centrifugation. II. Comparison with kinetic requirements
Authors: Ende H. A. , Hermans J. J. 
Published: April 2003

AbstractFour styrene–iodostyrene copolymers of uniform iodine content are examined in the density gradient centrifuge under conditions similar to those used in a previous study, in which the copolymer investigated showed compositional distribution. The results obtained determine the relation between the iodine content of a copolymer and its position in the density gradient. This enables one to compare the average square of the fluctuation in iodine content with that derived from the kinetic copolymer equation. The two results agree satisfactorily.
Radiation‐induced electrical conductivities in polyamide copolymers
Authors: Hedvig Péter 
Published: April 2003

AbstractRadiation‐induced conductivities as high as 10−12 ohm−1 cm.−1 were measured in polyamide copolymers irradiated by x‐rays and Co60 γ‐rays at dose rates of 0.1–20 r/sec. No temperature dependence for the induced conductivities could be detected between 10 and 60°C., while dark conductivities followed the usual exponential rule with activation energies between 1 and 2 e.v. Preirradiation of the samples resulted in a decrease of the induced conductivities. This effect could be controlled by addition of benzophenone and hydroquinone. A phenomenological model is presented for a possible explanation of the results.
On correlation of data in copolymerization
Authors: Mayo Frank R. 
Published: April 2003

AbstractEquation (3) is potentially useful for bringing out inconsistencies between experimental data and theoretical correlations and predictions of behaviors of monomers in copolymerizations. Equation (3) is a modification of Ham's eq. (1). His eqs. (1) and (4) are approximations which are sometimes quite good, and sometimes very poor.
Some calculations of intrinsic viscosity and molecular weight distribution for trifunctional, randomly branched polymers
Authors: Myers G. E. , Dagon J. R. 
Published: April 2003

AbstractComputations have been performed of the intrinsic viscosity of trifunctional, randomly branched whole polymers. Both the Thurmond‐Zimm and the Zimm‐Kilb treatments of the viscosity of branched polymers have been combined with the Beasley molecular weight distribution function. The Beasley distribution function has also been compared with a function derived by Flory for trifunctionally branched condensation polymers. The two functions are in good agreement at low extents of branching, but at higher branch contents the former function extends to significantly higher molecular weights.
Measurement of membrane potentials and test of theories
Authors: Lakshminarayanaiah N. , Subrahmanyan V. 
Published: April 2003

AbstractThe emf's of the system Ag, AgCl/NaCl (mI)/membrane/NaCl(mII)/AgCl, Ag containing phenol–formaldehyde sulfonate membrane have been measured at 30°C. The membrane phase has been analyzed for its electrolyte and water contents and intramembrane activity coefficients have been derived as a function of external electrolyte concentration. Transference numbers of Na+ counterion and water have been measured as functions of both current density and external concentration. The data have been used to test the principal theories of membrane potential. The fixed‐charge theory of Teorell and Meyer and Sievers did not give satisfactory agreement between observed and calculated emf's of membrane cells, whereas the Scatchard theory did.
Chain folding in amylose crystals
Authors: Manley R. St. J. 
Published: April 2003

AbstractCrystals of amylose were prepared by precipitation from aqueous solution with n‐butanol. The crystals are rectangular platelets, and crosses or rosettes formed by the intergrowth of single platelets. In the electron microscope they are seen to consist of layers 75 A. in thickness. Distinct spiral terrace growths related to screw dislocations were not observed, but the presence of dislocation edges suggests that the crystals thicken by a dislocation mechanism. Low‐angle, x‐ray measurements on aggregates of the crystals reveal a long spacing in good agreement with that calculated from shadow lengths. However, in contrast with other polymers, the long spacing appears to be invariant with crystallization temperature. Electron diffraction spot patterns show that the platelets are single crystals and indicate that the chain molecules are folded within the lamellae.
Association phenomena in carboxyl‐containing polymers
Authors: Yudelson Joseph S. , Mack Randall E. 
Published: April 2003

AbstractGelation effects were studied as a function of pH for the following polymeric materials: alginic acid, poly(methyl acrylate co acrylic acid), poly(ethyl acrylate co acrylic acid), and phthalated ethylcellulose. The effects of various addenda were also studied. The results suggest a gelation mechanism for all the polymers which consists of a balance of repulsive force interactions due to ionization of carboxyl groups, and of attractive force interactions due to hydrogen bonding. The groups involved in hydrogen‐bonding interactions are deduced. The melting points of phthalated ethylcellulose and poly(ethyl acrylate co acrylic acid) gels were obtained as a function of concentration and plots of log c versus reciprocal absolute temperature of melting gave linear curves. The heat of reaction for the formation of crosslinks was −8 ± 0.4 kcal./mole crosslinks. This is much lower than values obtained for gelatin gels and suggests that a single crosslink contains 1–2 hydrogen bonds.
cis‐polychloroprene
Authors: Aufdermarsh C. A. , Pariser R. 
Published: April 2003

Abstractcis‐Polychloroprene was synthesized by chlorinolysis of 1,4‐poly‐2‐(tri‐n‐butyltin)‐1,3‐butadiene. The latter was obtained by free radical polymerization of 2‐(tri‐n‐butyltin)‐1,3‐butadiene. The structure of cis‐polychloroprene was established by ozonolysis, and by infrared and NMR spectroscopy.
Amylose V complexes from dimethyl sulfoxide solutions
Authors: Germino F. J. , Valletta R. M. 
Published: April 2003

AbstractThis investigation has shown that it is possible to prepare V complexes of amylose from dimethyl sulfoxide solutions. Methanol, n‐propanol, acetone, and methyl ethyl ketone complexes have been prepared and their unit cell dimensions calculated from their x‐ray powder patterns. The small unit cell, with a helix diameter of 13.0 A., observed with a wet methanol complex from aqueous system, is also observed here. However, the wet and thoroughly dired ketone complexes prepared from DMSO have the larger helix diameter of 13.7 A. The results indicate that factors other than the size or type of complexing agent are important in determining the helix diameter of the amylose V complex. They also indicate that these factors are complex and probably interdependent. The effect of temperature on the helix diameter was explored.
Degradation of polycarbonates. IV. Effect of molecular weight on flexural properties
Authors: Golden J. H. , Hammant B. L. , Hazell E. A. 
Published: April 2003

AbstractThe effect of radiation dose and molecular weight on the tensile and flexural properties of polycarbonate, poly‐[2,2‐propane bis(4‐phenyl carbonate)], have been examined in detail. Tensile strength, flexural strength, and flexural modulus can be expressed as linear functions of radiation dose and are almost completely independent of molecular weight when the material is ductile. The strength of the brittle material (molecular weights less than 13,000) is however shown to be a linear function of reciprocal molecular weight. The effect of molecular weight on flexural modulus is also discussed. The presence of the equilibrium water content in the plastic has been shown to cause a fourfold increase in the rate of chain scission and an explanation of this effect is advanced.
Cyclopolymerization. V. Copolymerization of acrylic and methacrylic anhydrides with vinyl monomers
Authors: Smets G. , Deval N. , Hous P. 
Published: April 2003

AbstractThe copolymerizations of acrylic (AA) and methacrylic (MAA) anhydrides (M1) with styrene (St) and methacrylonitrile (MAN) have been examined; similarly that of acrylic anhydride with allyl chloride. In these systems the reactivity ratio of an open unit radical (r1) is equal to that of a cyclized radical (r3), and the usual Alfrey‐Price equation is valid. By using a graphical method the ratios of the cross propagation rate constant to the cyclization rate constant (k12/kc) have been also evaluated. The following values for r1, r2, and k12/kc respectively have been found, M1 being the anhydride: for the system AA (M1)–St, 0.1, 0.17, and 4; for the system AA–MAN, 0.9, 0.04, and 0.14; for the system AA–allyl chloride, 11.5, 0.01, and 0. For the same systems with MAA, the values of r1, r2, and k12/kc were 0.26, 0.12, and 0.2 with St, and 1.6, 0.27, and about zero with MAN. These data indicate also that the cyclization reaction is always more pronounced for methacrylic anhydride than for the acrylic anhydride.
Some elastic moduli of bisphenol A polycarbonate
Authors: Robertson Richard E. , Buenker Robert J. 
Published: April 2003

AbstractThe Young's modulus of oriented bisphenol A polycarbonate films were measured along, 45° to, and normal to the direction of orientation by the vibrating reed technique. The change in modulus with the degree of orientation was fitted to a theoretical curve, using an IBM 704 electronic computer. The basis for fitting the data to the theoretical curve was the assumption that the process of orienting the polymer molecules could be described by an affine transformation. The elastic moduli calculated are as follows: The Young's modulus for stretching the chain is 5.4 × 1011 dyne/cm.2; the Young's modulus for separating a bundle of parallel chains laterally is 1.76 × 1010 dyne/cm.2; and the shear modulus for the relative displacement of a bundle of parallel chains along their length is 2.00 × 1010 dyne/cm.2.
Apparent transfer constants of mercaptans in emulsion polymerization. II. Effect of reactions other than polymer chain transfer
Authors: Meehan E. J. , Kolthoff I. M. , Sinha P. R. 
Published: April 2003

AbstractWhen all the modifier is dissolved in the polymer particles the chain transfer constant, d log (RSH)/d log (M) of n‐octyl mercaptan at 90% conversion in the emulsion polymerization of butadiene (50°C) is 19, the same value as in bulk and in emulsion at 0% conversion. The relative rate of consumption of mercaptan and monomer is unaffected by variation of persulfate and presence of a diluent such as benzene. While mercaptan is consumed by addition to the polymer double bonds (nonmodifying reaction) in monomer‐free polybutadiene latex containing persulfate, this addition reaction is virtually suppressed completely in the presence of butadiene monomer. On the basis of the accuracy of the determinations of mercaptan and monomer a slight activation of polymer molecules at high conversion with subsequent cross linking cannot be excluded.
1,5‐hexadiene polymers. II. Copolymers of ethylene and 1,5‐hexadiene
Authors: Makowski Henry S. , Shim Benjamin K. C. , Wilchinsky Zigmond W. 
Published: April 2003

AbstractA series of crystalline ethylene‐1,5‐hexadiene copolymers containing 15–93 mole‐% ethylene were prepared with an AIR3/TiCl3–AlCl3 catalyst system. X‐ray diffraction analyses showed two distinct crystalline phases in the copolymers; one phase had the polyethylene structure whereas the other had the poly‐1,5‐hexadiene structure. However, the unit cell sizes of these two phases were significantly different from those of the respective homopolymers, indicating that both types of monomeric units are present in each of the copolymer phases. Physical property measurements on the copolymers support these conclusions.
2,7‐disubstituted 1,3,6,8‐tetraazopyrene and related polymers
Authors: Dawans F. , Reichel B. , Marvel C. S. 
Published: April 2003

Abstract2,7‐Disubstituted derivatives of 1,3,6,8‐tetraazopyrene were synthesized as model compounds for some polymers of similar structure. Conjugated and high molecular weight polymers were obtained by polycondensation of 1,4,5,8‐tetraaminophthalene with various diphenyl esters of bifunctional aromatic acids. The inherent viscosities of a number of polymers ranged from approximately 0.15 to 0.70. Most of the polymers are infusible and some of them are insoluble in the usual organic solvents. The thermal stability properties of the polymers were very good.