bluuebunny/crossref_metadata_2025_split huggingface dataset:
An estimate of the molecular weights of polythene
Authors: Mussa Carlo 
Published: April 2003

AbstractThe MW determinations of polythene made by Harris are matched by calculation together with the results of our fractionations carried by a method suggested by Nicolas. An evaluation of the MW and of their distribution in a set of polythene samples is obtained which is in agreement with the long branching hypothesis. The calculation of Beasley can be satisfactorily applied and values of the long branching parameters have been calculated for the examined samples.
Polymerization and polymers of N‐vinylpyrrolidone
Authors: Breitenbach J. W. 
Published: April 2003

AbstractExperiments are reported on the rate of polymerization of N‐vinylpyrrolidone in the presence and in the absence of azobisisobutyronitrile as initiator. The reactions of N‐vinylpyrrolidone in aqueous acid solution are mentioned. The limited degree of swelling of crosslinked polyvinylpyrrolidone is discussed. Degree of swelling is influenced by choice of solvent, by temperature and, in aqueous systems, by ions which are present on the network of the gel. These ionized groups can be introduced by copolymerization with unsaturated acids or by adsorption of ions from solution. Certain dyes are especially suitable for the formation, in this way, of polyelectrolyte gels having a low charge density.
Some aspects of the crystallization of nylon 66 (polyhexamethylene adipamide)
Authors: Boasson E. H. , Woestenenk J. M. 
Published: April 2003

AbstractA study has been made of crystallization phenomena in nylon 66 occurring after fusion at temperatures just above the melting point. It appeared to be possible to obtain optically negative spherulites in nylon 66 by crystallizing at temperatures between 250 and 258°C., after fusion at temperatures above 258 but below 265°C. The radial growth rate of the negative spherulites has been determined and has been found to depend on the crystallization temperature. The optically negative spherulites have a higher optical melting point than the optically positive spherulites hitherto observed in nylon 66. Another type of spherulitic structure with spherulites of a fibrous appearance, of which the optical sign cannot be determined, is reported. An attempt is made to explain the data obtained on the basis of the generally accepted crystallization mechanism, valid for linear high polymers.
Measure of permeability of plastic material, leather, and similar substances against moistness and water by the hygrophotographic method
Authors: Sivadjian J. 
Published: April 2003

AbstractThe hygrophotographic method which the author has elucidated with the help of special hygrosensitive plates and films described by him, permits a study of the permeability of different kinds of plastic materials, leather, and other analogous substances in water as well as in vapor. With this aim in view, it gives the time necessary to produce the decoloration of the hygrosensitive layer of the hygrophotographic plates kept in contact with these products, by the action of vapor diffused through the products examined. The different phases of the decoloration are fixed afterwards by direct photography.
Mechanism of retardation in emulsion polymerization of styrene
Authors: Meehan E. J. , Kolthoff I. M. , Tamberg Nora , Segal C. L. 
Published: April 2003

AbstractEmulsion polymerizations of styrene have been carried out with potassium persulfate as initiator and fatty acid soap as emulsifier in the presence of varying amounts of N,N‐dimethyl‐2,4‐dinitroaniline (DMDNA) and 1‐bromo‐2,4‐dinitrobenzene (BrDNB). The latter two substances are retarders. Rates of polymerization, rates of disappearance of retarder, and polymer molecular weight were determined. The ultraviolet spectrum of the retarded polymer showed conclusively the presence of bound DMDNA while the amount of bound DMDNA was determined by a spectrophotometric acid‐base titration with perchloric acid of the polymer dissolved in benzene. BrDNB was prepared using Br82 and the amount of retarder fragments in the polymer determined by radioactive measurement. The quantities of persulfate remaining and of sulfate formed were determined during polymerization strongly retarded by DMDNA. All the results are in quantitative agreement with the following mechanism. The rate‐determining step in initiation is the rate of thermal decomposition of persulfate in water into sulfate free radicals. The sulfate radical reacts with monomer to initiate polymerization. In the absence of retarder, growth is terminated either by chain transfer with monomer or by combination with a second sulfate radical. In the presence of retarder the growing radical may combine with retarder, forming a sluggish free radical to which monomer does not add, and which is terminated by reaction with a second sulfate radical. In this reaction a hydrogen atom is transferred yielding a polymer molecule and a bisulfate ion.
Molecular weight‐intrinsic viscosity relationship and molecular weight distribution of low pressure polyethylenes
Authors: Tung L. H. 
Published: April 2003

AbstractMolecular weights of low pressure polyethylene fractions were measured by an ebulliometric method and an osmotic pressure method. The results can be correlated by an equation, [η] = 5.10 × 10−4 M0.725, with the intrinsic viscosity measured at 130°C. in Tetralin, for a molecular weight greater than 3750. All three types of polymer fractions, Ziegler‐type low pressure polyethylene, Phillips low pressure polyethylene, and polymethylene from the decomposition of diazomethane, conform to the above correlation. The molecular weight distributions of two samples of Ziegler type polyethylene and one sample of Phillips' Marlex 50 were determined. All three distributions were found to be very broad and contained large amounts of low molecular weight materials.
Scattering of light by thin polymer films. An apparatus for measurement of scattering at very low angles
Authors: Plaza Alphonse , Norris Forrest H. , Stein Richard S. 
Published: April 2003

AbstractAn apparatus is described for studying the scattering from polymer films at angles to within 0.1° from the incident beam. A temperature‐controlled chamber for carrying out these measurements at elevated temperatures is also described. The performance of the apparatus in measuring the scattering from a polyethylene film is illustrated.
Wettability and friction of polytetrafluoroethylene film: effect of prebonding treatments
Authors: Allan A. J. G. 
Published: April 2003

AbstractThe wettability of polytetrafluoroethylene film surfaces has been studied by observing the equilibrium advancing contact angle formed by a drop of liquid on the surface. The surface treatment required to give good adhesion to various substrates produces a marked increase in the polarity of the surface as measured by the contact angles with a series of solutions of ethyl alcohol in water. Measurement of the coefficient of kinetic friction shows that the untreated side of treated material has the same coefficient as completely untreated film, but the treated side has a considerably higher friction. This higher friction of the treated surfaces is ascribed to the shearing of junctions in the bulk rather than shearing at the interface.
Dielectric studies of the methacrylate series. II. Poly‐n‐butyl methacrylate
Authors: Strella Stephen , Zand Robert 
Published: April 2003

AbstractThe complex dielectric constant of a pure molecular weight fraction of poly‐n‐butyl methacrylate was determined over a frequency range of 30 to 3 × 105 cps. and a temperature range of −74 to 114°C. The d.c. volume resistivity–temperature behavior was also determined. The data indicate the presence of two transition regions. Comparison of these data with those on polyethyl methacrylate shows that the transitions in the butyl polymer are further apart in temperature than in the ethyl polymer. Further, the data show that the ethyl chain is stiffer than the butyl chain. An attempt at superposition of the normalized complex dielectric constant was unsuccessful. Calculation of the distribution function of relaxation times for several temperatures shows a marked temperature dependence of this function.
Crosslinking of oriented rubber
Authors: Charlesby A. , von Arnim E. 
Published: April 2003

AbstractSmoked sheet rubber, previously oriented in the calendering process, was crosslinked by exposure to 2 M.e.v. high energy electrons in the absence of vulcanizing agents. Even after annealing the resultant rubber showed anisotropic elastic properties, having a high elastic modulus and a low elongation at break in the direction of orientation. It is suggested that radiation in addition to crosslinking causes main chain fracture and stress relaxation in stressed molecular chains. The G value for crosslinking (1.05) by electron irradiation agrees well with that (1.1) previously found by elastic measurements of pile irradiated rubber.
Ultrasonic degradation of cellulose nitrate. II. Effects of temperature, solvent, and other process variables
Authors: Thomas Berwyn B. , Alexander W. J. 
Published: April 2003

AbstractCellulose nitrate was degraded ultrasonically at 0 to 85°C. in the alkyl acetates from methyl to heptyl. In each solvent there is a high and low limit temperature where cavitation and degradation both cease. The upper limits are at the temperatures where vapor pressure of the solvent is about one‐half atmosphere, and cavitation evidently ceases because the solvent vapor pressure becomes too great for rapid bubble collapse. The lower limits of pressure and temperature vary in a linear manner, but have not been explained. The results confirm the need for cavitation as an initiator of the degradation mechanism, and explain some effects previously ascribed to solvent viscosity and temperature. When radio frequency power was varied, the rate of degradation was found to be independent of power so long as cavitation was present. In other experiments, degradation was found to be approximately constant to concentrations much lower than previously tested, whereas some proposed mechanisms would require that it should be reduced by dilution. Addition of a nonsolvent reduced the intrinsic viscosity of the polymer solution but did not reduce the extent of degradation; thus degradation is a function of the chain's length but not of its solvation. Finally, comparison of a series of celluloses from diverse sources showed that all gave about the same minimum degradable chain length, of 800–1000 DP. It was concluded that there was no evidence for the existence of weak links in the celluloses at shorter intervals.
Surface and interfacial monolayers of high polymers
Authors: Schick Martin J. 
Published: April 2003

AbstractThe monomer structure of several linear high polymers in monolayers has been studied with an automatic recording film balance and surface potentiometer of very high precision. The method is based on the resolution of the monomer structure from estimation of the limiting areas of the force—area and surface—potential area curves. The structures of poly(vinyl acetate), poly(vinyl alcohol), poly(methyl methacrylate), poly‐(methacrylonitrile), and ethoxylin polymer have been determined. In addition the secondary cohesion, which corresponds to its three‐dimensional equivalent, was related to the stability of the polymer film. It was found in the vinyl polymer series that secondary cohesion decreased in the order poly(vinyl alcohol), poly(methacrylonitrile), poly(methyl methacrylate), poly(methyl acrylate) to poly(vinyl acetate). Alternatively a comparison of specific areas at A/W and O/W interfaces renders conclusion on the rigidity of a polymer. Whereas poly(vinyl acetate) showed identical areas at both interfaces, poly(methyl methacrylate) spread to larger areas at the O/W interface. From this it is evident that the α‐methyl group in the vinyl chain exerted strong cohesive forces. This effect was even more pronounced with the ethoxylin resin with two benzene rings in the monomer unit. Application of a statistical mechanical equation for the two‐dimensional behavior of linear polymer indicated also that whereas poly‐(vinyl acetate) is a flexible chain, ethoxylin polymer is a rigid chain.
Intrinsic viscosity–molecular weight relationship for polychlorotrifluoroethylene
Authors: Walsh Eugene K. , Kaufman Herman S. 
Published: April 2003

AbstractA high temperature osmotic pressure technique has been used to obtain molecular weight data on fractions of polychlorotrifluoroethylene. Samples representing a range of molecular weight of 74,000 to 510,000 were studied. Intrinsic viscosity data were obtained on the samples at 130°C. using a dilution viscometer. The principal solvent used in these studies was 2,5‐dichlorobenzotrifluoride. The plot of π/C vs. C yields satisfactory linear relationships with a slope closely equal to zero. The log log plot of molecular weight and intrinsic viscosity gives the following relationship:

The value of the exponent 0.74 suggests a relatively rigid molecule. This is consistent with the results of x‐ray studies.
Polyalkylene sulfides. XIII. Polymers from 4‐vinyl‐1‐cyclohexene and d‐limonene
Authors: Marvel C. S. , Olson L. Elmer 
Published: April 2003

Abstract4‐Vinyl‐1‐cyclohexene and d‐limonene have been converted to dimercaptans by the addition of thiolacetic acid and subsequent hydrolysis. These dimercaptans have been added to the original nonconjugated diolefins to give low melting highly viscous polymers. In the case of 4‐vinyl‐1‐cyclohexene two monoaddition products of thiolacetic acid have been isolated and characterized. The ratio of the two products indicates two parts of adduct to the cyclohexene double bond to three parts of adduct to the vinyl group double bond are produced in the addition reaction.
Fibrous and globular aggregations of charged macromolecules
Authors: Oosawa Fumio 
Published: April 2003

AbstractThe dispersion‐aggregation equilibrium of charged macromolecules in solution is discussed. The aggregates of charged macromolecules formed by the short‐range attraction between molecules are, under suitable conditions, made fibrous owing to the longrange repulsion between them. As a result of calculations, a phase diagram is obtained and the size and shape of aggregates are determined by the values of the two dimensionless quantities defined by use of the following quantities: chemical potential difference between macromolecules in the macroscopic phase of aggregation and in the dispersed phase; surface free energy per macromolecule on the surface of macroscopic aggregates; magnitude of the long‐range repulsive potential between macromolecules, and the range of this potential. The states of aggregation are classified into five groups: (1) macroscopic globular aggregation; (2) macroscopic fibrous aggregation; (3) globular aggregation of finite size; (4) fibrous aggregation of finite size; and (5) no aggregation. Discontinuous transitions take place between these states and the critical points are given quantitatively. The change of state of aggregation under various conditions is described. The results of the present theory are proved to be useful in analyzing experimental data on aggregation phenomena in solutions of macromolecules and other colloidal particles.
A suggested method of plotting the data of fractionation and viscometry
Authors: Mussa C. , I. V.  
Published: April 2003

AbstractWhen for a given polymer a weight distribution formula is known or may be supposed, the experimental data obtained from its fractionation and from the viscometry of its fractions can be plotted, with a convenient choice of the coordinate system, in diagrams constituted by straight lines (or by lines tending toward linearity) as long as the relationship between the log of the intrinsic viscosities and the log of the degrees of polymerization of homogeneous fractions of the same polymer is also linear (or tending toward linearity). The straight‐line diagrams found by Wesslau in the case of low pressure polyethylene are a particular case of this kind of plot. The Wesslau, the exponential, and the Beasley distribution formulas have been considered, and curves and tabulated values are given to be used when the fractionation and viscometry data of polymers having these distributions are to be expressed in those coordinate systems in which they are represented by straight lines (or by lines tending toward linearity). Certin analytical features of the Wesslau distribution, compared with the other distributions, may suggest some considerations about the mechanism of synthesis of polymers similar, from this point of view, to low pressure polyethylene.
Polymerization of some fluorine‐containing olefin oxides
Authors: Jones F. B. , Stickney P. B. , Coleman L. E. , Rausch D. A. , Lovelace A. M. 
Published: April 2003

AbstractThe polymerization characteristics of six different fluorinated olefin oxides have been studied. The initial effort in this work was on the homopolymerization of 1,1,1‐trifluoro‐2,3‐butylene oxide. Attempts to polymerize this material have been made by mass polymerization over a broad temperature range using a number of different compounds as potential polymerization catalysts. Among these compounds were FeCl3, FeCl3 · 6H2O, AlCl3, a BF3‐etherate complex, KOH, gamma radiation from a cobalt‐60 source, a heterogeneous catalyst formed from aluminum triethyl and TiCl4, and a FeCl3‐propylene oxide complex. All of the polymeric products obtained from these experiments were liquids of a relatively low molecular weight. The highest molecular weight polymers were obtained using FeCl3, AlCl3, and BF3. An attempt was subsequently made to determine the relative polymerizability of other, more highly substituted, fluorinated olefin oxides. These were 1,1,1‐trifluoro‐2,3‐pentylene oxide, 1,1,1‐trifluoro‐2,3‐isopentylene oxide, 1,1,1,2,2,3,3‐heptafluoro‐4,5‐hexylene oxide, 1,1,1,‐2,2,3,3‐heptafluoro‐4,5‐heptylene oxide, and 1,1,1,2,2,3,3‐heptafluoro‐4,5‐isoheptylene oxide. FeCl3 and AlCl3 were found to be effective catalysts for the mass polymerization of these materials to form liquid polymers. It was observed that the tendency to polymerize decreases in this group of compounds as the amount and complexity of substitution on the ethylene oxide nuclcus increases. All of these monomers are less reactive toward polymerization than is trifluorobutylene oxide; as a result, lower molecular weight products were formed in lower yields.
Effect of diluents on fusion temperature of the crystalline regions in plain and tanned cowhide
Authors: Witnauer Lee P. , Fee Jeanne G. 
Published: April 2003

AbstractMelting (shrinkage) phenomena in plain cowhide were investigated by measuring the temperature at which contraction first occurred in specimens containing varying amounts of ethylene glycol, formamide, phenol, and water as diluents. Similar measurements were made on cowhide specimens which had been tanned with formaldehyde and with a vegetable tannin and contained water as the diluent. In all cases the temperature at which contraction first occurred was found to increase as the diluent concentration was decreased in general accord with the theory of melting‐point depression. The melting temperature of the crystallites in undiluted cowhide was found, by extrapolation of the data of each system to zero diluent content to be about 145°C. The melting temperatures of undiluted tanned cowhide, however, depended on the tanning agent employed. A value of 120°C. was obtained for the vegetable‐tanned cowhide, and 151° for formaldehyde‐tanned cowhide. The former value was verified experimentally by direct measurement. This evidence for a decrease in crystallite stability indicates that vegetable tannin acts as a diluent. The observations indicates that tanning reduces the availability of the amorphous regions to diluents either through a type of crosslinking and/or a reduction in the number of active sites. This accounts for the observed elevation of the commonly measured shrinkage temperature of hide specimens after tanning. In addition, the tanning agents can markedly modify the mechanical properties of the amorphous regions by acting as a plasticizer or stiffening agent. The heats of fusion, ΔHu, for cowhide diluted with glycol, formamide, and phenol were 2200, 1600, and 1800 cal./mole, respectively. However, with water as diluent for plain hide, ΔHu was 7200 cal./mole. Similar values were obtained with the tanned hide. Entropies of fusion, ΔSu, for cowhide diluted with glycol, formamide, and phenol (assuming two bonds per residue freed on melting) were 2.6, 1.9, and 2.2 cal./deg./bond, respectively, while for plain hide, vegetable‐tanned hide, and formaldehyde‐tanned hide diluted with water, the values were 8.5, 9.2, and 9.5 cal./deg./bond. In order to bring the entropy values for the water systems into agreement with the other diluent systems it is necessary to assume that eight bonds per residue are freed on melting.
The molecular and crystal structure of cellulose triacetate
Authors: Dulmage W. J. 
Published: April 2003

AbstractAn x‐ray diffraction study has been made of cellulose triacetate II. Small films of highly crystalline triacetate with good fibrous orientation and a fair degree of biaxial orientation have been prepared by repeated rolling at successively higher temperatures between 160 and 215°C. The x‐ray diffraction patterns exhibited several new reflections which made it possible to determine the unit cell. It has been found that cellulose triacetate II has four cellobiose acetate residues in a pseudo‐orthorhombic cell with a = 24.5, b = 11.56, and c = 10.43 A. Pairs of these residues are related by twofold screw axes in the c or fiber‐axis direction. The paired arrangement seems to be determined by a fitting of the natural zigzagging shape of the cellulose backbone which is exaggerated by the presence of the secondary acetyl groups. The glucose residues of such a pair are parallel and inclined at about 45° with respect to the a axis. A neighboring chain pair points in the opposite direction and the median planes of the cellobiose units of two such pairs are approximately mutually perpendicular. To accommodate this type of packing, one half of the primary acetyl groups must be twisted sharply out of the median plane of the parent glucose residues. A second statistical model which basically is very similar is also considered. There do not appear to be any strong interactions between chains.
Anionic polymerization of α‐methylstyrene
Authors: Worsfold D. J. , Bywater S. 
Published: April 2003

AbstractThe polymerization of α‐methylstyrene catalyzed by sodium naphthalene has been studied below 0°. Measurable amounts of monomer remained in equilibrium with the polymer down to −40°, even though the color indicated that active chain ends were still present. This behavior is expected of α‐methylstyrene since, due to a low heat of polymerization, the reverse of the chain propagation step must be important at these temperatures. From the equilibrium monomer concentrations determined experimentally, the heat and entropy of polymerization of α‐methylstyrene has been calculated.
An improvement in the graphic treatment of angular light scattering data
Authors: Yang Jen Tsi 
Published: April 2003

AbstractThe well‐known Zimm plot can be modified by plotting Kc/Rϑ sin2 (ϑ/2) against 1/sin2 (ϑ/2) with concentration c as a parameter, which gives a series of straight lines with a common intercept. By extrapolating to zero concentration one can determine the weight‐average molecular weight from the reciprocal of the slope and the radius of gyration from the common intercept on the ordinate. This method finds applications for macromolecules having very high molecular weights.