bluuebunny/crossref_metadata_2025_split huggingface dataset:
Donor–acceptor interactions in cationic polymerization. VII. Relationship between the degree of dissociation of complex and the molecular weight of polyisobutylene formed in the presence of some complexes of aluminum trichloride with electron donors
Authors: Zlámal Z. , Kazda A. 
Published: April 2003

AbstractThe concentration dependence of the specific conductivity of the complexes of aluminum trichloride with dibutyl ether, anisole, phenol, and diphenyl ether at equimolar ratios of the two compounds has been measured. Conductivity measurements have been carried out in ethyl chloride at −78.5°C. Except for dibutyl ether, all the complexes studied are associated over the whole concentration range and their degree of dissociation and molar conductivity are independent of the concentration. In the case of the BuOBu·AlCl3 complex these quantities begin to be independent of the concentration only at concentrations higher than 20 mmoles/l. The degree of polymerization or the molecular weight of polyisobutylene formed by the polymerization in the presence of given complexes is inversely proportional to the concentration of the anions present. This is especially evident from the fact that the relation between x and 1/M̄ is also linear in the case of the BuOBu·AlCl3 complex, whose degree of dissociation and therefore molar conductivity varies distinctly with the concentration of the complex. The comparison of the chain‐breaking efficiency of the anions derived from phenol and diphenyl ether with those derived from phenetole and anisole shows that the mixed aryl alkyl ethers split after reacting with aluminum trichloride under these conditions, so that the phenyl group becomes a part of the cation and the alkyl group a part of the anion. On the basis of the different behaviors of the ions and the dipoles, the differences in the dependence of the degree of polymerization on the dielectric constant of the medium in the cationic polymerization have been explained.
Studies on Ziegler‐Natta catalysts. Part V. Stereospecificity of the active center
Authors: Rodriguez L. A. M. , van Looy H. M. 
Published: April 2003

AbstractExperimental results on Ziegler‐Natta catalysts, based on observations made with the electron microscope, and a qualitative comparison of the stereospecificity of various catalyst combinations are given. The polymerization of olefin in these experiments is performed in the gas phase on dry catalysts in the absence of solvent or excess aluminium alkyl. The crystallographic structure of the lateral faces of α‐TiCl3 is established by electron microscopy and electron diffraction. The electron micrographs of α‐TiCl3–AlMe3 catalysts show that the active centers, which are revealed by the dotwise formation of polymer, are located along the growth spirals, on lateral faces, and on surface defects. These regions of the surface are the only regions in which the surface titanium atoms are incompletely coordinated. The presence of chlorine vacancies and exposed titanium atoms is therefore an essential condition for the formation of active centers. However, the number of active centers is small in comparison to the number of incompletely coordinated titanium atoms, and hence it is concluded that the normally occurring α‐TiCl3 sites with one vacancy do not yield active centers on reaction with aluminum alkyl. It is proposed that the reaction with aluminum alkyl on such sites leads ultimately to a bimetallic complex which fills the original vacancy on the titanium atom. That the complexation is reversible and that the deblocked alkylated site, which is of the type proposed by Cossee, is an active center is not excluded. Such a center would, however, give atactic polymer. Similar complex formation on a TiCl3 site having originally two vacancies would leave one vacancy on the titanium atom. This is believed to be the center of stereospecific polymerization. A model of this active center and a mechanism of polymer growth on it are proposed.
Preparation and polymerization of some vinyl ester amides of pinic acid
Authors: Griffith J. H. , Marvel C. S. , Hedrick G. W. , Magne Frank 
Published: April 2003

AbstractThe preparation of vinyl 2,2‐dimethyl‐3‐morpholinocarbonylcyclobutaneacetate, vinyl 2,2‐dimethyl‐3‐piperidinocarbonylcyclobutaneacetate, and vinyl 2,2‐dimethyl‐3‐di‐n‐butylaminocarbonylcyclobutaneacetate has been achieved by selective amination followed by vinyl interchange. Homopolymers and vinyl chloride copolymers containing 25 and 30 wt.‐% of the vinyl esteramides were prepared and evaluated as nonrigid plastics. The vinyl esteramides incorporated in vinyl chloride copolymers did impart some plasticization, but their effect was far below the effect of added plasticizer to a vinyl chloride polymer.
Flow rates of polymer solutions through porous disks as a function of solute. I. method
Authors: Rowland Fred W. , Eirich Frederick R. 
Published: April 2003

AbstractA method for studying the thickness of adsorbed polymer films, based on the reduction in effective cross section for liquid flow caused by the deposition of such a film on the interior of a capillary, is described. A sintered disk is used instead of a single capillary to raise the flow rate to an easily measured level, to avoid the difficulties of obtaining or fabricating the extremely fine capillaries which would be required, and to eliminate the extreme precautions needed to prevent plugging of a single capillary. Techniques for characterizing the sintered disks are presented. When applied to benzene solutions of stearic acid and of polystyrene, film thicknesses of 30 and 312 A., respectively, were obtained. This is in good agreement with present knowledge of fatty acid adsorption, and suggests that the polymer is adsorbed in a highly extended configuration. The application of this method to solutions of poly(vinyl acetate), poly(methyl methacrylate), and polystyrene in several solvents at various temperatures is described in a following paper.
Radiochemical determination of low unsaturations in polyisobutene
Authors: McGuchan R. , McNeill I. C. 
Published: April 2003

AbstractA radiochemical technique involving the use of 36Cl has been described previously for the measurement of butyl rubber unsaturations. This method has now been applied to the estimation of the much lower concentration of double bonds present in polyisobutene prepared by the cationic polymerization of isobutene at a low temperature. The nature of the reaction of polyisobutene with radiochlorine in the absence of air is examined, and the experimental results are discussed in relation to present theories of the mechanisms of chain termination in cationic polymerization.
Ferrocene‐containing polymers. XIII. Polymeric compounds possessing carboxyphenyl side groups
Authors: Neuse Eberhard W. , Koda Kazuko 
Published: April 2003

AbstractAs an extension of earlier work on the condensation of ferrocene with aldehydes, the polycondensation of ferrocene with p‐ and o‐carboxybenzaldehyde is described. While, in the former case, regular polycondensation occurs giving rise to a polymer composed of ferrocenylene and 4‐carboxybenzal units, a deviation from this route is observed in the o‐carboxybenzaldehyde case, where a polymer containing both carboxybenzal and 3,3‐phthalide bridging units between the ferrocenylene groups is formed instead. This unexpected behavior can be accounted for by a hydride abstraction mechanism. In support of the polymer structure proposed, 3‐ferrocenylphthalide and 3,3‐diferrocenylphthalide are isolated as intermediates or by‐products. In both polymer series, number‐average molecular weights up to 3000 (unsubfractionated) are measured. The polymers are soluble in a number of organic solvents and can be cured with epoxides.
Influence of addition of ethylene on the γ‐ray‐induced alternating copolymerization of ethylenimine and carbon monoxide
Authors: Kagiya Tsutomu , Narisawa Shizuo , Ichida Taizo , Fukui Kenichi , Yokota Hisao 
Published: April 2003

AbstractThe influence of the addition of ethylene on the γ‐ray‐induced alternating copolymerization of ethylenimine and carbon monoxide was investigated. A mixture of ethylenimine, carbon monoxide, and ethylene was irradiated to produce a polymer containing these monomeric units. The infrared spectrum of the copolymer showed the characteristic absorption peaks of the secondary amide and ketone bond and was different from that of the reaction product of polyketone with ethylenimine and that of the γ‐ray irradiation product of ethylene and poly‐ß‐alanine. The x‐ray diffraction diagram of the copolymer was different from those of poly‐ß‐alanine and polyketone and exhibited an amorphous structure. Paper chromatographic analysis showed that the hydrolysis product of the copolymer contained ß‐alanine and δ‐aminovaleric acid. These results indicate that terpolymerization of ethylenimine, carbon monoxide, and ethylene took place under γ‐ray irradiation and gave an amorphous polymer containing the units
\documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{&#x0F8FF;} ({\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm NHCO}\rlap{&#x0F8FF;}),\rlap{&#x0F8FF;} ({\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm CO}\rlap{&#x0F8FF;}),{\rm and}\rlap{&#x0F8FF;} ({\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm CH}_{\rm 2} {\rm NHCO}\rlap{&#x0F8FF;}) $\end{document}
Studies on anionic polymerization of lactams. Part II. Effect of cocatalysts on the polymerization of pyrrolidone
Authors: Barzakay S. , Levy M. , Vofsi D. 
Published: April 2003

AbstractThe rates of addition of pyrrolidonate magnesium bromide (PyMgBr) to N‐benzoyl‐, N‐acetyl‐, and N‐methylpyrrolidone were measured in solution in tetrahydrofuran (THF). The values found for the rate constants at 25°C. were 9.5 × 10−2, 2.8 × 10−2, and 5 × 10−4 l./mole‐sec., respectively. The rate constant for addition of PyMgBr to pyrrolidone was also measured and found to be 3 × 10−9l./mole‐sec. Possible causes for the large difference between the values of these constants are discussed.
Radiation‐induced polymerization of hexafluoropropylene at high temperature and pressure
Authors: Lowry R. E. , Brown D. W. , Wall L. A. 
Published: April 2003

AbstractThe radiation‐induced polymerization of hexafluoropropylene was studied in the pressure and temperature ranges of 4,500–15,000 atm. and 100–230°C., respectively. Retardation was a serious problem; data thought to apply to the unretarded polymerization are summarized below. At 1,500 rad/hr. the polymerization rate was 15%/hr. at 230°C. and 15,000 atm. The activation enthalpy and volume are 9.5 kcal./mole and −10 cc./mole, respectively. The rate varies as the square root of the radiation intensity. The largest intrinsic viscosity of the polymer is 2.0 dl./g.; values increase with temperature and pressure. At 130°C. and 10,000 atm. the intrinsic viscosity was the same at two radiation intensities.
Radiation‐induced solid‐state polymerization in binary systems. II. Relationship between polymerization rate and physical structure of binary systems
Authors: Kaetsu Isao , Sagane Norio , Hayashi Koichiro , Okamura Seizo 
Published: April 2003

AbstractThe radiation‐induced solid‐state polymerization of binary systems consisting of acrylic monomer (acrylamide, acrylic acid) and organic compounds was investigated. In the previous paper on binary systems the authors reported that the rate of polymerization increased in the solid state (eutectic mixture systems). The mechanism of rate increase has been investigated by examination of phase diagrams, viscosities, and surface tension of the binary systems. Viscosity and surface tension are the measure of the molecular interaction of the two‐component systems. In addition, the effect of linear crystal growth rate and half maximum width of the x‐ray diffraction diagram of the crystallization process were determined. The larger the molecular interaction between the two components, the slower the linear crystal growth rate of monomer. The size of the monomer crystal decreases and the dislocation density of the monomer crystals increases in systems with large molecular interaction. Consequently it can be concluded that the physical structure of a binary solid system is the most important parameter determining the rate increase of solid‐state polymerization. Dislocation on the grain boundary is more important than defects inside of the crystal lattice. It was found that the acceleration of polymerization rate is large in binary systems with larger molecular interaction. In some systems such as organic acid—amide systems with strong hydrogen bonds, glassy phases may be formed in which monomer may readily polymerize at very low temperatures.
Hydroformylation of high polymers
Authors: Ramp Floyd L. , Dewitt Elmer J. , Trapasso Louis E. 
Published: April 2003

AbstractA new class of polymeric materials has been prepared and subjected to preliminary evaluation. These materials were obtained by hydroformylation of diene‐based polymers. The olefinic bonds were saturated and aldehyde groups attached.
magnified image
The extent of reaction may be varied at will up to 100% double bond conversion. The properties of these polymers are dominated by the active aldehyde groups. One of the chief characteristics of simple aldehydes is their ability to polymerize forming mainly aldehyde trimers and tetramers. This same phenomenon has been shown to occur with polymeric aldehydes with consequent gel formation. The gelling tendency has been closely related to the aldehyde content per unit volume which may be conveniently varied by (1) the concentration of the initial polymer, (2) the degree of unsaturation in the polymer, and (3) the extent of double bond conversion. Any combination which gives a free aldehyde concentration in excess of 1 × 10−4 mole/ml. is very prone to gel. The loose gels can be readily reversed by conditions which depolymerize aldehydes. The propensity of the aldehyde polymers to crosslink upon evaporation of the solvent was used to form films. These films were not discolored by ultraviolet light but under such treatment became quite brittle. The products may be stabilized by conversion of the aldehyde groups to more stable derivative, in particular the acetal. The extent of acetal formation has been shown to be controlled by steric factors. Complete polyacetal formation was possible only when the aldehyde groups were well dispersed along the polymer chain. Certain aldehyde derivatives (acetals, oximes) are thermoplastic. They soften at lower temperature than commercial plastics.
Kinetics of amylose retrogradation
Authors: Doppert H. L. , Staverman A. J. 
Published: April 2003

AbstractThis article deals with the kinetics of the retrogradation of amylose in aqueous solutions of pH 4.0, 9.2, and 11.9. The course of the retrogradation is followed by means of light‐scattering measurements. From our interpretation of the light‐scattering data we conclude that the retrogradation mechanism appears to be in qualitative agreement with von Smoluchowski's theory on coagulation. From the rate of retrogradation one may tentatively conclude that only a small fraction of the collisions between the amylose aggregates leads to permanent coagulation. In order to explain this phenomenon, additional conditions are suggested for permanent attachment of two colliding aggregates. The relevant fraction is smaller at pH 11.9 than at the lower pH's, a fact which is ascribed to the mutual repulsions of the aggregates due to their negative charges.
Polyelectrolytic character of amylose. II.
Authors: Doppert H. L. , Staverman A. J. 
Published: April 2003

AbstractViscometric titrations of amylose are described. The curves confirm the earlier results of Rao and Foster. A more quantitative consideration is given concerning the changes of the electrostatic charge of the amylose molecules in the pH range of 11–12, where a minimum in the titration curve is found. A viscometric titration performed in solutions containing urea shows a considerably higher viscosity, especially at lower pH's; the curve, however, still shows a minimum between pH 11 and 12. Experiments on the dependence of [η] on the ionic strength at pH 12.7 also demonstrate the typical polyelectrolytic nature of amylose.
Effects of metal salts on polymerization. Part II. Polymerization of vinylpyridine complexed with the group IIb metal salts
Authors: Tazuke Shigeo , Sato Noritaka , Okamura Seizo 
Published: April 2003

AbstractThe following stoichiometric vinylpyridine complexes have been prepared: (4‐VP)2—Zn(SCN)2, (2‐VP)2—Zn(SCN)2, (MVP)2—Zn(SCN)2, (MVP)2—ZnCl2, (MVP)2—ZnBr2, (MVP)2—ZnI2, and (MVP)2—HgCl2, where 4‐VP, 2‐VP, and MVP denote 4‐vinylpyridine, 2‐vinylpyridine, and 2‐methyl‐5‐vinylpyridine, respectively. Results of radical polymerization initiated by azobisisobutyronitrile indicate that the effect of complex formation between the monomers and the metal salts is to enhance the rate of polymerization with the exception of the 2‐VP complex. The Rp for the solution polymerization in dimethylformamide increases in the following order: (1) (MVP)2—Zn‐(SCN)2 > (MVP)2‐ZnCl2 > (MVP)2—ZnBr2 > (MVP)2—ZnI2 > free MVP; (2) (4‐VP)2—Zn(SCN)2 > (MVP)2—Zn(SCN)2 > free MVP > (2‐VP)2—Zn(SCN)2; and (3) MVP + Zn(CH3COO)2 < MVP + Cd(CH3COO)2. When ethanol, acetone, or tetrahydrofuran is used as solvent, the change in Rp is more marked, partly due to insolubility of the PMVP complexed with the metal salts. The increase in Rp would be attributed to the change in kp since the molecular weights of PMVP are nearly proportional to Rp when (MVP)2—ZnX2 where X is Cl−, Br−, I−, or SCN− is polymerized in DMF under fixed conditions. Copolymerizations of MVP—ZnX2 complexes (where X is Cl−, Br−, I−, or CH3COO−) with styrene indicate that the e values of complexed MVP are more positive than that of free vinylpyridine, and the amounts of the positive shift in e values increase with decreasing polarizability of the halide anions. These results are discussed in terms of the charge‐transfer properties of anions, the nature of coordination bonds, and the structures of vinylpyridines. The complexed monomers are hardly polymerized by a cationic or an anionic mechanism. Radiation‐induced solid‐state polymerization gives polymers in low yields.
Study of crosslink formation by partial conversion properties. IV. Copolymerization of styrene with poly(ethylene fumarate)
Authors: Burnett G. M. , Pearson J. M. , Smith J. D. B. 
Published: April 2003

AbstractThe mechanism of the crosslinking reaction in the copolymerization of poly(ethylene fumarate) and styrene has been studied by using partial conversion number‐average molecular weights and viscosities. In dilute solution the reaction is mainly the formation of intramolecular crosslinks, illustrated by a reduced dependence of \documentclass{article}\pagestyle{empty}\begin{document}$\overline{\overline M}_n$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$[\overline{\overline \eta}]$\end{document} on conversion. Increasing the monomer concentrations increases the contribution from intermolecular reactions and gives a much greater dependence of \documentclass{article}\pagestyle{empty}\begin{document}$\overline{\overline M}_n$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$[\overline{\overline \eta}]$\end{document} on conversion.
Studies of thermal cyclizations of polyamic acids and tertiary amine salts
Authors: Kreuz John A. , Endrey A. L. , Gay F. P. , Sroog C. E. 
Published: April 2003

AbstractThermal conversion rates of the polyamic acid derived from pyromellitic dianhydride and 4,4′‐diaminodiphenyl ether are presented. Formation of the imide ring proceeds by fast and slow first‐order processes. Tertiary amines give ring closures faster by a factor of 10 than the free acid. The enhancement is an activation entropy rather than an activation energy effect.
Fluorothiocarbonyl compounds. VI. Free‐radical polymerization of thiocarbonyl fluoride
Authors: Barney A. L. , Bruce J. M. , Coker J. N. , Jacobson H. W. , Sharkey W. H. 
Published: April 2003

AbstractThiocarbonyl fluoride, CF2S, and thiocarbonyl chlorofluoride, CFClS, undergo addition polymerization in free radical‐initiated systems. In addition, both compounds copolymerize with various unsaturated compounds, including typical vinyl and vinylidene monomers. The chlorofluoride, because of its rapid polymerization rate, copolymerizes best with very active monomers, of which 2,3‐dichloro‐1,3‐butadiene is an example. Thiocarbonyl fluoride polymerizes best at low temperatures. The trialkylborane—oxygen redox couple has been adapted to free‐radical polymerizations and copolymerizations from −60 to −120°C. With such initiation CF2S has been copolymerized with terminal and internal olefins, vinyl compounds, allyl compounds, and acrylic esters. Copolymerization with propylene is unusual, in that it proceeds in a manner that strongly favors a product composed of two molecules of CF2S for each propylene. In other cases, product compositions are more responsive to the ratio of monomers charged.
Copolymerization of isopropenyl and isopropylidene oxazolones with styrene
Authors: Iwakura Yoshio , Toda Fujio , Torii Yoshinori 
Published: April 2003

Abstract2‐Isopropenyl‐4‐isopropyl‐2‐oxazolin‐5‐one (M2), was copolymerized with styrene (M1), and the monomer reactivity ratios were determined to be r1 = 0.31 ± 0.03, r2 = 1.12 ± 0.10. New isomerized oxazolones (M2), 2‐isopropylidene‐4‐methyl‐3‐oxazolin‐5‐one, 2‐isopropylidene‐4‐isopropyl‐3‐oxazolin‐5‐one, and 2‐isopropylidene‐4‐isobutyl‐3‐oxazolin‐5‐one were prepared and copolymerized with styrene. The monomer reactivity ratios were: r1 = 0.36 = 0.07, r2 = 0.0; r1 = 0.39 ± 0.06, r2 = 0.00 ± 0.10; r1 = 0.39 ± 0.10, r2 = 0.0, respectively. The isomerized oxazolones showed no tendency towards homopolymerization by radical initiator. From the results of infrared and NMR spectra and hydrolysis of the copolymer, it was indicated that the isomerized oxazolones participated in copolymerization in the form of 1–4 polymerization of the conjugated dienes (exo double bond at C2 and the CN in the ring). Copolymers reacted with nucleophilic reagents such as amines and alcohols.
Polymerization and crosslinking characteristics of a 3‐methoxybutyl acrylate
Authors: Costanza John R. , Vona Joseph A. 
Published: April 2003

AbstractPolymers of 3‐methoxybutyl acrylate (3‐MBA) were prepared by máss, solution, and emulsion polymerization techniques. The 3‐MBA polymers could be converted from soft, rubbery, soluble, thermoplastic films to hard, glossy, flexible, crosslinked films when exposed to air and/or transition metal catalysts at elevated temperatures. The crosslinked polymers are resistant to common organic solvents and to mineral acids. Strong alkalis degraded the crosslinked polymers. The second‐order transition temperature of poly‐3‐MBA is −56°C. as determined by volume dilatometry. A comparison of the crosslinking properties of poly‐3‐MBA and other alkyl and alkoxyalkyl polymers is discussed. An autoxidative mechanism is proposed for the crosslinking of 3‐MBA polymers.