bluuebunny/crossref_metadata_2025 huggingface dataset:
Birefringent and rheologic properties of milling yellow suspensions
Authors: Peebles F. N. , Prados J. W. , Honeycutt E. H.
Published: June 2010

Aqueous suspensions of Milling Yellow dye have been found to lie useful for engineering flaw studies by employing established birefringent techniques. In the present work, the basic birefringent and rheologic properties of Milling Yellow suspensions wore measured for a range of deformation rates important to the engineering applications. A concentric‐cylinder polariscope was used to measure the amount of birefringence and the angle of extinction for ten Milling Yellow suspensions at 25°C. varying in concentration from 1.25 to 1.46% dye by weight. The optical properties exhibited by these suspensions are similar to those of a number of colloidal suspensions as reported by past investigators. Rheologic data for Milling Yellow suspensions in the same concentration range were measured at 25°C. for deformation rates of 50–10 sec.−1 by means of a capillary viscometer. Over the complete range of deformation rates the rheologic data are accurately described with the Powell‐Eyring relationship for pseudo‐plastic materials.
On phenomenological rheo‐optic constitutive relations
Authors: Dill Ellis Harold
Published: June 2010

The birefringence exhibited by high polymers can be explained by considering light as an electromagnetic wave propagating through an anisotropic dielectric. The observed dependence of the birefringence on the deformation stale is described by expressing the dielectric tensor as a functional of the strain history. For small strains, the functional can be approximated by an integral so that the birefringence and strain are related by a law of the Boltzmann superposition integral form.
Studies of rates of spherulite deformation by low‐angle light scattering
Authors: Erhardt Peter , Sasaguri K. , Stein R. S.
Published: June 2010

The rates of spherulite deformation accompanying the elongation and contraction of polyethylene and the elongation of polybutene‐1 samples have been observed using a low‐angle light scattering technique. The light scattering pattern is obtained using a ruby pulsed laser which is flashed a predetermined time after the extension of the sample. It is found that spherulite deformation occurs in times less than 40 msec. which is less than the time required for the birefringence increase following deformation. Upon retraction, the light scattering pattern becomes symmetrical before the sample length has returned to its initial value. With quenched polybutene‐1, the rapid change in shape of the tight scattering pattern is accompanied by a slower change in intensity occurring over times comparable with that for the birefringence change. This is associated with changes in the crystal structure, orientation, and density within the spherulite following deformation.
Differential thermal analysis of polybutene‐1
Authors: Clampitt Bert H. , Hughes Richard H.
Published: June 2010

The three polymorphic forms of polybutone‐1 may be easily characterized by DTA: Form I has a DTA peak near 132°C; Form II has a peak near 118°C; and Form III has doublet peaks at 104° and 118°C. The kinetics of the room temperature transformation of Form II to Form I have been qualitatively investigated by DTA. The results indicate: (1) the thinner the film the faster the conversion rate and (2) the greater the catalysis residue in the system, the faster the conversion to Form I. The doublet in the Form III thermogram is due to the fact that the 104°C. transition corresponds to a phase change III to II with the 118°C. transition merely being the normal melting transition of Form II. Indeed, it is possible to heat Form III polybutene to 110°C, quench; and on standing it is found that the product has reverted to Form I.
Specific heat of synthetic high polymers. XL the glass transition in isotactic polypropylene
Authors: Abu‐Isa Ismat , Crawford V. A. , Haly A. R. , Dole Malcolm
Published: June 2010

The specific heat of various samples of isotactic polypropylene has been measured over the glass transition range from 230 to 310°K. A glass transition has been found, the magnitude of which is roughly proportional to the amorphous content of the sample. In highly crystalline samples the rise in cp with temperature over the glass transition range is probably partly caused by an increase in the number of modes of vibration that become active in this temperature range. A new thermodynamic name, the encraty, has been given to the function cp/T (equals (dS/dT)p or ‐ d2G/dT2). The encraty is abnormally low for quenched isotactic polypropylene for masons for which speculations only can be given at this time. Negative temperature drifts were observed below about 270°K.
Determination of free carbonyl and unbound water in polyacrolein by infrared spectrometry
Authors: Forbes J. W. , Schissler D. O.
Published: June 2010

The determinations of free carbonyl and unbound water contents of polyacrolein samples by standard chemical methods are not feasible because of labile hydration‐dehydration equilibria. The conditions used in the chemical determinations of carbonyl and water lead to quantitative dehydration and therefore always yield values of total carbonyl and total water content. An infrared method for the determination of free carbonyl and unbound water has been developed in which these labile equilibria are not perturbed. Polyacrolein, an insoluble and infusible substance, required the development, of a quantitative spectroscopic technique applicable to powdered solid samples. KBr pressed plate techniques are not applicable because they introduce the serious problem of water contamination inherent with the KBr methods. Free carbonyl and unbound water in polyacrolein have characteristic infrared absorption bands. The absorptivities of these bands were determined by appropriate standards. The method developed consists of spectroscopic examination of sample‐Fluorolube emulsions in fixed path infrared cells. The free carbonyl and the unbound water contents are then calculated as if the emulsion were a true solution of known concentration. The absorption due to the water bending mode at ∼6.1 μ is used for the calculation of the free water content, and the absorption due to the C=O stretching mode at ∼5.83 μ is used as a measure of the free carbonyl. An alternate method of analysis was developed after determining an absorptivity for the CH2 bending mode in polyacrolein and using this band as an internal reference.
Large‐scale elution fractionation of polymers
Authors: Kenyon A. S. , Salyer I. O. , Kurz J. E. , Brown D. R.
Published: June 2010

Fractionation of polymers is usually done on a very small scale where only viscosity, and possibly molecular weight measurement are made on the fractions. The elution fractionation system offers a possibility of fractionating on a sufficiently large scale to permit a thorough study of physical properties as a function of molecular weight. The elution column method was scaled up to fractionate one pound of polymer. Facilities were made so that the column could operate over a temperature range of 25 to 135°C. Each fraction was eluted by a separate solvent‐non‐solvent, mixture. The elution column was packed with Celite and the flow of the solvent‐non‐solvent mixture was controlled by a pumping system. Total fractionation time was 20 hours. The column temperature could be controlled to permit any temperature heating or cooling profile. The large scale elution column has been used to fractionate low and high density polyethylenes, ethylene copolymers, and polybutene‐1. Sufficient amount of polymer was obtained in each fraction to permit a study of mechanical properties as a function of molecular weight. From these fractions the effect of synthesized bimodal distributions on the melt flow and physical properties was investigated.
Transport through polymer membranes with a gradient of inhomogeneity
Authors: Rogers C. E.
Published: June 2010

Polyethylene membranes with a gradient of graft copolymer and structural composition from one surface to the other have been prepared by radiation‐initiated polymerization of sorbed monomer. The monomer is distributed in a concentration gradient across the film during permeation through the film. Transport of low molecular weight solvent vapors through the graded films proceeds at different rates dependent on the direction of flow relative to the gradient of polymer composition. The magnitude and, in some cases, the direction of this differential transport effect are very sensitive to the method of preparation of the membrane.
Degradation by mechanical action as a means of studying cellulose‐water interaction
Authors: Leopold B. , Fujii J. S.
Published: June 2010

A number of samples containing varying amounts of lignin, xylan, and glucomannan were prepared from spruce wood and subjected to vibratory ball‐milling m water, methanol, and benzene. The results support the idea that the main factor determining the extent of cellulose degradation by mechanical action is the plasticity of the substrate It was found that the presence of lignin greatly increases the extent of degradation probably as a result of mechanical restriction of the deformability of the system. On the other hand, glucomannan reduces the extent of degradation, while xylan has little or no effect. This is believed to be due to the location of part of the glucomannan inside the microfibril, where it is able to facilitate the penetration of water. Xylan is located on the outside of the fibril where a similar effect could not occur. It m also shown that the moisture regain of the samples varies with the hemicellulose content, but that the contribution of the glucomannan is less than that of the xylan This indicates that the mobility of the glucomannan molecule is restricted, presumably by its close association with the cellulose in the microfibril.
Quantitative studies of ringed spherulite deformation in polyethylene films
Authors: Moore Robert S. , Gieniewski Chester
Published: June 2010

Creep and creep recovery experiments were carried out on films of linear polyethylene containing ringed spherulites. Photographic light‐scattering patterns obtained during the experiments from the rings and spherulites were analyzed to determine the quotient of the extension ratio in the direction of stress to that at right angles to the stress direction, Xy/γz. Comparison with results derived from mechanical strain measurements indicated stronger time dependencies of creep and creep recovery as measured by light scattering than as determined from mechanical strain measurements for a sample of Marlex 6035 crystallized at 105°C. The results arc interpreted in terms of a model of spherulite response which incorporates chain tilting. The probable dependence of the deformation process on the crystallization conditions and the type of deformation experiment is pointed out.
Multiple phase transitions of polybutene‐1
Authors: Geacintov C. , Miles R. B. , Schuubmans H. J. L.
Published: June 2010

Multiple phase transitions of polybutene‐1 in the form III modification have recently been the subject of discussion by a number of authors. The exact nature of the observed phenomena has remained in doubt, leading to the proposal of divergent theories. Differential thermal analyses and x‐ray diffraction studies of polybutene‐1 in the form III modifications have shown that the nature of the phase transformations is a function of the heating rate. At very slow heating rates (1°C./day), an apparent form III to form I' crystal‐crystal transformation, believed to be related to a thermodynamic “selection” process, has been observed. At faster heating rates (0.2–0.3°C./min.), only part of the form III modification is able to undergo the transformation to form I' the remainder undergoes a melting transition at 96°C, followed by immediate recrystallization to form II. The form I' generated in this process melts at 100°C, and also recrystallizes to the form II modification. At very fast heating rates (20–50°C./min.), form III melts at 96°C, failing to recrystallize.
Theory of relaxation phenomena associated with the molecular motion in polymer crystals
Authors: Okano Koji
Published: June 2010

A theory of the relaxation phenomena associated with the molecular motion in polymer crystals (the so‐called crystalline relaxation) developed by the author is outlined. These relaxation phenomena are considered to arise from the viscous interaction between polymer chains in crystals due to the incoherent lattice vibrations. Based upon the equilibrium theory of the stability of polymer crystals developed by Peterlin et al., a semi‐quantitative theory of crystalline relaxation is given. The main conclusion reached is that the relaxation strength and the relaxation times depend strongly upon the thickness of platelike single crystals or lamellae. The experimental facts known so far agree, al least qualitatively, with the theory.
Relaxations in crystalline, paracrystalline, and glassy phases in polymers
Authors: Wada Yasaku , Tsuge Kenji , Arisawa Kunio , Ohzawa Yoshiyuki , Shida Ken‐Ichi , Hotta Yasuko , Hayakawa Reinosuke , Nishi Toshio
Published: June 2010

Mechanical and dielectric relaxations in crystalline phase (crystalline relaxation), glassy phase (local mode relaxation), and paracrystalline phase (paracrystalline relaxation) are interpreted in terms of torsional motion of chains in respective phases. A theory is developed on the relaxation strength, and a satisfactory agreement is found between theory and experiment for mechanical crystalline relaxations in normal paraffins. Dielectric crystalline relaxations in oxidized paraffins, poly(vinyl alcohol), and polyoxymethylene, dielectric paracrystalline relaxation in polyacrylonitrile, and local mode relaxations in several polymers are studied both experimentally and theoretically.
Deformation mechanism of polyethylene spherulite at elevated temperatures near crystal‐disordering temperature
Authors: Oda Takashi , Sakaguchi Nobuhiro , Kawai Hiromichi
Published: June 2010

The effects of temperature upon the orientation behavior of polyethylene crystallites during stretching of the bulk polymer have been measured by means of the x‐ray diffraction technique and interpreted in terms of the deformation mechanism of polyethylene spherulites. With increase of the stretching temperature, especially beyond the crystal‐disordering temperature, the crystal rotation around the crystal a axis probably due to the shearing deformation of crystal lamella along the (001) plane is promoted while the crystal rotation around the crystal b axis due to the untwisting of crystal lamella, is depressed, and the spherulite deformation may be represented by such a fashion as decreasing the number of shells in Wilchinsky's multiple concentric shell structure.
Dynamic viscoelastic properties of dilute polymer solutions
Authors: Tanaka Hidejiro , Sakanishi Akio , Kaneko Motozo , Furuichi Jiro
Published: June 2010

The intrinsic rigidities and the dynamic intrinsic viscosities have been determined from the high‐frequency measurements of viscoelastic properties of dilute solutions in which polymer molecules possess different conformations. Corresponding to them, the limiting relaxation times have been obtained from the steady‐flow viscosity measurements of the same solutions. Data are quantitatively compared with the molecular theories of viscoelasticities of dilute polymer solutions through normalized dispersion curves. Results for polyisobutylene in benzene at theta temperature agree with the Zimm theory (nondraining case) and in cyclohexane (good solvent) are intermediate between the House and the Zimm theory (partially freedraining). It appears that draining effects have some correlation with excluded volume effects. Concentration dependence of complex rigidities also shows correlation with chain expansion, and this phenomenon is due to interchain interaction. Results for poly‐γ‐methyl‐D‐glutamate and poly‐γ‐benzyl‐I‐glutamate in helix solvents show qualitative agreement with the Kirkwood‐Auer theory for rodlike polymers. Preliminary observations for D,L‐copoly‐γ‐bennyl glutamate in dioxane indicate some difference from the above results.
Plastic deformation of polyethylene. Mechanism and properties
Authors: Peterlin A.
Published: June 2010

Studies of single‐crystal deformation explain the small‐ and wide‐angle x‐ray observations of the cold drawing of PE, particularly the effects in the necking zone where the original spherulitic structure is transformed into a highly aligned fiber structure. Whole blocks of folded chains are broken out of the original crystals, which have undergone a substantial deformation by phase transformation, twinning, chain tilting, and slip, and are incorporated in the new fiber structure. The latter contains a great many highly strained tie molecules with an entropy and heat content lower than in a completely relaxed supercooled liquid. Melting experiments yield the heat content reduction which is a consequence of more extended chain conformation (intramolecular energy) and of closer chain packing (intermolecular energy). The entropy and enthalpy reduction explains the drastic decrease of sorption and diffusion of solvents first observed in wide‐line NMR experiments. Annealing at sufficiently high temperature (118°C.) lets the sample relax nearly instantaneously. The long period, heat content, diffusion, and sorption assume values corresponding to the temperature of annealing. If the plastic deformation is performed at so high a temperature that annealing effects are not more negligible (hot drawing), the drawn sample still consists of highly oriented crystals but the molecules in the amorphous regions are rather relaxed so that their density, entropy, and heat content do not appreciably differ from the values of a supercooled liquid.
Crystallization Kinetics of Polycarbonates in Solutions
Authors: Luňák S. , Bohdanecký M.
Published: June 2010

The crystallization kinetics in solutions of polycarbonates were studied in three mixed solvents at the critical solvent‐nonsolvent ratio. The dependence of the crystallization rate on the polymer concentration and molecular weight, on the temperature, and the chemical character of the solvent‐nonsolvent mixture was established. Some consequences were deduced for the precipitation fractionation.
Catalysis of the Propagation Reaction in Ziegler‐Natta Polymerization
Authors: Veselý K. , Ambrož J. , Mejzlík J. , Spousta E.
Published: June 2010

The results on the catalytic action of counterions of homogeneous ionic polymerizations are reviewed. By analogy, positively charged counterious play an important role in the heterogeneous system TiCl3–AlR3. This is illustrated by the influence of “defects” in the TiCl3 on the course of a given reaction. Counterions of different structures act in the polymerization as centers of different stereospecificity.
Zur Temperaturabhängigkeit der elektrischen Durchschlagfestigkeit amorpher Polymeren mil Relaxation unter der Glastemperatur
Authors: Artbauer J.
Published: June 2010

Analysis of the conditions for electric breakdown in amorphous polymers indicates that the reduction of electric strength with increasing temperature is due to molecular relaxation processes and change of the free volume. To verify this conclusion in the case of polymers with relaxation below the glass temperature Tg, the breakdown strength of a weakly plasticized polyvinyl chloride was measured in the neighborhood of Tg. The electric strength diminishes below Tg already; at Tg it begins to fall more rapidly. A change of Tg attained by altering the degree of plastification resulted in a corresponding shift of the point, where the breakdown strength–temperature curve begins to fall more steeply. These results agree essentially with the conclusions of the theoretical reasonings, in which the relaxation processes and free volume play a decisive part.
Diffusion of Polyisobutylene in Very Dilute Solutions
Authors: Porsch B. , Kubín M.
Published: June 2010

The diffusion of polyisobutylene in very dilute solutions was investigated. With the interferometric method used the maximum error in D was 2%. Diffusion coefficients of the fractions were measured as a function of molecular weight and concentration down to 0.02 g./dl. The hydrodynamical parameters of the coil were determined. A comparison of molecular weights of fractions measured by light scattering and computed from intrinsic viscosity and D was given. It was possible to characterize the polydispersity of polymers on the basis of diffusion measurements.
Micromethod for Estimation of the Degree of Crosslinking in Elastomers from Compression Modulus of Swollen Vulcanizates
Authors: Smith Derek A.
Published: June 2010

The method uses small specimens (of volume less than 0.1 cc.) which swell to diffusion equilibrium in hydrocarbon solvents within 8 hr. Measurements of deflection to better than 1 μ are made with a modified Wallace microhardness tester, which is described. The name “reticulometer” is proposed for this instrument. Using peroxide‐crosslinked natural rubbers swollen to equilibrium vr values of about 0.23 in n‐decane or in benzene, values for the concentration of physically active network chains determined by the present method were not greatly different from those determined by conventional “equilibrium” streus‐strain measurements in tension on the same samples. Detailed differences are discussed. The chief advantages of the microcompression method are: (a) the use of small samples of shape and size convenient for carrying out other conventional measurements of network chain density; (b) the rapid attainment of diffusion equilibrium encouraging the use of fully swollen specimens and minimizing the risk of inhomogeneous distribution of swelling agent; and (c) the rapidity of testing compared with tension measurements.
The thermodynamic properties of solutions of polystyrene and of low molecular weight model compounds
Authors: Pouchlý J. , Biroš J. , Šlc K. , Vondrejsová J.
Published: June 2010

Binary mixtures of polystyrene, two low molecular weight model compounds, ethyl‐benzene and 1,3‐diphenylbutane, and benzene have been studied. The mixing parameters of these systems have been determined by calorimetry, pyenometry, and osmometry, and by measurement of vapor pressures and degrees of swelling. The results correspond qualitatively to predictions from the cell theory and from theories based on the theorem of corresponding states. The enthalpy, entropy, and volume of mixing are more negative in the homologous series for a greater difference in the molecular sizes of the components; the free enthalpy of mixing, however, becomes less negative and thus the x parameter increases. Several equations, useful in evaluating the mixing parameters according to the new Flory et al.11,12 theory have been derived. The values of the interaction parameter x12 have been calculated by means of these, and it has been found that the theory represents the measured data semiquantitatively.
Crystal structures of some isotactic hydrocarbon polymers
Authors: Noether H. D.
Published: June 2010

Unit cell dimensions for several new isotactic polyhydrocarbons have been determined: Poly(vinyl cyclohexane)II, tetragonal, a = 20.48 A., c = 44.58 A., 247 helix; poly(vinyl cyclopentane); I: tetragonal, a = 20.14 A., c = 6.50 A., 41 helix; II: tetragonal, a = 20.11 A., c = 19.5 A., 123 helix; III: tetragonal, a = 37.3 A., c = 19.8 A., 103 helix; poly(vinyl cycloheptane): tetragonal, a = 23.4–23.5 A., c = 6.5 A., 41 helix; poly(vinyl cyclobutane): tetragonal, a = 34.1 A., c = 6.6 A., 41 helix; poly(3‐methyl butene), tetragonal, a = 34.3 A., c = 6.85 A., 41 helix, poly(allyl cyclopentane): tetragonal, a = 20.34 A., c = 47.49 A., 247 helix; poly(allyl cyclohexane): I: tetragonal a = 21.06 A., c = 20.09 A., 103 helix; II: hexagonal, a = 19.12 A., c = 6.33 A., 31 helix; poly(metamethyl styrene): tetragonal, a = 19.9 A., c = 78.9 A., 4011 helix; poly(4,4‐dimethyl pentene): tetragonal, a = 20.3 A., c = 13.8 A., 72 helix. Analysis of above unit cell data and those of the published literature seems to indicate that only 31 type helices can be accommodated in the hexagonal system, while the other isotactic structures between 3 and 4 monomers per turn crystallize in the tetragonal or orthorhombic systems. The various possibilities of expanding the central helix by varying the diameter and the pitch in order to satisfy the space requirement of the substituting side groups are discussed.
On some kinetic aspects of solid‐state polymerization
Authors: Papissov I. M. , Kabanov V. A. , Papissov I. M. , Kabanov V. A.
Published: June 2010

Solid‐state polymerization is considered as an irreversible phase transition of monomer erystals into polymer. The theoretical relationship between critical size of the polymer nucleus in a monomer crystal and single macromolecule dimensions is obtained on the assumption that the polymer nucleus formed by closely packed extended macromolecules has a cylindrical shape. By using this relationship it is shown that in some cases the growing of a single chain in a monomer crystal could be thermodynamically unfavorable. In such cases one should expect the propagation of bundles of macromolecules. Processes of this kind are characterized by a slow nucleation rate and autocatalytic acceleration at the polymer‐monomer interphase. At the same time it is supposed that in the course of irradiation of single macromolecules could instantly grow in some “hot” regions of a monomer crystal. If the “critical” nucleus has to contain more than one macromolecule, the “cooling off” of these regions should be followed with quenching of thermodynamically unstable single polymer chains, which then could be depolymerized under irradiation or annealed. This consideration is used to explain some cases of low limit conversions into polymer observed for a number of crystalline monomers.
Orientation and deformation of polystyrene molecules in a hydrodynamic field
Authors: Munk P. , Poupětová D. , Bohdanecký M. , Dillingerová M.
Published: June 2010

Flow birefringence and gradient viscometry methods have been used to measure several fractions of high molecular weight polystyrene in several solvents of different viscosity, but with virtually the same refractive index as polystyrene. The stress‐optical law, Zimm's and Peterlin's theories of orientation and deformation of the macro‐molecular coil, and Peterlin's theory of the influence of concentration on the hydrodynamic behavior of a polymer have been verified. The results of these tests are discussed from the viewpoint of anisotropy, of the intramolecular as well as intermolecular hydrodynamic interaction.
Modification of poly(vinyl alcohol) by heat in the presence of chromium compounds
Authors: Duncalf B. , Dunn A. S.
Published: June 2010

Films of poly(vinyl alcohol) containing 20 mole‐% residual acetate groups are readily soluble in cold water. Films heated to temperatures above 170°C. crystallize and become insoluble in water although they are swollen by it. Heating to temperatures above 240°C. produces films which are no longer swollen by water. Thermogravimetry shows that there is no extensive decomposition below 270°C., but differential thermal analysis reveals a strongly exothermic reaction in this temperature range. It is believed that a crosslinking reaction occurs in the 240‐270°C. range.
Polymerization of certain vinyl monomers in liquid crystals
Authors: Amerik Y. B. , Krentsel B. A.
Published: June 2010

While studying the phase transition of vinyl oleate, it was proven that vinyl oleate possesses the liquid crystal state. The radiation‐induced polymerization of vinyl oleate was carried out in liquid, liquid crystalline, and solid states. The presence of double bonds in substitution causes very slow polymerization of vinyl oleate in comparison with other vinyl ester of saturated fatty acids. The structure of forming polymer greatly depends on the phase state of the monomer in the process of polymerization. In liquidphase polymerization, the transparent polymer was generated and it was an isotropic, viscous liquid. If the polymerization was done in liquid crystal or crystal state, the crystalline polymer was obtained. The melting point of this polymer t = 34‐38°C. The considerable mobility of chains in poly(vinyl oleate) crystal, the inability to keep its form, and data from x‐ray patterns permitted us to consider its state as a liquid crystalline one.
Penetration and replacement of polyvinylpyridine layers adsorbed on a mercury surface by fatty alcohols
Authors: Miller Israel R.
Published: June 2010

Information on the structure of the adsorbed layer of polyvinylpyridine (PVP) was obtained by letting it compete for the surface sites with fatty alcohols, e.g., hexanol, amyl alcohol, octanol. The surface occupancy by either vinylpyridine residues or by the alcohols was obtained from differential capacity measurements. Below a threshold concentration of the fatty alcohol, which is a function of its standard free energy of adsorption, it does not displace the vinylpyridine from the surface at any potential. It penetrates, however, the loopholes left on the mercury surface by the adsorbed polyelectrolyte coil and provides a means for a determination of the loophole area. At higher concentrations the fatty alcohols start replacing the vinylpyridine residues in the surface over potential spans, which increase with alcohol concentration. The replacement process does not depend on polymer concentration but merely on the internal concentration of the residues in a polymer molecule near the surface. For evaluation of the concentration of the residues in the polymer similar competition experiments between fatty alcohols and ethylpyridine which is the monomeric analogon of PVP were carried out.
Inorganic polymers. Part III. The polymerization of P‐phenyl‐N,N′‐disubstituted phosphonic diamides
Authors: Shaw R. A. , Ogawa Takeshi
Published: June 2010

The thermal bulk condensation polymerization of a series of P‐phenyl‐N,N'‐disubstituted phosphonic diamides, PhP(O)(NHR)2, (R = Me, Et, Prn, Pri, Bua, Bui, Bus, But, eyclohexyl, or Ph) has been investigated. The relationships among the number average degree of polymerization, the substituents R, and the polymerixation times have been studied. For two of these diamides (R = Ph or eyclohexyl) only dimers were obtained. For the others, polymeric materials of number‐average molecular weights in the range 500‐1300 could be obtained. Attempts to use the cyclic dimer [PhP(O)NPh]2 as starting material for ring‐opening polymerizations were unsuccessful. The mechanisms of the polymerization reactions are discussed.
The effect of temperature on the cationic isomerization polymerization of 3‐methyl‐1‐butene and 3‐chloro‐3‐methyl‐l‐butene
Authors: Kennedy J. P. , Squires R. G.
Published: June 2010

The effect of temperature on the molecular weight and product structure of poly(3‐methyl‐1‐butene) and poly(3‐chloro‐3‐methyl‐l‐butene) obtained with A1C13 catalyst in ethyl chloride solvent in the temperature range from +10 to −130°C. has been investigated. The plot of the logarithm of molecular weights versus reciprocal temperature for poly(3‐methyl‐l‐butene) is linear between +10 and −80°C. (ΔEDP = −2.5 kcal./ mole). At about −80°C. there is a change in the mechanism and the curve assumes a lesser slope in the range from −100 to −130°C. (ΔEDP = −0.35 kcal./mole). The structure ratio P1.3p1.2 of the polymer, i.e., the ratio of the number of 1,3 enchainments in the polymer to the number of 1,2 units, is also a linear function of the reciprocal temperature in the range from +10 to about −100°C. At −100°C. there is a break in the linearity and the slope increases sharply indicating the formation of large amounts of 1,3 units. The structure ratio of poly(3‐chloro‐3‐methyl‐l‐butene) is also linear but it is only little affected by the temperature in the −30 to −130°C. range. A possible explanation for these findings is offered and differences between chlorine‐containing and hydrocarbon carbonium ions are discussed.
Solid‐state polymerization of styrene oxide and propylene oxide by high‐energy radiation
Authors: Tabata Yoneho , Sobue Hiroshi
Published: June 2010

Radiation‐induced polymerizations of styrene oxide and propylene oxide were carried out by using electrons from a Van de Graaff generator in the liquid and solid states of the monomers. It was found from the experiments that styrene oxide is polymerizable in both liquid and solid states; on the other hand, propylene oxide can be polymerized in the solid state only in the presence of styrene oxide. It was suggested that the chain transfer and isomerization reactions are rapid and play an important role in the polymerization of styrene oxide. Because polymerization of propylene oxide in bulk in the liquid and solid states is not possible, it may be suggested that the polymerization proceeds in an amorphous monomer phase or in a crystalline phase which is modified by the addition of styrene oxide.
Effect of pressure on radiation‐induced solid‐state polymerization of methacrylonitrile
Authors: Suzuki Toshihiko , Tabata Yoneho , Oshima Keichi
Published: June 2010

The effect of pressure up to 5000 atm. on the solid‐state polymerization of methacrylonitrile at low temperature was investigated. It was found that the rate of polymerization is always suppressed by pressure in the solid state at low temperatures, −43, −78, and −196°C. In polymerization at −78°C. the number of polymers is less at 5000 atm. than at 1 atm. while the molecular weight is clearly larger at 5000 atm. than at 1 atm. On the other hand, there is not such a large difference in the number of polymers between 1 and 5000 atm. at −43°C. In contrast with the polymerization at −78°C., the molecular weight is obviously higher at 1 atm. than at 5000 atm. It may be suggested that the pressure effect on the solid‐state polymerization of methacryloni‐trile is not due to the change of the entropy of activation by pressure, but by the change of the enthalpy of activation, except for polymerization at −43°C. under 1 atm.
Adsorption of polystyrene, poly(dimethyl siloxane), and poly(methyl methacrylate) from dilute solution
Authors: Eltekov Yu. A.
Published: June 2010

The polymer adsorption depends upon the character of pore structure and the nature of the adsorbent surface. The comparison of the polystyrene adsorption from the CCl4 solution on macroporous adsorbents with different pore diameters permits one to evaluate the size and shape of polymer macromolecule. A dense monolayer of adsorbed polystyrene macromolecules on the surface of rutile, graphitized carbon black, and aerosil is formed. The poly(dimethyl siloxane) macromolecules are displaced by hexane molecules from the surface of graphitized carbon black.
Some aspects of vapor‐induced crystallization of polycarbonate of bisphenol A
Authors: Mercier J. P. , Groeninckx G. , Lesne M.
Published: June 2010

A method is presented to crystallize polycarbonate of bisphenol A under constant vapor pressure of solvents at near ambient temperatures. Methylene chloride and acetone were used as crystallizing liquids. Acetone is more powerful in inducing crystallization but the final degree of crystallinity does not depend on the nature of the solvent. The crystalline degree is low as found in the literature for this polymer. This method is very useful to crystallize materials reluctant to thermally induced crystallization such as polycarbonate.
Macromolecular products of the reaction of ethylenimine with imides
Authors: Grundschober F. , Sambeth J.
Published: June 2010

The reaction of ethylenimine with unsubstituted and substituted imides of carboxylic acids has been investigated. The formation of macromolecular substances occurring by the opening of the rings of the reaction partners was observed. Depending on the conditions of reaction, either linear or crosslinked products containing amide, or amide and amine linkages, respectively, were obtained. When unsubstituted or substituted maleimides were used, monomeric aziridinylsuccinimides with great reactivity were obtained and were easily transformed into insoluble and infusible crosslinked resins. The mechanisms of the various polyaddition reactions are discussed, and the properties of the macromolecular products obtained are reported.
Stereoregularity of poly(methacrylic acid esters)
Authors: Matsuzaki K. , Ishida A. , Tateno N. , Matsuzaki Kei , Ishida Akira , Tateno Noriaki
Published: June 2010

l‐Menthyl methacrylate (l‐MnMA) and dl‐MnMA and their mixtures were poly merized with benzoyl peroxide (BPO), phenylmagnesium bromide (PhMgBr), and lithium aluminum hydride (LiAlH4), as catalyst. The isotacticity of the polymers of dl‐MnMA polymerized with PhMgBr was independent of the polymerization temperature and low. The tacticity of the polymers from the mixtures of l‐ and dl‐MnMA's polymerized with BPO hardly changed with monomer compositions, while that with LiAlH4 showed increase with the increase of l‐monomer contents. Thechange of the optical activity of PMnMA's with the stereoregularity is slight as compared with large variation of the tacticity of the polymers. Although both in radical and anionic polymerizations preference of one monomer to another monomer does not occur, in isotactic polymerization with LiAlH4 asymmetric induction of menthyl groups on the main chain configurations takes place. The tacticities of some poly(methacrylic acid esters) polymerized with PhMgBr under similar conditions were compared.
Degradation of polyphosphates in solution. III. Hydrolysis of linear long‐chain sodium polyphosphate
Authors: Strauss Ulrich P. , Krol George J.
Published: June 2010

Three samples of sodium polyphosphate (DP ≈ 30, 75, and 170) were degraded at pH 5 and 65.5°C., and specific rate constants for individual processes were determined. The first‐order rate constant for the formation of orthophosphate from endgroups was independent of chain length and about 50 times as large as the rate constant for the chain scission per interior phosphate group. The latter rate appeared to increase with increasing DP. The formation of trimetaphosphate was more than 10 times as fast at a given chain end than at a given middle group. Assuming that the reaction at the chain ends was independent of DP, the specific rate for the formation of trimetaphosphate from middle groups increased with DP also.
Infrared spectrum and structure of poly[3,3‐bis(chloromethyl)oxacyclobutane]
Authors: Enomoto S. , Opaskar C. G. , Krimm S.
Published: June 2010

Poly[3,3‐bis(chloromethyl)oxacyclobutane] is known to occur in two crystal forms, α and β, which exhibit the same fiber axis identity period but different unit cell cross‐sections. To test if these differences might be due to differences in conformation of the —CH2Cl side chains, normal coordinate calculations were carried out for the three possible isomeric structures: trans‐trans, trans‐gauche, and gauche‐gauche. It was found that the bands in the infrared spectrum could be assigned to frequencies of these three isomers. Furthermore, this correlation suggests that the α form is associated with the gauche‐gauche isomer, while the β form is associated with the trans‐trans isomer. The proportion of trans‐gauche isomer increases when the polymer is melted.
The role of free ions in reactions of olefins with soluble complex catalysts
Authors: Dyachkovskii F. S. , Shilova A. K. , Shilov A. E.
Published: June 2010

It was found that in the homogeneous catalytic system (C5H5)2TiCl2 + Al(CH3)2Cl the catalytic activity is due to the presence of free ions, presumably (C5H5)TiCH3 formed in the equilibrium: (C5H5)2TiCH3Cl. AlCH3Cl2 ⇄ (C5H5)2Ti+CH3 + Al(CH3) Cl3 ‐ Further evidence for the suggested mechanism has been found. By means of electrodialysis the formation of positive ions containing Ti was shown. Catalytic activity appears only in the presense of the latter. The increased cataivtiy activity in comparatively polar solvents (CH2Cl2, C2H4Cl2) is connected with the increased number of the ions. The linear dependence of log k (k is the rate constant of the reaction of free ion with an olefin) with 1/D (D is the dielectric constant) was found in five different solvents and their mixtures.
Dynamic‐mechanical analysis of olefin polymers
Authors: Tuijnman C. A. F.
Published: June 2010

The shape of the dynamic moduli vs. temperature curves of polymers fundamentally depends on the temperature dependence of the relaxational properties of the polymers. When the frequency dependence of the reduced loss modulus is represented by an empirical function describing the dispersion peak, the distribution of the relaxation times and the storage modulus vs. frequency curve corresponding to that peak can be calculated. The temperature dependence of the reduced moduli can then be expressed as a function of the activation energy of the relaxation process and of a single parameter describing the width of the relaxational distribution function. This analysis is useful for a better understanding of the loss modulus vs. temperature spectrum and is applied to a linear polyethylene. Furthermore, a discussion is given of the differences in the spectra of linear polyethylenes and polypropylenes, mixtures of polyethylene and polypropylene, and copolymers of ethylene and propylene. When ethylene is randomly built into a polypropylene chain, the β‐transition of polypropylene is shifted to lower temperatures over a distance which is determined by the ethylene content. No shift is observed in mixtures of polyethylene and polypropylene. Here, the β‐peak of the loss modulus vs. temperature spectrum is only lowered and its height is a measure of the amount of amorphous polypropylene. The height of the loss modulus in the α‐region is determined by the total fraction of crystalline material in the mixture, the height of the γ‐peak is proportional to the ethylene content. The loss modulus spectrum can, to a large extent, be used for distinguishing between these different polymers.
On the theory of thermal diffusion in dilute polymer solutions
Authors: Khazanovich T. N.
Published: June 2010

The thermal diffusion coefficient in highly diluted polymer solutions is calculated. The pearl necklace model is used for description of flexible macromolecule dynamics. It is assumed that the usual diffusion equation holds under non‐uniform temperature conditions, but the coefficients of equation are variables. Free‐draining flexible macromolecules are considered. The thermal diffusion coefficient is found to be proportional to the bead diffusion constant and therefore is controlled by the kinetic flexibility of chain. In accordance with experiment the thermal diffusion coefficient does not depend on molecular weight and concentration. With eq. (9) it is possible to calculate from experimental data the bead diffusion constant and therefore to obtain the kinetic rigidity of the polymer.
Theories of electronic behavior in macromolecular solids
Authors: Pohl Herbert A.
Published: June 2010

Many examples of electronically conducting aperiodic polymeric solids now exist. These supply enough inherent electronic carriers to be classed as semiconductors at laboratory temperatures. Such enhanced electronic conduction arises only in the presence of either (or both) donor‐acceptor action (usually intermolecular), or ekaconjugation (intramolecular). Quantum mechanical and experimental evidence shows that conjugation can be of two types; exhalted or “ekaconjugation” and self‐limited or “rubiconjugation.” These play a strong role in organic conduction. The energetics of carrier origins, the mobilities of carriers, and the effects of morphology and impurity are critically discussed, as well as the relative roles in electrical polarization mechanisms of variously excited electrons such as (a) ground‐state electrons—contributing to normal “electronic” polarizability, (b) Frenkel (or intermolecular) excitons, (c) Mott (or intramolecular) excitons, (d) Von Hippel polarons or “quasi‐bound” electrons, and (e) “free” electrons, i.e., those in the conduction band. Mott excitons and polarons in macromolecular solids can contribute in a new and strong fashion because of the unusual size of the monopoles present in the form of delocalized charges ranging over long molecular regions. This strong type of polarizability, recently observed, is called hyperelectronic polarization.
Band conduction and fluctuations in polymeric semiconductors
Authors: Burgess R. E.
Published: June 2010

The conditions for band conduction to occur in a semiconductor are reviewed in terms of order, bandwidth, effective mass, and momentum relaxation time. The nature of available experimental data and their validity and interpretation are discussed. In particular, the use of polycrystalline material, the effects of injection and trapping and uncertainties in the effective masses of the carriers, and the temperature dependence of the activation energy are considered. The commonly made but arbitrary assumption of intrinsic semiconduction is examined and the implications of the alternative hypothesis of extrinsic conduction are discussed. Detailed attention is devoted to the interpretation of the experimentally accessible parameters: conductivity, Seebeck coefficient, drift mobility, Hall coefficient, magnetoresistance, Dember effect, and possible reasons for incompatibility among these data are suggested. Breakdown mechanisms in high fields are briefly reviewed. The fluctuations of current or voltage in a polymeric semiconductor are discussed theoretically and the implications of the measurements of noise under various conditions are outlined. They may be used to (a) determine marked departure from thermal, elastic, and electrical equilibrium, (b) determine the relaxation times of electron transitions contributing to the conduction mechanism, and (c) indicate the mechanism and response time of the breakdown process in high fields.
The transmission of light by films of crystalline polymers
Authors: Clough S. , Rhodes M. B. , Stein R. S.
Published: June 2010

The transmission of polarized light by films of crystalline polymers depends on the size, shape, orientation, anisotropy, and arrangement of the constituent crystallites. Its measurement as a function of the polarization direction of the incident light and that of the analyzing polarization filter characterizes the structure. This may be readily followed during the crystallization or deformation of the polymer. The transmission depends upon some of the same optical parameters as does the scattering and provides complementary information. The scattering, measured as a function of angle, is capable of providing more information than the transmission but its measurement during rapid processes is more difficult. The utility of these techniques is illustrated for the isothermal crystallization of oriented polyethylene films and for the stress‐induced crystallization of rubber.
Poly(phenylene)triazoles: New thermally stable fibers
Authors: Lilyquist M. R. , Holsten J. R.
Published: June 2010

A chemical cyclocondensation reaction process has been developed to convert the easily prepared poly(phenylene)hydrazide to the corresponding high molecular weight poly‐3,5‐(m‐, p‐phenylene)‐4‐phenyl‐1,2,4‐triazole. Polytriazole fibers have been spun from formic acid solutions utilizing both wet and dry spinning techniques. These fibers develop a high degree of orientation and crystallinity on stretching at temperatures of 300°C. and higher. Such fibers retain approximately 30% of their initial breaking strength at a temperature of 300°C. and are not seriously degraded on exposure to elevated temperatures for prolonged periods. The fiber dimensional stability at temperatures above the glass transition temperature of 260°C. for the amorphous polymer was found to be directly related to the fiber orientation and crystallinity. The ease of fabrication and thermal stability of the phenylene triazole polymer makes this material potentially attractive for other end‐use applications such as films, protective coatings, and electrical insulation.