bluuebunny/crossref_metadata_2025_split huggingface dataset:
γ‐Irradiation‐ and radical‐initiated polymerization of N,N‐dimethylethenesulfonamide
Authors: Wiley Richard H. , Jäger Peter 
Published: April 2003

AbstractThe γ‐irradiation‐induced polymerization of N,N‐dimethylethenesulfonamide, m.p. −3 to −2°C., has been studied in the liquid, supercooled liquid, and solid states from −50 to +42°C. The polymerization is relatively slow (0.8%/hr.) at 0.13 Mr/hr. and is inhibited in the solid state. The activation energy (−16°C. super‐cooled liquid to 42°C.), −2.4 kcal./mole, indicates an ionic process. The radical‐initiated (peroxide, azobisisobutyronitrile, ultraviolet) polymerization gives low molecular weight products. The marked decrease in rate for the N,N‐dimethyl derivative as compared to that for ethenesulfonamide itself is attributed to an increased irradiation instability associated with N‐methyl structures which parallels that for amides and N‐methylamides in carbon tetrachloride.
Stereospecific polymerization of menthyl methacrylate
Authors: Sobue Hiroshi , Matsuzaki Kei , Nakano Shintaro 
Published: April 2003

AbstractMenthyl methacrylate was polymerized with phenylmagnesium bromide, n‐butyllithium, benzoyl peroxide, azobisisobutyronitrile, and γ‐rays as initiators. The polymers obtained were converted to poly(methyl methacrylate) (PMMA). From the infrared spectra and high resolution NMR spectra of PMMA derived, the stereoregularity of poly(menthyl methacrylate) (PMnMA) was estimated. PMnMA's polymerized with phenylmagnesium bromide and n‐butyllithium have an isotactic structure and those prepared with radical initiators have an atactic structure. The probability of isotactic addition σ of PMnMA polymerized with radical initiators was larger than that for PMMA. The optical activity of PMnMA increased with decreasing isotacticity, but the change is slight as compared with the variation of the stereoregularity of the polymers. It was concluded that PMnMA molecules would not form helices in solution.
Synthesis of a polymer chain having conjugated unsaturated bonds by dehydrohalogenation of polyhalogen‐containing polymers
Authors: Tsuchida Eishun , Shih Chung‐Nan , Shinohara Isao , Kambara Shu 
Published: April 2003

AbstractPolyvinyl chloride (I), polyvinylidene chloride (II) and further chlorinated products of polyvinyl chloride (III) can be completely dehydrohalogenated if appropriate conditions are chosen. The elementary analyses of the products fit the formula (CH)n. The infrared spectra and x‐ray diffraction patterns indicate that the structure of the products is similar to that of noncrystalline, trans‐polyacetylene. The absorption band due to CHCH (trans) is observed for all products; for the products from (II) and (III), the band due to CC also appears. All products show paramagnetic properties. The highest value of specific resistivity is about 104 ohm‐cm.
Stress relaxation in fibers: Effect of water and temperature
Authors: Whitney Cynthia Kolb , Hamilton R. L. 
Published: April 2003

AbstractThe effect of water on stress relaxation was studied for several fibers as a function of water temperature and other parameters. A quantitative measure of the effect was developed. A statistical model was developed, and it was found that the observed behavior could be interpreted in terms of a redistribution of forces among the various bonds within the fiber. The measure of the water effect, as defined here, could be used to study the connection between stress relaxation and other fiber properties.
General conclusions about the copolymerization of ethylene with other monomers by free radical catalysis
Authors: Brown Francis E. , Ham George E. 
Published: April 2003

AbstractThe behavior of ethylene in copolymerization with methyl acrylate, methyl methacrylate, vinyl acetate, diethyl fumarate, and diethyl maleate was investigated, and reactivity ratios for these systems reported. Significant deviations of all systems investigated, except ethylene–vinyl acetate, from the conventional copolymerization equation are noted and interpreted on the basis of substantial penultimate and penpenultimate effects. The consistency of the reactivity ratios developed in the systems ethylene–methyl acrylate and ethylene–methyl methacrylate with reported values for methyl acrylate–methyl methacrylate is shown by application of the relationship PabPbcPca = PacPcbPba.
Proof of validity of expanded copolymerization equations
Authors: Ham George E. 
Published: April 2003

AbstractGeneralized copolymerization equations which accounted for wide deviations from conventional copolymerization behavior of numerous systems involving highly polar or sterically hindered monomers had been previously proposed. This paper offers, for the first time, rigorous proof of the expanded equations for systems where one monomer is incapable of addition to its own radical. Empolying these equations, effects as far removed as four units from the end of the growing chain can be accounted for.
Radiation‐induced polymerization of 2‐methyl‐5‐vinyl‐pyridine
Authors: Tabata Yoneho , Kitano Hirokimi , Sobue Hiroshi 
Published: April 2003

AbstractRadiation‐induced polymerization of 2‐methyl‐5‐vinylpyridine was investigated in bulk in the temperature region of 50 to −196°C. The activation energy was found to be 5.7 kcal./mole for the liquid‐phase polymerization and 0.3 kcal./mole for the solidphase polymerization. It was observed that the rate of polymerization is proportional to the square root of the dose rate in the liquid‐phase polymerization and is proportional to the dose rate in the solid‐phase polymerization. DPPH and benzoquinone inhibited strongly the liquid‐phase polymerization, while the same inhibitors did not inhibit appreciably the solid‐phase polymerization. On the other hand, the solid‐phase polymerization was completely inhibited by acetone, pyridine, and methanol, while the liquid‐phase polymerization was not inhibited by the same additives. It was concluded that the polymerization in the liquid phase proceeds by a radical mechanism and the polymerization in the solid phase proceeds by a nonradical mechanism, probably an ionic or electronic mechanism.
CH2 rocking vibrations of linear oligomers of poly(p‐ethylene oxybenzoate) having hydroxyl and carboxylic acid endgroups
Authors: Ishibashi Matahumi 
Published: April 2003

AbstractInfrared spectra of poly(p‐ethylene oxybenzoate) and four of its oligomers (from monomer to tetramer) having hydroxy and carboxylic acid endgroups have been obtained in the range of 400–4000 cm.−1. An assignment of the CH2 rocking vibrations of the ethylene glycol linkage in the oligomers has been made on the basis of analysis of the spectra of the related compounds containing the OCH2CH2OH endgroup linked to phenyl residue, and containing the OCH2CH2O group between phenyl and benzoyl residues. This assignment suggests that the ethylene glycol linkages of the oligomers exist in a trans conformation. The similarity of the CH2 rocking vibrations in both the noncrystalline and crystalline phases of poly(p‐ethylene oxybenzoate) suggests that the ethylene glycol linkages exist essentially in the same (trans) conformation in both phases.
Probability theory of asymmetric chain growth in polymerization
Authors: Fueno Takayuki , Furukawa Junji 
Published: April 2003

AbstractProbability theory of Markov chains has been applied to the chain propagation step of binary and multicomponent copolymerizations. General equations are presented for the calculation of the fractional distribution of monomer units in linear copolymers of any arbitrary degree of polymerization. It is shown that in ordinary Markov processes, the effect of initiation progressively becomes unimportant as the chain length increases and that the polymer composition approaches its stationary limit determined by the transition probabilities alone. The possibility of preparing optically active polymers is discussed in the light of the theoretical results obtained.
Polyethylene crystallized from the melt under elevated pressure
Authors: Wunderlich Bernhard , Arakawa Tamio 
Published: April 2003

AbstractPolyethylene of the linear, low‐pressure type has been crystallized under pressure (up to 5400 atm.) from the melt. Crystallization conditions of constant supercooling and constant cooling rates were employed. The resulting solid was analyzed at atmospheric pressure. In contrast to solution crystallization under pressure above 2000 atm., extended chain lamellae of increasing thickness become dominant. These show a maximum melting point of 140°C. and in this research, densities of up to 0.994 g./cm.3. Combining these data on large crystals with the experimental maximum melting temperatures and thickness data on low and atmospheric pressure crystallized lamellae yields a surface free energy of 91 ergs/cm.2 for folded chain lamellae crystallized at low pressure.
The unperturbed dimensions of nylon 66
Authors: Saunders P. R. 
Published: April 2003

AbstractLight‐scattering and viscosity measurements have been performed on nylon 66 fractions dissolved in an ideal solvent. The relation between intrinsic viscosity and weight‐average molecular weight in this solvent is [η] = 19.2 × 10−4 Mw1/2, which indicates that nylon 66 obeys random coil statistics in solution. The unperturbed coil dimensions are given by the parameter (r02/M)1/2 = 96 × 10−10 cm. mole1/2 g.−1/2.
Polymer deformation. III. Annealing of drawn polyethylene single crystals and fibers
Authors: Geil P. H. 
Published: April 2003

AbstractPolyethylene single crystals plastically deformed by drawing as much as 100% and fibers that occasionally form during this deformation have been annealed at 121 and 125°C. Striations with a spacing similar to that measured with small‐angle x‐ray diffraction are observed on the fibers in contact with a substrate. No readily apparent change occurs during the annealing of freely suspended fibers. Similar striations are observed along slip bands and other grossly deformed regions within the crystals. Recrystallization through an “ameboid” motion occurs in both drawn and undrawn crystals on Mylar substrates and results in an irregular crystal boundary. The more usual type of recrystallization involving an increase in fold period appears to occur more readily at a given temperature in undrawn crystals than in the plastically deformed ones. The b axis in drawn crystals was found to rotate during the annealing treatment so as to be nearly perpendicular to the draw direction. Any polymer in the monoclinic unit cell returns to the more stable orthorhombic unit cell.
Polymer deformation. IV. Drawing of nylon 6 and polyoxymethylene crystals
Authors: Geil P. H. 
Published: April 2003

AbstractElectron micrographs of nylon 6 and polyoxymethylene crystals drawn on a Mylar substrate at room temperature indicate that the deformation of these crystals occurs through a combination of plastic deformation and the formation of cracks. In nylon 6 cracks are formed preferentially between hydrogen‐bonded planes but can also form so as to result in rupture of the hydrogen bonds. There was no evidence for twinning or a crystal transformation during the deformation of either polymer.
Homopolymerization of N‐allylacetamide and N‐allylstearamide
Authors: Jordan Edmund F. , Wrigley Arthur N. 
Published: April 2003

AbstractWhen benzoyl peroxide was decomposed at 90°C. in N‐allylacetamide and in N‐allylstearamide, d[M]/d[P] was about 2 and DP was between 9 and 10, because of a wastage of benzoyloxy radicals. These radicals formed benzoic acid and benzene as a consequence of hydrogen abstraction from the amide, and the resulting amide radicals became substituted with ester and phenyl groups from the initiator. N‐butylstearamide, a saturated model for N‐allylstearamide, gave corresponding products. Rates of peroxide decomposition indicated strong induced effects, decreasing in the order: N‐allylacetamide, N‐allylstearamide, N‐butylstearamide. Slopes of the linear plots of the four products (in moles per kilogram) against initiator (in equivalents per kilogram) in the three amides in the above order were: benzoic 0.521, 0.570, 0.575; benzene 0.027, 0.086, 0.168; amide substituted by benzoate 0.459, 0.320, 0.106; amide substituted by phenyl 0.087, 0.087, 0.142. Transfer, compared to substitution, increased with chain length and decrease in unsaturation, and induced peroxide decomposition was correspondingly lowered. Thus, kinetic chain decreased with acyl chain length and decrease in unsaturation. A mechanism that postulates polar species in the transition state when amides were solvents accounted for both transfer and aromatic substitution and helped explain the difference in behavior of N‐allylamides and allyl esters. Plots of amide entering polymer (in moles per kilogram) against initiator concentration (in equivalents per kilogram) were curves; plots of log (a – x) for amide disappearance against the same coordinate were linear. Slopes were: N‐allylacetamide −0.0742; N‐allylstearamide −0.1771.
Inadequacies in time–temperature equivalence
Authors: McCrum N. G. 
Published: April 2003

AbstractThe activation energy of the low temperature relaxation in polytetrafluoroethylene is obtained from creep experiments by using the analytical procedure known as time temperature superposition. The activation energy obtained is 25 kcal./mole which is rejected in favor of the value determined in internal friction experiments, 18 kcal./mole. The discrepancy is attributed to temperature variation of the limiting compliances which cause the value obtained using time–temperature superposition to be too high. Comparable discrepancies are anticipated for relaxations in crystalline polymers and amorphous polymers at temperatures below the glass transition.
Radiation‐induced polymerization of acrylonitrile in liquid ethylene
Authors: Tabata Yoneho , Hara Kiyoshi , Sobue Hiroshi 
Published: April 2003

AbstractA mixed system of acrylonitrile and ethylene was irradiated with γ‐rays from a Co60 source at −78°C. In the mixed system, ethylene did not polymerize, and only acrylonitrile polymerized. It was found that polymerizations due to both CC double bond and the CN triple bond of acrylonitrile occurred in the mixed system. The ratio of one type of polymerization to the other varied continuously with concentration of the monomer; the polymerization of CC only occurs in bulk (100% monomer), as well known, but on the other hand, the polymerization of CN occurs predominantly in a dilute solution of the monomer. The polymerization due to CN triple bond would be by an ionic mechanism, probably an anionic. The experiments showed that the polymerization of acrylonitrile in the ethylene solution proceeds by a partial ionic mechanism at moderate concentrations of the monometer. The product obtained by the polymerization in such a mixed system is a mixture of polymers having the following structures:
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Free radical polymerization and copolymerization of bicyclo‐(2.2.1)‐hepta‐(2.5)‐diene (norbornadiene)
Authors: Pellon Joseph , Kugel Robert L. , Marcus Ruth , Rabinowitz Robert 
Published: April 2003

AbstractA brief study of the homopolymerization of norbornadiene indicated that pre‐gel polymer is limited to product having reduced viscosities below 0.2 dl./g. Pre‐gel polymer of 17,000 molecular weight was isolated and characterized: pre‐gel polynorbornadiene is soluble in benzene or chloroform, softens at 220–240°C., is thermosetting and shows poor molding characteristics. A cast rod of polynorbornadiene was found to have a heat distortion temperature of 186°C. and a flexural strength of 13,300 psi. Copolymer reactivity ratios of norbornadiene (M1) determined with vinyl acetate were r1 = 1.3 and r2 = 0.8; with p‐chlorostyrene, r1 ≈ 0.01 and r2 ≈ 85. Thermal behavior of several copolymers was determined.
Refractive indices and compositions of crazes in several glassy polymers
Authors: Kambour Roger P. 
Published: April 2003

AbstractThe void contents of crazes in four glassy polymers have now been determined from measurements of craze refractive indices. The void contents of poly(methyl methacrylate), polystyrene, polycarbonate, and styrene‐acrylonitrile copolymer crazes are 40, 40, 45, and 60%, respectively. Available evidence suggests that craze void content does not depend on use of a crazing agent.
Refractive index and composition of poly(methyl methacrylate) fracture surface layers
Authors: Kambour Roger P. 
Published: April 2003

AbstractBy using the phenomenon of total internal reflection of light the refractive index of the thin layer present on fresh poly(methyl methacrylate) fracture surfaces has been measured. The fracture surface refractive index, 1.32, is the same as that of the craze in the same polymer. The fracture surface layer is accordingly thought to be craze like in structure.
Penultimate unit effects in terpolymerization
Authors: Ham George E. 
Published: April 2003

AbstractAlthough the effects of penultimate units in binary copolymerization have been extensively treated, the investigation of these effects in terpolymerization has been neglected. Undoubtedly, this neglect is attributable to the fact that possible effects arising from twenty‐seven different propagation possibilities must be considered. Fortunately, for practical purposes, it often occurs that only a few of the penultimate possibilities are important in determining copolymer composition, and that most of the propagating steps can be treated with regard to terminal unit effects alone. Simplified equations are presented which allow for such restrictions. These equations are applied to several experimental examples. In addition, simplified terpolymer equations are derived which allow for the circumstances where one or two homopropagation rate constants approach zero. Furthermore, methods are introduced for assessing K32/K31 where K33 approaches zero. These methods lead, in turn, to more precise assessments of Q and e for 1,2‐disubstituted olefins.
Free‐radical polymerization of olefins
Authors: Mortimer George A. , Arnold Lloyd C. 
Published: April 2003

AbstractPropylene, butene‐1, isobutylene, 3,3‐dimethylbutene‐1, and tetradecene‐1 were polymerized at high pressures at 130–150°C. with dixy1tert‐butyl peroxide initiator to give low molecular weight polymers. Free radical copolymerization of propylene and isobutylene was also demonstrated. Facile chain transfer to give relatively stable radicals was blamed for the low rates and degrees of polymerization. The molecular weights were shown to be controlled by chain transfer.
Stereospecific polymerization of 2‐substituted‐1,3‐butadienes. I. Crystalline polymers of 2‐tert‐butyl‐1,3‐butadiene
Authors: Marconi W. , Mazzei A. , Cucinella S. , Cesari M. 
Published: April 2003

AbstractSome results obtained in the stereospecific polymerization of 2‐tert‐butyl‐1,3‐butadiene are reported. The catalysts employed were prepared from TiCl4 and aluminum alkyls or soluble aluminum hydride derivatives. Polymers thus obtained were crystalline with a melting point of 106°C. and soluble in common solvents. X‐ray investigation shows the polymer to have a helical chain structure built on 11 monomeric units with cis configuration, distributed on three turns. The identity period along the chain axis is 15.3 A. A comparison of the infrared spectra of the crystalline and amorphous polymers is given. Attempts to obtain a crystalline 1,4‐trans polymer failed; this is in accord with the lower stability of such a configuration due to steric repulsion of the bulky group.
Polymerization in liquid sulfur dioxide. Part XXI. Effect of liquid sulfur dioxide concentration on cationic copolymerization of styrene with methyl acrylate in liquid sulfur dioxide
Authors: Matsuda Minoru , Ohshima Koichi , Tokura Niichiro 
Published: April 2003

AbstractThe effect of liquid sulfur dioxide concentration on cationic copolymerization of styrene (M1) with methyl acrylate (M2) was carried out with the use of boron trifluoride–ether complex as a catalyst. The reaction was carried out at 0°C. The monomer reactivity ratios r1 and r2 increased with increase in liquid sulfur dioxide concentration, and r1 was changed from r1 = 0.30 at [liq. SO2]0 = 6.58 mole/l., to r1 = 1.50 at [liq. SO2]0 = 13.16 mole/l., but r2 was not changed. These facts indicated that reactivity of carbonium ion of styrene in the propagation step was increased with increasing liquid sulfur dioxide concentration. The relation between the overall rate of copolymerization and liquid sulfur dioxide concentration is the same as in the case of the cationic homopolymerization of styrene, and polymolecular contribution of liquid sulfur dioxide on the overall copolymerization is shown from these observations.
A critical evaluation of mathematical molecular weight distribution models proposed for real polymer distributions. I. Effects of a low molecular weight cut‐off value
Authors: Kotliar A. M. 
Published: April 2003

AbstractIt is of considerable practical importance to be able to describe the distribution of molecular sizes of a polymeric material by a convenient mathematical expression. Since the various molecular averages of any distribution are obtained from a summation process, the general models require an analytical expression of the differential distribution and a corresponding definite integral generally having the integration limits of zero and infinity. In general, real polymer distributions do not fit these integration limits and an error, which can be very large, is therefore introduced. If the error in the various molecular weight averages due to changes in integration limits is of the order of or less than the error generally encountered in the experimental evaluation of the average, the distribution function can be considered to be applicable from a practical point of view. In addition, the selected model should fulfill the requirements of fitting known experimental facts such as: the polymerization kinetics, the effects of random degradation and crosslinking, fractionation data, and the effects of polymerization and processing on the differential distribution maxima. It should also conform to the rheological behavior based on current theoretical ideas. The integration limit criteria are applied to logarithmic normal type distributions, e.g., Wesslau, and generalized exponential type distributions, e.g., Schulz‐Zimm and Tung. The results show that logarithmic normal type distributions cannot be considered as useful models, while the generalized exponential type distributions can be valid and useful representations.