bluuebunny/crossref_metadata_2025 huggingface dataset:
A method of estimating molecular weight distributions of polymer fractions
Authors: Okamoto Hiroshi
Published: April 2003

A method of estimating molecular weight distributions of polymer fractions which was proposed previously is investigated. The distribution curves calculated by the proposed method are compared to the experimental curves. Several numerical experiments are also carried out to discuss a nonsystematic change of the fractionation parameters.
Some aspects of thermal decomposition of polyoxymethylene and irradiated polyoxymethylene
Authors: Torikai Sadao
Published: April 2003

The thermal decomposition of polyoxymethylene and irradiated polyoxymethylene in vacuum was carried out and the kinetic aspects of thermal decomposition discussed. Although decomposition of low viscosity polyoxymethylene followed a pattern in which log (polymer residue) was roughly linear with decomposition time, the high‐viscosity polyoxymethylene which was obtained by the post‐polymerization of irradiated solid formaldehyde showed the two components different in stability. However the concentrations of the components depended on the decomposition temperature. After the thermal decomposition, the sample could not be further stabilized by acetylation, while this initial polymer could be highly stabilized by acetylation. The irradiated polymer also could not be thermally stabilized by acetylation, though the first component of the irradiated polyoxymethylene disappeared after acetylation. The components of the polymer irradiated at 100°C., ∼4 Mr (ηsp/c = 0.23) showed three components the concentrations of which are independent of decomposition temperature. In irradiation at room temperature, or in the case of irradiation by the electron beams from a Van de Graaf generator at a high dose rate, the evacuation at 100°C. of the irradiated sample after irradiation disclosed the clear dependence of formation of stable polymer on dose, and the formation of three components which are independent of the decomposition temperature.
Coupled vinyl and acetal ring‐opening polymerization
Authors: Goodman Murray , Abe Akihiro
Published: April 2003

4‐Methylene‐1,3‐dioxolane and its derivatives were polymerized by cationic catalysts. Infrared and ultraviolet studies showed that the polymers of 2,2‐dimethyl‐ or 2‐methyl‐1,3‐dioxolane possess appreciable carbonyl content. This indicates that the polymerization takes place in such a manner that the carbon–carbon double bond opening is coupled with a concurrent acetal ring rearrangement in the propagation step to give “ketoether” sequences. 4‐Methylene‐1,3‐dioxolane, on the other hand, was found to polymerize mostly at the carbon–carbon double bond. Copolymerization of these monomers with acrylonitrile under ultraviolet irradiation was also studied.
Thermal decomposition of model compounds of polyvinyl chloride. II. Gaseous thermal decomposition of unsaturated chain end model compounds
Authors: Asahina Mitsuo , Onozuka Mitsuo
Published: April 2003

The gaseous thermal decomposition of model compounds with unsaturated chain ends which correspond to abnormal structures in polyvinyl chloride is studied. The allyl type chloride which is located in the main chain, but not at the end of polymer is more unstable than all kinds of abnormal structures present at the end of the polymer chain. Thus, it may be supposed that the sites of initiation of decomposition are formed during polymerization with chain transfer to polymer.
Dilute solution properties of partly urethanized polyvinyl alcohol
Authors: Sakurada Ichiro , Nakajima Akio , Shibatani Kyoichiro
Published: April 2003

Partly urethanized polyvinyl alcohol samples, in a range of degree of urethanization up to about 10 mole‐%, were prepared by treatment of polyvinyl alcohol with urea. These were fractionated in a water–n‐propanol system into fractions, each having nearly the same nitrogen content. The degree of polymerization of the partly urethanized polyvinyl alcohol was estimated from the intrinsic viscosity of polyvinyl alcohol obtained by hydrolysis of the corresponding urethanized polymer. The effects of introduced urethane residue on solubility and dissolved state of polymer were investigated in water and theta solvents. Further, some thermodynamic parameters in water were discussed in relation to those of partly acetylated polyvinyl alcohol.
Radiation‐induced copolymerization of acrylonitrile with styrene
Authors: Tabata Yoneho , Hashizume Yoshio , Sobue Hiroshi
Published: April 2003

Radiation‐induced copolymerization of acrylonitrile with styrene was carried out over a wide range of temperatures. It was found that the rate of copolymerization is proportional to the square root of the dose rate. An apparent activation energy of 6.90 kcal./mole was obtained for the copolymerization in an equimolar mixture of monomers. The rate of copolymerization increased with the molar concentration of acrylonitrile in the monomer mixture. Monomer reactivity ratios were determined as rAN = 0.03, rSt = 0.33 for the copolymerization at 15 and 0°C., rAN = 0.28, rSt = 0 at −20°C. in the liquid state of monomers. On the other hand, the monomer reactivity ratios were obtained as rAN ≃ 0 and rSt ≃ 0 for the copolymerization in the solid state at −78°C. It was concluded from these experimental results that there is a great difference between the liquid‐state and solid‐state copolymerizations, both in the polymerization mechanism and the structure of copolymers.
Determination of 1,2‐glycol units in polyvinyl alcohol
Authors: Harris Henry E. , Pritchard J. G.
Published: April 2003

A titrimetric method, involving the determination of the periodate consumption by means of iodine and arsenious oxide, was applied to the determination of 1,2‐glycol units in polyvinyl alcohol by periodate cleavage. The method gave consistent results regardless of the molecular weight of the sample, and is believed to be accurate to ±0.05% glycol units. In contrast, it was shown that the well‐known Flory‐Leutner viscometric method gave results which were about 20% lower than those obtained by the first method for samples of molecular weight greater than about 40,000, and gave grossly unrealistic results for samples of much lower molecular weight. Details of the methods and sources of error are discussed.
Efficiency and frequency of grafting of methyl methacrylate to granular corn starch
Authors: Brockway C. E.
Published: April 2003

PMMA content of graft copolymers with granular starch can be determined by acid hydrolysis with sufficient precision to allow reasonable estimates of efficiency and frequency of grafting. Preparation of the graft copolymer by initiation of methyl methacrylate with hydrogen peroxide and activators results in products containing long PMMA side chains attached to the starch at very infrequent intervals, but the length and frequency of attachment can be varied considerably by changes in the ratios of reactants. The highest frequency achieved was with PMMA of number‐average molecular weight of about 30,000, attached at a frequency of one chain per 230–250 glucose units in the starch. Under the more favorable conditions, oxidized starch yielded product of significantly more frequent grafting than did unmodified starch. Gradual addition of monomer, initiator, and activator to the starch slurry gave slightly higher frequency of grafting than did complete addition of all reactants at the start of the polymerization.
Statistical theory of the polymerization of polyepoxide monomers
Authors: Fukui Kenichi , Yamabe Tokio
Published: April 2003

A statistical study of the ring‐opening polymerization of polyepoxides is made under the assumption of equal rates of initiation and propagation. The Poisson‐type distribution and the gel point formula are characterized by the following equations:

where p is the number of monomeric units, v is the number of propagating ends in a polymer, α is f[M]0/[I], p and pc are the fraction of reacted functional groups and its critical value, f is the number of functional groups on the monomer, and [I]0 and [M]0 are the initial concentrations of initiator and monomer, respectively.
Influence of catalyst depletion or deactivation on polymerization kinetics
Authors: Friedlander Herbert N.
Published: April 2003

Kinetic models based on the time dependence of the deactivation of catalyst sites have been fitted to data on reaction kinetics taken from the literature for polymerization of various olefins on a series of ionic and coordinate catalysts (both homogeneous and heterogeneous) for a variety of polymerization conditions. In clean coordinate polymerization systems where termination is unimportant, the propagation reaction plays a major role and is influenced by the number of active catalyst sites. The number of sites remains constant in some catalysts but varies in most. First‐order deactivation of catalyst sites leads to dead‐end kinetics similar to that described by Tobolsky for free‐radical polymerization with catalyst depletion by first‐order decomposition. Second‐order deactivation leads to kinetics linear in the logarithm of time. In heterogeneous polymerization, it is difficult to find a physical model for interaction of isolated sites required for higher‐order deactivation. The experimental data are fitted equally well by a mixed‐order model assuming sites of different stability exhibiting first‐order deactivation. At low conversions, the models are difficult to fit to experimental data in which monomer concentration is varing. Further experiments are required to test the models, obtain exact values for rates constants, and determine the influence of catalyst deactivation on molecular weight and molecular weight distribution.
Polymerization of the carbon–nitrogen double bond in carbodiimides
Authors: Robinson G. C.
Published: April 2003

Polymerization of one of the carbon‐nitrogen double bonds in carbodiimides has been effected with n‐butyllithium catalyst in hydrocarbon solvents at 25°C. Monomers converted to polymer include diethylcarbodiimide, di‐n‐butylcarbodiimide, di‐n‐hexylcarbodiimide, diphenylcarbodiimide, diallylcarbodiimide, and methylisopropylcarbodiimide. Monomers which failed to polymerize were dicyclohexylcarbodiimide, diisopropylcarbodiimide, and methyl‐tert‐butylcarbodiimide. Thermal polymerization and depolymerization of diethylcarbodiimide was investigated and the polymers were characterized. Polymers with an inherent viscosity of 0.1–0.4 (formic acid solvent) were obtained in this work. The steric limitations on the nature of the substituents at the backbone nitrogen and the pendant nitrogen of the polymer chain were elucidated. The cis–trans isomerism possible at the pendant nitrogen is discussed. The failure of a solution of polydiethylcarbodiimide in aqueous acetic acid (presumably a polyelectrolyte) to behave on dilution as a polyelectrolyte is tentatively attributed to the stiff polymer backbone. Depolymerization of these polymers appears to be an unzipping.
Effect of chemical reagents on the fine structure of cellulose. Part I. Action of diazomethane
Authors: Spedding H. , Warwicker J. O.
Published: April 2003

An infrared and x‐ray study of the action of diazomethane on the fine structure of ramie and regenerated cellulose (fiber and film) has been made. It has been found that the methylation process affects the disordered regions, and also parts of the structure that are sufficiently highly ordered to be detected by x‐ray methods but whose hydrogenbond order is too low to be detected by the infrared‐deuteration technique. The effect of partial methylation on the hydrogen bonding in the noncrystalline regions is described and discussed. The conclusion drawn from the results is that diazomethane can react in the noncrystalline and the imperfectly crystalline regions, but not in the highly ordered crystalline regions.
Studies in condensed phosphates. Part VII. Metachromatic reactions of sodium polymetaphosphate and its derivatives
Authors: Mehrotra R. C. , Gupta V. S.
Published: April 2003

Metachromatic behavior of the complex metaphosphates is almost identical to that of Graham's salt and is quite different from that of either simple or mixed trimeta‐ or other lower phosphates. With toluidine blue, the wavelength of maximum absorption shifts from 630 to 530 mμ in all the above cases. Addition of calcium or barium chlorides did not show any change in the optical density or wavelength of maximum absorption except at 4.0 × 10−4M barium chloride concentration.
Cyclo‐ and cyclized diene polymers. I. Polymerization of conjugated dienes to ladder cyclo‐polymers with complex catalysts
Authors: Gaylord N. G. , Kössler I. , Štolka M. , Vodehnal J.
Published: April 2003

Polymerization of isoprene, butadiene, and chloroprene with complex catalysts consisting of alkyl or arylmagnesium bromide or triethylaluminum and excess TiCl4 leads to the formation of powdery, insoluble, probably crosslinked polymers with high density and high heat resistance (>370°C). The structure of these polymers differs from that of those prepared at higher molar ratios of organometallic compound to titanium tetrachloride. The infrared analysis of the powdery polymers and comparisons with the spectra of cyclized 3,4‐polyisoprene and cyclized 1,4‐cis‐polyisoprene indicate that the polymer chain consists of fused six‐membered saturated rings in the form of a linear ladder or spiral ladder structure. The residual linear segments with 1,4 units, present in the predominantly cyclic polymers, may be isomerized to a cyclic form by the action of H2SO4. Removing the linear segments from the polymer chain further improves the heat resistance. It is proposed that the cyclic structure is formed during the polymerization from 1,2‐polymer and not as a result of the action of catalyst components on primarily formed linear chains. The cyclic structure may be ascribed to all three investigated polymers.
Polymerization of chlorinated diphenylsiloxanes
Authors: Ganci James B. , Bettelheim Frederick A.
Published: April 2003

Chlorinated diphenylsiloxanes were prepared by acid‐ and base‐catalyzed polymerization of the corresponding diols in polar organic solvents. Under mild conditions, cyclic tetramers were isolated. More forcing conditions in the presence of base yielded resins containing largely cyclic species which showed extensive cleavage of the phenyl groups. The order of the phenyl group cleavage among the polymers indicated that the inductive effect of the substituent halogen plays a dominant role.
Thermal stability of the copolymer of sulfur dioxide and cis,cis‐1,5‐cyclooctadiene
Authors: Frazer A. H.
Published: April 2003

The copolymer of sulfur dioxide and cis,cis‐1,5‐cyclooctadiene has been synthesized under a variety of conditions and pyrolyzed. Degradation of this copolymer followed first‐order kinetics to a first approximation at 220°C. or above. Random cleavage of the polymer chain accompanied the pyrolysis as it was carried out in these experiments. Pyrolysis of the copolymer up to 75% loss of weight yielded the monomers as cracking products and in the mole ratio of the copolymer composition.
Experimental data on dilute polymer solutions. Hydrodynamic properties and statistical coil dimensions of poly(n‐butyl methacrylate). Part II
Authors: Van Leemput R. , Stein R.
Published: April 2003

Viscometric measurements were carried out on poly(n‐butyl methacrylate) fractions in chloroform, benzene, toluene, and dioxane. Light‐scattering and viscometric measurements on these fractions were carried out in isopropanol over a narrow range of temperatures. The Flory‐Fox Θ‐temperature was obtained by graphical interpolation on a plot of the second virial coefficient versus the reciprocal of the absolute temperature. Values of Φ, calculated according to the Flory‐Fox equation were found to be abnormally low, notwithstanding the application of heterodispersity corrections, a mean value of 1.62 × 1023 being found in isopropanol in the temperature range investigated. The dependence of [η] on the mean radii of gyration is found to be less than that predicted by the Flory‐Fox theory. The light‐scattering dimensions systematically appear to be too large in the ideal solvent, a discrepancy that cannot be explained by accumulated experimental factors.
Density gradient centrifugation of a graft copolymer
Authors: Ende H. A. , Stannett V.
Published: April 2003

A well‐defined graft copolymer of polystyrene and cellulose acetate has been investigated using the density gradient ultracentrifugation method. The initial sample showed two peaks. These were found to be pure graft copolymer and polystyrene; the latter was easily removed by further extraction of the mixture with benzene. The composition of the graft copolymer was determined from the buoyant densities of the graft and the two homopolymers and found to be 49% polystyrene, 51% cellulose acetate compared with 44.1 and 55.9%, respectively, estimated from the weight loss after acid hydrolysis.
The effect of simultaneously occurring processes on the course of polymer crystallization
Authors: Banks W. , Sharples A. , Hay J. N.
Published: April 2003

The possibility that simultaneously occurring processes may account for the anomalous fractional values of the Avrami exponent found in recent polymer crystallization experiments is considered, and, on balance, rejected. A more likely explanation is that one of the assumptions used in deriving the Avrami equation is at fault. This leads to the conclusion that the Avrami parameters cannot be used diagnostically to provide information on crystallization mechanism, as has been considered to be the case in the past.
Fracture processes in polymeric materials. V. Dependence of the ultimate properties of poly(methyl methacrylate) on molecular weight
Authors: Berry J. P.
Published: April 2003

The influence of molecular weight on the fracture surface energy, Young's modulus, tensile strength, and inherent flaw size in poly(methyl methacrylate) has been determined. In common with other mechanical properties, the dependence of the fracture surface energy on molecular weight can be represented by γ = A – (B/M), where M is the molecular weight, and A and B are arbitrary constants. By extrapolation, the upper limiting value is 1.55 × 105 ergs/cm.2, while the surface energy, and hence the tensile strength, should become zero for a polymer of molecular weight 25,000. This value is in good agreement with that found directly from brittle strength measurements.
X‐ray‐induced polymerization of diphenylvinylphosphine oxide
Authors: Allcock H. R.
Published: April 2003

Diphenylvinylphosphine oxide was polymerized in the molten state by x‐irradiation to give polymers with molecular weights up to 10,000. The results of variations in total radiation dose, dose rate, and temperature, are consistent with a free radical polymerization mechanism in which chain transfer is important. Infrared spectra of the polymers provided evidence that phenyl groups are involved in the chain transfer processes.
Kinetic study of the polymerization of α‐d‐styrene and/or styrene by homogeneous catalysis. Part I
Authors: Overberger C. G. , Diachkovsky F. S. , Jarovitzky P. A.
Published: April 2003

Increases in the rates of polymerization of α‐d‐styrene and/or styrene by homogeneous catalysis with the (C5H5)2TiCl2–Al(C2H5)2Cl catalyst system were shown to be directly proportional to the α‐d‐styrene monomer concentration. These rate increases were explained by an increase in the concentration of active centers. Polymer intrinsic viscosities were shown to be independent of the α‐d‐styrene monomer concentration. Changes in the polymerization rates were correlated with observed changes in the catalyst composition measured spectrophotometrically. A scheme is suggested to explain the observed results.
Configuration and hydrodynamic properties of fully acetylated guaran
Authors: Koleske Joseph V. , Kurath Sheldon F.
Published: April 2003

Fully acetylated guaran, (guaran triacetate, GTA), was fractionated and the fractions in the weight‐average degree of polymerization range of 171 to 12,400 were characterized by light scattering and viscometry. At high molecular weights, non‐Newtonian flow was observed and after appropriate correction the intrinsic viscosity was found to be independent of shear gradient. Analysis of viscosity results according to the theory of Kurata and Yamakawa indicated that at high molecular weights the molecule is nondraining and that excluded volume effects are absent. Polymolecularity was estimated from ultracentrifuge and osmotic pressure measurements on certain key fractions and in the case of one fraction it was possible to determine the distribution of molecular weights and to demonstrate the validity of the Zimm‐Schulz distribution. The ratio of the mean square radius of gyration to the molecular weight was found to decrease with increasing molecular weight indicating a non‐Gaussian behavior that cannot be accounted for by the Porod‐Kratky chain model. The dependence of radius of gyration on chain length is identical to that observed for hydroxyethyl cellulose and cellulose tricaproate indicating that the β‐1,4‐linked D‐glucose chain of cellulose and the β‐1,4‐linked chain of GTA have similar configurations, in spite of chemical and structural differences between the anhydro sugar units. The α‐1,6‐linked D‐galactose side groups on every other mannose unit of GTA do not appear to affect main chain configurations to any great extent. Equivalent bond lengths calculated from intrinsic viscosity and from light scattering indicate that it is necessary to distinguish between the hydrodynamic and light‐scattering radius of gyration The Flory coefficient calculated from the light‐scattering radius of gyration was found to increase with increasing molecular weight. When the hydrodynamic radius of gyration was used in the calculation, agreement with the theoretical Flory constant was within experimental error.
Calculation of copolymerization reactivity parameters from product probabilities
Authors: Ham George E.
Published: April 2003

The premise is examined that there exists for each monomer in copolymerization a reactivity parameter p, such that a product probability may be calculated for any combination of three monomers in binary or ternary polymerization, where = Pab‐PbcPca = PacPcbPba. The consistency of this equation and its derived equation, r12r23r31 = r13r32r21, with the Q–e scheme is demonstrated. Simplified equations are presented relating monomer and copolymer composition for any number of monomers: a/b = Pba/Pab, a/c = Pca/Pac,…, up to a/j = Pja/Paj, where j is the final component in the copolymerization and each probability includes possibilities of reaction of a given radical with monomers a–j.
Prediction of ionic copolymerization reactivity ratios
Authors: O'Driscoll Kenneth F.
Published: April 2003

It is shown that it is possible to predict the reactivity ratios for the copolymerization of a given monomer pair if each monomer has been separately copolymerized with a third monomer, and the product of the reactivity ratios of one of these separate copolymerizations is equal to unity. This latter condition is frequently met in ionic copolymerizations and is sometimes true in free radical copolymerizations. Literature data for five trios of monomer are examined to show the validity of the predictions.
Kinetics and mechanism of the trialkylboron‐catalyzed polymerization of methyl methacrylate in the presence of oxygen
Authors: Hansen Richard L.
Published: April 2003

The rate of the bulk polymerization of methyl methacrylate catalyzed by triethylboron‐oxygen was investigated. The rate was studied as a function of initial triethylboron and oxygen concentrations as well as temperature. The effect of hydroquinone was determined. The polymerization rate was also investigated using several other trialkylboranes. The initial rate of the triethylboron‐catalyzed polymerization was found to depend on the square root of the oxygen concentration and on the square root of the difference between the triethylboron and oxygen concentrations. The rates at higher conversions were consistent with an initiation mechanism requiring consideration of reactions at all three boron–carbon bonds. An initiation mechanism involving oxidation to peroxide followed by a reduction utilizing unoxidized boron–carbon bonds is advanced. Ethyl radical, produced in this reduction, is the initiating species. The overall activation energy taken from initial rates was 2.4 ± 0.3 kcal./mole in the range 0–45°C. A very slow polymerization with triethylboron was observed in the absence of oxygen. Hydroquinone behaved as a typical inhibitor for the aerobic polymerization but did not inhibit the polymerization in the absence of oxygen.
Ionic copolymerization of styrene and p‐methylstyrene
Authors: Phillips B. D. , Hanlon T. L. , Tobolsky A. V.
Published: April 2003

The copolymerization of styrene and p‐methylstyrene has been initiated by Friedel‐Crafts metal halides, benzoyl peroxide, a Ziegler catalyst from triethylaluminum and titanium tetrachloride, alkali metal dispersions, and alkali metal‐naphthalene complexes in a variety of polar and nonpolar solvents. The composition of the initial copolymer from an equimolar monomer mixture was used as the basis for comparison of these systems. By a suitable choice of initiator and solvent, the copolymer composition was varied within the range 25–79 wt.‐% styrene. Cationic catalysts yield copolymers with low styrene contents while anionic and electron transfer initiator produce copolymers with high styrene contents. The compositions of the initial copolymers are briefly discussed in relation to the ionic character of the growing polymer–gegenion ion pair and the polarity of the reaction medium.
Polymerization in liquid sulfur dioxide. Part XXII. Comparison of retarding effects of bases on the radical polymerization of acrylonitrile in liquid sulfur dioxide
Authors: Matsuda Minoru , Tokura Nichiro
Published: April 2003

The radical polymerization of acrylonitrile was carried out in liquid sulfur dioxide and in benzene, with addition of aniline, dimethylaniline, dimethyl‐0‐toluidine, and diethylaniline to these systems. The temperatures of polymerization were 40, 50, and 60°C. It was found that the chain transfer reaction occurs more easily in liquid sulfur dioxide than in benzene; this was attributed to the differences in the polarity of the terminal radical of the growing chain in both solvents. The difference of activation energies due to the difference of bases is not so large. The frequency factors are rather important in both solvents for chain transfer reactions. The isokinetic relation is also discussed.
Homopolymers and terpolymers of 5,7‐dimethyl‐1,6‐octadiene
Authors: Wilbur J. M. , Marvel C. S.
Published: April 2003

Polymerization of 5,7‐dimethyl‐1,6‐octadiene with a 2/1 molar ratio of triisobutylaluminum/vanadium oxychloride, triisobutylaluminum/titanium tetrachloride or triisobutylaluminum/vanadium tetrachloride affords an elastic homopolymer. Attempted polymerization of the isomeric 3,7‐dimethyl‐1,6‐octadiene under the same conditions failed. Elastomeric terpolymers of ethylene, propylene, and 5,7‐dimethyl‐1,6‐octadiene have been prepared with these same coordination catalysts.
Endgroup studies in persulfate‐initiated vinyl polymer by dye techniques. Part I. Initiation by persulfate alone
Authors: Ghosh Premamoy , Chadha Subhash Chander , Mukherjee Asish R. , Palit Santi R.
Published: April 2003

Quantitative determination of endgroups of poly(methyl methacrylate), polystyrene and poly(vinyl acetate) obtained by aqueous initiation with K2S2O8 under varied conditions have been made by the application of two sensitive dye techniques, called the dye partition technique and the dye interaction technique. The description of the dye techniques are given in detail. Sulfate (OSO3−) and hydroxyl (OH) endgroups are generally found to be incorporated in the polymers to an average total of 1.5 to 2.5 endgroups per polymer chain. Hydroxyl endgroups are always present to a fairly large extent. The proportion of sulfate endgroups in polymers is highly dependent on the pH of the polymerizing medium; it increases with the alkalinity of the medium and sharply decreases under acid conditions.
Copolymerization of 4‐cyclopentene‐1,3‐dione with acrylonitrile and methyl methacrylate
Authors: Hamb F. Lynn , Winston Anthony
Published: April 2003

The copolymerization of acrylonitrile and methyl methacrylate with 4‐cyclopentene‐1,3‐dione (M2) is reported. The copolymers were prepared by heating the monomer feeds in sealed tubes with α,α′‐azobisisobutyronitrile. Infrared bands for both the β‐diketone and the nitrile, in the case of acrylonitrile, or ester, in the case of methyl methacrylate, indicated that copolymerization had occurred. The acrylonitrile copolymers were insoluble in the common solvents and swelled on treatment with dimethylformamide and dimethylsulfoxide. The methyl methacrylate copolymers were partially soluble in the usual solvents with the solubility and gel content varying with the composition of the copolymers. Solution viscosities indicated high molecular weights. The reduced specific viscosity of the sodium salt of the 0.05 methyl methacrylate copolymer increased with decreasing concentration, a characteristic typical of polyelectrolytes. The compositions of the copolymers were determined from the nitrogen analyses for acrylonitrile copolymers, and the ultraviolet absorption of the β‐diketone for the methyl methacrylate copolymers. The molar extinction coefficient of the β‐diketone structural unit was estimated from a study of model compounds. The reactivity ratios were evaluated by the usual methods. For the acrylonitrile (M1)–4‐cyclopentene‐1,3‐dione (M2) system, r1 = 3.67, r2 = 0.21. For the methyl methacrylate (M1)–4‐cyclopentene‐1,3‐dione (M2) system r1 = 7.4, r2 = 0.083. For each system Q and e values for 4‐cyclopentene‐1,3‐dione were evaluated. The average values are Q = 0.20, e = 1.42. The behavior of 4‐cyclopentene‐1,3‐dione is compared with maleic anhydride and N‐butylmaleimide with respect to the reactivity of the monomer, the reactivity of the radical, and the effective polarity of the double bond.
Molecular configuration and hydrodynamic behavior of poly‐N‐tert‐butylacrylamide in methanol
Authors: Jennings B. R. , Jerrard H. G.
Published: April 2003

The results of a light‐scattering study of six samples of poly‐N‐tert‐butylacrylamide in methanol are presented. Some confirmatory results have been obtained with the use of an ultracentrifuge. The derivation of molecular parameters from Zimm plots and centrifugation data is briefly described. Methanol is found to be a good solvent for poly‐NTBA, in which it behaves as a stiff molecule expanded beyond random flight predictions. The effect of the stiffness on the Zimm plots and on the interpretation of the results is discussed. Values of the weight‐average and number‐average molecular weights (M̄w and M̄n), the z‐average and number‐average radii of gyration (pz2)1/2 and (pn2)1/2 and the corresponding end‐to‐end distances (rz2)1/2 and (pn2)1/2 are found. r2 = 161N̄, where N is the degree of polymerization and r̄ is measured in Angstroms. Values are also obtained for the length of the statistical element, the Kratky‐Porod persistence length, the coiling factor, the molecular expansion factor, the second osmotie virial coefficient, (A2), and the Flory constants Φ and Kv. Equations for the variation of (pn2)1/2 and of A2 with molecular weight are derived: they are (pn2)1/2 = 3.76 × 10−9 M̄n−0.515 and A2 = 0.082 M̄w−0.515, respectively. The value of Φ is considerably less than that normally predicted, and possible reasons for this are suggested. Empirical relations involving the excluded volume effect are mentioned.
Polymerization of acetaldehyde. Part V. Polyaldol condensation of acetaldehyde by alkali metal amalgam as catalyst. II
Authors: Imoto Tatsuya , Matsubara Tsutomu
Published: April 2003

In a previous paper, it was reported that an acetaldehyde polymer of the poly‐(vinylalcohol) type was obtained by polymerization of acetaldehyde with sodium amalgam as catalyst. In the present, more detailed investigation, it was found that the catalyst concentration, the reaction time, the reaction temperature, and the solvent concentration have certain effects on the molecular weight and the yield of polymer. At the early stage of this polymerization, the yield is proportional to the square root of the reaction period. So, at this stage, the reaction may be assumed to be diffusion‐controlled. Several solvents and the two‐stage polymerization have influences upon this polymerization.
Polymerization of higher aldehydes. IV. Crystalline isotactic polyaldehydes: Anionic and cationic polymerization
Authors: Vogl O.
Published: April 2003

Low temperature polymerization of aldehydes in solvents of low dielectric constants yields crystalline isotactic polyaldehydes. Alkali metal alkoxides were found to be the best initiators; but alkali metals, alkali metal alkyls, Grignard reagents, lithium aluminum hydride, and aluminum organic compounds also work effectively. Isotactic polyaldehydes were also obtained by cationic initiation (stannic bromide, solid BF3 etherate). The stereoregularity increases with the increase of the space requirements of the side chain.
Electron transfer polymers. XXIII. Interactions of the quinhydrone type in polyvinylhydroquinone solutions
Authors: Kamogawa Hiroyoshi , Giza Yueh‐Hua Chen , Cassidy Harold G.
Published: April 2003

An investigation was made of the pink‐orange color that reaches maximum intensity at the midpoint of the titration of homopolymers of vinylhydroquinone. It was shown that during oxidative titration the hydroquinone absorption at 295 mμ decreases in intensity while quinone absorption at 254 mμ, increases. At the midpoint of the titration absorption at approximately 455 mμ, the pink color, reaches its maximum intensity, with relatively low extinction coefficient. The position of the maxima does not change with extent of oxidation; the specific extinction coefficient is independent of concentration and degree of polymerization, but somewhat dependent on the nature of the solvent. When the functional groups were somewhat separated along the chain by copolymerization with an alternating comonomer, styrene, α‐methylstyrene, or acrylamide, there was no appreciable shift in the ultraviolet absorption peaks with oxidation, but in the visible region the intensity at 455 mμ was greatly decreased, compared with homopolymer, at all degrees of oxidation around the midpoint. Analysis of the spectroscopic data led to the conclusion that the number of quinhydronelike interactions is low relative to the number of groups that are not interacting.
On the theory of divalent ion binding by polyelectrolytes
Authors: Strauss Ulrich P. , Lifson Sheneior
Published: April 2003

The problem of the binding of a divalent counterion by two adjacent binding sites of a uniform linear polyelectrolyte has been investigated for both finite and infinite chain lengths. Allowance has been made for interactions between adjoining ionized groups and for the presence of a univalent counterion which may also be bound. For the case of finite chain lengths, the partition function is obtained in terms of a 3 × 3 matrix containing the conditional probabilities of the possible states of a polyelectrolyte group. By a novel method, the expression for the partition function is then simplified to a finite polynomial containing only the coefficients of the secular equation, but not its eigenvalues. From this expression for the partition function, the quasi‐grand partition function for the infinitely long chain is calculated. It is shown that for both cases of finite and infinite chain length, closed explicit expressions relating the degrees of ionization and ion binding to the ion activities and the interaction parameter may be obtained from which the eigenvalues of the matrix have been eliminated. The applicability of the new method of calculation to other problems involving finite linear Ising lattices is briefly discussed.
Chemically heterogeneous populations of copolymer latex particles. Preparation, fractionation, and characterization
Authors: Yannas J. B. , Isgur I. E.
Published: April 2003

The chemical homogeneity of copolymer latex particle populations was studied as a function of polymerization conditions. The comonomer system chosen was styrene–butadiene, and the polymerization variables included the comonomer addition rate and the amount of emulsifier introduced during the reaction. It was found that under conditions of variable comonomer addition rate and with introduction of excess emulsifier during the reaction, a bidisperse latex is produced which contains two chemically distinct particle populations. These populations were separated from one another using a centrifugation technique reported recently and were characterized by electron microscopy and chemical analysis. Each particle population was relatively monodisperse with respect to particle size and differed from its counterpart with respect to average particle size and comonomer ratio. Other combinations of the polymerization variables mentioned above yielded latices with chemically homogeneous particle populations.
Infrared and nuclear magnetic resonance studies of the microstructures of polychloroprenes
Authors: Ferguson Raymond C.
Published: April 2003

High resolution infrared and nuclear magnetic resonance spectra confirm the structure of cis‐polychloroprene prepared by a stereospecific route. Head‐to‐tail, head‐to‐head, and tail‐to‐tail sequence isomerism in both cis‐ and trans‐polychloroprenes has been discovered and measured quantitatively by high resolution NMR spectroscopy. The irregularity in the microstructure of neoprenes proves to be more extensive than was previously suspected.
Anionic polymerization and oligomerization of methacrylonitrile by alkali metal alkoxides
Authors: Feit Ben‐Ami , Wallach Joseph , Zilkha Albert
Published: April 2003

The anionic homogeneous polymerization of methacrylonitrile by alcoholic solutions of alkali metal alkoxides in dimethylformamide was studied. The molecular weight was found to be directly proportional to monomer concentration and inversely proportional to methanol concentration in accordance with the equation DP = (Kp/Kt) [MAN]/‐[CH3OH], as consistent with termination by methanol. The average Kp/Kt value obtained was 2.1–2.2. This low value enabled the formation of low oligomers at relatively high methanol concentrations. This is in contrast with the previous results of a parallel polymerization system with acrylonitrile, where only the cyanoethylation product together with relatively high polymers, and no intermediate oligomers, were formed. The physical properties of the oligomers (n = 2–5) are given.
Amylose V complexes from 2‐aminoethanol solutions
Authors: Valletta R. M. , Germino F. J.
Published: April 2003

The amylose V complexes with methanol, 1‐propanol, 1‐butanol, and acetone have been prepared from 2‐aminoethanol solutions at 95°C. and their unit cell dimensions calculated from their x‐ray powder patterns. The study shows that amylose V complexes having helix diameters of 13.0 A., 13.7 A., and a mixture of 13.7 A. and 13.0 A. can be produced in systems devoid of water. Further, the results indicate that the helix diameter in this system is affected by the temperature of the amylose solution prior to the formation of the V complex. In addition, there seems to be correlation between crystal structure of the amylose, size of its helical diameter, and its conformation in solution.
Salicylaldehyde–formaldehyde polymers and their metallic chelates
Authors: Winslow Eugene C. , Manning Albert A.
Published: April 2003

Salicylaldehyde–formaldehyde polymers were prepared with the use of oxalic acid, formic acid, sulfuric acid, and sodium hydroxide as catalysts. A non‐catalyzed polymer was prepared also at an elevated temperature with the use of a pressure bomb. Metallic chelates of the oxalic acid‐catalyzed polymer were prepared with various metallic cations. Each of the polymers was examined for solubility characteristics and for thermal stability. The chelates were similarly examined. The molecular weights of the polymers were in the 700–800 range as determined by freezing point depression. Chelated polymers were stable in air at temperatures which were about 50°C. higher than the decomposition temperature of the corresponding nonchelated polymers.
Electron radiation of aqueous methyl cellulose solutions
Authors: Hillend W. Jack , Swenson Harold A.
Published: April 2003

Solutions (4%) of commercial methyl cellulose (85,000 weight‐average moleculas weight) were radiated with electrons under varied atmospheres of oxygen at dose rates of 0.15, 0.45, and 4.5 Mrad/min. to total doses of 0.45, 4.5 and 10.0 Mrad. Sampler irradiated at the highest dose rates formed gels whose strength was estimated in a Brook‐field viscometer. After dispersing by stirring, the gels were clarified by centrifugation before viscosity, light‐scattering, and sedimentation measurements were made. Molecular weight increases to as high as 270,000 were found, and the sedimentation coefficients increased correspondingly. The intrinsic viscosity of the irradiated polymer solutions, on the other hand, did not increase as the molecular weight doubled or tripled. This is interpreted to be the result of recoupling of hydrolyzed fragments to produce branched molecules of smaller volume and greater weight. High dose rates promoted molecular weight increases while the presence of oxygen, low dose rates, and low polymer concentration favored degradation. The carboxyls evidently produced in the oxidative degradation resulted in a lowered pH of the irradiated solution and in polyelectrolyte viscosity behavior. Boiling an irradiated polymer solution at pH 10.5 reduced molecular weight from 270,000 to 165,000, showing the presence of alkali‐labile as well as alkali‐stable bonds. The gels on the other hand could be dispersed by stirring or heat as well as by alkali. Although branching may affect gelation to some extent, the molecular weight and sedimentation of the samples in solution appear to be approaching a maximum at the dosage level where the more labile bonding of the gelation phenomenon sets in.
On the deformation of networks of very stiff random chains existing in certain colloidal gels
Authors: Hermans Jan
Published: April 2003

The deformation of the random chains consisting of stiff particles which occur in gels of certain colloids is analyzed. The results of this analysis are used to obtain an expression for the elasticity modulus of infinite networks consisting of such chains. It is found that the shear modulus is proportional to the number of chains between crosslinks per unit of volume and to the average inverse length of the chains.
Polymer degradation. II. Mechanism of thermal degradation of polyoxypropylene glycol–toluene 2,4‐diisocyanate polymer (POPG–TDI) and a block polyether glycol–TDI polymer
Authors: Ingham J. D. , Rapp N. S.
Published: April 2003

Further studies on the thermal degradation of POPG‐TDI polymer have been carried out. It has been shown that at temperatures of ∼200°C., the predominant degradation process involves random scission of the urethane linkages to give substantial amounts of isocyanate and hydroxyl. Kinetic data suggests that the weakest links in POPG‐TDI polymer are spaced at intervals of ∼10,000 in molecular weight and that they may be eliminated by pretreatment of the POPG with ethylene oxide to form a block copolyether which is used to prepare the polyurethane. At temperatures exceeding 250°C. and a greater conversion to volatile fragments (>10%) the kinetics of degradation of POPG‐TDI are similar to results for POPG and indicate scission of the polyether bonds by a combination of intramolecular proton abstraction and free radical unzipping reactions, in agreement with previous studies of POPG of much higher molecular weight.
Diffusion of oxygen in gamma‐irradiated polyethylene
Authors: Giberson R. C.
Published: April 2003

Theories of gas flow in polymers developed by Michaels and co‐workers have been used to calculate the diffusion coefficient for oxygen in γ‐irradiated polyethylene. The value obtained is in good agreement with that obtained from an independent method. The possible effect of dose rate on Michaels' theories is presented.
Synthesis and characterization of poly‐s‐triazinyleneimides
Authors: Ehlers Gerhard F. L. , Ray James D.
Published: April 2003

Poly‐s‐triazinyleneimides have been prepared from melt reactions between aminoand chloro‐substituted s‐triazine derivatives. The polymers, which have been characterized by melting ranges, inherent viscosity, solubility, elementary analysis, and thermogravimetric analysis, are brittle resins of relatively low molecular weight. Poly‐6‐phenyl‐N‐methyl‐2,4‐s‐triazinyleneimide, with an inherent viscosity of 0.35, had the highest molecular weight of the polymers synthesized. Poly‐6‐chloro‐N‐phenyl‐2,4‐s‐triazinyleneimide, exhibited considerable mechanical strength at room temperature, apparently due to strong secondary bonding forces.
Investigations on the continuous copolymerization of acrylonitrile with methyl methacrylate in a heterogeneous system
Authors: Bero Maciej , Laczkowski Marceli , Pstrocki Henryk
Published: April 2003

Investigations were carried out on continuous copolymerization of acrylonitrile with methyl methacrylate in a tank type reactor and in a heterogeneous system. It was found that the reaction rate of copolymerization is directly proportional to the concentration of comonomers in the reactor and proportional to the residence time to the −0.65 power. Investigations on the influence of the concentration of initiator upon the reaction rate gave evidence of a change in the mechanism of termination reaction at higher concentrations of initiator in the system. The molecular weights of the copolymers, at sufficiently long residence times, were constant. The composition of the copolymers obtained was in accordance with theoretical anticipations. Some discrepancies between the equations derived and the experimental results were tentatively explained on the basis of the influence of the heterogeneous nature of the system.
Graft copolymerization of vinylpyrrolidone onto polydimethylsiloxane
Authors: Yasuda H. , Refojo M. F.
Published: April 2003

Graft copolymers of polyvinylpyrrolidone (PVP) onto polydimethylsiloxane have been prepared by the mutual irradiation technique utilizing high energy electrons (3 M.e.v.) generated by Van de Graaf. Water has been shown to have an acceleration effect of polymerization of vinylpyrrolidone and a reduction in the penetration of the monomer solution in the polymer. The dependence of the molecular weight of polyvinylpyrrolidone on the dose, and the dependence of the penetration of the grafted layer in the trunk polymer on the dose and the water content in the monomer solutions have been determined. The graft copolymers are hydrophilic and their hydrophilicity is proportional to the amount of polyvinylpyrrolidone grafted onto the silicone. The location of the graft copolymer is determined by staining and sectioning and sectioning technique. Grafting varied from surface grafting to apparently homogeneous grafting depending on the water content in the monomer solution and on the total dose.
Study of crosslink formation by partial conversion properties I. Copolymerization of poly(ethylene fumarate) and styrene
Authors: Burnett G. M. , Hay J. N. , Smith J. D. B.
Published: April 2003

The copolymerization reaction of poly(ethylene fumarate) and styrene has been studied in dilute solution by the change in number‐average molecular weight with conversion. The partial conversion molecular weight is found to vary with conversion and to be a guide to the overall reaction mechanism, which is that of crosslink formation.