bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoplastic properties of polyacrolein and its acetals
Authors: Fischer R. F. , Stewart A. T.
Published: April 2003

Free‐radical polyacrolein is an essentially pure head‐to‐tail vinyl polymer which results in its being a poly‐ 1,5‐dicarbonyl compound. The proximity of these carbonyl groups results in a partial cyclization (laddering) in the polymer or in its derivatives, which in turn has about the same effect on modulus as adding methyl groups to the backbone chain of a polyacrylate or pendant phenyl groups to the backbone chain of polyethylene. Above a viscosity‐average molecular weight of about 200,000, respectable high polymer properties are attained, comparable to those of poly(methyl methacrylate) or polystyrene with higher heat deflection temperatures. Although thermal properties are sufficient to withstand boiling water, actual water and solvent resistances are marginal to poor.
Glass temperature and crystal modification of linear polymethylene
Authors: Magill J. H. , Pollack S. S. , Wyman D. P.
Published: April 2003

The preparation of high molecular weight linear polymethylene is described at low temperatures. The onset of a polymorphic transformation (triclinic to orthorhombic) is observed on warming this low crystallinity (∼50%) polymer to about −25°C. Relative rates of transformation above this temperature are also given. No significant increase in crystallinity occurs on warming the polymer up to room temperature, where some triclinic phase still persists. Annealing polymethylene at 100°C. leaves only the orthorhombic material which is approximately 80% crystalline. A glass transition temperature around −30°C., is reported for the low crystallinity polymer.
Effect of some additives on the crystalline transformations of polybutene‐1
Authors: Rubin I. D.
Published: April 2003

Differential thermal analysis (DTA) was used to study the effect of α‐chloronaphthalene, diphenyl ether, glycerin, and carbon black on the solid‐state transformation of form II to I and the high‐temperature transition of form III to II of isotactic polybutene‐1. α‐Chloronaphthalene and diphenyl ether greatly accelerated the transition of II to I while glycerin and carbon black had no appreciable effect on it. The differences in the rates are attributed to variations in the ability of the additives to create defects which would aid in the nucleation and, possibly, growth of the new crystalline phase. The DTA thermogram of structure III crystallites normally shows two peaks. The addition of α‐chloronaphthalene and diphenyl ether to structure III crystallites resulted in a DTA thermogram with only one peak. Glycerin and carbon black had no effect on the thermogram. These results are discussed in relation to a possible mechanism for the transformation.
Terpolymers of ethylene and propylene with d‐limonene and β‐pinene
Authors: Magin Ralph W. , Marvel C. S. , Johnson Edward F.
Published: April 2003

An experimental program was undertaken to produce a series of ethylene–propylene terpolymers containing either limonene (dipentene) or β‐pinene from a variety of Ziegler‐Natta type catalysts. All attempts to obtain a satisfactory vulcanizate from the limonene EPT and β‐pinene EPT rubbers were unsuccessful.
Kinetics of reaction of ferricyanide with mercaptan solubilized in polystyrene latex
Authors: Meehan E. J. , Kolthoff I. M. , Tsao M. S.
Published: April 2003

The rate of reaction of ferricyanide with n‐octyl mercaptan solubilized in polystyrene latex has been measured. The mercaptan was dissolved completely in the latex polymer particles before the addition of ferricyanide. The latices were prepared with potassium myristate, sodium tetradecyl sulfate, and dodecylammonium chloride, as surfactants. In each latex the reaction was first‐order to ferricyanide, mercaptan, and hydroxyl ion. The rates in myristate and tetradecyl sulfate latices were approximately equal, but smaller by about five orders of magnitude (extrapolated to the same pH) than the rate in the dodecylammonium chloride latex. The reaction apparently occurs on the surface of the polymer particles and thus is favored in the latex with positively charged particles on the surface of which the ferricyanide is adsorbed as counterion.
Dilute solution properties of polyoctene‐1. Analysis by the kurata‐stockmayer method
Authors: Kinsinger Jack B. , Ballard Larry E.
Published: April 2003

Dilute solution properties of polyoctene‐1 have been measured by light scattering, osmometry, and viscometry and Mark‐Houwink expressions determined in two thermodynamically good solvents and one solvent at the Flory (θ) temperature. The data have been interrelated and analyzed by the Kurata‐Stockmayer technique and are shown to have good correspondence with the theory in some cases and moderately poor in others. However, the data are not sufficiently precise to permit all aspects of the adequacy of such a two‐parameter theory to be judged.
Polymerization of vinylcyclohexane with TiCl3–Al(C2H5)3 catalysts
Authors: McCarty W. H. , Parravano G.
Published: April 2003

The polymerization of vinylcyclohexane was followed dilatometrically in cyclohexane and n‐heptane solvents with TiCl3–Al(C2H5)3 as catalyst. In n‐heptane constant rates were obtained, while in cyclohexane a slow change of the initial rate to a lower steady‐state value was found. Polymerization rates were first order to [TiCl3] and [monomer] for concentrations >0.80 mole/l., and second order for monomer concentrations <0.80 mole/l. The rate was highest at [Al(C2H5)3] 0.005 mole/l. (Al/Ti = 0.28). Polymer intrinsic viscosity increased with time, with increasing monomer concentration, and with decreasing temperature. It was independent of [Al(C2H5)3]. A kinetic model which can account for these observations involves the alkylation of the TiCl3 surface by reaction with Al(C2H5)3 as the site‐generating step. It is also suggested that monomer molecules partake in the site‐generating step by reaction with the partially reduced TiCl3 surface. This possibility demands a rate of polymerization dependent upon the monomer concentration to a power between 1 and 2. The lower the liquid phase monomer concentration the higher the exponent of the monomer concentration in the rate expression. The melting point of the polymer was 280–285°C. The solubility of polyvinylcyclohexane was investigated for fifteen paraffinic and aromatic hydrocarbons. Only two polymer fractions exhibited amorphous x‐ray spectra, and both of these occurred at [Al(C2H5)3] 0.005 mole/l. The rate of polymerization of vinylcyclohexane is compared with that of propylene, pentene‐1, and stryrene on similar catalyst.
Some anomalous viscosities of poly‐γ‐methyl‐L‐glutamate (PMLG) solutions and relations between the aging of the solutions and the structure of spherulites grown from them
Authors: Ishikawa Saburo
Published: April 2003

Poly‐γ‐methyl‐L‐glutamate was obtained by the NCA method in chloroform with the use of triethylamine, diethylamine, and n‐hexylamine as initiators. After polymerization, the solution was allowed to stand at 20 ± 2°C., and thin films cast from solvent, with short aging periods (∼1 month), no spherulites formed in the films. Aging periods of 2–6 months yielded positive spherulites; after much longer aging periods (6–10 months), negative spherulites were observed. In the positive spherulites, the helical axes oriented along the radius, but in negative spherulites the helical axes oriented along the tangential direction. These positive and negative spherulites were constructed of microfibrils about 45–67 A. in diameter. The relative viscosity of the aged solutions was also measured. The longer the aging time, the lower the viscosities of these aged solutions; the viscosities decrease sharply to 3 months of aging, and with aging times of 4–20 months the changes in viscosity are very small. However, the viscosity changes in every measurement and always increases during the measurement. Details of changes in viscosity are different depending upon the initiator used and the aging time. These results indicate that the decrease in viscosity is caused by intermolecular aggregation, while the increase during measurement is due to a breakup of the aggregates. Thus, the changes in the soluble state of the polymer in the aged solution seem to be closely related to the growth of both types of spherulites. The initiator has a significant influence on the structure of these aggregates. Polymer prepared with nHA initiator formed no spherulites, regardless of the aging time. No evidence was observed of the presence of the folding orientation of these α‐helical molecules or microfibrils, which indicates that the crystallization habits of helical molecules, such as polypeptides, are different from those of polyethylene. The crystallization mechanism of polypeptides is not by the so‐called folding mechanism, but by the side‐by‐side crystallization mechanism, as proposed by Ishiara or Flory. A difference in the mechanism of growth of positive and negative spherulite is also proposed.
Fluorothiocarbonyl compounds. V. Polymerization of thiocarbonyl compounds
Authors: Middleton W. J. , Jacobson H. W. , Putnam R. E. , Walter H. C. , Pye D. G. , Sharkey W. H.
Published: April 2003

Thiocarbonyl fluoride, fluoroalkylthio acid fluorides, and fluorothioketones are converted to high molecular weight polymers by anionic initiation at low temperatures. Amorphous poly(thiocarbonyl fluoride), (CF2S)n, is a tough elastomer that is highly resilient. Poly(thiocarbonyl fluoride) has a melting point of 35°C. and slowly crystallizes at room temperature to an opaque, stiff plastic. The glass transition point of the polymer is very low, being −118°C. as determined by the torsion pendulum method. Poly(trifluorothioacetyl fluoride) and polyhexafluorothioacetone are also elastomeric, but neither has the high resilience that is characteristic of poly(thiocarbonyl fluoride). Polyhexafluorothioacetone slowly depolymerizes at room temperature.
Preparation and characterization of some star‐and comb‐type branched polystyrenes
Authors: Altares T. , Wyman D. P. , Allen V. R. , Meyersen K.
Published: April 2003

Star‐type polystyrenes, polymers with p branches attached to a common multifunctional center, and comb‐type polystyrenes, polymers with an average of p branches attached at random to a polymeric backbone, have been prepared by the reactions, respectively, of polystyryllithium of narrow chain length distribution with appropriate p‐functional molecules or with backbone polystyrene chains of narrow chain length distribution, containing the prerequisite number of benzylic‐type chloromethyl groups. The synthesis, isolation, and characterization of these types of polymers are illustrated by specific examples. Problems which are inherent to the system, e.g., metal–halogen interchange reactions, different reactivities of the chloromethyl groups, isomerization of the polystyryllithium, and other possible reactions and their consequences are discussed.
Electrically controlled anionic polymerization of methyl methacrylate
Authors: Funt B. L. , Bhadani S. N.
Published: April 2003

Methyl methacrylate was polymerized in solutions of dimethylformamide containing quaternary ammonium salts. The course of the reaction was controlled by an electrolytic current passed through the solution. Results over a wide range of initial monomer concentrations at seven selected constant currents served to delineate the dependence of polymer yield on the control parameters. Polymer formation was directly dependent on monomer concentration and on the square root of the impressed current. The propagation reaction is anionic, and this was confirmed through inhibitor and copolymerization studies. Different solvents were tested and of these, dimethylacetamide was found to provide the best reaction medium. Molecular weights of approximately 50,000 were obtained. They were independent of salt, current, and monomer concentration, but were affected by the type of solvent and the temperature.
Dependence of the association of poly(methacrylic acid) with divalent cations on the stereoregularity of the polymers
Authors: O'Neill J. J. , Loebl E. M. , Kandanian A. Y. , Morawetz H.
Published: April 2003

The complexation of Cu2+ and Mg2+ with isotactic and syndiotactic poly(methacrylic acid) was studied by dialysis equilibrium over a range of degrees of ionization of the polymeric acid. It was found that the isotactic polymer has the higher affinity for Cu2+, while Mg2+ is bound more strongly to the syndiotactic species.
Heterogeneous polymer systems. II. Mechanism of stabilization of polymeric oil‐in‐oil emulsions
Authors: Molau Gunther E.
Published: April 2003

Polymeric oil‐in‐oil emulsions (POO‐emulsions) are a new class of emulsions comprising two immiscible polymer solutions and a graft copolymer as an emulsifying agent. A mechanism of stabilization of POO‐emulsions has been proposed which explains why graft copolymers act as POO‐emulsifiers, why they accumulate in the interface of POO‐emulsions, and why they provide coalescence barriers. The basic hypothesis is that the emulsifying graft copolymers accumulate in the interface as a result of the phenomenon of phase separation of polymers in solution, and that this phenomenon also provides the repulsive forces between colliding droplets which stabilize POO‐emulsions. The formation of micelles of graft and block copolymers as a result of phase separation has been discussed, and a literature survey on the behavior of graft and block copolymers in solution has been included to support the proposed mechanism.
Effects of concentration of urethane linkage, crosslinking density, and swelling upon the viscoelastic properties of polyurethanes
Authors: Shibayama Kyoichi , Kodama Minekazu
Published: April 2003

Viscoelastic properties of unswollen and swollen specimens of homologous series of polyurethanes were studied in the glass‐to‐rubber transition region. In the case of unswollen specimens, a large discrepancy was found to exist between the thermal expansion coefficient of specific volume and that of free volume derived by comparing the WLF equation with Doolittle's equation in which the parameter B was assumed to be unity. As a possible way to account for this discrepancy, B is assumed to be a decreasing function of temperature supposing that the thermal dissociation of secondary linkage between polar groups may have a decreasing effect on the size of elemental unit of molecular motion. In the case of swollen specimens, this discrepancy was found to disappear. Differences between specimens swollen in ethyl acetate and n‐propanol were observed in the spread of the array of relaxation modulus versus temperature curves in a homologous series. As a cause of this phenomenon it is suggested that the mechanisms of imparting free volume to the system are different for ethyl acetate and n‐propanol because of characteristic interactions between swelling agents and polymers.
Epoxy compounds. VIII. Stereoregular and stereorandom polymerization of phenyl glycidyl ether with tertiary amines, and infrared spectra of poly(phenyl glycidyl ether)
Authors: Tanaka Yoshio , Kakiuchi Hiroshi
Published: April 2003

Crystalline and amorphous polymers have been obtained from the polymerization of phenyl glycidyl ether in the presence of tertiary amines. The crystalline fraction is high melting and insoluble at room temperature. The amorphous fractions are soluble at room temperature and their molecular weights are found to be ∼950 in benzene at 30°C. The yields of the crystalline fraction and the amorphous paste fraction decreased considerably with increasing the catalyst concentration and reaction temperature above 50°C. The yield of the liquid fraction, however, increased with increasing concentration of the catalyst and the reaction temperature. The x‐ray diffraction analysis of the crystalline fraction shows that the fraction has 47–50% crystallinity and that its diffraction pattern is similar to that of poly(phenyl glycidyl ether) obtained by Noshay and Price. The infrared spectra of these fractions have been obtained in the region of 650–4000 cm.−1. These data are compared with those of polystyrene and poly(styrene oxide) and are used to make an assignment of the normal modes of the poly(phenyl glycidyl ether) molecule. On the basis of analyses of polystyrene and poly(styrene oxide), and a study of the combination bands, it has been possible to make a fairly satisfactory assignment of all of the benzene ring fundamentals of the CH2, CH, and skeletal modes.
Polyaddition reactions of bisethyleneureas and 1,1,3,3‐diethyleneurea with polymethylene dimercaptans in LiCl‐dimethylformamide
Authors: Iwakura Yoshio , Sakamoto Munenori , Yoneyama Michio
Published: April 2003

Polyaddition reactions of 1,1′‐tetramethylenebis(3,3‐ethyleneurea) (IIa), 1,1′‐octamethylenebis(3,3‐ethyleneurea) (IIb), 1,1′‐p‐phenylenebis(3,3‐ethyleneurea) (IIc), 1,1′‐(4,4′‐diphenylmethane)bis(3,3‐ethyleneurea) (IId) and 1,1,3,3‐diethyleneurea (III) with polymethylene dimercaptans were investigated. 1,1′‐Polymethylenebis(3,3‐ethyleneureas) and polymethylene dimercaptans successfully reacted at 80–95°C. in the presence of triethylamine to give poly(urea sulfides) with intrinsic viscosities up to 1.1 in about 90% yield when dimethylformamide, dimethylacetamide, or N‐methyl‐2‐pyrrolidone containing lithium chloride as a solvent were used. The other ethyleneureas, however, failed to give high molecular weight polymers.
Characterization of ethylene–propylene block copolymers by proton magnetic resonance
Authors: Porter Roger S.
Published: April 2003

A high‐resolution proton magnetic resonance compositional analysis has been developed for propylene polymers containing 0–40 wt.‐% ethylene as either homopolymer or copolymer blocks. The test is independent of tacticity and provides qualitative information on copolymer sequencing and propylene chain structure. The analysis was developed using a series of standard reference polymers synthesized to contain various ratios of C14‐tagged ethylene and propylene. The compositional standards were established by radiotracer analysis for C14 and by preparing weighed physical mixtures of homopolymers. Spectra were obtained at 200 ± 10°C. by placing externally heated polymer solutions into a conventional probe of a Varian A‐60 proton spectrometer. All measurements were made on ± 10% polymer solutions in diphenyl ether. Analyses are accurate to about ± 10% at higher ethylene concentrations. The method is sensitive, with less precision, to below 1% for ethylene either as blocks or homopolymer.
Alternative copolymerization of aziridines and carbon monoxide by γ‐ray irradiation
Authors: Kagiya Tsutomu , Narisawa Shizuo , Ichida Taizo , Fukui Kenichi , Yokota Hisao , Kondo Masatsune
Published: April 2003

The copolymerization of carbon monoxide and aziridines such as ethylenimine and propylenimine was carried out by γ‐ray irradiation. Aziridines and carbon monoxide were allowed to copolymerize under γ‐ray irradiation from a Co60 source and gave a crystalline solid copolymer. The yield of the copolymer increased with reaction temperature. The composition of copolymers obtained did not depend on the feed ratio of monomers and was found to be almost equimolar. The copolymer of ethylenimine and carbon monoxide melted at about 322–335°C. with decomposition and has an infrared spectrum identical with that of poly‐β‐alanine obtained by the hydrogen‐migration polymerization of acrylamide. The hydrolyzed product of the ethylenimine–carbon monoxide copolymer was confirmed to be β‐alanine by paper chromatography. These results lead to the conclusion that the copolymerization of aziridines and carbon monoxide took place alternatively by γ‐ray irradiation, and produced crystalline poly‐β‐alanines.
Relationship between viscosity and direct current conductivity in PVC
Authors: Kallweit Juerg‐Heinrich
Published: April 2003

In general, the d.c. conductivity σ has been considered to be inversely proportional to the viscosity η, but the relation ση = const. has not been proven in the case of the system poly(vinyl chloride)‐dioctyl phthalate. The experimental results can be described by σηm‐1/m = constant if the plasticizer content is not too high. The ion mobility seems to depend on a local effective viscosity, which differs from that viscosity which is derived from retardation experiments.
Donor–acceptor interaction in cationic polymerization. VI. Influence on the molecular weight of polyisobutylene of some anions derived from the complexes of aluminum trichloride with some electron donors
Authors: Zlámal Z. , Kazda A. , Ambrož L.
Published: April 2003

The concentration dependence of the specific conductivity of complexes of aluminum trichloride with ethanol, diethyl ether, and phenetole in a molar ratio of 1 : 1 and in 2EtOH·AlCl3 and EtOH·2AlCl3 complexes has been measured. Conductivity measurements were carried out in ethyl chloride at −78.5°C. Molar conductivity and the degree of dissociation of the complexes studied are concentration‐independent which proves an extensive association of ions. Polymerizations of isobutylene carried out in the presence of these complexes and under the same conditions as the conductivity measurements have shown that the molecular weight of polyisobutylene formed is inversely proportional to the concentration of the complex over the whole range of concentrations studied. It can be deduced from the relation between the specific conductivity and the molecular weight that only the ionized part of the complex asserts itself in the chain‐breaking processes. The chain‐breaking efficiencies of various anions are given and allow one to draw conclusions about the mode of ionization of donor molecules after the interaction with the acceptor, viz. aluminum trichloride.
Vinyl polymerization by cobaltic ions in aqueous solution: Part I. Polymerization of methyl methacrylate
Authors: Jijie K. , Santappa M. , Mahadevan V.
Published: April 2003

Polymerization of methyl methacrylate initiated by cobaltic ions in perchloric, nitric and sulfuric acids was studied in the temperature range 15–25°C. In all three acids, water oxidation occurred as a side reaction. In HClO4 and HNO3 media monomer oxidation was shown to be an additional complicating feature. Rates of cobaltic ion disappearance, monomer disappearance, and chain lengths of polymers were measured with variations in [M], [Co3+], [H+], initially added [Co2+], and temperature. In HClO4 and HNO3 experimental results favored simultaneous initiation by Co3+ and CoOH2+ species, while in H2SO4, Co3+ ions alone were the active entities. An appropriate kinetic scheme to fit all the experimental observations is proposed. The various rate constants were evaluated.
Vinyl polymerization by cobaltic ions in aqueous solution. Part II. Polymerization of acrylonitrile and methyl acrylate
Authors: Jijie K. , Santappa M. , Mahadevan V.
Published: April 2003

Polymerization of methyl acrylate in HClO4 and HNO3 was studied in the temperature range 10–15°C. The kinetics of the polymerization were found to be very simple, involving initiation and termination by cobaltic ions. Kinetic studies on polymerization of acrylonitrile in HClO4 and HNO3 revealed that water oxidation, and monomer oxidation were side reactions as in the case of methyl methacrylate. Experimental evidence favored the simultaneous initiation by Co3+ and CoOH2+ species. In H2SO4, certain unusual features were encountered. At low [Co3+], linear termination as well as termination by mutual combination occurred. Another interesting aspect was that CoSO4+ initiated at low [Co3+]. This was unlike the case of other monomers in H2SO4. The rates of polymerization and rates of cobaltic ion disappearance were measured with respect to changes in [M], [Co3+], [H+], temperature, etc. The various rate constants were evaluated.
Polymerization in liquid ammonia: Acrylate esters and vinyl thiolacetate
Authors: Leonard F. , Hanks G. A. , Kulkarni R. K.
Published: April 2003

Methyl ethyl and n‐propyl acrylates when polymerized by sodium in liquid ammonia, contain an average of one amino group per polymer chain, which is indicative of amide anion initiation and chain transfer to the solvent ammonia. Isopropyl acrylate and the higher homologs contain considerably less nitrogen than required by one amino group per chain indicative of another initiating and terminating mechanism. Three alternate mechanisms are discussed. Of these, alkoxide initiation seems to be the most plausible. Vinyl thiolacetate polymers prepared under the same conditions also contain less nitrogen than required by one amino group per chain. The polymer structure is predominantly poly(vinyl thiol) with intramolecular or intermolecular disulfide bridges. The acetate part of the molecule is concomitantly split off to form acetamide.
Radiation‐induced cis–trans isomerization of polyisoprenes and temperature dependence of the equilibria
Authors: Tsurugi Jitsuo , Fukumoto Tsugio , Yamagami Masayuki , Itatani Hiroshi
Published: April 2003

The cis‐trans interconversion of polyisoprenes in solutions induced by γ‐radiation in the presence of a sensitizer, which is any one of organic bromides or n‐butyl mercaptan, was studied by using hevea and gutta percha as starting substances. The percentage cis remaining or converted after irradiation were determined by the infrared absorption. The equilibrium constants for the interconversion at 22, 60, and 100°C. were found to be 3.00, 5.25, and 7.33, respectively. The first‐order rate constants for cis → trans and trans → cis isomerizations at 22°C. were calculated to be 9.05 and 2.91, respectively. The results were interpreted by the mechanism proposed by Golub, according to which the double bonds from π complexes with radiolytic fragments from sensitizers give a radical transition state capable of interconversion. However, our results showing that heating shifts the equilibrium toward trans isomer are not in accord with the mechanisms of the radiation‐induced isomerization of polybutadiene of Golub and those for photoisomerization of aromatic azo compounds.
Inorganic coordination polymers. VIII. Cobalt(II) and zinc(II) phosphinate polymers and copolymers
Authors: Rose Selwyn H. , Block B. P.
Published: April 2003

The preparation, properties, x‐ray powder patterns, and TGA curves are given for cobalt(II) dimethyl‐, methylphenyl‐ and diphenylphosphinate. The polymeric character of cobalt(II) methylphenylphosphinate is demonstrated by its colligative properties and melt indexes. These cobalt(II) phosphinates along with hybrid copolymers of zinc(II) or cobalt(II) were prepared by the reaction of the metal acetate with the appropriate phosphinic acid or mixture of phosphinic acids. A consideration of the hybrid copolymers leads to the conclusion that both the zinc(II) and cobalt(II) dimethyl‐ and diphenylphosphinates are likewise polymeric. Thermal stability is discussed in terms of the structures suggested, and it is shown that crystallinity is related to polymer symmetry.
Permeation, sorption, and diffusion of water in ethyl cellulose
Authors: Wellons J. D. , Stannett V.
Published: April 2003

The permeability of ethyl cellulose to water vapor and liquid water was measured as a function of temperature. A change of slope was found in the Arrhenius plots at about 50°C., close to the glass transition. The sorption isotherms showed essentially zero heat of mixing in agreement with other workers. The diffusion constants were measured in four ways, viz., sorption, desorption, time lag, and by dividing the permeability constants by the equilibrium solubility coefficients. The time lag method gave diffusion constants which were independent of concentration, whereas the other three methods led to diffusion constants which steadily decreased with concentration. All the methods, however, extrapolated to about the same value at zero concentration. The decreasing diffusivities are believed to be due to the clustering of water molecules in the polymer. However, no clustering appeared to take place under the conditions of the time lag measurements.
Tailored heterogeneity indices in anionic polymerization
Authors: Eisenberg A. , McQuarrie D. A.
Published: April 2003

Equations are derived for the differential molecular weight distribution curve and for the heterogeneity index for several types of delayed initiator addition in anionic polymerization. All the results are in closed and easily used form, and depend only upon the product of the rate constant of the propagation reaction, the total initiator concentration, and a parameter representative of the rate of initiator addition. The results are plotted versus the above‐mentioned product, so that one can determine the heterogeneity index to be expected under a wide range of the variables involved.
Catalysis in the polymerization of silicic acid
Authors: Moulik S. P. , Mullick D. K.
Published: April 2003

Some aspects of the condensation polymerization of silicic acid have been discussed in a systematic manner. Empirical relationships between the time of gelation and the catalyzer concentration, with both H+ and OH− catalysis, have been suggested. These are found to be consistent with the observations of various authors. Also the activities of both the ionized and un‐ionized species present in the system account for some anomalous observations and the pH optimum for the maximum time of gelation. The idea of a secondary salt effect, introduced by Brönsted, has been found to be helpful in understanding catalyst function.
Macroreticular redox polymers. III. Characterization of some hydroquinone–quinone redox polymers
Authors: Kun Kenneth A. , Kunin Robert
Published: April 2003

A series of hydroquinone–quinone redox polymers on highly and lightly crosslinked macroreticular styrene–divinylbenzene matrices was characterized for redox capacity, reactivity, equilibria, and redox potential. The effects of cerium(IV), iron(III), and oxygen on determinations of redox capacity are described.
Cationic polymerization of cyclic olefins
Authors: Mizote A. , Tanaka T. , Higashimura T. , Okamura S.
Published: April 2003

The polymerization and the polymerizabilities of indene, benzofuran, and 1,2‐dihydronaphthalene are discussed from the point of view of ring strain, ring stabilization, and steric hindrance in the transition state. Monomer reactivities of these olefins were estimated from copolymerization with styrene and from the rate of addition of iodine bromide in acetic acid. Rates and degrees of polymerization are compared with monomer reactivities and resonance energies of indene, 1,2‐dihydronaphthalene, and benzofuran as a measure of ring strain and stabilization. It is found that indence is 1.5–2.0 times more reactive than styrene. This high reactivity of indene is attributed to the ring strain in the monomer state and to the low amount of steric hindrance in the transition state of the coplanar five‐membered cyclic olefin. 1,2‐Dihydronaphthalene is strained and therefore reactive, but propagation to higher molecular weight products is impeded due to the steric hindrance. The reactivity of benzofuran is decreased by conjugative stabilization of CC double bonds at the reaction site.
Polymers from aryl glycidyl ethers
Authors: Gibb T. B. , Clendinning R. A. , Niegisch W. D.
Published: April 2003

High molecular weight, linear polyethers were prepared by polymerizing a series of ring‐substituted phenyl glycidyl ethers by using the ferric chloride–propylene oxide and dibutylzinc–water catalyst systems. The α‐naphthyl, β‐naphthyl, p‐phenylphenyl, the o‐, m‐, and p‐methyl, and the o‐ and p‐chlorophenyl polymers resemble the parent polymer in that they are readily crystallizable polyethers which have melting points above 170°C. The other substituted poly(phenyl glycidyl ethers), including the o‐ and p‐isopropyl, p‐tert‐butyl, p‐octyl, and 2,4,6‐trichloro derivatives show much less tendency to crystallize and are lower melting. The x‐ray and electron diffraction data established that poly(o‐chlorophenyl glycidyl ether) crystallizes in an orthorhombic unit cell; data obtained in a parallel study of unsubstituted poly(phenyl glycidyl ether) did not allow assignment of a specific structure.
Application of the flory‐mandelkern equation to individual unfractionated polymer samples
Authors: Kalfus Maurycy , Mitus Jan
Published: April 2003

A method is developed for the application of the Flory‐Mandelkern equation to the determination of the weight‐average molecular weights of individual, broad, unfractionated polymer samples. The method includes appropriate averaging of the sedimentation constants and of the intrinsic viscosity of an unfractionated polymer sample in a θ solution from the velocity sedimentation data. By means of the method, individual samples of polystyrene, poly(isooctyl methacrylate) and of the copolymer of styrene with 20% isooctyl methacrylate prepared under the same emulsion polymerization conditions from commercial monomers have been investigated. Appropriate θ solvents have been found by the Elias method. Equations for the dependence of the sedimentation constants and of the intrinsic viscosities in the θ solvents on the molecular weights have been established for the polymers without fractionation. Osmometric and light‐scattering measurements as well as Archibald experiments have shown that by the proposed method the molecular weight cut‐off effect is eliminated in the above equations and in the polydispersity parameter Mw/Mn. Molecular weight distributions have been determined for the polymer samples.
Molecular vibrations of irregular chains. I. Analysis of infrared spectra and structures of polymethylene chains consisting of CH2, CHD, and CD2 groups
Authors: Tasumi M. , Shimanouchi T. , Kenjo H. , Ikeda S.
Published: April 2003

Various samples of irregularly deuterated polyethylene were prepared and their infrared spectra were studied. The results support the previously proposed view that poly‐trans‐CHDCHD or ‐cis‐CHDCHD obtained with Al(i‐Bu)3–TiCl4 is an irregularly deuterated chain consisting of the CH2, CHD, and CD2 groups. A simplified calculation of the CHD scissors and CDH rocking vibration frequencies has been made for various model chains. The assignments of the CDH rocking vibration bands in the region of 700–500 cm.−1 have been given on this basis.
Molecular vibrations of irregular chains. II. Configurations of polydideuteroethylene
Authors: Tasumi M. , Shimanouchi T. , Ikeda S.
Published: April 2003

A simplified calculation of the CHD scissors vibration frequencies has been made for (CHD)n of various configurations. The correlation between the CHD scissors frequency and the local configuration has been established. On this basis the infrared absorption bands of poly‐trans‐CHDCHD and poly‐cis‐CHDCHD appearing in the region of 1350–1280 cm.−1 have been interpreted in greater detail.
Analysis of the base‐catalyzed phenol–epichlorohydrin condensation
Authors: Brode George L. , Wynstra John
Published: April 2003

The amount of abnormal addition of phenoxide to epichlorohydrin and phenyl glycidyl ether was determined as a function of reaction conditions. The isomer distribution resulting from attack at either position of these unsymmetrical epoxides was quantitatively measured by vapor phase chromatography of the resulting product mixtures. While both epoxides reacted predominantly in the expected normal fashion, small quantities of abnormal addition products were found whose concentrations were temperature‐dependent. The analytical method also permitted a study of the effect of temperature on side reactions involving hydrolytic solvents.
Efficiencies of some ethyl acrylate chain terminators
Authors: Levy Leon B. , Fisher Gene J.
Published: April 2003

A group of substituted phenols, quinone, and tropone were used to retard AIBN‐initiated ethyl acrylate polymerization in ethyl propionate solution at 44.7°C. in the absence of oxygen. It was concluded that the efficiency of retardation depended upon the ability of the terminator to stabilize a positive charge on its reaction site in the transition state. Tropone was found to be a particularly good retarder. The radical‐trapping efficiency of 2,2‐diphenyl‐1‐picrylhydrazyl in this system was found to be 50–60%.
Reaction of n‐butyllithium with poly(vinyl chloride)
Authors: Shiina K. , Minoura Y.
Published: April 2003

The reactions of poly(vinyl chloride) and butyllithium in tetrahydrofuran were investigated. A deep purple color developed at first with addition of butyllithium to the THF–PVC solution, and a spontaneous color change of the misture occurred successively to blue, green, and finally pale vellow. In these reaction stages, the PVC might be butylated, dehydrochlorinated, and partially lithiated by BuLi. These facts were substantiated by the results of successive reactions with various substances such as Michler's ketone, carbon dioxide, and styrene.
Some polymers of high dielectric constant
Authors: Rosen Robert , Pohl Herbert A.
Published: April 2003

A class of highly conjugated macromolecules exhibiting extraordinarily high effective dielectric constants (DK = 50–900) is described. These polymers are of the polyacene radical quinone type, are highly purified, and exhibit electronic semiconduction. The dielectric constant varies only slightly with pressure (up to 20 Kbar), but strongly with frequency (300–300,000 cps) and moderately with temperature and field strength. The latter effect of field strength on the effective dielectric constant (and on the conductivity) required the development of special measurement techniques which are described. The unusual dielectric behavior can be accounted for assuming the presence of what amounts to a thermally generated plasma of electrons and holes, each locally mobile on extended regions of associated π‐orbitals on the molecules. The postulated resulting “hyperelectronic” polarization of the locally mobile charges in external fields fits the observed high magnitude of the polarizability, as well as its field, frequency, and temperature dependence.
Vanadium‐ or vanadylacetylacetonate as a cocatalyst for the terpolymerization of ethylene, propylene, and dicyclopentadiene
Authors: Cunningham Robert E.
Published: April 2003

Vanadium trisacetylacetonate [V(C5H7O2)3] and vanadyl bisacetylacetonate [VO‐(C5H7O2)2] were found to be satisfactory catalysts (with Al2Et3Cl3cocatalyst) for the terpolymerization of ethylene, propylene, and dicyclopentadiene to unsaturated, sulfurcurable elastomers. Polymerization solvents of heptane or benzene were used. Best yields of terpolymers were obtained in benzene. Terpolymers with unsaturations of greater than ≃0.20 mole CC/kg. can be cured with a sulfur‐based vulcanzing recipe. Both acetylacetonates produced terpolymers, in benzene, with practically equivalent properties. They also appeared to be nearly equal to corresponding terpolymers made with catalysts of VOCl3or VCl4.
Continuous fractionation of polymers in solution by thermal diffusion
Authors: Kössler Ivo , Krauserová Helena
Published: April 2003

The possibility of carrying out continuous fractionation of polymers by the thermodiffusion method was investigated. From the working space of a plate‐type column, fractions of polymer were continuously withdrawn simultaneously with filling of the column with fresh solution from a storage vessel. After equilibrium had been established, the distributions of molecular weights of the fractions were determined by a modified Baker and Williams method. In the same apparatus, and at constant temperature and concentration, fractionation, which may be characterized by a limiting viscosity number, is dependent on the total rate of withdrawal and on the ratios of amounts of polymer withdrawn in various places on the column.
Polymerization of lactam ethers
Authors: Ogata Naoya , Asahara Tomohiko , Tohyama Syunroku
Published: April 2003

Preparation and polymerization of lactam ethers which contain an amide and an ether group in the same ring are described. Seven‐membered lactam ethers give relatively low molecular weight polymers with an anionic or cationic catalyst, while with diethylzinc as catalyst, the 2,7‐dimethyl lactam ether of a seven‐membered ring gives a crystalline polymer having a melting point of 220°C. A polymerization mechanism is discussed.
Synthesis and characterization of branched polystyrene. Part I. Synthesis of four‐ and six‐branch star polystyrene
Authors: Gervasi J. A. , Gosnell A. B.
Published: April 2003

The synthesis of very well defined four‐ and six‐branched polystyrene has been carried out. Anionic polymerization initiated by butyllithium in benzene–tetrahydrofuran medium gave single chains of narrow distribution. Coupling this living polystyryllithium with bis(trichlorosilyl)ethane gave a maximum of four branches. Coupling with the cyclic trimer of phosphonitrilic chloride gave a maximum of six branches. The reaction procedures have been discussed and mechanisms suggested for some of the reactions.
Electron paramagnetic resonance of ultraviolet‐irradiated polyolefins
Authors: Browning H. L. , Ackermann Hazel D. , Patton H. W.
Published: April 2003

If films of polyolefins are ultraviolet‐irradiated at liquid nitrogen temperature, alkyl radicals which can be examined by EPR are produced. No EPR spectra are observed from polyolefins irradiated at room temperature in air. Ultraviolet irradiation of polyolefins containing small alkyl side chains generally produces radicals corresponding to the pendant group or methyl radicals if the side chains contain a methyl branch. For some polymers the radical species could not be identified with certainty. Stabilization studies indicate that an optimum concentration of ultraviolet stabilizer is necessary for maximum stabilization of polyolefins. Preliminary results of EPR studies of the ultraviolet irradiation of various polyolefins are given, and some possible radical species are discussed.
Polyamides having long methylene chain units
Authors: Saotome Kazuo , Komoto Hiroshi
Published: April 2003

Three series of polyamides having long methylene chain units have been prepared from p‐xylylenebisethylamine and 2,2′‐pphenylenebisethylamine with aliphatic dicarboxylic acids of long methylene chain units; aliphatic diamines of long methylene chain units with terephthalic, p‐benzenediacetic, and p‐benzenedipropionic acids; and aliphatic diamines with aliphatic dicarboxylic acids, both having long methylene chain units. The effects of the length of the methylene chain units on the melting point, the glass transition temperatures and the densities of these polyamides were investigated. The aromatic polyamides, in which even methylene chains are joined between a phenylene and an amide group generally have higher melting points than the corresponding ones with odd methylene chains. On the plots of the melting points and the densities of the aliphatic series against the amide concentrations, both the melting point and the density extrapolated to the zero amide concentration are found below the values for polymethylene.
Structure and physical properties of glow discharge polymers. I. Polymers from hydrocarbons
Authors: Jesch K. , Bloor J. E. , Kronick P. L.
Published: April 2003

The polymers deposited from the vapors of pentane, ethylene, butadiene, benzene, styrene, and naphthalene subjected to glow discharge have been analyzed by infrared absorption techniques. The reaction products show unsaturation, hydrogenation, and branching in the polymer chains. Aromaticity is present only in polymers from aromatic monomers.
Polymerization in the crystalline state. VIII. Polymerization in N‐carboxy anhydrides of γ‐benzyl glutamate, γ‐methyl glutamate, and ϵ‐carbobenzoxylysine
Authors: Kovács Gábor , Kovács Eszter , Morawetz Herbert
Published: April 2003

The kinetics of the solid‐state polymerization of the N‐carboxy anhydrides (NCA) of the L‐ and racemic forms of γ‐benzyl glutamate (BG), γ‐methyl glutamate (MG), and ϵ‐carbobenzoxylysine (CL) were studied as a function of temperature and aqueous vapor pressure. The reaction of the L‐forms of BG and MG was characterized by an induction period, while the CL derivative reached its maximum polymerization rate at the outset of the reaction. Water vapor had only a minor effect in accelerating the reaction and reducing the chain length of the polypeptides formed. The racemic monomers were found to have different crystal structures from those of the L‐isomers and the racemic MG and CL derivatives polymerized much more slowly than the corresponding optically active crystals. All polymers gave diffuse x‐ray diffraction patterns. Infrared spectra of the L‐polypeptides showed that they were largely in the α‐helical form. The polymer derived from the racemic BG–NCA had a content of α‐helical material which suggested that it consisted of polypeptides with long blocks of D and L residues.
Thermally resistant polymers containing the s‐triazine ring
Authors: Anderson D. R. , Holovka John M.
Published: April 2003

Aromatic dinitriles cyclize to form aromatic polymers containing the s‐triazine ring. In this paper, these polymers are compared thermally with each other and with aromatic melamine polymers prepared via the aromatic diamine and cyanuric chloride. One perfluoroaromatic melamine polymer was prepared and compared with the other two types of polymers. The polymers (triazines and melamine) in which biphenyl was the backbone were increasingly stable up to 1000°C. in nitrogen. The triazine polymers as a group were the most stable. The perfluoroaromatic polymer was the most stable melamine up to 500°C. in air but was very unstable above 700°C.
Degradation of pectin by γ‐radiation under various moisture conditions
Authors: Wahba I. J. , Massey L. M.
Published: April 2003

By using D50 and D37 doses for 50 and 63% decreases in the solution viscosity of pectin, an evaluation was made of the effectiveness of radiation at different moisture levels. The relation between radiation effectiveness, as measured by the D50 value, and the pectin: water ratio was expressed in a simplified empirical equation. The indirect effect of radiation in dilute aqueous solutions decreased progressively with increasing pectin concentration. On the other hand, a protective effect was produced by small additions of water to dry pectin and a minimum in degradation (i.e., maximum D50 and D37 values) was attained at about the 20% moisture level.

The relation between the intrinsic viscosity of dilute aqueous solutions of pectin irradiated air‐dry and the number‐average molecular weight and D37 values was determined. By using the former relation, the number of chain scissions per unit of absorbed energy was measured at different moisture levels.

The importance of moisture control in comparative radiation studies was emphasized. An approximately 26‐fold increase in the radiation sensitivity of pectin was produced by an increase in the moisture content from the 20 to the 99% level. Varying the moisture content therefore provides a good means of altering the sensitivity of pectin and similar materials to radiation damage.
Macromolecular models for branched PVC. I. Copolymer of vinyl chloride with isopropenyl chloride
Authors: Caraculacu Adrian A.
Published: April 2003

A new type of model for study of polymer anomalies by copolymerization is proposed. For branched PVC, the vinyl chloride–isopropenyl chloride copolymer was used as the macromolecular model. A regulatory and inhibitory action of isopropenyl chloride during the polymerization was demonstrated. To determine the composition of the copolymer, methods based on elemental analysis and NMR and infrared spectra were utilized. It was found that the copolymer composition is very close to that of the polymerization mixture. The structure of the copolymer was studied from infrared spectra. It was found that both forms TCHH and THHH are present, the former being present in a larger quantity. The possibility of the utilization of spectral methods on macromolecular systems to determine the structure and content of a chlorine atom bound to a tertiary carbon atom (ClT) in the presence of an excess of chlorine bound to a secondary carbon was verified.