bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of polymers from cyclic dienes. V. Cationic polymerization of cyclopentadiene, influence of polymerization conditions on the polymer structure
Authors: Aso Chuji , Kunitake Toyoki , Ishimoto Yoshikazu 
Published: April 2003

AbstractCationic polymerization of cyclopentadiene was studied with several Friedel‐Crafts catalysts, and the influence of polymerization conditions on the polymer structure was investigated. Polycyclopentadiene contained higher amounts of the 1,2 structure when a stronger catalyst and a more polar solvent were used. This fact is discussed in terms of the tightness of the growing ion pair. The polymer structure did not vary with polymerization temperature in toluene solvent. In methylene chloride at around 0°C. the structural variation with catalysts was much smaller, suggesting a freer nature of the growing ion pair. The viscosity data also support the change in the structure of the ion pair under similar conditions. The use of aliphatic hydrocarbon solvents gave the highest contents of the 1,2 structure. This results was ascribed to the lack of solvation, considering the dependence of the polymer structure on the monomer concentration, which was found only in this solvent. Furthermore, isomerization during propagation was observed in polar solvents at higher temperature.
Water‐absorption properties of an acetal copolymer
Authors: Braden M. 
Published: April 2003

AbstractThe kinetics of sorption from the liquid phase to equilibrium and desorption were studied over the temperature range 0–80°C. Equilibrium uptake was found to increase linearly with concentration in this range. Sorption‐desorption kinetics showed the diffusion coefficients to decrease with increasing concentration, although the extent of this dependence did not appear in itself to be temperature‐dependent. The apparent diffusion coefficient obeyed the law D = D0 exp {− E/RT} over the temperature range studied, giving E = 9.9 kcal./mole and D0 = 0.45 cm.2 sec.−1. These values are compared with corresponding values for other polymers.
Catalytically active form of ferric acetate hydroxide for the insertion polymerization of propylene oxide
Authors: Osgan M. 
Published: April 2003

AbstractHydrated ferric oxides prepared in the presence of acetate ions show substantially higher catalytic activity over that of ordinary hydrated ferric oxide (for the polymerization of propylene oxide). The maximum in activity is reached at a ratio of acetate to iron of 2. It is suggested that the active species are formed through the trinuclear μ‐acetato–ferric complex. This would imply that the insertion mechanism requires a particular geometry with probably a minimum of three coordination centers.
Polymers from the vinyl ester of dehydroabietic acid
Authors: Fukuda Wakichi , Marvel C. S. 
Published: April 2003

AbstractThe vinyl ester of dehydrogenated abietic acid has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, and butadiene and terpolymerized with styrene and acrylonitrile. Both in the homopolymerization and the copolymerization, the vinyl ester of dehydroabietic acid has given lower molecular weight polymers than were obtained with the vinyl ester of tetrahydroabietic acid. Polymers containing the vinyl ester of dehydroabietic acid can be readily crosslinked with peroxide.
Peroxide crosslinking of poly(n‐alkyl methacrylates)
Authors: Bartoň J. 
Published: April 2003

AbstractThe action of dicumyl peroxide on poly(n‐butyl methacrylate) and poly(n‐nonyl methacrylate) produces degradation and crosslinking reactions in both polymers. Crosslinking and degradation of poly(n‐alkyl methacrylates) are influenced also by the initial molecular weight of the polymer as well as by the type of alkyl group. The ratio of degradation to crosslinking p/q determined on the basis of the equation of Charlesby and Pinner, S + S0.5 = (p/q) + (1/qPn) is for poly(n‐butyl methacrylate) of viscosity molecular weight 0.923 × 106 and 2.16 × 106 of 0.78 and 0.60, respectively; for poly(n‐nonyl methacrylate) of weight average molecular weight 3.83 × 105, p/q is 0.16. Crosslinking efficiencies (moles of crosslinks per mole of decomposed dicumyl peroxide) of the above polymers are relatively very low: 0.014, 0.005, and 0.039, respectively. The critical concentration of dicumyl peroxide necessary for the formation of gel, provided it undergoes complete decomposition, is for the above polymers 1.82, 1.65, and 0.98 wt.‐%, respectively. Under the critical concentration of dicumyl peroxide the limiting viscosity number of poly(n‐butyl methacrylate) increases with increasing concentration of dicumyl peroxide. An initial decrease of the value of the limiting viscosity number, which is characteristic for polymers undergoing simultaneous degradation and crosslinking, was not observed.
Determination of propagation and termination rate constants for some methacrylates in their radical polymerizations
Authors: Yokota Kenji , Kani Masaru , Ishii Yoshio 
Published: April 2003

AbstractRotating sector determinations of kp and 2kt for ten methacrylates undergoing radical polymerization were carried out at 30°C. Ester groups in the monomers were: isopropyl, ethyl, β‐cyclohexylethyl, methyl, γ‐phenylpropyl, β‐phenylethyl, β‐methoxyethyl, benzyl, β‐chloroethyl, and phenyl. Values of kp obtained were 121, 126, 1190, 141, 149, 228, 249, 1250, 254, and 411 l./mole‐sec., respectively; values of 2kt × 10−6 were 4.52, 7.35, 32.8, 11.6, 0.813, 1.88, 9.30, 41.9, 6.71, and 11.9 l./mole‐sec., respectively.Omitting the data for the β‐cyclohexylethyl and benzyl esters, a Taft correlation, log kp = (0.70 ± 0.18)σ* + 2.2, was established, where σ* denotes Taft's polar substitutent constants for the above‐mentioned ester groups. The steric substituent constants Es were found to have no influence on kp. Combination of kp with r2 data from copolymerization studies with styrene or methyl methacrylate as M1 comonomer revealed that the more reactive monomer gave rise to the more reactive polymer radical. Monomer viscosities and molar volumes of the ester groups were found to correlate with 2kt.
Synthesis and crystal structure of isotactic poly‐4‐phenyl‐1‐butene
Authors: Golemba F. J. , Guillet J. E. , Nyburg S. C. 
Published: April 2003

AbstractPoly‐(4‐phenyl‐1‐butene) was prepared by using a titanium tetrachloride–triethyl‐aluminum catalyst. The crystalline polymer melts at 158°C. Double orientation could not be obtained but all the reflections on the x‐ray fiber diagram can be indexed on the basis of an hexagonal cell (a = 20.8 A., c (fiber repeat) = 6.61 A.). However the crystal structure proposed does not belong to an hexagonal space group but to the monoclinic (pseudo‐orthorhombic) space group Pa (a = 10.4 A., b = 18.0 A., c = 6.61 A.). The 31 helix, common to systems of this type, is consistent with an isotactic (not syndiotactic) configuration for the polymer chain.
Thermostability of some isomeric polyoxadiazoles
Authors: Rodè V. V. , Bondarenko E. M. , Korshak V. V. , Rusanov A. L. , Krongauz E. S. , Bochvar D. A. , Stankevich I. V. 
Published: April 2003

AbstractThe thermal stability of the isomeric poly‐1,2,4‐oxadiazole (PO‐2) and poly‐1,3,4‐oxadiazole (PO‐3) was investigated. The isomerism of the ring substantially influenced polymer thermostability. The weight losses in PO‐2 occur above 220–230°C. in vacuo, but PO‐3 degrades only at 280–300°C. The weight changes in isomeric polyoxadiazole at lower temperatures are connected with the completion of the cyclization process. At higher temperatures degradation of the oxadiazole ring takes place, and as a result carbon and nitrogen oxides, 4,4′‐dicarboxy (diphenyl ether) dinitrile and other products are evolved. The mechanism of polymer thermal degradation is examined; it is shown that the weakest bonds are CO and NO. These data are in a good agreement with the results of calculation of the π‐electron systems of unsubstituted oxadiazole cycles in the framework of the molecular orbital treatment in the Hückel approximation. It is shown that the oxygen in the oxadiazole ring oxidizes the products of thermal degradation of polymers and a cell effect takes place. The thermal oxidation of isomeric polyoxadiazoles does not differ essentially from the degradation in vacuo. It was found that the formation of intermediate products such as peroxides and hydroperoxides does not take place, and oxygen does not act as an initiator of polymer degradation.
The mechanism of consumption of ceric salt with cellulosic materials
Authors: Ogiwara Yoshitaka , Ogiwara Yukie , Kubota Hitoshi 
Published: April 2003

AbstractEfforts were made in the present study to elucidate the mechanism of graft copolymerization of cellulose in the presence of a ceric salt as initiator. When cellulose is treated with an aqueous solution of the ceric salt, ceric ion is consumed in a roughly first‐order reaction in the oxidation of cellulose and in the adsorption on cellulose, and the ratio of the rate constants of oxidation and adsorption is about 1:3 in the case of sulfite pulp. Ceric ion is adsorbed so strongly on cellulose as not to be readily desorbed by treatment with water, dilute acid, or dilute alkali. The number of moles of adsorbed ceric ion was approximately equal to the number of moles of the total carbonyl groups in the cases of cotton and sulfite pulp, which are low in hemicellulose content, and was several times as large in the cases of kraft pulp and semichemical pulp, which contain about 22% hemicellulose. In these samples, however, it was interesting to note that the amount of the adsorbed ceric ion was roughly equal to the amount consumed in oxidation. Cellulose on which ceric ion is adsorbed reacts with methyl methacrylate to yield graft copolymers; a higher molecular weight of grafts, smaller number of grafts, and lower graft efficiency than in a standard polymerization were observed. Since the stability of the adsorbed ceric ion is high, a contribution of the adsorbed ceric ion to the graft copolymerization appears small, and the oxidation reaction, which proceeds slightly more slowly than adsorption, seems more important to the graft copolymerization.
Rate of sulfonation of bead polymers of styrene crosslinked with 1,2,4‐ and 1,3,5‐trivinylbenzene
Authors: Wiley Richard H. , Devenuto A. 
Published: April 2003

AbstractBead copolymers of styrene crosslinked with 1,2,4‐ and 1,3,5‐trivinylbenzene (TVB) are sulfonated at different rates. The copolymer beads with 4% 1,3,5‐TVB sulfonate more slowly than do those with 8% 1,2,4‐TVB. The 8% 1,2,4‐TVB crosslinked polystyrene beads sulfonate at about the same rate as do the beads prepared with 8% p‐DVB crosslinkage.
Ordered structures of styrene–butadiene block copolymers in the solid state
Authors: Bradford E. B. , Vanzo E. 
Published: April 2003

AbstractSeveral narrow molecular weight distribution block copolymers were prepared by a two‐stage anionic polymerization technique. Films cast from these solutions were studied by electron microscopy. Replicas showed that the film surfaces were composed of layered structures with various orientations. Micrographs of ultrathin sections of stained films demonstrate that layered structure occur throughout the film. The widths of the copolymer layer spacings increase with increasing molecular weight and agree quite well with the calculated values.
Molecular weight distribution of cellulose esters by gel permeation chromatography and fractional precipitation
Authors: Brewer Richard J. , Tanghe Leo J. , Bailey Sharon , Burr John T. 
Published: April 2003

AbstractFractional precipitation and gel permeation chromatography yield comparable information on the molecular weight distribution of various cellulose esters. The GPC technique applied to samples obtained by fractional precipitation gives a much more definitive analytical tool than either method used independently. One practical application of this work showed the same molecular weight distribution of two cellulose acetates prepared by different methods.
Cationic polymerization of the geometrical isomers of β‐methylstyrene and anethole
Authors: Mizote A. , Higashimura T. , Okamura S. 
Published: April 2003

AbstractCationic polymerization of the geometrical isomers of β‐methylstyrene and anethole (p‐β‐methoxy‐β‐methylstyrene) was studied in order to clarify the relation between the geometrical structure of the α,β‐disubstituted olefins and their monomer reactivities, subsequent to previous work. Polymerization was carried out in toluene or ethylene dichloride with stannic chloride at 0°C. trans‐β‐Methylstyrene was 1.3 to 1.5 times more reactive than cis‐β‐methylstyrene to the styrene carbonium ion; copolymerization between the trans and the cis isomers of β‐methylstyrene showed little difference in monomer reactivity. By contrast, the cis anethole was 1.5–2.0 times more reactive than the trans, according to copolymerization between the two isomers together. The lower reactivity of the cis‐β‐methylstyrene could be explained by steric hindrance in the cis isomer, proposed by Overberger et al.
Retardation of radical polymerization by phenylacetylene and its p‐substituted derivatives
Authors: Higashiura K. , Oiwa M. 
Published: April 2003

AbstractRadical polymerizations of styrene and methyl methacrylate in the presence of phenylacetylene and five of its p‐substituted derivatives were carried out with the use of 2,2′‐azobisisobutyronitrile as the initiator at 60°C. The initial overall rates of the polymerizations of styrene and methyl methacrylate in the presence of phenylacetylene were not proportional to the square root of the initiator concentration under the experimental conditions employed. The relationship between the overall polymerization rate and the concentration of the phenylacetylenes could be expressed by the Kice equation for the rate of a radical polymerization in the presence of a terminator. From this relationship the rate constant (ks) of the reaction of a growing polymer radical with the phenylacetylenes and the constant Cs = (ks/kp), where kp is the propagation rate constant of vinyl monomers, were determined. The Cs value thus obtained agree well with that derived from the relationship between the number‐average degree of polymerization and the molar ratio of the phenylacetylenes to the vinyl monomer. Therefore the mechanism of the reaction may be considered as being one in which the growing radical reacts with the ethynyl group of the phenylacetylenes to yield a comparatively stable radical which terminates mainly by reaction with the growing radical, and so apparently the phenylacetylenes retard the vinyl polymerization. The substituent effects on the reaction were discussed on the basis of the following modified Hammett equation proposed by Yamamoto and Otsu: log [Cs(p‐sub. PA)/Cs(PA)] = ρσ + γER where PA represents phenylacetylene, σ and ER are the Hammett polar substituent constant and resonance substituent constant, respectively, and both ρ and γ are reaction constants. The γ value for the polymerization of both styrene and methyl methacrylate was 1.7. The ρ value was 1.0 for the polymerization of styrene and approximately zero for that of methyl methacrylate. These results demonstrate that the reactivity of the phenylacetylenes with the growing chain is influenced by both polar and resonance effects of their p‐substituents in the degradative copolymerization of styrene and only by the resonance effect in that of methyl methacrylate.
Preparation of p‐[(S)(—)‐2‐phthalimidopropionyl] polystyrene
Authors: Janović Z. , Fleš D. 
Published: April 2003

AbstractSamples of atactic and isotactic polystyrene were acylated with N‐phthaloyl‐L‐alanyl chloride under the conditions of Friedel‐Crafts reaction. The degree of acylation was strongly dependent on molecular weight, but not on the tacticity of polystyrene. Similarly the specific rotation of acylated polymers was not influenced by the structure of the polymer chain.
Interaction of simple acids with nylon. Part 2: Diffusion of simple acids
Authors: Marshall J. 
Published: April 2003

AbstractThe paper deals with the diffusion of two mineral acids, hydrobromic and sulfuric acids, and two simple dye acids, NOG (C. I. Acid Orange 7) and SY (C.I. Food Yellow 3), in water‐swollen nylon 66. Anion self‐diffusion coefficients were obtained by radiotracer techniques. The bromide ion and the SY anion self‐diffusion coefficients show very little variation with concentration in the amino‐dyeing region, whereas the H2SO4 and NOG anion diffusion coefficients are concentration‐dependent. The variation of the H2SO4 anion diffusion coefficient with concentration is consistent with the formation of small quantities of the highly mobile bisulfate ion. The low SO4 diffusion coefficient may be explained by the interaction of this ion with single, fixed sites in the polymer. The variation of the NOG anion diffusion coefficient with concentration does not follow a simple D = D0[1/(1 − θ)] relationship at intermediate concentrations but the rapid increase observed as the available sites became saturated, i.e., as θ → 1, is consistent with a site saturation model.
A study of the enzymic degradation of CMC and other cellulose ethers
Authors: Wirick M. G. 
Published: April 2003

AbstractAccelerated enzymic degradation of a series of six sodium carboxymethylcelluloses (CMC) varying in degree of substitution (DS) from 0.41 to 2.45 demonstrated that stability improves with increasing substitution, the DS 2.45 sample being essentially refactory to enzyme attack. The concentration of completely unsubstituted anhydroglucose (AHG) units in these samples, determined by acid hydrolysis followed by a glucose assay, is less at all substitution levels than would be expected from the relative etherification rates of the C2, C3, and C6 hydroxyls reported in the literature. Assuming random distribution of the unsubstituted AHG units, the frequency of single (IU) and multiple adjacent (xU) sequences can be predicted. Consideration of the extent of enzymic degradation, expressed in terms of the decrease in average molecular chain length deduced from [η] measurements, indicated that in CMC chain scission occurs only at xU sites. A limited comparison of the performance of methyl‐, hydroxyethyl‐, and hydroxypropylcelluloses under identical conditions revealed that, by contrast, in these ethers enzyme‐induced chain scission is possible not only at xU but also adjacent to 1U. The hydroxyalkyl and methyl groups appear to offer approximately equivalent protection against enzyme attack.
The optical rotation of gelatin films
Authors: Coopes I. H. 
Published: April 2003

AbstractOptical rotation measurements of a series of relatively thick gelatin films prepared under a variety of drying conditions were made. The technique permits rotation measurements to be made during the drying process. It is found that the temperature and humidity of the drying air do not significantly affect the rotation of the films at temperatures below about 25°C. wet bulb. Above this temperature the rotation drops sharply. Films containing formaldehyde and mucochloric acid as hardeners tend to have lower rotations than unhardened films. Various types of gelatin show differences in the gel state, but not when dried. The results of these experiments indicate that in general gelatin tends to acquire the same level of ordered structure during drying, regardless of the drying conditions and type of gelatin. This tendency is inhibited only by high temperatures or the establishment of stable intermolecular crosslinks by hardeners.
Polylactones derived from polymethacrolein and styrene–methacrolein copolymerizations
Authors: Smith W. E. , Ham G. E. , Anspon H. D. , Gebura S. E. , Alwani D. W. 
Published: April 2003

AbstractEmulsion polymerization of methacrolein produces a polyacetal which can be converted through the action of sodium hydroxide to an alternating copolymer of methallyl alcohol and sodium methacrylate. Support for the alternating structure was gained primarily through a study of the polylactone formed through subsequent acidification of the sodium salt. Thus, the poly(methallyl alcohol–sodium methacrylate) copolymer was acidified under selected conditions to give a soluble polylactone containing 14.2 mole‐% of residual acid and hydroxyl groups. This number agrees quite closely with the value of 13.5 mole‐% which one would predict from the random cyclization of a true alternating copolymer. Cyclization of a random copolymer of poly(methallyl alcohol–sodium methacrylate) in a random fashion would have resulted in a value of about 36.8 mole‐%. The results also support both the 1,2 vinyl polymerization of methacrolein and a nonrandom attack of the polymethacrolein by base. In a completely separate set of experiments, the value of r1 and r2 for the copolymerization of styrene (M1) and methacrolein (M2) were determined to be 0.22 ± 0.02 and 0.88 ± 0.02, respectively.
Effect of alcohols on the gamma‐radiation‐induced polymerization of ethylene
Authors: Suganuma Fujio , Machi Sueo , Mitsui Hiroshi , Hagiwara Miyuki , Kagiya Tsutomu 
Published: April 2003

AbstractGamma‐radiation‐induced polymerization of ethylene in alcohols such as methyl, ethyl, n‐propyl, isopropyl, n‐butyl, isobutyl, sec‐butyl, tert‐butyl, and n‐pentyl alcohols was carried out under a pressure of 400 kg./cm.2at 30°C. at a dose rate of 1.4 × 105 rad/hr. in a batch reactor of 100 ml. capacity. The yield and molecular weight of polymer formed in the alcohols (except tert‐butyl alcohol) were much lower than those of the bulk polymerization under the same conditions, whereas the addition of tert‐butyl alcohol increased the yield and reduced the molecular weight. From the infrared spectra of the polymers and those of the bromination products it was concluded that only primary OH exists in the polymer formed in methyl alcohol and that both primary and secondary OH are in the polymer formed in other primary alcohols. Both secondary and tertiary OH were observed in the polymer when the secondary alcohols were used, and only tertiary OH in the case of tert‐butyl alcohol. These polymers were found to contain small amounts of vinylidene unsaturation and methyl group. On the basis of these results the roles of the alcohols in the polymerization are discussed.
Free‐radical copolymerization of 9‐vinylanthracene
Authors: Katz D. , Relis J. 
Published: April 2003

AbstractFree‐radical copolymerization of methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate with 9‐vinylanthracene was studied, and the reactivity ratios r1 and r2 were calculated. In the light of earlier data on copolymerization of 9‐vinylanthracene with styrene results show that the difference in polarity of the monomers participating in the copolymerization has an insignificant influence compared with that of the steric factors involved in the reaction.
Quantitative study on hydrogen bonding between urethane compound and ethers by infrared spectroscopy
Authors: Tanaka Takehide , Yokoyama Tetsuo , Yamaguchi Yukio 
Published: April 2003

AbstractA quantitative infrared spectroscopic study of a model urethane‐type compound was carried out in order to obtain basic data on hydrogen bonding in polyurethanes. First, the absolute intensity of free NH groups of N‐phenylurethane, which was adopted as the model urethane, was determined by Wilson‐Wells' method to be 3.59 × 103l./mole‐cm.2. The free NH of this urethane absorbed at 3447 cm.−1, and hydrogen‐bonded NH absorbed near 3300 cm.−1. Then, the extents of hydrogen bonding of the urethane at various concentrations were determined, and the hydrogen bonding between the urethane and ethers was studied by using the above‐mentioned absolute intensity. For comparison, diphenylamine was also used as proton donor. Di‐n‐butyl ether and poly‐(oxyethylene glycol) were examined and proved to be able to act as proton acceptors. The frequency shifts of NH stretching vibration of diphenylamine and N‐phenylurethane caused by hydrogen bonding with di‐n‐butyl ether were 96 cm.−1 and 150 cm.−1, respectively. The equilibrium constants were 4.8 × 10−1l./mole for the former system 4.6 × 10−1l./mole for the latter.