bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autoxidation of polystyrene catalyzed by cobalt salt and sodium bromide in chlorobenzene–acetic acid
Authors: Le‐Khac‐Bi  , Kamiya Yoshio 
Published: April 2003

AbstractIn the oxidation of atactic polystyrene initiated by azobisisobutyronitrile, the kinetic chain length was obtained as 1.5. In the presence of cobalt salt and bromide ion, the rate of oxidation is first order with respect to the concentration of polymer and second order with respect to the concentration of cobalt. In addition, this rate is dependent on the molar ratio of NaBr to cobalt, independent of the partial pressure of oxygen and the molecular weight of polystyrene. The overall energy of activation is 22.5 kcal/mole. The molecular weight decreased from 152000 to 10 800 under the present conditions of oxidation. Carbon monoxide and carbon dioxide are the only significant volatile products. The primary product of oxidation is hydroperoxide. Benzaldehyde, acetophenone, and phenol were found as final products. The acetophenone‐type structure and methyl endgroups were observed. The formation of phenol presented a large selfinhibiting effect in the oxidation of polystyrene. The oxidation of isotactic polystyrene gave a maximum rate of oxidation twofold higher than that of atactic polystyrene and a value of 17.0 kcal/mole for the overall energy of activation.
Polymerization of vinyl chloride
Authors: Enomoto S. 
Published: April 2003

AbstractPolymerization of vinyl chloride (VC) was studied. natural evolution of HCl from VC occurred in the polymerization. VC, VC‐αd1, VC‐β,βd2 and VC‐d3 were used to study the reactivities of the hydrogen atoms in the polymerization and the β‐hydrogen atoms contributed to the chain transfer. Chemical and physical methods were used to observe irregular structures, such as branching, double bonds, and head‐to‐head or tail‐to‐tail addition, and also to confirm the relation between conversion and the irregular structures.
Kinetics of polymerization of N‐tert‐butylacrylamide. Part II
Authors: Cavell E. A. S. , Gilson I. T. 
Published: April 2003

AbstractThe effect of ferric chloride on the kinetics of the radical polymerization of N‐tert‐butylacrylamide has been investigated in methanol solution at 25°C, with the use of 4,4′‐dicyano‐4,4′‐azodipentanoic acid as initiator. A shrinkage factor of 0.193 mmole polymerized for 1 mm contraction in a capillary of 1 mm diameter has been obtained from density measurements. In the absence of ferric chloride, rates of polymerization were found to be proportional to the concentration of monomer and to the square root of the initiator concentration. With ferric chloride present, the rate of polymerization becomes directly proportional to the initiator concentration and inversely proportional to the concentration of ferric salt. From measurements of the rates of production of ferrous iron, the specific rate constant of the initiation reaction has been found to be (1.8 ± 0.4) × 10−6sec−1 at 25°C, compared with a value of 7.63 × 10−8 sec−1 calculated from the kinetic data obtained with no ferric salt present. The value of the ratio kp/k4. where kp is the propagation coefficient and k4 is the velocity coefficient for termination by ferric chloride, has been calculated to be 6.0 × 10−4 at 25°C, which is considerably smaller than the value found for the ferric chloride‐terminated polymerization of acrylamide in water. This markedly lower value of kp/k4 has been attributed principally to the steric effect of the tert‐butyl group on the magnitude of kp.
Synthesis of difunctional polystyrenes and their incorporation in block copolymers with bisphenol a polycarbonate
Authors: Berger M. N. , Boulton J. J. K. , Brooks B. W. 
Published: April 2003

AbstractBlock polymers of polystyrene and bisphenol A polycarbonate have been prepared and their bulk viscosities studied as functions of both shear stress and polystyrene block length. The polystyrene blocks were α,ω‐diacid chlorides prepared from the reaction of “living” polystyrenes with diacid chlorides. These reactions were studied in order to discover the most effective way of preparing the polystyrene diacid chlorides. The polystyrene diacid chlorides are best prepared by reaction of disodiopolystyrene with phosgene. The flow properties of the block copolymers depend on the composition of the polymers but do not depend on the length of the polystyrene blocks.
Fluorocyclopropanes. IV. Copolymers of perfluorocyclopropene
Authors: Sargeant P. B. , Krespan C. G. 
Published: April 2003

AbstractPerfluorocyclopropene undergoes free‐radical copolymerization with ethylene, isobutylene, cis‐ and trans‐2‐butene, vinyl acetate, methyl vinyl ether, vinyl chloride, styrene, acrylonitrile, tetrafluoroethylene, vinyl fluoride, and vinylidene fluoride. The copolymerization proceeds most readily with electron‐rich olefins such as methyl vinyl ether (to yield a 1:1 copolymer), but conditions were found to give copolymers with electron‐deficient olefins such as tetrafluoroethylene and vinylidene fluoride. Copolymers with methyl vinyl ether, tetrafluoroethylene, vinyl fluoride, and vinylidene fluoride were examined in detail. Evidence is presented that the perfluorocycloproply ring is incorporated intact into the copolymer and can be subsequently isomerized to a perfluoropropenyl unit by heating at 200–300°C.
ESR spectra of poly(methacrylic acid) and poly(methyl methacrylate): Reinterpretation of the 9‐line spectrum
Authors: Iwasaki Machio , Sakai Yoshiro 
Published: April 2003

AbstractThe temperature dependence of the ESR spectra of poly(methacrylic acid) and poly‐(methyl methacrylate) γ‐irradiated at room temperature was studied between −196°C and +25°C. The conventional 9‐line spectrum was observed throughout this range with no significant spectral change, in contrast to the propagating radical ··· CH2°C(CH3)COOR found in methacrylic acid monomer or barium methacrylate dihydrate irradiated at −196°C. In addition, the irradiation of methacrylic acid monomer with a low dose at 0°C gave the same 13‐line spectrum as that of the propagating radical obtained by the irradiation at −196°C, while prolonged irradiation at 0°C gave the same conventional 9‐line spectrum as that of poly(methacrylic acid) or poly(methyl methacrylate). The conventional 9‐line spectrum has a much weaker 4‐line component than that of the propagating radical. The difference comes from the surrounding matrix, and the conventional 9‐line spectrum is well interpreted by introducing the concept of the distribution of the conformational angle in the irregular polymer matrix. From simulation of the ESR spectrum, it was found that the intensity of the 4‐line component is very sensitive to the distribution, and that the observed 9‐line spectrum is well reproduced assuming a Gaussian distribution (half‐height width of 5–6°) around the most probable conformation which is nearly the same as that of the propagating radical, where the conformational angles of the two CHβ bonds to the half‐filled p‐orbital are 55° and 65°.
Oxidative polymerization of diethynyl compounds
Authors: Hay Allan S. 
Published: April 2003

AbstractDiethynyl compounds are readily polymerized to high molecular weight linear polymers by oxidative coupling with oxygen in the presence of an amine complex of a copper salt as catalyst. Organometallic moieties can also be introduced into these polymers. Thus polymers in which silicon, arsenic, and mercury are part of the polymer backbone have been synthesized.
Cocatalysis by epoxides in the polymerization of tetrahydrofuran with trityl hexachloroantimonate initiator
Authors: Kuntz Irving , Melchior M. T. 
Published: April 2003

AbstractThe polymerization of tetrahydrofuran (THF) with (C6H5)3C+SbCl6‐ initiator is markedly accelerated by small concentrations of propylene oxide or other epoxides. Molar concentrations of propylene oxide 4 to 10 times those of the carbonium‐ion salt showed increasing conversion to polymer. The equilibrium conversion level at different temperatures with epoxides is the same as in their absence; the approach to equilibrium is first‐order in THF. NMR experiments in the presence of propylene oxide indicate the formation of a trityl ether intermediate. The cocatalysis effect is interpreted on the basis of an acceleration in the initiation process in the system.
Dilute solution properties of a polyurethane. I. Linear polymers
Authors: Beachell Harold C. , Peterson Jean C. 
Published: April 2003

AbstractA linear polyurethane of high molecular weight was prepared in solution by the polyaddition of equimolar amounts of ethylene glycol and methylene bis(4‐phenyl isocyanate). The polymer was fractionated by using a direct sequential extraction procedure, with a solvent–nonsolvent system consisting of N,N′‐dimethylformamide (DMF) and acetone (A). The resulting fractions were characterized by viscosity and lightscattering measurements. The relationship between the intrinsic viscosity and molecular weight was found in DMF at 25°C. to be [η] = 3.64 × 10−4M0.71. The unperturbed polymer chain dimensions were determined from intrinsic viscosity measurements carried out under experimentally determined theta conditions.
Radical polymerization behavior of hydroxystyrenes
Authors: Kato Masao 
Published: April 2003

AbstractHomopolymerizations of m‐ and p‐hydroxystyrene and their copolymerizations with styrene and methyl methacrylate by use of azobisisobutyronitrile as initiator were investigated, and the results were compared with those obtained previously o‐hydroxystyrene. Intrinsic viscosities of m‐ and p‐hydroxystyrene polymers obtained by bulk and solution polymerizations were ca. 2 to 3 times larger than those of o‐hydroxystyrene polymers obtained by the similar conditions. The structures of the polymers thus produced were investigated by infrared and ultraviolet spectroscopy. These studies suggested that all of the homopolymers consisted mainly of structures of normal vinyl type polymer. Rp was proportional to [I]0.52 for m‐hydroxystyrene and to [I]0.50 for p‐hydroxystyrene, for o‐hydroxystyrene Rp was proportional to [I]0.72. A reasonable chain transfer mechanism for these monomers was postulated. The apparent activation energies of polymerization for m‐ and p‐hydroxystyrene were found to be 20.1, and 18.0 kcal/mole, respectively, compared to the value of 21.5 kcal/mole for o‐hydroxystyrene. Monomer reactivity ratios and Q − e values for m‐ and p‐hydroxystyrene were determined, and the results were also compared with the case of o‐hydroxystyrene. Copolymerization generally gave a polymer with relatively high intrinsic viscosity, even in the case of o‐hydroxystyrene.
Influence of structure of 1,1,3‐trimethyl‐5‐carboxy‐3‐(p‐carboxyphenyl)indan upon polyamide properties
Authors: Ridgway James S. 
Published: April 2003

AbstractCopolyamides of nylon 66 and 1,1,3‐trimethyl‐5‐carboxy‐3‐(p‐carboxyphenyl)indan (PIDA) were prepared by melt polycondensation of nylon 66 salt with PIDA in combination with hexamethylenediamine, trans‐1,4‐cyclohexanebis(methylamine), and m‐xylylenediamine. In addition, hexamethylenediamine‐PIDA was incorporated into the copolymer system of nylon 66–poly(hexamethylene terephthalamide). The effect of PIDA upon the intrinsic viscosity, crystallinity, density, melting point, moisture regain, tenacity, initial modulus, and the boiling‐water shrinkage of such polyamides was determined. Particular emphasis was placed upon the influence of PIDA on the glass transition temperature of the polyamides. The effect of moisture on the glass transition temperature was also discussed. The physical properties of PIDA copolymers indicate that crystallinity virtually disappears above 20 mole‐% PIDA concentration; however, the glass transition temperature measured at 0 and 30% RH increases sharply with increased PIDA concentration.
Copolymerization of acrylonitrile. I. Copolymerization with styrene derivatives containing nitrile groups in the side chain
Authors: Ronel Samuel H. , Kohn David H. 
Published: April 2003

AbstractAcrylonitrile was copolymerized in bulk with cinnamonitrile (I), ethyl benzylidenecyanoacetate (II), and benzylidenemalononitrile (III) by radical initiation up to low conversions. The conventional scheme of copolymerization fitted all the three copolymer pairs.
Water flow through polymeric and nonaqueous liquid membranes
Authors: Lakshminarayanaiah N. , White M. S. 
Published: April 2003

AbstractOsmotic and isotopic water flows through polymeric and nonaqueous liquid membranes have been measured. The polymeric membranes were of the polyethylene–styrene graft copolymer type containing sulfonic acid groups. The nonaqueous liquid membranes were water‐saturated 1‐butanol and benzene. Osmotic water flux through both types of membranes was larger than isotopic (THO) water flux. Using these data, values for the equivalent pore radius for these membranes have been derived. The significance of such values has been briefly discussed.
Production of organometallic polymers by the interfacial technique. I. Interfacial production of polyalkyloxysilanes and a study of some reaction variables
Authors: Carraher Charles E. 
Published: April 2003

AbstractThe first interfacial synthesis of polyalkyloxysilanes of the form where R′ = alkylene, and R″, R = alkyl or aryl is reported. It is found, in the range studied for the stirred systems, that as organic solvent viscosity and organic phase volume are increased, rate of polymer formation is decreased. Little difference in polymer formation rate is observed when the nature of the diol is varied, but considerable difference is noted when the nature of the organosilane is varied such that the most electropositive silane has the highest rate of polymer formation. Molecular weight is approximately constant as diol is changed but varies markedly when the silane is changed, so that the silane with the most bulky substance will give polymer with the lowest molecular weight.
Production of organometallic polymers by the interfacial technique. II. Kinetic study of the production of polyoxyethyleneoxy(diphenylsilylene) by the interfacial technique
Authors: Carraher Charles E. 
Published: April 2003

AbstractThe stirred interfacial production of polyoxyethyleneoxy(diphenylsilylene) was found to be five‐thirds order and dependent on the concentrations of both ethylene glycol and diphenyldichlorosilane, indicating that the character of the rate‐determining step involves reaction of the ethylene glycol or ethylene glycol derivative and diphenyldichlorosilane or diphenyldichlorosilane derivative. A model consisting of ethylene glycol droplets residing in the organic phase is proposed which follows the rate expression:

This is in agreement with experimental findings. A rate constant of 1.4 × 10−4c.2/3 m2/3‐sec is found. The rates in unstirred interfacial systems are found to be slower than in the stirred systems.
Polymers from 12‐hydroxymethyltetrahydroabietic acid and its vinyl and acrylate esters
Authors: Saga Motoo , Marvel C. S. 
Published: April 2003

Abstract12‐Hydroxymethyltetrahydroabietic acid has been homopolymerized by melt condensation and homopolyester has been obtained. Vinyl 12‐hydroxymethyltetrahydroabietate has been prepared from 12‐hydroxymethyltetrahydroabietic acid by vinyl interchange procedure with vinyl acetate, and has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, and terpolymerized with styrene and acrylonitrile. The acrylate ester of 12‐hydroxymethyltetrahydroabietic acid also has been prepared from 12‐hydroxymethyltetrahydroabietic acid and acrylyl chloride. The acrylate thus obtained has been homopolymerized and copolymerized with vinyl chloride and vinyl acetate. Polymers thus obtained have been characterized.
Reaction of polyepichlorohydrin with magnesium and grignard reagents
Authors: Minoura Yuji , Hironaka Hisashi , Kasabo Toshiyuki , Ueno Yukio 
Published: April 2003

AbstractThe reaction of polyepichlorohydrin with magnesium in tetrahydrofuran at reflux temperature was studied in the hope of obtaining a polymeric Grignard reagent. The polymeric Grignard reagent could not be obtained, but dechlorination occurred. It was confirmed that the Grignard reagent of polyepichlorohydrin was formed as an intermediate during the dechlorination. The reactions of polyepichlorohydrin with Grignard reagents were carried out in tetrahydrofuran at reflux temperature. Benzylmagnesium chloride and allylmagnesium chloride were used as Grignard reagents. It was found that the chlorine atom in polyepichlorohydrin can be replaced by benzyl and allyl groups. The extent of the substitution increased with increasing concentration of Grignard reagent. Dechlorination and scission of the ether linkage occurred simultaneously as side reactions.
Accessibility of cotton and chemically swollen cottons to methylating reagents
Authors: Head Frank S. H. , Hadfield Gladys E. 
Published: April 2003

AbstractStandard Acala cotton, and modified cottons obtained from it by swelling in 5N sodium hydroxide, 62% sulfuric acid, or 81% phosphoric acid, have been methylated with moist ethereal diazomethane or with a toluene solution of dimethyl sulfate in the presence of 2N sodium hydroxide. The accessibility of cotton to either reagent is increased by swelling in the order sulfuric acid <phosphoric acid <5N sodium hydroxide. Each fiber is more accessible to the alkaline methylating agent than to diazomethane. The results confirm the view of Roberts et al. that a more rapid methylation of accessible hydroxyl groups in the surfaces of crystalline aggregates is followed by a slower penetration of the ordered material. Analysis of the methylated products and interpretation of the results on similar lines suggests that aggregates of approximately two elementary fibrils (found in cotton methylated with moist diazomethane) are split into single fibrils by 81% phosphoric acid or 2N sodium hydroxide and that mercerization transforms the elementary fibrils into smaller units, but an alternative explanation is possible. Progressive penetration of the elementary fibrils by swelling agents may increase the amount of accessible material without decreasing the size of the fibrils.
Kinetics of dispersion polymerization of soluble monomers. I. Methyl methacrylate
Authors: Barrett K. E. J. , Thomas H. R. 
Published: April 2003

AbstractThe kinetics of the free‐radical‐initiated polymerization of methyl methacrylate in n‐dodecane to produce dispersions of polymer stabilized with a steric barrier of soluble polymer chains have been determined by thermal analysis. The mode of the polymerization can be described in terms of a bulk polymerization within the monomerswollen polymer particles. A theoretical expression has been derived on the basis of a reaction scheme in which all the radicals produced in the diluent phase are transferred immediately to the polymer particles, monomer swells the polymer particles in partition equilibrium with monomer in the diluent, and polymerization proceeds within the polymer particle according to the kinetics of bulk polymerization, taking into account Trommsdorff acceleration and plasticization effects.
Radiation chemical studies of protein reactions: Effect of radiation on the breaking of secondary bonding in protein
Authors: Nisizawa Mizuho 
Published: April 2003

AbstractThe effect of radiation on the breaking of secondary bonding in protein was studied by measuring the viscosity change at different radiation doses and urea concentrations. An experimental equation for the viscosity change was obtained, and the observed behavior was explained on the basis of the molecular mechanism. The general equation for the viscosity change is given by ηred = A(X − Be−kx) + C log R, where ηred is the reduced viscosity of the solution, R is the dose of γ‐radiation, X is the concentration of urea, and A, B, C, and k are adjustable constants.
Synthesis of polyamides from rigid and sterically hindered dicarboxylic acids and diamines under mild conditions
Authors: Overberger Charles G. , S̆ebenda Jan 
Published: April 2003

AbstractThe rate of polycondensation of piperazine with the 2,4‐dinitrophenyl, succinimido, phthalimido, and 4‐nitrophenyl esters of bicyclo[2.2.2]octane‐trans‐2,3‐dicarboxylic acid was measured and found to decrease in this sequence. In the reaction of two moles of piperazine with one mole of diester, the reactivity of both ester groups was equal. In equimolar mixtures, the second ester group reacts with the second group about ten times slower because of steric hindrance. In the reaction of the esters with N,N′‐dimethylethylenediamine no such effects were observed. The aminolysis of the N‐hydroxyphthalimido ester stops at low conversions unless a very large excess of triethylamine is added. The catalytic effect of 1,2,4‐triazole on the aminolysis was proportional to the triazole concentration. From the rate of ester consumption in the presence of pure triethylamine, the extent of possible racemization of the optically active dicarboxylic acid was estimated. In view of the rate data, the extent of polycondensation, and side reactions, only 2,4‐dinitrophenyl and N‐hydroxysuccinimido diesters are suitable for the synthesis of polyamides derived from rigid and sterically hindered dicarboxylic acids.
Thermal degradation of polymers with phenylene units in the chain. I. Polyphenylenes and poly(phenylene oxides)
Authors: Ehlers G. F. L. , Fisch K. R. , Powell W. R. 
Published: April 2003

AbstractThe thermal degradation of polyphenylenes and poly(phenylene oxides) was studied under vacuum at temperatures between 350 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. Overall mechanisms for the thermal breakdown have been proposed. Polyphenylene decomposes to form polymer carbon, while hydrogen is the major volatile product. Some ring breakdown occurs with evolution of methane. Poly(phenylene oxide) forms mainly low molecular weight chain fragments, partially with hydroxyl endgroups. Some of the ether linkages decompose with ring breakdown, yielding carbon monoxide, water, and some carbon dioxide. Pendent groups on polyphenylenes and poly(phenylene oxides) are removed at the lower temperatures. The hydroxyl group yields essentially carbon monoxide and dioxide (the carbon being supplied by the rings), the methyl group methane, and the methoxy group methane and some methanol.
Effect of polymer crystallinity on the wetting properties of certain fluoroalkyl acrylates
Authors: Pittman Allen G. , Ludwig Barbara A. 
Published: April 2003

AbstractThe wetting properties of a series of polyacrylates containing the fluoroalkyl group \documentclass{article}\pagestyle{empty}\begin{document}$ [\rlap{--} ({\rm CF}_{\rm 2} \rlap{--} )_2 {\rm CF}_2 {\rm H}\ $\end{document} have been studied. Where n is 7 and 9, the polyacrylates are highly crystalline at room temperature. Since the polymers were prepared under atactic free‐radical conditions and the polyacrylates with shorter alkyl groups (where n is 3 or 5) were not crystalline at room temperature, the crystallinity is presumed to occur as a result of side‐chain packing and not involve the backbone. The polymers become more wet‐table (higher γc) as polymer crystallinity was reduced by quenching or heating past Tm. Correlations have been made between the work of Zisman and co‐workers on the wetting properties of various fluorinated acid monolayers and the wetting properties of these fluoroalkyl acrylates. The results obtained in this study concerning the influence of polymer crystallinity on surface wetting are discussed in relation to the findings of Schonhorn and Ryan on the wettability of polyethylene single crystal aggregates.