bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterophase polymerization of 4‐ vinylpyridine with butyllithium
Authors: Spiegelman P. P. , Parravano G.
Published: April 2003

The butyllithium‐initiated polymerization of 4‐vinylpyridine in hydrocarbon media proceeded by an anionic addition mechanism. The colorless, soluble reactants rapidly formed a granular, intensely colored, polymer precipitate at temperatures below −30°C. in heptane and toluene diluents. When the reaction was carried out in an impurity‐free environment, the highly colored reaction mixture remained unchanged for indefinite periods of time, and further addition of monomer produced continued growth of polymer chains. A dilatometric technique was employed to follow the rate of polymerization in toluene media. The experimental methods that were used for manipulation of solutions in vacuo resulted in polymerization (30–50% conversion) during an initial unsteady temperature period followed by a constant temperature interval during which rate measurements were obtained. Initial monomer and initiator concentrations were varied over a fourfold range. Rate measurements were made in the temperature interval −30°C. to +30°C. The dilatometric kinetic experiments together with additional, independent observations established that the rate was proportional to monomer concentration, and to the one half power of the initiator concentration, suggesting an equilibrium complex formation of growing polymeric anions. Rate constants were computed from the values of the rates obtained from the dilatometric kinetic experiments and the square root of the effective initiator concentration. A calculation of the temperature dependence of the rate constants produced an activation energy of 12.7 kcal./mole. As predicted by anionic polymerization theory, the polymer formed in these reactions had a number‐average molecular weight equal to the ratio, (weight of polymer)/(equivalents of initiator). The polymer was fractionated by elution chromatography with tert‐butyl alcohol and benzene solvent–nonsolvent mixtures. The molecular weight distributions of the polymer, constructed from fractionation data, showed a bimodal distribution in two fairly narrow molecular weight ranges. This uncommon molecular weight distribution is due to occlusion of a portion of the active growing chain ends in the polymer precipitate. These trapped reaction sites (which in these experiments amounted to 95% and up of the total initiator concentration) no longer produced chain growth due to the absence of available monomer. The remaining “effective” reaction sites thus grow to high molecular weight and are responsible for the observed kinetics.
α–γ Transition of nylon 6
Authors: Arimoto H.
Published: April 2003

The mechanism of the α‐γ transition of nylon 6 due to iodine treatment and the structure of the γ‐form of nylon 6 are discussed on the basis of results of x‐ray diffraction and polarized micro‐infrared absorption measurements on doubly oriented and iodine‐treated specimens. The plane of the amide group and that of the methylene group are both parallel to the rolled plane, which is parallel to the hydrogen‐bonded molecular sheet in the α‐form of nylon 6. The plane of the amide group is preferentially twisted to a direction roughly perpendicular to the rolled plane on coordination of iodine to the oxygen of the amide group and this preferential orientation of the amide group is retained on the removal of iodine. The preferential orientation of the amide group in the molecule supports the pleated sheet structure proposed by Kinoshita for the γ‐form of polyamides. Infrared bands are examined, the preferential orientation of the amide group being taken into account. The structure of the γ‐form of nylon 6 is composed of pleated sheets of similarly directed molecular chains joined by hydrogen bonds between the adjacent molecules and in such a packing of sheets the directions of molecular chains are alternately inverse along the direction of stacking of sheets.
Investigation of the stereoregularity of poly(vinyl alcohol)
Authors: Fujii Kiyoshi , Mochizuki Takani , Imoto Saburo , Ukida Junji , Matsumoto Masakazu
Published: April 2003

Studies of the steric structures of poly(vinyl alcohol), as deduced from studies of the structures of its esters, particularly poly(vinyl formate) are described. Two types of tactic poly(vinyl formate) crystallize with different structures, corresponding to their different molecular structures. Therefore, the type of molecular stereoregularity in poly(vinyl formate) samples can be deduced from an examination of the crystals produced by a given crystallization treatment. From the results of the study of the poly(vinyl formate) crystals, some conclusions can be drawn concerning the steric structure of poly(vinyl alcohol). Crystallizabilities of other tactic poly(vinyl esters) have also been investigated.
Copolymerization of tetrafluoroethylene with isobutene induced by ionizing radiation
Authors: Tabata Yoneho , Ishigure Kenkichi , Oshima Keichi , Sobue Hiroshi
Published: April 2003

Radiation‐induced copolymerization of tetrafluoroethylene with isobutene was carried out in the liquid state of the monomers at low temperature. The composition curve of the tetrafluoroethylene–isobutene copolymer was obtained. Infrared spectra, x‐ray diffraction, and melling points of the copolymers obtained were also measured. It was concluded from these experimental results that an alternating crystalline isobutene tetrafluoroethylene copolymer can be obtained by a radical process induced by ionizing radiation. This seems to be the first case in which an alternating crystalline copolymer was obtained by a radical mechanism over an extremely wide range of molar concentration of the components in the monomer mixture.
Preparation and polymerization of vinyl esters of cyclic and polychloro fatty acids
Authors: Marvel C. S. , Hill J. C. , Cowan J. C. , Friedrich J. P. , O'Donnell J. L.
Published: April 2003

Homopolymers and vinyl chloride copolymers have been prepared from the vinyl esters of mixed hydrogenated cyclized linolenic acid, 9,10‐dichlorostearic acid, 9,10,12,13‐tetrachlorostearic acid, 13,14‐dichlorobehenic acid, 9(10)‐phenylstearic acid and technical behenic acid. Vinyl 13,14‐dichlorobehenate (29%)‐vinyl chloride (71%) gave a copolymer with a brittle temperature of ‐2°C. All of the other copolymers with vinyl chloride had brittle temperatures of 16°C. or higher and behaved more like rigid plastics.
Cationic polymerization of 9‐vinylanthracene
Authors: Michel R. H.
Published: April 2003

9‐Vinylanthracene has been polymerized in a wide variety of cationic systems. Under these conditions of polymerization, the vinyl group and the center ring of the anthracene nucleus act as a 1,3,5‐triene system. Evidence for the structure of the product was obtained from infrared, ultraviolet, and particularly nuclear magnetic resonance spectroscopy. In the presence of trifluoroacetic acid, poly‐9‐vinylanthracene was converted to poly‐9,10‐dimethyleneanthracene.
Thermoelectric determination of polymer molecular weights
Authors: Cantow Manfred J. R. , Porter Roger S. , Johnson Julian F.
Published: April 2003

An apparatus is described for the determination of number‐average molecular weights, based on the thermoelectric method as proposed by Hill. With this improved instrument, temperature differences of down to approximately 5 × 10−5°C. can be recorded. This allows determination of molecular weights up to 40,000 for the case of coiled macromolecules in a poor solvent. The accuracy of measurements, for all molecular weights, has been established by using benzene solutions of polyisobutenes of narrow and defined molecular weight distributions.
Preparation and polymerization of 1,2‐epoxypropyl 2,3,4,6‐tetra‐O‐acetyl‐β‐D‐glucopyranoside
Authors: Gupta P. Das , Whistler Roy L.
Published: April 2003

Allyl D‐glucopyranoside tetraacetate is prepared by reaction of acetobromo‐D‐glucose with allyl alcool. The glycoside is not readily polymerized by free radical mechanism but on conversion to the epoxide with peracids, polymerization is easily induced with triethylaluminum. The product with a D. P. of 250 is soluble in organic solvents. On alkaline deacetylation the hydrophylic polymer is water soluble but the aqueous solution possess comparatively low viscosity.
Copolymerizations in electron‐donor solvents with organolithium catalysts
Authors: Reich Leo , Stivala Salvatore S.
Published: April 2003

A general scheme is postulated for copolymerizations in electron‐donor solvents with organolithium catalysts. The general mathematical expression obtained is simplified by utilizing two extreme conditions. The simplified equations are shown to be consistent with experimental evidence. While it is difficult to decide in favor of either solvation theory or O'Driscoll's concepts, the latter is favored based upon simplicity, plausibility and experimental evidence.
Redox polymerization of unsaturated polyester resins. II. Effect of copromoter metals on the redox polymerization activity of vanadium chelates
Authors: Svoboda Glenn R.
Published: April 2003

Of a series of copromoter metal species investigated, it was found that several of these were strongly effective in synergizing the redox polymerization activity of vanadyl acetyl acetonate. Notable among these were Cu+2, Fe+3, Ti+3–Ti+6, Be+2, Al+3, and Th+4. Particularly notable was the effect of Ti+3–Ti+6, which strongly synergized the rate at which complete polymerization was obtained, eg., within 15 min. as compared to 20 hr. when vanadyl acetyl acetonate was used alone. Synergism with copromoter metal species was noted with as low as 2 mg. titanium used in conjuction with 2 mg. of vanadyl ion as the chelate. A minimal concentration for synergistic effect was noted for those metal species thus studied. This was found to range from 0.18 to 0.41 mmole of copromoter metal species per 100 g. of resin system. Advantage was taken of the peculiar effect of manganic acetyl acetonate to prolong gel times without affecting the rate at which complete polymerization was obtained. By using manganic acetyl acetonate in conjuction with vanadyl acetyl acetonate, it was possible to prolong the shelf‐life of a prepromoted resin from 17 to at least 110 days.
Preparation of polyconjugated systems by new reaction of dihydrohalogen polymerization
Authors: Paushkin I. M. , Nizova S. A.
Published: April 2003

The reaction of dihydrohalogen polymerization was suggested by the authors as a method for the preparation of polymers with conjugated double bonds on the basis of α,β‐dihalogen derivatives, oxides, and hydroxides. The reaction was carried out in an autoclave a t 200°C.; the reaction time was 6 hr. Polymers, obtained from α,β‐dibromopropylnitrile, α,β‐dibromopropyl alcohol, and α,β‐dibromoethylbutyl ether, are black and brown powders soluble in concentrated acids. The polymers show a sharp peak in EPR‐spectra characteristic of polyconjugated systems with concentration of paramagnetic particles of 1017–1019/g. The infrared spectra have characteristic absorption bands peculiar to polyconjugated systems.
Polymerization of isoprene with normal‐, iso‐, secondary and tertiary butyllithium
Authors: Kuntz Irving
Published: April 2003

When isoprene (3.3M) in n‐heptane is polymerized at 23.1°C. by the different butyllithiums (0.004M), the times to reach 50% conversion to polymer are 3.5, 2.3, 2.0, and 2.2 hr. for the normal, iso, secondary, and tertiary butyllithiums, respectively. When the same experiment is carried out at an initiator concentration of 0.02M, the t0.5 for the same sequence of isomers is 3.1, 2.6, 1.4, and 1.3 hr., respectively. In these and other experiments, the inherent viscosity of the polymers prepared with tert‐butyllithium appears to be lower than those obtained with n‐butyllithium. The stereochemistry of the polyisoprene polymers obtained with the different initiators is identical. The results with n‐and isobutyllithium at 0.02M concentration seem to show the greatest deviation from first‐order kinetics. Using data from experiments at different initiator concentrations and constant isoprene concentrations, the kinetic order in tert‐butyllithium has been found to be 0.54 ± 0.17. These observations reflect differences in initiation rate for the varied butyllithiums. The kinetic order in initiator indicates that the growing isoprenyllithium chains are involved in dimer formation whose dissociation is the slow step in the propagation reaction.
Interaction of poly(methacrylic acid) and bivalent counterions. I
Authors: Mandel M. , Leyte J. C.
Published: April 2003

The calculation of formation curves of metal‐polyacid complexes from titration curves is discussed. The interaction of bivalent ions of Cu, Cd, Zn, Ni, Co, and Mg with poly(methacrylic acid) is investigated by this method. These metals seem to form complexes involving two carboxylate groups for each ion in a large domain of pH values. Formation constants for these complexes are given which decrease according to the order indicated above.
Effects of swelling on proton relaxation in vinyl polymers
Authors: Bonera G. , Chierico A. , Rigamonti A.
Published: April 2003

Polystyrene and poly(methyl methacrylate) were swelled with the respective monomers and with suitable organic solvents. By means of a special experimental arrangement the spin‐lattice relaxation times of the protons of the swelling agent and of those of the swelled polymer were measured separately. Differences between the spin‐lattice relaxation time of the polymer during polymerization and that of the polymer swelled by the monomer are revealed and seem to point out a different degree of mobility in the polymer chains. In some instances an indication of differences in the motions that produce the relaxation is gained from the observed differences in the behavior of a polymer obtained through thermal polymerization and that of the same polymer obtained by ultraviolet radiation‐induced polymerization. With regard to the swelling agent there is also some experimental evidence pointing out the remarkable role taken by internal rotations of molecular groups in the mechanism of relaxation.
Effect of blending on the molecular weight distribution of polymers
Authors: Haward R. N. , Wright B. , Williamson G. R. , Thackray G.
Published: April 2003

The effect of blending polymers of different molecular weight on the Q value (Q = M̄w/M̄n) of the blend has been considered. A mathematical expression is derived, and its shows by a simple application to monodisperse systems that blending over a wide molecular weight range is necessary to give high Q values. These principles are then applied to the case of Ziegler and Phillips type high density polyethylenes having wide log‐normal molecular weight distributions. In this way it is shown that only blending over a very wide melt index range, e.g., 1000/1, can be expected to have a measurable effect on Q. A series of physical measurements on blended and homogenized Ziegler polyethylenes shows no significant differences between blends and directly produced polymers.
Copolymerization of propylene and styrene
Authors: Ashikari Nobuyuki , Kanemitsu Takayuki , Yanagisawa Kazuo , Nakagawa Kisaku , Okamoto Hiroshi , Kobayashi Shōgo , Nishioka Atsuo
Published: April 2003

Copolymerizations of propylene and styrene were carried out with various Ziegler‐Natta type catalysts in order to find the catalytic activity, the monomer reactivity ratios, and some properties of the copolymer. The polymerization products were confirmed to be copolymers from the facts that special behaviors were observed in the infrared and NMR spectra and that the melting point dropped with increasing styrene content. Generally, copolymer produced with a AlR3–TiCl4 catalyst had low stereoregularity and comparatively low molecular weight. On the contrary, a copolymer produced with a AlR3–TiCl3 catalyst had high stereoregularity and high molecular weight (viscosity). In order to reduce the viscosity various additives were examined. Monomer reactivity ratios obtained by the catalysts areas follows: for Al(i‐Bu)3–TiCl3: r1 = 20.0 ± 3.5, r2 = 0.20 ± 0.13; for AlEt3–TiCl3: r1 = 20.5 ± 3.0, r2 = 0.30 ± 0.15; for AiEt3–VCl4: r1 = 7.2 ± 0.7, r2 = 0.16 ± 0.08. All cases show that the reactivity of propylene is much larger than that of styrene.
Thermodynamic parameters for isotactic and atactic poly‐l‐pentene
Authors: Krigbaum W. R. , Woods J. D.
Published: April 2003

Precipitation temperature measurements have been the exclusive source of thermodynamic parameters used for the comparison of polymers differing in tacticity. The Flory theta temperatures differ for the various tactic forms, although not in a manner which exhibits any obvious consistency. The precipitation temperature entropy parameters, on the other hand, have been larger for the isotactic polymer in every case but one. The theoretical treatment underlying the evaluation of ψ1 from precipitation temperature data is, unfortunately, not strictly valid. Thus, the interpretation of this behavior is in some doubt. We report the results of an osmotic study of isotactic and atactic poly‐l‐pentene in phenetole at three temperatures. For the isotactic and atactic modification the respective values found were Θ = 329.0 and 321.5°K., while for ψ1 the values were 0.45 and 0.72. The theta temperatures fall in the same order as those previously obtained for a closely related system, poly‐l‐butene–anisole, by precipitation temperature measurements. The osmotic ψ1 values are larger than those reported here‐tofore for other systems, but of more importance, they fall in the reverse of the order consistently obtained from precipitation temperatures. This suggests that the regular variation of the precipitation temperature ψ1 values can not have its origin in local pair interaction effects; instead, it must reflect some difference in the concentration dependence of the chemical potential for solutions of the various tactic forms.
Temperature coefficient of unperturbed dimensions from solution properties
Authors: Bianchi Umberto
Published: April 2003

Values of d ln r02/dT, for polystyrene, poly(vinyl acetate), poly(methyl methacrylate), and polydimethylsiloxane recently obtained by different authors are compared. The large discrepancies among values reported are taken as an indication of the effects played by polymer–solvent interactions on unperturbed dimensions.
Thermochemistry of polymerization. Part I. Thermochemical aspects of copolymerization
Authors: Sawada Hideo
Published: April 2003

A new theoretical relationship for the heat of copolymerization is described. The heat of copolymerization for low conversion copolymers can be related to the heats of homopolymerization, the polymer composition, and two parameters which characterize the alternation tendency in copolymerization.
Some considerations on nonstationary‐state kinetics of vinyl polymerization
Authors: Burkhart R. D. , Faucher J. A.
Published: April 2003

When primary free radicals approach their stationary‐state concentration at a rate which is of the same order of magnitude as that with which chain radicals approach their stationary‐state concentration, the familiar nonstationary‐state equation relating the chain radical concentration to the time of reaction is no longer adequate. An accurate mathematical description of this situation has now been obtained which not only allows one to examine the dependence of chain radical concentration on the reaction time but also provides a basis for predicting under what conditions the primary radicals will be slow to approach a steady state. On the basis of these results the degree of error which is introduced into measurements of termination rate constants has been calculated and an experimental approach for measuring specific rate constants of chain initiation has been suggested.
Polyorganosilazanes
Authors: Krüger Carl R. , Rochow Eugene G.
Published: April 2003

Since dialkyldichlorosilanes yield almost entirely the cyclic trimeric and tetrameric silazanes by ammonolysis, a method had to be found to convert these oligomers into polymers. This can be done by heating the cyclic compounds with a catalytic amount of ammonium halides, preferably ammonium bromide or ammonium iodide, at 160°C. or more over a period of 6–8 hr. at atmospheric pressure. During this time ammonia is evolved, and there remains an oily polymer containing some silicon–halogen bonds. These are converted into SiN bonds by treating the raw polymer in ethereal solution with gaseous ammonia, yielding colorless waxy polysilazanes after evaporation of the solvent. The structures, spectra, properties, and reactions of these new polymers are discussed.
Proton magnetic resonance study of sorption of water and alcohols by wool
Authors: Bradbury J. H. , Forbes W. F. , Leeder J. D. , West G. W.
Published: April 2003

Measurements have been made of the proton magnetic resonance spectra of water, methanol, and ethanol sorbed by wool. The line widths of the spectra are related to the freedom of movement (mobility) of the sorbate molecules within the protein structure. At any particular value of molar sorption it is found that the mobilities of water, methanol, and ethanol are approximately equal, but the increase in volume of the wool increases in this series in the approximate ratio of 1 : 2 : 3. Thus, when a comparison is made of the mobility of the three sorbates at equal values of the volume swelling it is found that the order of mobility is water > methanol > ethanol.
Graft copolymerization with styrene and methyl methacrylate in very viscous medium
Authors: Lazár M. , Pavlinec J.
Published: April 2003

The influence of the viscosity of the medium on the rate and efficiency of a chemically initiated graft copolymerization with styrene and methylmethacrylate was studied. The increase in viscosity was reached partly by formation of the respective homopolymers, partly by the atactic polypropylene. The transfer constant to the atactic polypropylene from growing polystyrene macroradicals and the ratio of the rate constants of reaction of primary radicals with atactic polypropylene and with styrene were determined. It was found that the total efficiency of grafting styrene to atactic polypropylene increases with increasing concentration of polypropylene in the initial mixture and that the conversion of monomer is not a major influence in this case. On the contrary, for grafting of methyl methacrylate to atactic polypropylene a decrease of total efficiency with conversion of monomer was observed. This indicates that the gel effect is not only a function of viscosity of medium but also of the character of polymers in the reaction mixture.
Stereoregular polymerization of vinyl alkyl ethers with metal sulfate–sulfuric acid complex catalysts
Authors: Lal Joginder , McGrath James E.
Published: April 2003

The polymerization of vinyl alkyl ethers at room temperature or above, to give crystallizable polymers is of considerable interest for both theoretical and practical considerations. The polymerization of these monomers has been studied with metal sulfate–sulfuric acid complex catalysts at 0°C. or above to give high molecular weight, isotactic polymers. Ferric hydrosulfate hydrate and aluminum hexahydrosulfate heptahydrate (AHS) were used as catalysts. The nature of the solvent employed during polymerization with these heterogeneous catalysts was found to be quite important from the point of view of polymerization rate and stereoregularity of the polymer. A vinyl ether having a linear alkyl group polymerizes considerably faster than a monomer having a branched alkyl group. The apparent first‐order rate constant values for the AHS‐catalyzed polymerization of vinyl alkyl ethers having n‐alkyl groups indicate the following sequence: ethyl > n‐butyl > n‐hexyl = n‐octyl. In the temperature range of 30–58°C. the overall activation energy for the polymerization of vinyl n‐butyl ether in heptane with AHS catalyst was found to be 9.7 kcal./mole. Vinyl n‐butyl ether was copolymerized with β‐vinyloxyethyl methacrylate (M2) using AHS catalyst. The average values of r1 = 0.82 and r2 = 0.004 were obtained.
Kinetics of polymerization of molten trioxane
Authors: Kučera Miloslav , Spousta Eduard
Published: April 2003

Conversion curves of molten trioxane polymerization at temperatures between 70 and 90°C. have been measured. Their analysis has established that the rate‐controlling step of the reaction
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is the addition of a trioxane molecule to the active center. Values of the rate constants k1 and k3k4/k2 as well as the rate constants of initiator deactivation ks have been determined. Initiator deactivation causes premature leveling off of the conversion curves, especially at lower temperatures of polymerization (70–80°C.). The activation energies of the rate constants have been determined.
Initiation of the bulk polymerization of trioxane
Authors: Kučera Miloslav , Spousta Eduard
Published: April 2003

Kinetic analysis of the induction periods of trioxane polymerization shows that although the interaction of the initiator with a trioxane molecule is slow, the reaction of the initiator with free formaldehyde (followed by the splitting of trioxane) is quick and yields active centers. Kinetic relations have been developed for the amount of free formaldehyde in the first stages of the reaction between the initiator and trioxane, for the rate of formation of active centers and for the time dependence of the conversion of trioxane during the induction period. Kinetic formulas are compared with experimental data.
Lattice modes of polyethylene
Authors: Enomoto S. , Asahina M.
Published: April 2003

A modified Urey‐Bradley type force field was adopted to study the lattice modes of polyethylene by the GF matrices method with the intermolecular force constants which were estimated from the intermolecular potential function of methane. The frequencies of the modes were calculated at intervals of 30° for the phase differences along the a axis and the b axis. The elastic moduli of polyethylene crystal along both axes were also obtained from the intermolecular potential function.
The influence of molecular weight distribution on some properties of polystyrene melt
Authors: Ballman Richard L. , Simon Robert H. M.
Published: April 2003

The viscosities of a number of monodisperse polystyrene melts have been measured using a capillary rheometer. The materials covered a molecular weight range of 43,000–460,000. Shear rates of 1.54–1540 sec.−1 and temperatures of 350–450°F. were studied. The effect of molecular weight distribution of polydisperse polystyrene was also measured. It was found that while low shear viscosity was dependent on Mw, higher shear melt viscosities depended on averages between Mw and Mn until at 1000–2000 sec.−1, Mn controlled viscosity. Agreement with the 3.4‐power dependence of zero shear viscosity was good. Similar exponential relationships were found, with higher rates of shear, corresponding to smaller values of the exponent. Constant values of the exponent were found at constant shear stress but not at constant shear rate. Agreement with the constancy of the activation energy for viscous flow for various molecular weights and distributions at constant shear stress was good. However at constant shear rate, ΔE decreased as the molecular weight average increased and as the distribution broadened. Viscosity versus shear rate master curves were constructed by using the Buehe‐Harding procedure. All monodisperse polystyrenes showed excellent fit with the master curve. Other molecular weight distributions did not. Master curves also were constructed for measurements of dynamic viscosity versus frequency for monodisperse polystyrene. These curves when compared to steady state viscosities failed to confirm the correspondence of ηa to either |η*| or to η′.
Viscosity of amorphous polymers
Authors: Dibenedetto A. T.
Published: April 2003

An amorphous polymer is characterized as a homogeneous array of N identical, n‐center polymer segments which can be described in terms of four molecular constants. A mechanism for viscous flow (or self diffusion) is visualized as a positional exchange of two adjacent polymer segments in a hole the size of a segment‐pair. The activation energy for the viscous flow is the energy required to overcome the cohesive bonding to neighboring segments plus the work of compression required to form a hole of molecular dimensions. The effect of chain entanglement is estimated by using the theories of Bueche. An equation is derived for the viscosity in terms of a characteristic temperature, T0, a free volume expansion coefficient, β′, a fractional free volume for the glassy state fg0, an average segmental length, 2λn, and the four measurable molecular constants. This equation describes the lower limiting viscosity of polyisobutylene, polystyrene, and poly(vinyl acetate) over a viscosity range of up to a factor of 108 and for the whole temperature range of available data. It is shown that the characteristic temperature, T0, is close to the measured glass transition temperature, the free volume expansion coefficient, β′, is about 0.4 of the thermal expansion coefficient of the rubber and the fractional free volume fg0, is 0.1 for all the polymers. The size of the jumping unit in viscous flow is calculated to be about 0.1–0.3 of the size of an equivalent freely orienting segment.
Electron exchange polymers. XXII. Preparation and properties of poly‐2‐vinylphenothiazine
Authors: Kamogawa Hiroyoshi , Larkin Joel Marie , Tǒei Kyoji , Cassidy Harold G.
Published: April 2003

A new electron exchange polymer, poly‐2‐vinylphenothiazine, was prepared from 2‐vinylphenothiazine by thermal polymerization in an acetylating solvent (acetic anhydride) to form poly‐2‐vinyl‐N‐acetylphenothiazine. This was hydrolyzed with alcoholic alkali to yield greyish white poly‐2‐vinylphenothiazine, which is soluble in pyridine, dimethylformamide, chloroform, dioxane, and tetrahydrofuran, but not in aqueous solvents. The polymer could be oxidized with air in the presence of light, and oxidation with ferric chloride or bromine in tetrahydrofuran could be followed spectrophotometrically. On treatment with bromine followed with aqueous dimethylamine, the polymer became soluble in 90% acetic acid, in which solvent it could be reduced with titanium trichloride and reoxidized with bromine.
Determination of a Mark‐Houwink type relationship for poly‐N‐tert‐butylacrylamide in methanol
Authors: Cavell E. A. S. , Gilson I. T. , Jennings B. R. , Jerrard H. G.
Published: April 2003

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This investigation has shown that it is possible to prepare V complexes of amylose from dimethyl sulfoxide solutions. Methanol, n‐propanol, acetone, and methyl ethyl ketone complexes have been prepared and their unit cell dimensions calculated from their x‐ray powder patterns. The small unit cell, with a helix diameter of 13.0 A., observed with a wet methanol complex from aqueous system, is also observed here. However, the wet and thoroughly dired ketone complexes prepared from DMSO have the larger helix diameter of 13.7 A. The results indicate that factors other than the size or type of complexing agent are important in determining the helix diameter of the amylose V complex. They also indicate that these factors are complex and probably interdependent. The effect of temperature on the helix diameter was explored.