bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron‐transfer polymers. XXXVIII. Further investigation of “polymer effects” with self‐protected polymer
Authors: Nakabayashi Nobuo , Wegner Gerhard , Cassidy Harold G. 
Published: April 2003

Abstract3‐Methacrylyloxymethyl‐5,7,8‐trimethylchroman‐6‐01 (MMC) was prepared, polymerized, and copolymerized. Poly‐MMC, a reduced redox polymer, is stable to air and is oxidized readily. The redox behaviors of poly‐MMC and copolymers with vinyl acetate were compared with that of 3‐propionyloxymethyl‐5,7,8‐trimethylchroman‐6‐o1 (PMC), the model monomer. The titration curves of the polymers were flat as is usual with redox polymers, and showed higher midpoint potentials than the model monomer. One factor in this “polymer effect” was found to be adsorption of oxidized polymer on the electrode. But there seem still to be present other factors yet to be clarified.
Polyimides having pendant hydroxy and acetoxy groups. I. Synthesis of polyimides from pyromellitimide and bisepoxides
Authors: Iwakura Yoshio , Hayano Fusakazu 
Published: April 2003

AbstractPolyimides having pendant hydroxy groups were prepared by addition of pyromellitimide with bisepoxides. Tertiary amines and quaternary ammonium halides were effective as a catalyst. The polyimides were soluble in dichloroacetic acid and had inherent viscosities in the range 0.16–0.19 dl/g. Thermogravimetric analysis showed that a rapid weight loss of the polymers occurred at about 400°C. The pendant hydroxy groups were easily acetylated by treating the polymers with a mixture of acetic anhydride and pyridine. The acetylated polyimides were soluble in dimethylformamide, dimethylacetamide, and dioxane and melted at 120–150°C.
α‐Trifluoromethyl vinyl acetate. II
Authors: Haas Howard C. , MacDonald Ruby L. , Chiklis Charles K. 
Published: April 2003

AbstractLow conversion, low molecular weight homopolymers of α‐trifluoromethyl vinyl acetate have been obtained by pyridine initiation and also by employing very large amounts of benzoyl peroxide. Since allylic hydrogens are not present, it appears that the limiting factor in the polymerization of isopropenyl esters is a slow rate of chain growth rather than degradative chain transfer. Copolymerization of the fluoromonomer (M2) with vinyl acetate (M1) yields values of r1 = 0.25 and r2 = 0.20, and for the fluoromonomer values of 0.069 and 1.51, respectively, for Q and e. Whereas ultraviolet initiation of equimolar mixtures of α‐trifluoromethyl vinyl acetate and vinyl acetate yields low molecular weight copolymers, diisopropyl percarbonate‐initiated room temperature bulk copolymerizations and emulsion copolymerizations yield polymers of high DP. Differential thermal analysis of an equimolar copolymer of vinyl acetate and the fluoromonomer surprisingly yields a sharp endotherm reminiscent of crystalline polymers. The unhydrolyzed copolymers in acetone and the alcoholyzed copolymers in 0.1N alkali exhibit Huggins k′ values of 0.3–0.4. Like ordinary poly(vinyl alcohol), the polyfluoroalcohols lose viscosity in dilute alkali due to retrograde aldol condensations. The solubilities of the polyfluoroalcohols, together with their thermal behavior, NMR spectrum, polarized infrared spectrum, refractive index, abilities to form visible polarizers, and other properties are also described.
Polymerization of perhydro‐1,5‐diazocine‐2,6‐dione
Authors: Iwakura Y. , Uno K. , Akiyama M. , Haga K. 
Published: April 2003

AbstractPerhydro‐1,5‐diazocine‐2,6‐dione polymerized in solid state in the presence of water in vapor phase and produced poly‐β‐alanine almost quantitative yield. Further, this monomer was found to polymerize rapidly on heating above its melting temperature without water. The results of x‐ray diffraction measurement and thermal analysis suggest that this solid‐state polymerization is like partial melt polycondensation.
Reactivities and NMR spectra of vinyl ethers
Authors: Yuki Heimei , Hatada Koichi , Takeshita Masatoshi 
Published: April 2003

AbstractCopolymerizations of n‐butyl vinyl ether (M1) with other vinyl ethers were carried out in toluene at −78°C with EtAlCl2 catalyst and the monomer reactivity ratios were determined. It was found that the relative reactivity of alkyl vinyl ether log 1/r1 is higher when the alkyl group is more electron‐donating and the reactivity correlates linearly with the Taft σ* of alkyl group in the monomer. The NMR spectra of vinyl ethers and of vinyl ether–trialkylaluminum complexes were investigated. Close correlations were found between the spectral characteristics and the relative reactivity of vinyl ether in the copolymerization. The degree of resonance contribution in alkyl vinyl ether was also discussed on the basis of NMR data.
Photo and thermal polymerizations sensitized by donor–acceptor interaction. II. Photopolymerization and electronic spectroscopy of the isobutyl vinyl ether–acrylonitrile system
Authors: Tazuke Shigeo , Okamura Seizo 
Published: April 2003

AbstractPhotopolymerization of acrylonitrile (AN), an acceptor monomer, was found to be accelerated in the presence of isobutyl vinyl ether (IBVE), a donor monomer. The propagation is completed by a radical mechanism as judged by copolymer compositions; in contrast to the N‐vinylcarbazole–AN system studied previously. This photopolymerization system is entirely stable if kept in the dark. The comparison of the relation between Rp and [IBVE]/[AN] ratio in the monomer feed found for the spontaneous photopolymerization with that for radical polymerization initiated by azobisisobutylonitrile in the dark leads to the conclusion that the rate of photoinitiation is enhanced by the interaction between AN and IBVE, whereas the propagation step by a radical mechanism is retarded by increasing concentration of IBVE. The contact charge‐transfer complex between IBVE and AN was confirmed by electronic spectroscopy of the polymerization system, which showed photosensitization by charge‐transfer interaction. The spectroscopic study of other weak donor–weak acceptor systems is also discussed.
Polymerization behavior of N‐(p‐vinyl)phenylacrylamide
Authors: Kamogawa Hiroyoshi 
Published: April 2003

AbstractThe polymerization behavior of N‐(p‐vinyl)phenylacrylamide, synthesized from p‐aminostyrene and acryloyl chloride by means of the Schotten‐Baumann reaction was studied. Due to a marked difference in electron density between the two double bonds, this monomer provided soluble polymers by both cationic and anionic polymerization procedures, the cationic and anionic polymers mainly carrying, as side chains, the acrylamide and styrene moieties, respectively. The polymerization behavior of the residual double bonds was also investigated for both polymers, leading to crosslinked, insoluble products.
Four‐center type photopolymerization in the solid state. I. Polymerization of 2,5‐distyrylpyrazine and related compounds
Authors: Hasegawa Masaki , Suzuki Yasuzo , Suzuki Fusae , Nakanishi Hachiro 
Published: April 2003

AbstractCrystalline 2,5‐distyrylpyrazine (DSP) was found to polymerize into a linear high polymer with extremely high crystallinity by the action of sunlight or ultraviolet light. Based on this discovery, photopolymerizability of the related diolefins having the general formula, trans,trans‐Ar′CHCHArCHCHAr′ was surveyed. As a result, 1,4‐bis[β‐pyridyl‐(2)‐vinyl]benzene (P2VB) was found to polymerize in the same way as DSP. The polymers as polymerized, showed a high melting temperature (>330°C) and were soluble only in strong acids. The structure of the polymers was investigated by means of several customary methods involving infrared and NMR spectrum studies. It was concluded that both poly‐DSP and poly‐P2VB consist of a linear structure having a recurring cyclobutane ring in the main chain. General properties of this novel polymer were studied.
Diffusion‐controlled rate constant of termination reaction in radical polymerization
Authors: Ito Katsukiyo 
Published: April 2003

AbstractSmoluchowski's theory has been modified and the improved theory was applied to diffusion‐controlled polymerization. This application proved that the rate‐controlling process is not transrational diffusion but the segmental diffusion. The segmental diffusion‐controlled rate constant was derived by the collision theory. This rate constant explains the experimental fact that the diffusion‐controlled rate constant of bimolecular termination in radical polymerization of alkyl methacrylate is inversely proportional to solution viscosity and independent of the molecular weight of the polymeric free radical.
Preparation of polyhydrouracils and polyiminoimidazolidinones
Authors: Dyer Elizabeth , Hartzler Jon 
Published: April 2003

AbstractPolyhydrouracils and polyiminoimidazolidinones were prepared by ring formation along the chain of appropriately substituted polyureas. Cyclization of 2‐carbomethoxy‐ethyl‐substituted polyureas in a polyphosphoric acid medium gave the polyhydrouracils. The polyurea precursors were prepared from N,N′‐bis(2‐carbomethoxyethyl)‐1,6‐hexanediamine and N,N′‐di(2‐carbomethoxyethyl)‐1,4‐cyclohexanebis(methylamine) with methylenebis(4‐phenyl isocyanate), 2,4‐toluene diisocyanate, and 3,3′‐dimethoxy‐4,4′‐biphenylene diisocyanate. These polyureas were soluble in m‐cresol, dimethylformamide, and chloroform, had inherent viscosities of up to 0.8, and could be cast into tough films. The polyhydrouracils had similar physical properties and could also be cast into films. The polyhydrouracils melted at temperatures 100–150°C higher than their polyurea precursors. Polyiminoimidazolidinones were prepared by cyclization of α‐cyanoalkyl‐substituted polyureas in the presence of n‐butylamine. The intermediate polyureas, which were not isolated, were prepared from methylenebis(4‐phenyl isocyanate) with N,N′‐bis(1‐cyanocyclohexyl)‐1,6‐hexanediamine, N,N′‐bis(1‐cyanocyclohexyl)‐m‐xylylenediamine and N,N′‐bis(1‐cyanocyclopentyl)‐1,6‐hexanediamine. The polyiminoimidazolidinones were soluble in m‐cresol, dimethylformamide, and chloroform and had low inherent viscosities of 0.14–0.28. Thermogravimetric analyses showed that the polyhydrouracils underwent rapid decomposition at 400°C, whereas an analogous unsubstituted polyurea decomposed at 300°C. On the other hand, the polyiminoimid‐azolidinones showed no greater thermal stability than the unsubstituted polyurea.
Effects of metal salts on polymerization. Part VII. Radical polymerization and spectra of vinylpyridine in the presence of cobaltous chloride
Authors: Tazuke Shigeo , Shimada Kiyoo , Okamura Seizo 
Published: April 2003

AbstractThe radical polymerizability of vinylpyridines in the presence of cobaltous chloride was studied in DMF solution, and the results were correlated with the spectroscopic data obtained for methanol solution. In general, the behavior of vinylpyridine complexed with cobaltous chloride is qualitatively the same as that of zinc complexes reported previously. The rates of polymerization were enhanced by the addition of cobaltous chloride when 4‐vinylpyridine(4‐VP) or 2‐methyl‐5‐vinylpyridine(MVP) was the monomer, whereas the polymerization of 2‐vinylpyridine(2‐VP) was retarded by cobaltous chloride. The monomer reactivity of all the vinylpyridines was also enhanced by complex formation as studied by copolymerization with styrene. The enhancement of reactivity of 4‐VP complexed with cobaltous chloride is somewhat smaller than that of the corresponding zinc complex.
Preparation and properties of condensation polymers containing a phosphorus–nitrogen heterocycle and derivatives of hydroquinone
Authors: Horn Hans‐Georg , Becke‐Goehring Margot 
Published: April 2003

AbstractCondensation polymers were obtained by the reaction of several aromatic dihydroxy compounds (especially substituted hydroquinones) and 1,3‐dimethyl‐2,4‐dithio‐2,4‐dichloro‐1, 3‐diaza‐2,4‐diphosphetidine. The condensation polymers thus obtained were investigated on their thermal behavior. The thermal stability is lowered in the following series: hydroquinone ≈ resorcinol > tetramethylhydroquinone ≫ tetrachloro‐hydroquinone ≈ tetrafluorohydroquinone ≫ pyrocatechol. The infrared spectra of these new polymers have been measured and are discussed in detail.
Effect of nitrobenzene in the styrene–cellulose acetate graft polymerization system
Authors: Hamburger C. Joseph 
Published: April 2003

AbstractThe effect of nitrobenzene, a polymerization retarder, upon the direct γ‐ray‐induced graft polymerization of styrene onto pyridine‐swollen cellulose acetate film was studied. When the films were not highly swollen, small nitrobenzene additions caused an increase in the amount of grafted polystyrene and grafted cellulose acetate. However, when the substrate was highly swollen, nitrobenzene additions reduced the amount of grafted polystyrene without pronounced changes in the amount of grafted cellulose acetate. The number‐average molecular weights of the grafted side chains were always two to three times those of the homopolystyrene formed in the bulk monomer solution, which is indicative of hindered chain termination within the substrate film under all reaction conditions. Nitrobenzene additions prevented polystyrene crosslinking reactions, probably because the termination reactions in the presence of nitrobenzene occur by disproportionation rather than by coupling of chain ends. Viscometric results indicated that the polystyrene side chains were branched.
Polymerization of coordinated monomers. I. Stereoregulation in the free‐radical polymerization of methyl methacrylate‐zinc chloride or methyl methacrylate–stannic chloride complexes
Authors: Okuzawa Shinjiro , Hirai Hidefumi , Makishima Shoji 
Published: April 2003

AbstractStereoregulation in free‐radical polymerization was studied for the polymerization of the 2:1 or 1:1 complex of methyl methacrylate with ZnCl2 or SnCl4. The complexes were polymerized with the use of a free‐radical initiator or γ‐ray irradiation either in the liquid or solid state at various temperatures ranging from −196 to 110°C, and the tacticities of the resulting polymers were determined by NMR spectroscopy. The polymers had different and characteristic values of tacticities depending upon the complex species, i.e., the kind of metal chloride and the stoichiometry. The tacticities were found to be independent of the polymerization temperature in both the liquid and solid states, in contrast with the fact that tacticities of the polymer from pure monomer changed markedly with the temperature. A temperature dependence appeared in the polymerization system, which contained more monomer than that corresponding to the 2:1 complex. The effect of the viscosity or the solid phase on the stereoregulation was examined in comparison with the polymerization of a mixture of methyl methacrylate and liquid paraffin. Two possible explanations regarding the stereoregulation mechanism are offered in relation to the structures of the complexes.
Degradation of Na amylose xanthate in dilute caustic soda solution during ripening
Authors: Pramanik Ananda , Chowdhury P. K. 
Published: April 2003

AbstractNa amylose xanthate was prepared from potato starch by xanthation of amylose in dilute NaOH solution. Pure xanthate was then isolated and viscometric and turbidimetric studies on its ripening characteristics were carried out for a period of about 200 hrs. Prolonged ripening in air degraded the amylose chain without formation of gel. To study the nature of ripening more precisely, it was carried out in an identical way under N2 and followed both viscometrically and turbidimetrically. The refractive‐index increment (dn/dc) of the xanthate solutions during ripening under both air and nitrogen was continuously measured so as to avoid any possible error in computing correct molecular weights during ripening. Light‐scattering molecular weights (M̄w) thus computed during the course of degradation of Na amylose xanthate extending for about 200 hr under both air and nitrogen were found to obey a first‐order rate equation, In (M0/Mt) = Kt where Mo is the initial molecular weight, Mt the molecular weight at time t of ripening, and K the rate constant of the degradation process.
Photo‐oxidation of poly(vinyl chloride)
Authors: Kwei Kwei‐Ping Shen 
Published: April 2003

AbstractThe photo‐oxidation of PVC has been studied over the temperature range 30–150°C. Initiation with ultraviolet (2537A) radiation has been correlated with the presence of minute amounts of ozone. The contribution of atomic oxygen and singlet oxygen (1Δg) molecules to the initiation mechanism is discussed. The β‐chloroketones probably formed in the photo‐oxidation of PVC, decomposed according to a Norrish type I reaction without loss of chlorine atoms. The gaseous products of the photo‐oxidation of PVC at 30°C were carbon dioxide, carbon monoxide, hydrogen, and methane. Hydrogen chloride was obtained only when PVC was heated at high temperatures. When PVC was photo‐oxidized and then heated at high temperature, benzene was obtained in addition to hydrogen chloride. The gaseous products from the photo‐oxidations of model compounds, such as 4‐chloro‐2‐butanone and 2,4‐dichloropentane, were also compared with those from PVC. Hydrogen chloride was detected only after photo‐oxidation at temperatures of 25°C or higher. Therefore, it was concluded that hydrogen chloride is mainly a product of thermal decomposition. Since unsaturation was not observed in photo‐oxidized PVC films, the cause of discoloration is unclear. When PVC was modified by stabilizers or additives, the oxidative degradation was further complicated by side reactions with the additives.
Polymers from siloxane‐containing epoxides
Authors: Patterson William J. , Bilow Norman 
Published: April 2003

AbstractThe synthesis and polymerization of seven epoxy polymer precursors which contained the siloxane linkage in varying structural arrangements was carried out. The polymers prepared from such precursors have utility as embedding compounds for electrical circuits. Polymerization of these epoxy intermediates with siloxane‐containing diamines resulted in solid, thermosetting materials for which dielectric data were obtained. Dielectric constants of 3.1 were measured at 1 keps for polymers prepared by polymerization of 1,9‐bis[p‐(2,3‐epoxypropyl)phenyl]decamethylpentasiloxane with 1,3‐bis(p‐am‐inophenoxy)tetramethyldisiloxane, whereas polymers derived from 1,4‐bis{[p‐(2,3‐epoxypropyl)phenyldimethylsiloxy]dimethylsilyl}benzene and the same diamine were characterized by slightly higher dielectric constants and a high degree of toughness, being nonbrittle at −50°C.
Cationic copolymerization of 3,3‐bis(chloromethyl) oxetane with vinyl compounds
Authors: Higashimura Toshinobu , Masuda Toshio , Okamura Seizo 
Published: April 2003

AbstractCopolymerizations of 3,3‐bis(chloromethyl)oxetane (BCMO) with some vinyl compounds were carried out with cationic catalysts in various solvents to determine what kind of vinyl compound is able to copolymerize with BCMO. p‐Methylstyrene (pMS), 2‐chloroethyl vinyl ether (CEVE), α‐methylstyrene (αMS), and isobutene (IB) were used as comonomers. The rate of consumption of each monomer was measured by gas chromatrography. Plots of copolymer composition in the copolymerization of BCMO with pMS were characterized by S‐shaped curves in several solvents. As poly‐BCMO is insoluble and the vinyl polymers are soluble in benzene, the polymers obtained were separated into benzene‐soluble and benzene‐insoluble fractions, and the composition of each fraction was determined by elemental analysis. It was found that pMS, CEVE and IB formed a copolymer with BCMO, but αMS produced no copolymer with BCMO. Thus the formation of copolymer between a cyclic ether and some vinyl monomers was observed by a cationic mechanism. The cross‐propagation mechanism is discussed on the basis of these results.
Spin‐probe studies. II. Applications to polymer characterization
Authors: Rabold Gary Paul 
Published: April 2003

AbstractThe spin‐probe technique has been employed to study interactions between several small organic nitroxides and host polymers in which they are dissolved. By this method one is able to study the mobility of the dissolved molecule in its microscopic environment using electron spin resonance spectroscopy. The behavior of one nitroxide has been examined in twelve different polymers and copolymers. An ESR line shape parameter has been correlated with Tm and Tg. In addition, energy barriers for the rotation of the dissolved nitroxides in the polymers have been calculated. They range from 7.8 to 18 kcal/mole, depending on the structure of the nitroxide and the polymer. Similar experiments in a hydrocarbon solvent afford a rotational energy barrier of 3.8 kcal/mole.
Free‐radical‐induced polymerization of epoxides in the presence of maleic anhydride
Authors: Suga Sohei , Aoyama Hajime 
Published: April 2003

AbstractThe free‐radical‐induced reactions of cyclohexene oxide in the presence of maleic anhydride have been found to lead to polyether in presence of AIBN and to a mixture of polyether, ester, and maleic anhydride adduct of polyether with di‐tert‐butyl peroxide (DTBP), the amounts of the mixture components depending on the concentration of DTBP and the temperature. Analogous reactions in the presence of succinic anhydride lead to no polyether. The obtained polyether has no hydroxyl group. The reaction appears to consist of three different steps, radical initiation, cationic propagation, and radical termination.
Electron‐transfer polymers. XL. Redox polyamides
Authors: Nakabayashi Nobuo , Cassidy Harold G. 
Published: April 2003

AbstractBy condensing a hydroquinone bis‐lactone of 1,4‐dihydroxybenzene‐2,5‐bis(ethyl‐2′‐carboxylic acid) with diamines such as hexamethylene diamine, piperazine, 4‐aminoethylpiperidine, or 1,3‐di‐(4′‐piperidinyl) propane, redox polyamides can be prepared. The lactone functions protect the hydroxyl groups until the polymerization occurs at which point, due to the opening of the lactone rings, free hydroquinone hydroxyls appear. The resulting polymer is oxidizable. When the oxidized polymer is reduced the viscosity is higher than that of the original reduced polymer.
Role of cations in radiation grafting and homopolymerization
Authors: Huglin M. B. , Johnson B. L. 
Published: April 2003

AbstractThe grafting of acrylic acid in aqueous solution to nylon 6 film has been studied in the presence of ferrous, ferric, and cupric salts. The mutual irradiation technique was adopted using a 60Co source. The anions were found to have no effect on the grafting or homopolymerization, but both of these processes were suppressed by the cations in the following order of effectiveness: Cu2+ > Fe2+ > Fe3+. The rate constant for the capture of hydroxyl radicals by acrylic acid has been determined as 6 × 109 1. mole−1 sec−1 by pulse radiolysis using the CNS− competition method. By invoking this result, mechanisms have been suggested for the process of chain termination by metal cations.
Sodium hydride‐initiated polymerizations of vinyl monomers in aprotic solvents
Authors: Needles H. L. 
Published: April 2003

AbstractPolymerizations of several vinyl monomers at 25°C in aprotic solvents (dimethyl sulfoxide, N,N‐dimethylacetamide, and hexamethylphosphoric triamide) using sodium hydride dispersion as initiator yield low to intermediate molecular weight polymers. The molecular weight of the resulting polymer as well as the mode of initiation depends on the monomer and aprotic solvent used. Initiation of polymerization of monomers with available α hydrogens (methyl acrylate, acrylonitrile) involves monomer anion, while initiation of a monomer with no α hydrogen (methyl methacrylate) proceeds by a more complex mechanism. In contrast, initiation of styrene and α‐methylstyrene proceeds by dimsyl anion addition to monomer in dimethylsulfoxide. Although the triad tacticities and number‐average molecular weights of poly(methyl methacrylate) samples obtained from all three aprotic solvents are nearly the same, poly(methyl methacrylates) prepared in dimethyl sulfoxide and N,N‐dimethylacetamide give polymers having polydispersities of ∼3, while a very polydisperse polymer is obtained in hexamethylphosphoric triamide.