bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation‐induced polymerization of sodium allylsulfonate at high pressure
Authors: Sasuga Tsuneo , Morishita Norio , Udagawa Akira , Kusama Yasuo , Takehisa Masaaki 
Published: April 2003

AbstractIrradiation of sodium allylsulfonate in aqueous solution at high pressure (up to 9000 kg/cm2) gave a deliquescent white powder which is insoluble in organic solvent. The product was addition polymer of allylsulfonate from the high‐resolution NMR and infrared spectra. The rate of polymerization was proportional to the third and second powers of monomer concentration in the initial and later stages, respectively. From the high dependence of the rate on monomer concentration, the reaction was deduced to proceed in an associated monomer or micelle. The rate of polymerization was increased by addition of sodium chloride. The G value for monomer consumption was about 104 at high pressure, which suggests that the degradative chain transfer is not important in the polymerization. Overall activation volumes were −7 and −5 ml/mole in the initial and later stages, respectively.
Alternating copolymerization of the styrene–methyl methacrylate system complexed with diethylaluminum chloride
Authors: Funt B. Lionel , Pawelchak Gordon A. 
Published: April 2003

AbstractThe rate and molecular weight profiles were obtained for the spontaneous alternating copolymerizations conducted with diethylaluminum chloride. The rate formally fitted an expression, R = kp[MMA][Sty], and the rate constant was established by two distinct methods: (1) from the yield versus time data and (2) from initial rate over a range of initial concentrations; it was determined as 5.4 × 10−6 l./mole‐sec with Ea = 4.2 kcal/mole. Molecular weights were determined by gel‐permeation chromatography. No increase in molecular weight was observed with increased reaction time. Thus living centers or diradicals are not involved in the process. The M̄n shows a steady decrease with increase in monomer‐diethylaluminum chloride concentration but the rate is maximum at equimolar monomer concentrations. The data are interpreted on a chain‐transfer mechanism and show close agreement to a model in which the excess complexed acceptor monomer is the transfer agent. The chain‐transfer constant of 7.1 × 10−4 l./mole‐sec is several orders of magnitude greater than for uncomplexed systems.
Synthesis of polyamides from active 1‐benzotriazolyl diesters and diamines under mild conditions
Authors: Ueda Mitsuru , Okada Kohji , Imai Yoshio 
Published: April 2003

AbstractThe effect of the solvent on the inherent viscosity of polyamides was investigated in the polycondensation of new active 1‐benzotriazolyl diesters, such as 1,1′‐(adipolydioxy)bisbenzotriazole and 1,1′‐(isophthaloyldioxy)bisbenzotriazole, with diamines. The preferred polymerization media were polar aprotic solvents, including N‐methyl‐2‐pyrrolidone and hexamethylphosphoramide. The solution polycondensation at room temperature afforded a series of polyamides having inherent viscosities as high as 1.8 from both aliphatic and aromatic diamines. The 1‐benzotriazolyl diesters were more reactive than di(2,4‐dinitrophenyl) isophthalate toward diamines. Prior to polymer synthesis, the aminolysis of some active monoesters was carried out as a model compound study.
ESR and NMR study of the γ‐ray‐induced postpolymerization of vinyl monomers adsorbed on zeolite
Authors: Quaegebeur Jean Pierre , Seguchi Tadao , Bail Henri Le , Chachaty Claude 
Published: April 2003

AbstractThe γ‐ray‐induced postpolymerization of acrylonitrile and methyl methacrylate adsorbed on Linde zeolite 13X irradiated at 77°K has been studied between 303 and 343°K as a function of the amount of adsorbed monomer and of the irradiation dose. The change in the nature and the concentration of free radical with temperature and duration of the postpolymerization was followed by the ESR method, whereas the formation of polymer was monitored continuously by the decay of the 1H‐NMR absorption line of the monomer under high‐resolution conditions. It was found that the overall postpolymerization kinetics may be accounted for by assuming an exponential decay of radical propagation and recombination reactions with chain length. The tacticity of the polymer recovered by destroying the matrix in hydrofluoric acid was determined by 13C‐NMR. The probability of isotactic addition of AN and MMA is larger than in the radical polymerization in solution owing likely to the association of adsorbed monomer molecules in pairs preforming an isotactic diad.
Functional polymers. II. Preparation and polymerization of methyl 5‐vinylsalicylate, methyl 5‐vinylacetylsalicylate, 5‐vinylsalicylic acid, and 5‐vinylacetylsalicylic acid
Authors: Bailey D. , Tirrell D. , Vogl O. 
Published: April 2003

AbstractFour new derivatives of 5‐vinylsalicylic acid were prepared and their homopolymerization and copolymerization with acrylic acid and methacrylic acid investigated. Methyl 5‐vinylsalicylate was prepared in a six‐step synthesis from methyl salicylate in an overall yield of 35%. Acetylation in the last step yielded methyl 5‐vinylacetylsalicylate. Hydrolysis of methyl 5‐vinylsalicylate gave 5‐vinylsalicylic acid which was acetylated to 5‐vinylacetylsalicylic acid (5‐vinyl aspirin). The 5‐vinyl‐substituted salicylic acid derivatives could be readily homopolymerized and copolymerized with acrylic acid and methacrylic acid to give various compositions of copolymers. It is worth noting that even the monomers with free phenol groups could be readily polymerized with azobisisobutyronitrile as radical initiator to high molecular weight polymers without interference of the phenolic OH group.
Synthesis of polypyridazinophthalazinediones from dibenzoylphthalic acids and aromatic dihydrazines
Authors: Imai Yoshio , Ueda Mitsuru , Aizawa Tatsuo 
Published: April 2003

AbstractA novel class of polypyridazinophthalazinediones has been synthesized by the solution cyclopolycondensation in m‐cresol of dibenzoylphthalic acids with aromatic dihydrazines such as bis(4‐hydrazinophenyl)methane and bis(4‐hydrazinophenyl) sulfone. The polyheterocycles derived from 4,6‐dibenzoylisophthalic acid, which had inherent viscosities of up to 0.5, were soluble in m‐cresol and hot dichloroacetic acid, whereas the polymers from 2,5‐dibenzoylterephthalic acid were practically insoluble in organic solvents. Thermogravimetric analyses showed that all the polymers underwent weight losses of 10% at 490–520°C in both air and nitrogen.
Reactivity ratios for acrylic acid–methyl acrylate copolymerization in 1,4‐dioxane
Authors: Eldridge R. J. , Treloar F. E. 
Published: April 2003

AbstractWe report values of reactivity ratios for the copolymerization in 1,4‐dioxane of acrylic acid (AA) and methyl acrylate (MA), measured as part of work on ion‐binding to polyelectrolytes at different charge densities. Ryabov et al.1 have shown the reactivity ratios for this and similar systems to depend on the nature and amount of the solvent used.
Triphenylmethyl hexafluoroarsinate‐initiated polymerization of 1,2‐butylene oxide
Authors: Leborgne Alain , Malhotra Shadi Lal , Blanchard Louis‐Philippe 
Published: April 2003

AbstractThe polymerization of 1,2‐butylene oxide initiated with triphenylmethyl hexafluoroarsinate in the −20 to +25°C temperature range with 1,2‐dichloroethane as solvent is characterized by a rapid nonstationary initial stage. This is followed by a second slower stage, during which the disappearance of monomer is first‐order with respect to its concentration. The conversion of monomer at the end of the first stage is related to the initial catalyst concentration but not to the initial monomer concentration. Invoking the hypothesis of an instantaneous initiation reaction, the experimental results lead to the conclusion of the existence of a unimolecular termination step. Propagation‐to‐termination rate constant ratios yield a propagation–termination activation energy difference of 5.9 kcal/mole. The termination step proposed is thought to involve the formation of stable macrocyclic oxonium ions. These, in turn, can reactivate the polymerization by an intramolecular reaction leading to the formation of new active centers. An energy of activation of 8.7 kcal/mole was calculated for this reactivation. GPC analyses of the reaction products recovered at the end of the first stage revealed the presence of large proportions of oligomers. Based on kinetic data, the formation of oligomers is explained by a backbiting process similar to the reactivation reaction suggested for the initiation of the second stage.
Diffusion control in radiation graft polymerization with varying dependence of rate on monomer concentration
Authors: Imre Kaya , Odian George , Rabie Abdelgewad 
Published: April 2003

AbstractThe quantitative effect of diffusion control on the rate of radiation‐initiated graft polymerization has been studied theoretically for systems in which the diffusion‐free reaction may show various dependencies of rate on monomer concentration other than the usual first‐order dependence. The study is also very general in that it can be applied to systems involving a variety of different modes of initiation and termination. Whether the grafting process is diffusion‐free or diffusion‐controlled has been analyzed in terms of the interaction of the initiation rate Ri, the propagation and termination rate constants kp and kt, the equilibrium solubility M of the monomer in the polymer, the polymer film thickness L, the diffusivity D of the monomer in the polymer, and the diffusion‐free kinetic order of dependence v of the grafting rate on monomer concentration. The dependence of the grafting rate for both the diffusion‐free and diffusion‐controlled reactions on these parameters is expressed both by mathematical experssions and graphically. Diffusion control is shown to occur at a critical value of the parameter A which is proportional to L(kpRiw/ktzD)1/2M(ε−1)/2 where w, z, and v have different values depending on the specific modes of initiation, propagation and termination in a particular grafting system. The grafting rate is shown to vary with the value of A according to specific mathematical expressions. In comparing diffusion‐free to diffusion‐controlled reaction, it is shown that the former is independent of L and D while the latter is directly dependent on L and inversely on D1/2. Further, the change from diffusion‐free to diffusion‐controlled reaction involves a change in the dependence of rate on monomer from v‐order to [(v − 1)/2]‐order. The nonsteady‐state as well as the steady‐state reaction rates have been analyzed.
Study of radiation‐induced polymerization of vinyl monomers adsorbed on inorganic substances. X. Influence of H2O on the styrene–silica gel system
Authors: Fukano Kazuyuki , Kageyama Eiichi 
Published: April 2003

AbstractTo elucidate the reaction mechanism of radiation‐induced polymerization of the styrene—silica gel system, the influence of H2O as adsorbed water and inhibitor of cationic polymerization was investigated by two methods. Monomer conversion decreased as H2O increased. In general, percent grafting decreased as H2O increased, but the presence of a small amount of H2O increased the percent grafting. Grafting at 16 Mrad has a maximum value at a water content of about 0.2%. This seems to be due to two effects of H2O: percent grafting increases due to restraint of cationic polymerization by H2O, but the percent grafting decreases due to adsorption water which interrupts the contact of styrene with silica gel. In GPC spectra, the low molecular weight peaks of both graft polymers and homopolymers decreased when H2O was added. The GPC results suggest that the number of positive holes which initiate cationic polymerization is very large.
Some aspects of plasma polymerization investigated by pulsed R.F. discharge
Authors: Yasuda H. , Hsu T. 
Published: April 2003

AbstractThe polymerization of organic compounds in glow discharge (plasma polymerization) was investigated by using pulsed R.F. discharge (100 μsec on, 900 μsec off). The effects of pulsed discharge on polymer deposition rate, pressure change in plasma, ESR signals of free spins in both plasma polymer and substrate, and the contact angle of water on the plasma polymer surface were investigated for various organic compounds. The results are correlated to the mechanisms of polymer formation in plasma (plasma polymerization) which has been postulated as repeating processes of stepwise (propagation) reactions. The effect of the pulse is different from one group of organic compounds to another depending on whether or not they contain an olefinic double bond and/or a triple bond. The main difference seems to be the addition polymerization which can occur exclusively during the off‐period of pulsed discharge. Ultraviolet emission from pulsed discharge is much less than from continuous discharge. Consequently, the fragmentation of the monomer and the free‐radical formation in the substrate are less with the pulsed discharge. Properties of polymers from some organic compounds formed in continuous and in pulsed discharge were found to be significantly different, and the differences were postulated from the changes of polymerization mechanisms in the pulsed discharge.
Studies on never‐dried cotton
Authors: Kulshreshtha A. K. , Patel A. R. , Baddi N. T. , Srivastava H. C. 
Published: April 2003

AbstractThe differences in the porous and crystalline structure of cell walls in never‐dried and nature‐dried cottons have been examined by measurements of dye adsorption and desorption, centrifugal liquid retention, and decrystallization due to swelling in sodium hydroxide. Equilibrium dyeings of these two cottons have been carried out at 50 and 60°C with two direct dyes, Chlorazol Sky Blue FF and Chrysophenine G, and the adsorption isotherms obtained. The dye uptake at limiting saturation is found to be quite large for never‐dried cotton as compared to nature‐dried cotton, indicating a larger number of sites available to dye molecules in the former sample. However, dyeing parameters such as affinity and differential heat of dyeing are found to have lower values for never‐dried cotton. This is attributed to the “frozen” structure of a large amount of water held by never‐dried cotton, which retards the adsorption of dye molecules. Studies on retention of liquids (glycerol and water) by cotton by use of centrifugation techniques reveal a larger amount of pore volume in never‐dried cotton than in nature‐dried cotton. X‐Ray studies on decrystallization of cotton by swelling in NaOH indicate that the phase transformation to cellulose II in never‐dried cotton is complete at 25% (w/w) concentration of NaOH, whereas under identical swelling conditions about 10% residual, unconverted cellulose I is found in the case of nature‐dried cotton. A somewhat similar anomaly is found in the dye desorption measurements. Under conditions when the dye can be completely stripped from nature‐dried cotton, the never‐dried cotton has been shown to retain about 50% to 80% of the adsorbed dye. These observations are attributed to irreversible pore closure during drying of never‐dried cotton. Structural collapse occurring during drying of never‐dried cotton, after subjecting it to solvent exchange with a large number of organic liquids, was studied by x‐ray diffraction, optical microscopy, and centrifugal liquid retention techniques. It was demonstrated that the structural collapse is proportional to the polarity of the organic solvent employed in the final exchange of never‐dried cotton, prior to drying. It is concluded that the structural collapse and the development of inaccessible zones in fiber during drying can be reduced if the water in never‐dried cotton is exchanged with a nonpolar solvent.
Reactivity of polymer substituents. Aminolysis of p‐nitrophenyl ester residues attached to various polymer backbones
Authors: Su Chin‐Pao , Morawetz Herbert 
Published: April 2003

AbstractStyrene, methyl acrylate, and N,N‐dimethylacrylamide were copolymerized with small proportions of p‐nitrophenyl acrylate or p‐nitrophenyl esters of CH2CHCONH(CH2)nCOOH (n = 1,3,5). The aminolysis of these copolymers in dioxane and chlorobenzene solution was compared with the corresponding reaction of low molecular weight analogs. The ratio of the reactivity of the polymer substituent and its analog was found to be insensitive to the nature of the amine but strongly dependent on the nature of the polymer backbone. Poly(dimethylacrylamide) chains carrying active ester substituents were in some cases much more reactive than their analogs due to the activating effect of the dimethylamide groups. In the case of the p‐nitrophenyl acrylate–styrene copolymer, the aminolysis exhibited a dispersion of the rate constant due to its sensitivity to stereoisomerism in the vicinity of the active ester, but no similar effects were observed with the other copolymers.
Polymerization of propylene carbonate
Authors: Soga Kazuo , Tazuke Yutaka , Hosoda Satoru , Ikeda Sakuji 
Published: April 2003

AbstractPolymerization of propylene carbonate was carried out at 120–180°C mainly with the use of diethylzinc catalyst. The polymer was a pale‐yellow, viscous material of relatively low molecular weight (1000–4000). From the spectroscopic analysis of the polymer and its hydrolyzed product, the polymer was determined to have the structure
magnified image
where x ⋍ 0.50, y ⋍ 0.25, and z ⋍ 0.25. This strongly suggested that the polymerization of propylene carbonate proceeded via 2,7‐dimethyl‐1,4,6,9‐tetraoxaspiro[4,4]nonane (DTN) as an intermediate compound. Hence, DTN was synthesized and polymerized with the use of diethylzinc catalyst. The structure of the polymer thus prepared coincided exactly with that of the polymer from propylene carbonate. From these, a plausible mechanism of the polymerization was developed.
Termination rate constant in free‐radical polymerization
Authors: Mahabadi H. K. , O'Driscoll K. F. 
Published: April 2003

AbstractThe specific rate constant for the termination reaction between two flexible polymer molecules with active chain ends has been considered in relation to the segmental diffusion of chain ends in solution. The probability of reaction between two chain ends per unit time when the centers of gravity of two polymer molecules are at a distance of separation has been calculated by using the Smoluchowski equation and a Gaussian distribution of chain ends. The time during which two polymer molecules are in contact has also been calculated by using the diffusion equation and the potential energy function for intermolecular interaction. The rate constant may then be completely expressed as a complex function of the intramolecular linear expansion factor, molecular weight, and the frictional properties of the reacting polymers' segment. This expression predicts that the rate constant is inversely proportional to solvent viscosity, decreasing with increasing molecular weight to some extent, and is affected by the excluded volume effect and chain flexibility. The complete expression for the rate constant has been simplified and the result compared with experimental data. Close agreement is found between the calculated rate constants and those experimentally obtained.
Reaction of poly(vinyl alcohol) with tetravalent ceric ion
Authors: Ikada Yoshito , Nishizaki Yasuko , Iwata Hiroo , Sakurada Ichiro 
Published: April 2003

AbstractPoly(vinyl alcohol) (PVAI) was oxidized by ceric ion, Ce(IV), in aqueous HNO3 medium at different temperatures and found to be degraded as a result of selective cleavage of the 1,2‐glycol unit existing in PVAl. The rate of oxidation increased with increasing temperature. The aldehyde groups formed at the ends of the degraded polymer upon oxidation were relatively stable at 0°C. With rise of temperature, the aldehyde groups reacted either with excess of Ce(IV) to carboxylic acids or with hydroxyl groups of PVAl molecules to give acetal linkage. When the acetalization predominated over the oxidation to carboxyl group, gelation of the reaction mixture was observed. Based on these results, a plausible mechanism of oxidation of PVAl with Ce(IV) and the subsequent reactions is discussed.
Vinyl polymerization. 351. Polymerization of methyl methacrylate initiated with α‐amylase and copper(II) ion in water
Authors: Imoto Minoru , Sakade Naoya , Ouchi Tatsuro 
Published: April 2003

AbstractThe polymerization of MMA initiated by a system of α‐amylase, cupric chloride, and water was carried out. The effects of the amounts of water, copper(II) ion, and MMA on the conversion of MMA were studied. The overall activation energy was estimated to be 55 kJ/mole. Urea, known as a denaturing agent for protein, was found to increase the rate of polymerization and efficiency of grafting onto α‐amylase.
Molecular weight distribution in thermal polymerization of styrene
Authors: Ito Katsukiyo 
Published: April 2003

AbstractThe molecular weight distribution in thermal polymerization, for which the termination rate is comparable with the transfer rate, is analyzed by assuming that (1) the termination rate is independent of chain length; (2) the rate is translational diffusion‐controlled; and (3) the rate is influenced by the excluded volume. The theoretical distribution, based on the assumption that the rate is translational diffusion‐controlled, is the best fit to the experimental data at high temperature. The dependence of the rate on chain length is stronger at higher temperature (>80°C). The ratio of the termination rate to the transfer rate increases with increasing temperature.
Reduction of poly(4‐vinylpyridine)‐coordinated ferriprotoporphyrin IX by N‐benzyl‐1,4‐dihydronicotinamide in N,N‐dimethylformamide
Authors: Tsuchida Eishun , Hasegawa Etsuo , Ohno Hiroyuki 
Published: April 2003

AbstractThe reduction of a ferriprotoporphyrin IX–pyridine or poly(4‐vinylpyridine) complex by N‐benzyl‐1,4‐dihydronicotinamide in N,N‐dimethylformamide to yield a corresponding ferro complex was studied kinetically and thermodynamically by spectral measurements. The reduction was confirmed to proceed via the intermediate. The rate of the reduction of the ferric iron was faster in the poly(4‐vinylpyridine) complex than in the pyridine complex. This was caused by the adsorption of the reductant to the polymer ligand, causing the increase in the frequency factor of the reaction.
Acceleration of aminolysis of nitrophenyl esters by quaternized modifications of polyethylenimine
Authors: Spetnagel Wayne J. , Klotz Irving M. 
Published: April 2003

AbstractDerivatives of polyethylenimine, containing free primary amines but with secondary and tertiary amines fully quaternized, were prepared. The residual primary amines of the polymer markedly accentuated the rates of cleavage of nitrophenyl esters. This modified polymer exhibits a pKa, determined from kinetics of its reactions, close to that for small molecules with a primary amine adjacent to a charged aminoethyl group. Thus, the primary amine group of the polymer stays relatively distant from all charged nitrogens on the macromolecule except its immediately adjacent neighbor on the chain.
Cyclopolymerization of diallylsilanes
Authors: Billingham N. C. , Jenkins A. D. , Kronfli E. B. , Walton D. R. M. 
Published: April 2003

AbstractA survey has been made of the polymerizability of diallysilanes, including a number of new compounds. Rates of polymerization are generally low with radical or Ziegler‐Natta techniques, but excellent yields are often obtained when the initiator is aluminum bromide.