bluuebunny/crossref_metadata_2025 huggingface dataset:
γ‐Ray‐induced copolymerization of ethylene and vinyl chloride in liquid carbon dioxide
Authors: Hagiwara Miyuki , Miura Takeshi , Kagiya Tsutomu
Published: April 2003

The γ‐ray‐induced copolymerization of ethylene and vinyl chloride with the use of liquid carbon dioxide as a solvent was studied under a total pressure of 400 kg/cm2, with a dose rate of 2.5 × 104 rad/hr at 30°C. A rubberlike, sticky polymer is obtained when the molar concentration of vinyl chloride is less than 30% in the monomer mixture, and the polymer is a white powder at higher concentrations of vinyl chloride. Infrared, x‐ray, and differential thermal analyses confirm that the polymerization products are noncrystalline, true random copolymers. The rate of copolymerization decreases markedly when a small amount of vinyl chloride is added to ethylene monomer. In the range of vinyl chloride concentration higher than 5%, however, the rate and the molecular weight of copolymer increase with increasing concentration of vinyl chloride. It has been concluded from kinetic considerations based on these results that the rate of initiation increases proportionally with the concentration of vinyl chloride. Further, the growing chain radicals are shown to be deactivated by the cross‐termination reaction between the radicals with terminal unit of ethylene and vinyl chloride, and no transfer reaction occurs.
Epoxide polymers: Synthesis, stereochemistry, structure, and mechanism
Authors: Vandenberg E. J.
Published: April 2003

Epoxide polymerization studies have yielded technically important catalysts and polymers. The polymers were studied by cleaving them with Group IA organometallics to monomer, dimer, and trimer glycol fragments. The identification of these glycol fragments has established that the crystalline polymers from the cis‐ and trans‐2,3‐epoxybutanes are respectively racemic and meso‐diisotactic and that the amorphous polymer from the cis‐oxide is disyndiotactic. These studies also showed that the amorphous fraction from propylene oxide polymerization with coordination catalysts contains substantial head‐to‐head and tail‐to‐tail segments. This work has led to a much better understanding of the mechanism of epoxide polymerization. These facts were established: (1) epoxides polymerize with inversion of configuration of the ring‐opening carbon atom; (2) monosubstituted epoxides polymerize largely by attack on the primary carbon with a coordination catalyst; and (3) two or more metal atoms must be involved in the coordination polymerization of epoxides.
Electron‐transfer polymers. XXXVIII. Further investigation of “polymer effects” with self‐protected polymer
Authors: Nakabayashi Nobuo , Wegner Gerhard , Cassidy Harold G.
Published: April 2003

3‐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

Polyimides 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

Low 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

Perhydro‐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

Copolymerizations 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

Photopolymerization 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

The 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

Crystalline 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

Smoluchowski'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

Polyhydrouracils 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

The 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

Condensation 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

The 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

Stereoregulation 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

Na 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

The 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

The 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

Copolymerizations 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

The 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

The 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

By 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

The 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

Polymerizations 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.
Polymerization of vinyl compounds with heterocyclic groups. IV. Thermal polymerization of 2‐vinylthiophene
Authors: Aso C. , Kunitake T. , Shinsenji M. , Miyazaki H.
Published: April 2003

2‐Vinylthiophene was found to undergo thermal polymerization. With benzene as diluent, the overall rate of polymerization was proportional to the 2.5 power of monomer concentration, suggesting that the thermal initiation is a termolecular process. The following Arrhenius equation was obtained from the polymerization data for the range 55–100°C:

The activation energy of the thermal initiation was estimated to be 28.2 kcal/mole, which was similar to those values obtained for styrene and 2‐vinylfuran. When a dilute solution of the monomer in bromobenzene was heated in an ampoule at 151°C, a dimer, mp 82°C, was obtained in a good yield. The spectroscopic data indicated that the dimer was a Diels‐Alder type adduct. The initiation of the thermal polymerization was considered to involve hydrogen abstraction by monomer from the Diels‐Alder dimer, in common with the initiation of other vinylaromatic monomers.
Stereospecific polymerization of benzyl vinyl ether by BF3·OEt2
Authors: Yuki Heimei , Hatada Koichi , Ota Koji , Kinoshita Ikuya , Murahashi Shunsuke , Ono Katsuhiro , Ito Yoshiyuki
Published: April 2003

Polymerization of benzyl vinyl ether was carried out by BF3·OEt2, and the effects of polymerization conditions on the stereoregularity of the polymer were studied by NMR analysis. The polymerization at −78°C in toluene gave a highly isotactic polymer. The isotacticity of the polymer was independent of the catalyst concentration but increased with a decrease in the initial monomer concentration and decreased slightly on raising the reaction temperature. When the polymerizations were carried out in toluene—nitroethane mixtures, a gradual decrease in the isotacticity and a rapid decrease in the molecular weight of the polymer were observed with increasing nitroethane in the solvent. The molecular weight of the polymer was almost constant, regardless of the catalyst concentration, and increased with increasing initial monomer concentration and decreasing polymerization temperature. When the polymerization was performed in toluene at −78°C with a small amount of water or benzyl alcohol, a linear relationship was found between the reciprocal DP of the polymer and water or benzylalcohol concentration. The mechanisms of the initiation reaction and the stereoregulation in the polymerization were also discussed.
Polymerization of β‐cyanopropionaldehyde. VI. Anionic polymerization initiated by aromatic hydrocarbon—sodium complexes
Authors: Hashimoto Kazuhiko , Sumitomo Hiroshi
Published: April 2003

Further investigation on an anionic polymerization of β‐cyanopropionaldehyde was made with use of polystyryl—disodium, naphthalene—sodium, and tetraphenylethylenedisodium complexes as initiators. Styrene—β‐cyanopropionaldehyde block copolymer was separated from the gross polymer obtained by the polymerization of β‐cyanopropionaldehyde with polystyryl—sodium. The polymerization initiated by naphthalene—sodium and tetraphenylethylene—disodium complexes resulted in the formation of an aldol condensation‐type product having a low molecular weight. It was found that initiators of weaker basicity may start the carbonyl polymerization, whereas those of stronger basicity cause the aldol condensation of β‐cyanopropionaldehyde through the withdrawal of proton from the monomer.
Untersuchungen zur molekulargewichtsverteilung von polyäthylenterephthalat
Authors: Gehrke Klaus , Reinisch Gerhard
Published: April 2003

The molecular weight distribution of carefully prepared thermostabilized poly(ethylene terephthalate) was determined immediately after polycondensation in vacuo (P̄n = 121) and after the melt was stirred at 280°C for 5.5 hr under nitrogen (P̄n = 123). The fractionation was carried out by successive precipitation in liquid phases. The samples were separated into 25 fractions including refractionation. The Flory distribution was observed in all samples.
Aromatic copolyimide–amides II
Authors: Wrasidlo W. , Augl J. M.
Published: April 2003

Six thermally stable polyimide‐co‐amides have been synthesized from sulfurylbis[N‐(4′‐phenylene)‐4‐(chloroformyl)‐phthalimide] and various aromatic diamines. Linear, high molecular weight final polymers were obtained by one step low‐temperature solution condensations in dimethylacetamide. Thermal properties such as glass transition and polymer decomposition temperatures and solution properties such as viscosities and solubilities varied significantly with polymer structure. Tough, flexible films of these polymers were cast from solution. The thermal‐oxidative stabilities of films were strongly dependent on structure, solvents used, and impurities present.
Mechanism of decoloration by solvent of thermally degraded poly(vinyl chloride)
Authors: Matsumoto Tsunetaka , Mune Isao , Watatani Seiji
Published: April 2003

The mechanism of decoloration of thermally degraded poly(vinyl chloride (PVC)) by solvents has been investigated systematically. The main results obtained are as follows. Good solvents for PVC, especially tetrahydrofuran, methyl ethyl ketone, and dioxane are effective for decoloration. The solvent peroxide which is formed by autoxidation of solvent contributes to decoloration. The number of double bonds in degraded PVC decreases as the decoloration proceeds and at the same time the solvent peroxide existing in solvent is consumed. Moreover, the existence of solvent fragments in decolored PVC is recognized. From these results, it is most reasonable to conclude that the decoloration mechanism is as follows: the solvent partially is changed to a solvent peroxide by autoxidation, and the solvent peroxide reacts with polyene double bonds of degraded PVC and breaks down conjugated double bonds, and consequently degraded PVC is decolored.
Grafting of maleic anhydride on polyethylene. III. Influence of polyethylene concentration on the course of the reaction in a homogeneous medium
Authors: Porejko Stanisław , Gabara Włodżimierz , Błażejewicz Teresa , Łȩcka Maria
Published: April 2003

The effect of the polymer concentration on the grafting of maleic anhydride on polyethylene was studied at different temperatures and at different monomer and initiator concentration. The character of the curves obtained suggests the importance of the termination reactions and the appearance of the gel effect at higher polymer concentrations.
Copolymers of modified starches with polyacrylonitrile
Authors: Fanta George F. , Burr Robert C. , Russell C. R. , Rist C. E.
Published: April 2003

A study was made of the ceric ammonium nitrate‐initiated graft polymerization of acrylonitrile (AN) onto a number of modified starches that had been reduced in molecular weight by either acid, hypochlorite, or enzyme treatment. With highly soluble starches, much of the starting material was recovered as ungrafted carbohydrate, and the reaction product was largely dimethylformamide‐soluble polymer with a high polyacrylonitrile (PAN) content. The molecular weight of grafted PAN was lower when the modified starches existed as granules in water dispersion; however, heating (60°C) an aqueous slurry of an acid‐modified corn starch (with intact granules) before the reaction had relatively little effect on the composition of the copolymer. Decreasing the concentrations in water of modified starch and AN resulted in more frequent and lower molecular weight grafts of PAN. Aqueous methanol as a reaction medium for an acid‐modified starch with intact granules led to more frequent grafting of lower molecular weight PAN than when water alone was used. The number of grafted chains, however, was fewer than found with unmodified wheat starch under comparable conditions. A modified starch with the granule structure completely broken down gave no detectable reaction in aqueous methanol.
Thermogravitational effect in macromolecular solutions
Authors: Gaeta F. S. , Cursio N. M.
Published: April 2003

We have investigated in a thermogravitational apparatus the behavior of solutions containing macromolecular solutes and of suspensions of ultramicroscopic particles such as viruses and ribosomes. We have obtained very high separation ratios with all the solutes studied, the value of the separation being characteristic of each solution. The reproducibility of the results is good, and the dependence on the geometrical and physical parameters involved fits the predictions of the phenomenological theory. Our results prove that fractionation of very high molecular weight particles is feasible by this method, and also that the characterization of the macromolecular species and the determination of the mass and shape of the particles of the solute seem to be within the possibilities of the thermogravitational method when this is applied to very high molecular weight materials.
Sulfur modification of polyethylene surfaces. III. Frustrated multiple internal reflection spectroscopy of sulfonated polyethylene surfaces
Authors: Olsen Douglas A. , Osteraas A. Jean
Published: April 2003

The previous publications of this series show by indirect means that atomic sulfur inserts into the carbon—hydrogen bonds of polyethylene surfaces. In this study, frustrated multiple internal reflection (FMIR) spectroscopy was used to obtain direct evidence of the nature of the surface groups of the modified polyethylene. The FMIR spectra of surfaces consisting of the products of sulfonic acid groups were virtually identical, regardless of whether the original sulfonic acid surface had been prepared by direct sulfonation or by oxidation of surface thiol groups. The latter groups resulted from the insertion of atomic sulfur into the carbon—hydrogen bonds of the surface. These results establish that sulfur is indeed inserted into polyethylene surfaces.
Stereospecific polymerization of o‐methoxystyrene by anionic initiators
Authors: Yuki Heimei , Okamoto Yoshio , Kuwae Yoshiteru , Hatada Koichi
Published: April 2003

o‐Methoxystyrene was polymerized with n‐butyllithium (n‐BuLi), Na naphthalene, and K dispersion as initiators in tetrahydrofuran (THF) and toluene. The stereoregularity of the polymer was investigated by means of the NMR spectroscopy. The methoxy resonance of the spectrum split into ten components due to the tactic pentads. It was found by x‐ray examination that the polymer obtained by n‐BuLi in toluene at −45°C was crystalline and highly isotactic. In THF, the stereospecificity of the polymerization was independent of the initiator, and the isotacticity of the polymer increased with increasing reaction temperature. In toluene, the stereospecificity depended on the initiator; i.e., n‐BuLi gave a polymer with higher isotacticity than that given by phenylsodium. The fraction of isotactic triad of the polymer obtained by n‐BuLi in toluene at −78°C was more than 90%, but 50% at 50°C. The presence of ca. 1% THF in toluene led to a steep decrease in the isotacticity even at −78°C. The tacticity of the polymer given by Na naphthalene was not affected by the existence of NaB(C6H5)4 in THF. The polymerization in THF could be explained by Bovey's “single σ” process, while a penultimate effect was observed in the polymerization by n‐BuLi in toluene.
Polymerization of methyl methacrylate under ultrasonic irradiation. Part IV. Effect of ultrasonic irradiation on Grignard catalyst and stereoregularity of the polymers produced in dioxane–tetrahydrofuran mixed solvent
Authors: Osawa Zenjiro , Kimura Takao , Kasuga Takao
Published: April 2003

Two series of polymerization of methyl methacrylate with Grignard reagent in dioxane—tetrahydrofuran mixed solvent was carried out under ultrasonic irradiation. In series A, catalyst was added to the mixture of monomer and solvent, and in series B, catalyst was previously mixed with solvent. The effect of ultrasonic irradiation on Grignard catalyst and the microstructure in reacting sites were discussed on the basis of the stereoregularity of the polymers produced. The stereoregularity of the polymers in series A was higher than that in series B. The effect of ultrasonic irradiation on the stereoregularity was completely reversed in series A and B and it increased in the former and decreased in the latter. It was, therefore, assumed that ultrasonic irradiation affected the microstructure in the reacting sites in series A, while it increased the relative amount of R2Mg which gave polymers with poor stereoregularity in series B.
Poly‐2,5‐distyrlpyrazine and its properties
Authors: Fujishige Shoei , Hasegawa Masaki
Published: April 2003

Four possible structural models with novel steric character are proposed for poly‐2,5‐distyrylpyrazine: two of them are extended chains and the others are kinked coils. In order to prove the molecular characteristic of the new polymer, a procedure to solubilize the polymer into some organic solvents was developed. It was recognized by viscometry that no significant degradation of the polymer does occur during the preparation. The lack of the shear rate dependence of the dilute solution viscosities would seem to indicate that the polymer molecule in solution can be regarded as a chain, not extended linearly, but kinked randomly. The crystallization of the polymer proceeds only in the presence of a sufficient amount of the solvent which enables the polymer chains to move and crystallize. These imply that the possible structure of the polymer is constructed of 1,2‐ or 1,3‐cis type cyclobutane linkages with restricted rotation.
Metal coordination polymers. II. Molecular weight studies of beryllium phosphinate polymers in toluene
Authors: Slota P. J. , Grieve C. M. , Fetter N. R. , Bilbo A. J.
Published: April 2003

The number‐average molecular weights of beryllium 4‐biphenyl(phenyl)phosphinate, di‐n‐pentylphosphinate, di‐n‐heptylphosphinate, and trifluoromethyl(phenyl)phosphinate are degraded by the presence of water in toluene. It is proposed that easily hydrolyzable POP bonds contribute, in part, to the bonding of these polymers.
Polymerization of coordinated monomers. II. Stereoregulation in the free‐radical polymerization of methacrylonitrile–zinc chloride or methacrylonitrile–stannic chloride complexes
Authors: Hirai Hidefumi , Ikegami Tadashi , Makishima Shoji
Published: April 2003

The effect of complex formation on stereoregulation in free‐radical polymerization was studied. Complexes of methacrylonitrile with ZnCl2 and SnCl4 were prepared and their properties and structures examined. The complexes were polymerized by initiation of α,α′‐azobisisobutyronitrile or by irradiation with γ‐rays from a60Co source or ultraviolet rays either in solution or in bulk at various temperatures ranging from −78 to 100°C. The triad tacticities of the resulting polymethacrylonitrile were determined by converting it to poly(methyl methacrylate) for NMR spectroscopy. The radicals in complexed forms were studied by ESR spectroscopy with the polymerization system in toluene irradiated with ultraviolet rays at −120°C. The tacticities of the resulting polymers and their dependencies on the polymerization temperature were found to be characteristic of the complex species, i.e., the kind of metal chloride and the stoichiometry, being different from the tacticities and the dependencies, respectively, of the polymer obtained with pure methacrylonitrile. The 2:1 and the 1:1 complexes with SnCl4 were found to give an eleven‐line and a nine‐line spectrum, respectively. On the basis of the results of both the tacticities and the ESR spectra, it was estimated that the proportion of the intracomplex reaction was 40%, and that the probabilities of isotactic diad addition of intra‐ and intercomplex reaction were 0.70 and 0.48, respectively.
Combination of cellulosic materials and metallic ions
Authors: Ogiwara Yoshitaka , Kubota Hitoshi
Published: April 2003

Cellulosic materials (DP, SCP) and PVA fibers were treated with four kinds of metallic ions (Ca2+, Fe2+, Fe3+, Ce4+), and the adsorption behavior was studied to elucidate the manner in which the celluloses and the metallic ions were combined. The effects of treatment temperature, time, and concentration upon the amount of the metallic ions adsorbed were examined. With Ca2+ and Fe2+, the effects of such factors on the adsorption were slight, while with Fe3+ and Ce4+ the effects of time, temperature, and ion concentration were pronounced. Also, it was evident that the amount (molar) of equilibrium adsorption of Ca2+ or Fe2+ was approximately the same as the content of carboxyl groups in the cellulose sample, and the amount of equilibrium adsorption of Fe3+ or Ce4+ was approximately the same as that of total carbonyl group content. When the samples which had adsorbed these metallic ions were treated with 0.1N hydrochloric acid, the Ca2+ and Fe2+ were completely desorbed while about 80% of the adsorbed Fe3+ and Ce4+ remained. These results indicate that there are two types of combinations of cellulosic materials and metallic ions involved: one is thought to be an ionic bond, while the other is considered to be a chelate bond.
Investigation of the epoxide–carboxylic acid reaction in model compound and polymerization reactions
Authors: Alvey Francis B.
Published: April 2003

The reaction of epoxide and acid has been studied in the model reaction of bisphenol‐A diglycidyl ether and acetic acid with several base catalysts at 60, 95, and 115°C. The results suggest that no greater than 5% side reactions occur. A series of polyhydroxylester polymers were prepared from bisphenol‐A diglycidyl ether and adipic acid. The polymers gel rapidly upon heating at 200°C. Terpolymers of bisphenol‐A diglycidyl ether, bisphenol‐A, and azelaic acid were prepared. These also gel at 200°C when 50 mole‐% of the active hydrogen reactant is azelaic acid.
A contribution to the theory of the structural glass transition
Authors: Bartenev G. M. , Razumovskaya I. V. , Sanditov D. S. , Lukyanov I. A.
Published: April 2003

The equations characterizing the temperature dependence of the mobility of molecules in the glass transition region are compared and analysed. A relationship between the parameters of the relaxation theory of the glass transition and the concept of free volume is established. The Williams‐Landel‐Ferry equation is treated in terms of the relaxation theory of glass transition.
Polyaryleneimides of meso‐ and dl‐ 1,2,3,4‐butanetetracarboxylic acid dianhydrides
Authors: Loncrini D. F. , Witzel J. M.
Published: April 2003

High molecular weight polyarylene amic acids have been prepared by reacting aromatic diamines with equimolar amounts of either meso‐or dl‐1,2,3,4‐butanetetracarboxylic acid dianhydride (TCBA) in organic polar solvents. Heat converted these soluble precursors to insoluble polyimides having good high‐temperature physical properties.
Copolymerization of acrylonitrile. II. Physical and mechanical properties of copolymers with styrene derivatives containing nitrile groups in the side chain
Authors: Ronel Samuel H. , Kohn David H.
Published: April 2003

Copolymers of acrylonitrile with cinnamonitrile (I), ethyl benzylidenecyanoacetate (II), and benzylidenemalononitrile (III) were prepared in suspension up to high conversions. Films and molded specimens were made from the copolymers and their basic physical and mechanical properties, such as solubility, viscosity, glass transition temperature, and tensile and compressive strength were determined. Further, treatment by heat and ultraviolet light, the permeability of water vapors, and the behavior of films in a weathering tester were studied.
High‐temperature polymerization of ϵ‐caprolactam by using as catalyst the Li, Na, or K salts derived from MAlEt4 or MOAlEt2·AlEt3 and monomer
Authors: Konomi T. , Tani H.
Published: April 2003

High‐temperature polymerization of ϵ‐caprolactam by using the salts derived from MAlEt4 (where M is Li, Na, and K) and monomer as catalyst was carried out. Polymerization occurs at 140–170°C, a temperature at which alkali metal caprolactamate has almost no catalytic activity for initiation. m‐Cresol‐insoluble polymer was obtained at temperatures lower than 231°C. Formation of a m‐cresol‐insoluble polymer depends on the polymerization temperature and time, and was observed under conditions where Al(Lac)3 has no catalytic activity. All the polymers obtained by NaAl(Lac)4–n(NHBu)n (n = 1 or 2) at 202°C were soluble in m‐cresol. These trends observed in the case of MAl(Lac)4 are considered to be due to initiation by Al(Lac)3, which is a component of the catalyst used.
Chain transfer in anionic polymerization. Determination of chain‐transfer constants by using carbon‐14‐labeled chain transfer agents
Authors: Gatzke Arnold L.
Published: April 2003

A method is described in which 14C‐labeled chain‐transfer agents are employed to measure chain‐transfer constants in anionic polymerization as low as 10−6. Each chain‐transfer step incorporates one molecule of the chain‐transfer agent into the polymer so that measurement of the activity and conversion allows evaluation of the chain‐transfer constant. This method is independent of the initiator concentration and efficiency, making the technique especially useful when problems with the initiator are encountered. The experimental procedure is described in detail for the case of chain transfer to toluene in the n‐butyllithium‐initiated polymerization of styrene, where CRH was found to be 5 × 10−6. A mathematical treatment is given showing the relationship between the degree of polymerization (DPn) and chain transfer.