bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vinylhydroquinone. IV. Preparation and polymerization behavior of 2‐methyl‐5‐vinylhydroquinone derivatives
Authors: Iwabuchi Susumu , Kojima Kuniharu , Nakahira Takayuki , Uchiyama Takashi , Sakata Junji , Shimizu Hisashi 
Published: April 2003

AbstractAs in the case of vinylhydroquinone (I), its alkyl‐substituted derivative, 2‐methyl‐5‐vinylhydroquinone (II) was found to copolymerize with methyl methacrylate by tri‐n‐butylborane in cyclohexanone at 30°C. II was prepared from the O,O′‐bisether compound, 2‐methyl‐5‐vinyl‐O,O′‐bis(1′‐ethoxyethyl)hydroquinone (III). The monomer reactivity ratios (M2 = II) were determined to be r1 = 0.37 and r2 = 0. No homopolymerization proceeded under the same conditions. Ordinary free‐radical initiators, such as azobisisobutyronitrile and benzoyl peroxide, were not effective in the homopolymerization of II. 1:1 Copolymers were obtained from II and maleic anhydride by using tri‐n‐butylborane as an initiator. The copolymers exhibited no definite melting range and decomposed at 370–375°C endothermally (DSC). The polymerization behavior of III was also investigated. Although tri‐n‐butylborane did not initiate the homopolymerization of the monomer, azobisisobutyronitrile was capable of initiating the homopolymerization and copolymerization of III. The monomer reactivity ratios (M1 = styrene) were determined to be r1 = 0.83 and r2 = 0.18. The ratios gave the following Q and e values; Q = 0.15 and e = −2.2.
Synthesis and polymerization of N‐(p‐vinylbenzyl)‐3‐carbamoyl‐1,4‐dihydropyridine and redox behavior of the oligomer
Authors: Tsuchida Eishun , Hasegawa Etsuo , Ohno Hiroyuki 
Published: April 2003

AbstractIn order to prepare a soluble dihydropyridine‐type redox polymer, N‐(p‐vinylbenzyl)‐3‐carbamoyl‐1,4‐dihydropyridine was synthesized and characterized by elemental analysis, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The polymerization of the vinyl monomer in N,N‐dimethylformamide or chloroform was also studied. Only oligomers were obtained by radical polymerization. The reduction of various compounds by the oligomer thus prepared was examined in heterogeneous or homogeneous solution.
Measurement of particle size distribution in the discrete phase of high‐impact polystyrene. I. Errors in direct coulter counter techniques
Authors: Craig T. O. , Quick R. M. , Jenkins T. E. 
Published: April 2003

AbstractThe published Coulter Counter method for measuring particle size distribution of the discrete phase in rubber‐modified polystyrene is shown to be subject to serious limitations, especially when the data generated are used to compute discrete phase volume fractions. The source of error is time‐dependent swelling of the particles in DMF which is used to isolate them from the polystyrene matrix for the counting operation.
Measurement of particle size distribution in the discrete phase of high‐impact polystyrene. II. An improved coulter counter procedure
Authors: Craig T. O. , Quick R. M. , Jenkins T. E. 
Published: April 2003

AbstractAn improved Coulter Counter procedure is described for determining the size distribution and volume fraction of the elastomeric discrete phase in high‐impact polystyrene. The method isolates the discrete phase from a dispersion of the whole polymer in DMF by centrifugation and redisperses the discrete phase in an aqueous surfactant solution, thus allowing the particles to deswell and resume the dimensions they had in the polystyrene matrix. By measuring a Coulter Counter size distribution on the aqueous dispersion, a discrete‐phase volume fraction can be reliably derived for the original impact polystyrene. The method is rapid and precise.
Preparation and some properties of nylon 46
Authors: Gaymans R. J. , Van Utteren T. E. C. , Van Den Berg J. W. A. , Schuyer J. 
Published: April 2003

AbstractNylon 46 was synthesized from the salt of 1,4‐diaminobutane and adipic acid. High molecular weight polymers could be obtained by reaction for 1 hr at 215°C in a closed system and at least for 1 hr in vacuo at a temperature in the range 290–305°C. The reactions at 290°C were found to have taken place in the solid state and those at 305°C in the melt. The highest molecular weights (M̄w ca. 45,000) were obtained by reaction at 290°C with a nylon salt with a pH of 7.8–8.0. The molecular weight characteristics were studied with end‐group analysis, viscometry, light scattering, and ultracentrifugation. The polymers were found to be gel‐free and monodisperse (M̄w/M̄n ∼ 1.15). Films could be cast from formic acid. From x‐ray diffraction patterns, measured on such films, spacings of 3.74 and 4.30 Å were calculated, whereas a long period of 66 Å was also found. The infrared spectra showed all the usual amide bands of even–even polyamides. The melting temperature was found to vary between 283 and 319°C, depending on the thermal history of the sample. Water absorption measured on a cast film showed this to be very hygroscopic (7.5% at 65% RH), while a highly crystalline sample absorbed only little water (1.6% at 65% RH).
Water‐soluble copolymers containing N‐vinylcarbazole
Authors: Mulvaney J. E. , Chang Daniel M. 
Published: April 2003

AbstractWater‐soluble or dispersable copolymers of N‐vinylcarbazole (VCbz) with sodium N‐acryloylsulfanilate (SAS), or sodium styrene‐sulfonate (SSS), or N,N,N‐triethyl‐N‐[2‐(methacryloxy) ethyl]‐ammonium iodide (TAI), or N,N,N‐trimethyl‐(p‐vinylbenzyl)ammonium chloride (TVBA) were prepared by using a radical initiator. VCbz and SAS were copolymerized in N,N‐dimethylacetamide. Copolymers containing more than 49% SAS were water‐soluble. In the case of VCbz and SSS, copolymerization was also carried out in DMAN to yield water‐soluble copolymers when the SSS content was greater than 36%. VCbz–TAI and VCbz–TVBA were similarly copolymerized in DMAN to give water‐soluble polymers when the TAI content was greater than 58% or the TVBA content was 60%. In addition, a copolymer of VCbz and methyl acrylate was partially hydrolyzed with NaOH in tetrahydrofuran to yield a water‐dispersable polymer.
Copolymers of vinylcyclohexane with styrene: Peculiarity of thermal behavior, parameters of crystal structure, and structural transitions
Authors: Kharas G. B. , Kleiner V. I. , Stotskaya L. L. , Karpacheva G. P. , Krentsel B. A. , Nechitailo N. A. , Dzyubina M. A. , Litvinov I. A. , Artamonova S. D. 
Published: April 2003

AbstractThermal behavior, the parameters of crystal structure, and the structural transitions of copolymers of vinylcyclohexane with styrene were studied. Heating in air of the copolymers and of mechanical mixtures of homopolymers results in thermooxidative destruction. For all samples, the oxidation starts at 210–220°C. The antioxidant effect on thermal stability of copolymers was studied. Differential thermal analysis (DTA) data were used to determine the melting points of homopolymers and crystal copolymers. The method of x‐ray diffraction on large scattering angles was used to determine the dimensions and type of unit cells, the degree of crystallinity, the dimensions of the coherent scattering regions (the dimensions of crystallites) of copolymers of various compositions, and to compare them to the parameters of the structure of polyvinylcyclohexane and polystyrene. Information on molecular motion intensity and structural transitions in homopolymers and copolymers with changing temperature was obtained by the spin‐probe technique.
Radiation‐induced oxidation of solid poly(ethylene oxide). I. Experimental results
Authors: Decker Christian 
Published: April 2003

Abstractγ‐Initiated oxidations of solid poly(ethylene oxide) (PEO) have been carried out at ambient temperatures and the dependence of the rate of oxygen consumption on rate of initiation, O2 pressure, and crystallinity has been determined. At 25°C, the radiation yield G for O2 absorbed is 117–281, depending on dose rate, and decreases moderately with increasing crystallinity. The principal oxidation products are formate and hemiformal groups, hydroperoxides, and some volatile compounds, mainly formaldehyde and carbon dioxide. The rates of O2 consumption and formation of products and chain scission are little affected by a change of the temperature in the range −23 to +55°C except for hydroperoxide, the formation of which requires an activation energy of 4 kcal/mole. Experiments with 2,6‐di‐tert‐butyl‐p‐cresol show that essentially all of the initiating PO2· radicals escape cage termination; G value for formation of the initiating peroxy radicals was estimated from the inhibition period to be 5.0 ± 0.3.
Optical properties and conformations of asymmetric polyamides derived from optically active trans‐1,2‐cyclopropanedicarboxylic acid
Authors: Overberger C. G. , Shimokawa Y. , Montaudo G. 
Published: April 2003

AbstractOptical properties and conformations, in solution, of optically active polyamides derived from (+)(S)‐trans‐1,2‐cyclopropanedicarboxylic acid with secondary diamines such as trans‐2,5‐dimethylpiperazine (DMPIP), piperazine (PIP), or N,N′‐dimethylethylenediamine (DMED) have been investigated and compared with the corresponding diamide model compounds. The results suggest that the rigid DMPIP and PIP polyamides may exist in ordered conformations in 2,2,2‐trifluoroethanol (TFE) and tetramethylene sulfone (TMS), while reversible conformational transitions to highly extended forms may be induced by the addition of methanesulfonic acid (MSA). In MSA/TMS mixtures, a change in the optical properties, and thus possibly in the conformations, can be observed around 0.5 mole fraction of MSA. A study of CD at higher temperature indicates that the conformations of the DMPIP and PIP polymides tend to be randomized on heating in TMS and probably also in MSA. No evidence for salt effects on conformation has been observed. Possible ordered conformations have been proposed.
Energy transfer and radical formation in the system poly(methyl methacrylate)–2‐methyltetrahydrofuran
Authors: Torikai Ayako , Kinugawa Kazuhisa , Kuri Zen‐Ichiro 
Published: April 2003

AbstractESR spectra of γ‐irradiated poly(methyl methacrylate) (PMMA) at 77°K and the effect of additives have been studied. γ‐Irradiation of PMMA containing a small amount of 2‐methyltetrahydrofuran as an additive at 77°K gives MTHF radical. Yields of MTHF radical increase with increasing MTHF concentration and reach a plateau value, and are independent of photobleaching with visible light. Yeilds of polymer radical are reduced by the addition of MTHF. Some elementary processes for the MTHF radical formation are proposed on the basis of the experimental results.
Soluble bimetallic μ‐oxoalkoxides. VII. Characteristics and mechanism of ring‐opening polymerization of lactones
Authors: Hamitou A. , Ouhadi T. , Jerome R. , Teyssié Ph. 
Published: April 2003

AbstractThe ring‐opening polymerization of unsubstituted lactones by Al2Zn and Al2Co(II) μ‐oxoalkoxides in homogeneous organic phase is described. Under these conditions, the chain propagation is very fast and proceeds without transfer or termination reactions. The composition and structure of the main products resulting from the first polymerization steps have been determined, and fit with a monomer insertion mechanism into the aluminum‐alkoxide bonds of the catalyst.
Oligomérisation anionique de l'ethylène. I. Etude cinétique
Authors: Magnin Henri , Rodriguez Firmin , Abadie Marc , Schué François 
Published: April 2003

AbstractA kinetic study of ethylene oligomerization in hexane, in the presence of n‐BuLi–TMEDA complexes, allowed us to suggest a new mechanism for anionic ethylene oligomerization. n‐BuLi and n‐Bu(CH2CH2)Li species have the same reactivity. The RLi–TMEDA complex in a 1‐to‐1 stoichiometry is the active species. The following kinetic equation has been established:

It reflects the intervention of associated species (n‐BuLi–TMEDA)2 as well as the influence of the concentration of the complexing agent on the kinetics of oligomerization.
Copolymerization of anhydroglucose and anhydromannose derivatives: Structure, reactivity, and conformational analyses
Authors: Kobayashi Kazukiyo , Schuerch Conrad 
Published: April 2003

AbstractPhosphorus pentafluoride‐catalyzed copolymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐(p‐methylbenzyl)‐β‐D‐glucopyranose (TXGL, monomer G) and 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐β‐D‐mannopyranose (TBMN, monomer M) appears to follow classical copolymerization theory. Reactivity ratios calculated by the procedure of Mayo and Lewis were rG = 0.90 ± 0.08, rM = 11.5 ± 0.80, from which sequence distributions were calculated. A conformational analysis of anhydro sugar polymerization is presented to explain differences in reactivity of monomers and their derived cations in polymerization and copolymerization. The polymers and copolymers were characterized by viscosity, 1H‐ and 13C‐NMR spectroscopy, optical rotation, and circular dichroism. The reaction gives stereoregular polymers as have other polymerizations and copolymerizations of this class.
Copolymerization of propylene oxide and carbon disulfide with diethylzinc–electron‐donor catalyst
Authors: Adachi Nobuo , Kida Yasuji , Shikata Kazuo 
Published: April 2003

AbstractCopolymerization of propylene oxide with carbon disulfide was studied by using a catalyst consisting of diethylzinc (ZnEt2) and various electron donors. Tertiary amines, tertiary phosphines, and hexamethylphosphoric triamide were the effective donors for the copolymerization, but ZnEt2–water, alcohol, and primary or secondary amines having high activities for the homopolymerization of propylene oxide were not effective for the copolymerization of propylene oxide and carbon disulfide. The copolymers obtained were of low molecular weight and had a monomer unit ratio (CS2/PO) of 0.5–0.7. In addition, a considerable amount of 1,3‐oxathioran‐4‐methyl‐2‐thion was isolated as a by‐product.
Soluble bimetallic μ‐oxoalkoxides. IX. ε‐caprolactone and β‐propiolactone block copolymerization
Authors: Hamitou A. , Jerome R. , Teyssié Ph. 
Published: April 2003

AbstractThe fast and living ring‐opening polymerization of lactones by bimetallic μ‐oxoalkoxides in homogeneous organic phase has led to successful block copolymerization. The catalyst is coordinatively associated in organic media; however, interaction with lactones can induce, following their nature, different rearrangements of the catalytic aggregates, depending on the nature of these lactones. Consequently, ε‐caprolactone and β‐propiolactone block copolymers are quantitatively obtained only in the presence of a completely dissociated catalyst.
Regular copolyamides. II. Preparation and characterization of regular aliphatic copolyoxamides
Authors: Chang H. J. , Vogl O. 
Published: April 2003

AbstractRegular copolyoxamides were prepared from diamine‐oxamides and aliphatic diacid chlorides by interfacial and solution polymerization. Interfacial polymerization is preferred with diamineoxamides where the diamine portion has two to six methylene groups and the diamine‐oxamides are readily soluble in water. Regular aliphatic polyoxamides from diamine‐oxamides are readily soluble in water. Regular aliphatic polyoxamides from diamine‐oxamides with more than six methylene groups in the diamine portion of the molecule are better prepared by solution polymerization in dimethyl acetamide. Regular aliphatic oxamides are soluble in trifluoroacetic acid and hexafluoroisopropanol and show a considerable alternation of the melting point behavior in the diamine portion of the polyamides with up to five methylene groups. Copolyoxamides with two and four methylene groups melt higher than the copolyoxamides with three and five methylene groups. Aliphatic copolyoxamides/adipamides melt at approximately 260°C and show a steady decrease in melting points to about 220°C for polyoxamides with twelve methylene groups.
Stereoelective cationic polymerization of propenyl ether by asymmetric catalysts
Authors: Higashimura Toshinobu , Hirokawa Yoshitsugu 
Published: April 2003

AbstractIn order to elucidate the possibility of stereoelective cationic polymerization (asymmetric selective polymerization) of olefinic monomers, racemic cis‐ and trans‐1‐methylpropyl propenyl ether and racemic 1‐methylpropyl vinyl ether were polymerized by asymmetric alkoxyaluminum dichlorides. In the polymerization of racemic cis‐1‐methylpropyl propenyl ether with (−)‐menthoxyaluminum dichloride in toluene at −78°C, the polymer obtained showed a positive optical activity, and the residual monomers were converted by BF3OEt2 into a polymer having a negative optical activity. Thus, the stereoelective polymerization of racemic cis‐1‐methylpropyl propenyl ether was beyond any doubt attained in homogeneous cationic polymerization. In the polymerization of the trans isomer by the same catalyst, an optically active polymer was hardly formed. In the polymerization of racemic 1‐methylpropyl vinyl ether which has no β‐methyl group, stereoelectivity was not observed at all. The cis‐1‐methylpropyl propenyl ether did not produce an optical active polymer in the polymerization catalyzed by (S)‐1‐methylpropoxyaluminum dichloride or (S)‐2‐methylbutoxyaluminum dichloride under the same polymerization conditions.
Isothermal degradation of poly‐2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole
Authors: Lerner N. R. 
Published: April 2003

AbstractThe isothermal degradation of poly‐2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole in vacuo has been studied. Measurement of the increase in pressure with time, coupled with infrared analysis, was used to determine the distribution of the degradation products. Processes A and B with different second‐order rate laws were determined to be significant in the temperature range of 550–700°C. Process A leads to the formation of equimolar quantities of hydrogen and ammonia and has an activation energy of 68 kcal/mole. Process B leads to the production of HCN, NH3, and H2 in the ratio of 1:1:2.5 and has an activation energy of 77 kcal/mole. The activation energies and the rate laws are consistent with a mechanism in which the initial degradation step is the bimolecular reaction of two aromatic rings.
Dimerization of methylstyrenes by acetyl perchlorate and trifluoromethanesulfonic acid
Authors: Nishii Hideo , Higashimura Toshinobu 
Published: April 2003

AbstractRing‐substituted methylstyrenes (p‐, m‐, and o‐methylstyrenes) in conjunction with acetyl perchlorate (AcClO4) or trifluoromethanesulfonic acid as catalysts gave their linear unsaturated dimer in high yield in benzene at temperatures from 50 to 70°C. In particular, the yield of o‐methylstyrene dimer was as high as 90% in the AcClO4 catalysis at 50°C. The dimer yield depended on solvent and catalyst. The terminal structures of the dimers and higher oligomers were analyzed by NMR spectroscopy. Oligomers with a cyclic terminal structure increased in the products at higher temperature. The dimer yield was improved by codimerizing p‐methylstyrene with less reactive m‐methylstyrene or styrene with AcClO4 catalyst. The dimers obtained partly consisted of linear unsaturated codimers.
Polysalt complexes of poly(crown ethers) and sodium carboxymethylcellulose
Authors: Varma A. J. , Smid J. 
Published: April 2003

AbstractInsoluble polysalt complexes are formed on mixing aqueous solutions of poly(vinylbenzo‐18‐crown‐6) (P18C6) and sodium carboxymethylcellulose (CMC) in the presence of certain salts. Potassium salts are especially effective, converting the neutral P18C6 into a polycation which then interacts with sodium CMC. Nearly quantitative precipitation can be achieved at low KCl concentration (ca. 0.005M) for a crown/carboxylate ratio of approximately 5, while for 0.1–0.2M KCl the precipitation is close to completion at a crown/CMC ratio of about 2. The precipitates solubilize again on addition of water or concentrated KCl. Precipitation also occurs with CsCl but not with NaCl. Potentiometric measurements were carried out to determine the complex formation constant of the three alkali ions to P18C6. Their values can be used to rationalize the observed phenomena. Charge equivalence appears to play an important role in the formation of the polysalt complexes.
Polymérisation anionique des diènes. V. Configurations des oligopolyisoprènyl–lithium en milieu benzènique et en présence de dioxanne. Étude par résonance magnétique protonique: Haute résolution (RMP‐HR)
Authors: Salle Robert , Gole Jean , Pham Quang‐Tho 
Published: April 2003

AbstractBy PMR, three dioxane–Li+ complexes have been detected for the oligopolyisoprenyl–lithium–dioxane mixtures in benzene solution. The (4‐1) living end isomerizes into the cis configuration when the sample temperature or the dioxane concentration is increased, but the isomerization phenomenon is reversible only if dioxane/Li+ ratios are smaller than unity. The specificity of the vinyl addition (86%), mainly (4‐3) (70%), due to the stronger negative charge at the Cγ carbon atom is effective only at low temperature (+15°C). At higher temperature, because of the steric hindrance of the methyl group, this stereospecificity decreases.
Influence of the solvents on the γ‐ray polymerization of acrylic acid. I.
Authors: Laborie Francoise 
Published: April 2003

AbstractBulk polymerization of acrylic acid is controlled by linear plurimolecular H‐bonded aggregates of the monomer. It is proved that it is not the precipitating medium that is responsible for the accelerated rate of the polymerization, but the presence of the H‐bonded plurimolecular aggregates. It has been shown that the presence of the previously formed polymer is important, as it gives a matrix effect which allows the monomer aggregated to be stabilized by associating with the polymer. In polymerizing acrylic acid solutions, two types of solvents have been characterized: first, the polar solvents which do not destroy the H‐bonded aggregates up to high dilutions. Then, in the presence of hydrocarbons or chlorinated solvents, 10–20% of the solvents dissociate the aggregates. A very striking parallelism is observed between the polymerization kinetics and the associated form of the monomer.
Polymers with potential pharmaceutical properties: Fixation of histamine on the macromolecular chain of polyisoprene
Authors: Pinazzi C. , Rabadeux J. C. , Pleurdeau A. 
Published: April 2003

AbstractThe fixation of histamine [2‐(4‐imidazolyl)ethylamine] along or at the end of the chain of a low molecular weight 1,4‐polyisoprene prepared by an anionic process has been studied, and the structure of the resulting polymers determined in comparison with those of organic model molecules similarly obtained.
Superacid polymers: Synthesis and analysis of AlCl3–sulfonic acid resin complexes
Authors: Magnotta V. L. , Gates B. C. 
Published: April 2003

AbstractCrosslinked poly(styrenesulfonic acid) beads in contact with AlCl3 vapors at 115°C reacted to give HCl and a complex incorporating S, Al, and Cl in the ratio 2:1:2. Electron microprobe x‐ray analysis showed that the complexes were distributed uniformly throughout the polymer structure, which consisted of 200 Å microspheres surrounded by a labyrinth of pores. The polymer is a very strong proton donor, comparable to the superacid solution SbF5 + FSO3H. Its structural and acidic properties are inferred to be similar to those of the complex formed from AlCl3 and H2SO4.
Use of ESR to investigate formation of free radicals on compounding rubbers with carbon blacks
Authors: Jamroż M. , Kozłowski K. , Sieniakowski M. , Jachym B. 
Published: April 2003

AbstractAn ESR method was used to investigate the formation of free radicals during rubber mastication and filling of rubber with various carbon blacks. The ESR spectra of natural rubber and styrenebutadiene rubber with various carbon blacks are of a complex character. A narrow component line is superimposed on the much broader signal line of carbon black. The changes in this narrow spectral line with plasticization time and with carbon black content in the rubber–filler system result from interactions between the rubber macromolecules and filler particles.