bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical electron‐transfer process of polymers containing N‐methylphenothiazine
Authors: Morishima Yotaro , Itoh Yoshihiro , Koyagi Atsufumi
Published: April 2003

For a fundamental study of the electrochemical behavior of electroactive polymers a series of poly(3‐vinyl‐10‐methylphenothiazine) (polyMPT), copolymers of 3‐vinyl‐10‐methylphenothiazine and methyl methacrylate (MMA) (copolyMPT), and 3‐ethyl‐10‐methylphenothiazine (EMPT) (a related monomer model) were prepared. The methylphenothiazine groups in these compounds showed reversible, one‐electron oxidation waves in the triangular‐were voltammograms. From a detailed comparison of the voltammograms between these polymers and EMPT it was revealed that the electroactive groups in poly MPT were not the “noninteracting” centers in the strict sense, whereas those in copolyMPT, in which the centers are spaced with the MMA segments, were typically noninteracting in nature; that is, in polyMPT the oxidation takes place at the potential 40 m V lower than that of EMPT and copolyMPT exhibited a wave identical to that of EMPT in shape and potential. The exhaustive electron transfer occurred from polyMPT to the electrode. On the other hand, a significant number of centers remained unoxidized in copolyMPT. The self‐exchange electron transfer within the polymer coil facilitates the exhaustive oxidation. For this event the proximity of the centers was an essential factor.
A study of the photochemical response of o‐nitrobenzyl cholate derivatives in P(MMA‐MAA) matrices
Authors: Reichmanis E. , Gooden R. , Wilkins C. W. , Schonhorn H.
Published: April 2003

Ortho‐nitrobenzyl cholate esters have been successfully used as photosensitive components in solution inhibition deep UV photoresists. The photochemical behavior of a variety of substituted o‐nitrobenzyl cholate derivaties has been examined and resist sensitivity is related to the quantum yield of the reaction. The most efficient system examined is o, o′‐dinitrobenzyl cholate/P(MMA‐MMA), where the quantum yield of photoreaction is 0.2 and resist sensitivity is ca. 150 mJ/cm2 for a 1.5 μm film. The mode of resist behaviour on irradiation and development is also reported.
Melt spinning of syndiotactic 1, 2‐polybutadiene for preparation of carbon fibers
Authors: Ashitaka Hidetomo , Kusuki Yoshihiro , Asano Yukihiko , Yamamoto Shuji , Ueno Haruo , Nagasaka Akira
Published: April 2003

The thermal crosslinking and loss of vinyl unsaturation of syndiotactic 1, 2‐polybutadiene(s‐PB) at 180–230°C were prevented by stabilizers with 3, 5‐di‐t‐butyl‐4‐hydroxybenzyloxy group. The s‐PB samples (mp 140–198°C and MW 20,000–70,000) that contained the stabilizers could be melt‐spun at a temperature below 220°C into 1‐denier fibers to be used for the preparation of carbon fibers. The s‐PB fibers with higher mp and/or higher MW could be obtained by the addition of a high boiling solvent such as tetralin. The relationship between the molecular structures of s‐PB and the properties of resulting s‐PB fibers, including the degree of molecular orientation measured by birefringence and x‐ray diffraction, is presented. Spun fibers showed small swellings here and there along the fiber axis, which would have resulted from the inhomogeneity of the melt of s‐PB spun at a temperature slightly above the melting point. The gelation was unlikely to occur.
Polyaromatic ether‐sulfone‐ketones with fluorosubstituted p‐cyclophane units as crosslinking sites
Authors: Lin See , Marvel C. S.
Published: April 2003

Polyaromatic either‐sulfone‐ketones containing fluoro‐substituted p‐cyclophane units were prepared from isophthaloyl chloride, terephthaloyl chloride, diphenyl ether, diphenoxydiphenyl sulfone, and a small amount of 1,1,2,2,9,9,10,10‐octafluoro‐[2,2]‐p‐cyclophane (type A) or pseudo‐p‐1,12,2,9,9,10,10‐octafluoro‐[2,2]‐p‐cyclophane bis‐acid chloride (type B) by Friedel‐Crafts‐type polymerization. The p‐cyclophane units were incorporated as crosslinking sites. Crosslinking was achieved by curing polymers at 300–350°C for several days. The polymers obtained, containing 1–10 wt % fluoro‐substituted p‐cyclophane units, were moderately soluble in dichloromethane, DMF, and sulfuric acid with inherent viscosities between 0.4 and 0.6. Laminates on glass fiber were made with excellent thermal stability.
The investigation of chemically crosslinked polypropylene by spin‐lattice relaxation time
Authors: Kunert K. A. , Jurkiewicz A. , Piślewski N.
Published: April 2003

Our previous NMR investigations of chemically crosslinked polypropylene (PP) were focused mainly on testing the relation between NMR relaxation times as a function of crosslinking compound concentrations and the influence of structural factors found by this method on mechanical and other properties of this polymer.1,2 In these investigations, however, we did not consider the state of mobility of any part of the polypropylene chain under the influence of the network; therefore in this article we have attempted a clarification of this problem.
Optical activity of alternating copolymers of chiral α‐olefins with alkyl acrylates
Authors: Aglietto Mauro , Carlini Carlo , Veracini Carlo Alberto
Published: April 2003

The synthesis of high‐molecular‐weight substantially alternating copolymers of alkyl acrylates with optically active α‐olefins is reported. “Induced optical activity” on the side‐chain ester chromophores, depending on the chemical structure of the chiral α‐olefin, is indicated by CD measurements. Data are reported supporting the conclusion that this induced optical activity is related to a preferential chiral conformation of the macromolecules due to a cooperative effect.
Investigation of the structure of silk film regenerated with lithium thiocyanate solution
Authors: Bhat N. V. , Ahirrao S. M.
Published: April 2003

The Silk fibers of the mulberry (Bombyx Mori) were dissolved in a 70% lithium thiocyanate solution. Dissolved silk was regenerated by casting the films from the solution after dialyzing. The films were investigated by infrared (IR) spectroscopy and x‐ray diffraction analysis. It was found that the freshly prepared film was amorphous. The transformation to the β‐form could be brought about by heating, solvent induced crystallization, ultraviolet (UV) radiation, and prolonged storage. The mechanism of this transformation is discussed.
The synthesis of crosslinked copolymers of maleilated chitosan and acrylamide
Authors: Berkovich L. A. , Tsyurupa M. P. , Davankov V. A.
Published: April 2003

By acylating chitosan with maleic anhydride in formamide medium trisubstituted products (on one amine and two hydroxyl groups of the saccharide unit) have been obtained, as has been confirmed by IR spectroscopy, titration carboxylic groups, and determination of the content of olefin bonds. By copolymerizing trisubstituted maleilated chitosan and acrylamide in water solution crosslinked polymers have been obtained. Their swelling in water decreases with an increase in the share of maleilated chitosan in the initial mixture of reagents and with a decrease in dilution of the initial mixture of reaction components. Consumption of maleilated chitosan double bonds in this case varies from 40 to 70%.
Laser‐initiated copolymerization of maleic anhydride with styrene, vinyltoluene, and t‐butylstyrene
Authors: Sadhir R. K. , Smith J. D. B. , Castle P. M.
Published: April 2003

Laser‐initiated polymerization of charge transfer monomer complexes has been investigated using an argon ion laser. The influence of solvents, monomer feed ratio, and irradiation time on the copolymer yield and composition was evaluated. The polymer yield was found to be directly proportional to the irradiation time and the molar concentration of maleic anhydride in the monomer feed. An enhanced rate of polymerization was obtained by substituting electron donating groups in the donor monomer. Polymerization, initiation, and propagation mechanisms, via charge transfer complexes, have been discussed. Comparison of laser‐induced polymerization with UV‐induced polymerization suggests that laser initiation is an energy‐efficient process.
Copolymerization of styrene with [(2‐methacryloyloxy)propoxy]trialkyl(aryl) silanes
Authors: Bajaj P. , Gupta D. C.
Published: April 2003

Styrene was copolymerized with [(2‐methacryloyloxy)propoxy]‐trimethylsilane (2‐MAPTMS), [(2‐methacryloyloxy)propoxy]‐dimethylphenylsilane (2‐MAPDMPS), and [(2‐methacryloyloxy)‐propoxy]‐diphenylmethyl silane (2‐MAPDPMS) in toluene at temperatures between 60 and 90°C using azobisisobutyronitrile (AIBN) as initiator. The compositions of the copolymers were determined by silicon estimation. The reactivity ratios were calculated by the Kelen–Tüdös method. The reactivity ratio r1 (styrene) is higher for styrene‐2‐MAPDPMS than for the styrene‐2‐MAPDMPS and styrene‐2‐MAPTMS copolymerzation system. The difference between the activation energies E11 – E12 favors self‐propagation of the polystyryl radical, whereas the ratio of preexponential factors A11/A12 favors cross propagation. For the 2‐MAPTMS radical, the difference E22 – E21 favors cross propagation but the ratio A22/A21 favors self‐addition. The intrinsic viscosities and the theramal behavior of the copolymers were also studied.
Backbone‐assisted reactions of polymers. V. Kinetics of isomerization of poly(chloromethylthiirane) and poly(3‐chlorothietane) in solution
Authors: Zussman Melvin P. , Tirrell David A.
Published: April 2003

The reversible isomerization of poly(chloromethylthiirane) and poly(3‐chlorothietane) represents a new kind of polymer reaction and a new method of copolymer synthesis. In chloroform, in dichloromethane, or in nitrobenzene the reaction is well described by reversible first‐order kinetics. A rate increase of ca. 40% on changing the solvent from chloroform to nitrobenzene is consistent with an isomerization mechanism that involves a rate‐determining attack of the backbone sulfur atom on the neighboring carbon‐chlorine bond and rapid ring‐opening of the thiiranium ion intermediate by chloride ion.
Photocrosslinking of polymethoxymethylstyrene and copolymers containing (2,2‐disubstituted‐1,3‐dioxolan‐4‐yl)methoxymethylstyrene
Authors: Fukuda Hiroyuki , Nakashima Yoshihiro
Published: April 2003

Methoxymethylstyrene (MSt), (2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methoxymethylstyrene (MMSt), and (2‐ethyl‐2‐methyl‐1,3‐dioxolan‐4‐yl)methoxymethylstyrene (EMSt) were synthesized and homopolymerized and copolymerized. The photochemical behavior of resultant homopolymers and copolymers with methyl methacrylate (MMA) and styrene (St) were investigated. The infrared (IR) and ultraviolet (UV) spectra of poly(MSt) showed that new bands ascribed to methyl benzoate residue increase rapidly with irrdiation time in air, but no detectable changes are observed in vacuum. The solubility measurements of poly(MSt) indicate that the main factor in crosslinking is the direct coupling of the benzyl radical generated by UV irradiation, which was confirmed by photopolymerization of MMA by means of benzyl methyl ether. It was also found that copolymers of MMSt or EMSt with MMA or St are easily crosslinked by UV irradiation. From the results of solubility measurements of these copolymers irradiated both in air and in vaccum, it was concluded that not only the 1,3‐dioxolane structure but also the benzyl methyl ether structure takes part in photocrosslinking, as we expected.
Copolymerization of vinyl acetate with ethyl α‐cyanocinnamate
Authors: Kharas Gregory , Kohn David H.
Published: April 2003

Trisubstituted ethylene, ethyl α‐cyanocinnamate, is readily copolymerized with vinyl acetate by a conventional radical initiator. Terminal, penultimate, and “complex” copolymerization models were applied by using the data of composition of the copolymers obtained in bulk and by copolymerization in benzene, ethyl acetate, and chloroform. The model based on the participation of the monomer complexes describes satisfactorily the deviation from the terminal copolymerization model. The proton NMR analyses of the monomer mixtures indicate that the interaction between the monomers leads to the formation of weak monomer complexes. Kinetic studies of the initial rate dependence on the total monomer concentration and monomer feed composition enabled us to evaluate the degree of participation of the free uncomplexed monomers and the monomer complex in the propagation reactions. The contribution of the complexed monomers in the propagation stages increases with the increase in total monomer concentration. The initial rate of the copolymerization is proportional to the square root of the initiator concentration, thus confirming the bimolecular termination of the macrochains. The rate constants of the addition reactions of the complex and free monomers were evaluated from the kinetic studies. The quantitative kinetic treatment provided information regarding the relative weight of the termination reaction and indicated that the termination in the system occurs predominantly by the cross‐termination reaction between two growing polymer radicals with different kinds of monomer units at the ends. Additional information on the termination in this system was obtained from viscosity measurements.
Metal(II) 4,4′,4″,4′″‐phthalocyanine tetramines as curing agents for heat resistant epoxy formulations
Authors: Achar B. N. , Fohlen G. M. , Parker J. A.
Published: April 2003

Pure metal(II) 4,4′,4″,4′″‐phthalocyanine tetraamines (MPTA) have been used to cure epoxy resins in a homogeneous reaction. Infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analytical studies were used to characterize these materials and to evaluate the optimum curing conditions. Considerable improvement in the heat resistance of the epoxy resin cured with MPTA over those cured with other commonly used curing agents was observed. This was expected from the highly aromatic structure of the phthalocyanines. A noteworthy feature of these cured materials is their high anaerobic char yield, 73.5–75%, higher than in any heretofore known cured epoxy systems. Preliminary mass spectral studies on the cured polymers are presented.
Photoinduced electron transfer at the polymer‐solution interface. I. Surface property‐reactivity relation
Authors: Tazuke Shigeo , Takasaki Ryuichiro
Published: April 2003

Photooxidation of leuco crystal violet(LCV) to the dye(CV+) by interfacial sensitization with polymer‐bonded pyrenyl groups was studied. Poly(ethylene‐g‐acrylic acid) was esterified by 1‐hydroxymethylpyrene in tetrahydrofuran (THF) (Film 1) or in acetonitrile (Film 2). Film 2 had a more condensed but thinner pyrene‐containing surface layer than Film 1. Differences in surface structure were investigated by fluorescence and absorption spectra, as well as by measuring contant angle to water as a function of the total amount of bonded pyrene. Films 1 and 2 behaved differently in the photoreaction, which was interpreted as due to the difference in the affinity of LCV solution to the film surface, hence the diffusion of LCV into the film. The quantum efficiency of CV+ formation (ϕcv+) is therefore the function of the thickness of the photoabsorbing layer and the effective reaction volume determined by the depth of LCV diffusion. The role of excimer formation and energy migration among pyrenyl groups was concluded to be of minor importance.
Catalysis of enantiomeric ester hydrolysis by N‐decanoyl‐L‐histidine in polymer domains
Authors: Ihara Yasuji , Kimura Yoshiharu , Nango Mamoru , Kuroki Nobuhiko
Published: April 2003

Catalytic hydrolysis of enantiomeric substrates by N‐decanoyl‐L‐histidine was studied at pH 7.30, 0.02M phosphate buffer, and 25°C in the presence of quaternized polymers. The rate of reaction is remarkably accelerated in the presence of polyethylenimine derivatives, but the observed stereoselectivity depends on the structure of the substrates.
The incorporation of heavy metals into diazo‐type electron beam resists
Authors: Lewis C. R.
Published: April 2003

Metals may be chemically incorporated into organic lithographic resists that contain or can be functionalized with OH groups. A wide range of metal incorporation (0.04–12% of total solids by weight) has been demonstrated for AZ‐1370 (Shipley), a diazo‐type photo‐ and electron resist. The novolac component of the resist is reacted with an organometallic halide, RyMX (R = alkyl, aryl; M = transition or main group metal; X = CI, Br; 1 ≤ y ≤ 4, depending on M) to introduce the corresponding organometallic function into the resist.
Synthesis, characterization, and solution properties of 5‐ethyl‐substituted poly(L‐prolines). Synthesis of cis‐ and trans‐5‐ethyl‐L‐proline and optically active poly(cis‐5‐ethyl‐D‐proline)
Authors: Yang Wayne W.‐Y. , Overberger C. G. , Venkatachalam C. M.
Published: April 2003

This article reports a continuation of our work on the substituent effects on the preferred helical conformations and the mutarotation of substituted poly(L‐prolines). The size of the substituent has been increased from a methyl group to an ethyl group in the 5 position. The purpose is twofold: (i) according to our theoretical conformational energy calculations, an ethyl group in the 5 position can exert a greater steric effect than can a methyl group; and (ii) the rotation‐isomerization of the ethyl group introduces a new intriguing fact to the problem. The cis isomer of 5‐ethylproline was synthesized by catalytic hydrogenation of Δ′‐2‐ethylpyrroline‐5‐carboxylic acid, whereas for trans‐5‐ethylproline, a chemical separation method involving p‐toluenesulfonyl chloride was used. The resolution of cis‐5‐ethylproline and the assignment of absolute configurations have been carried out by fractional crystallization and circular dichroism spectroscopic techniques, respectively. Poly(cis‐5‐ethyl‐D‐proline) was obtained from its corresponding N‐carboxyanhydrides via a ring opening polymerization.
Solid‐state thermal polymerization of sodium acrylate
Authors: Verneker V. R. Pai , Vasanthakumari R.
Published: April 2003

Initiation and propagation processes in thermally initiated solid‐state polymerization of sodium acrylate have been studied. The kinetics of initiation, followed with the electron spin resonance technique, leads to an activation energy E of 28.8 kcal/mol, which is attributed to the formation of dimeric radicals. The activation energy of 16 ± 1 kcal/mol obtained for the solid‐state polymerization of sodium acrylate by chemical analysis and differential scanning calorimetry has been attributed to the propagation process.
The pyrolysis and nonflaming oxidative degradation of poly(vinylfluoride)
Authors: Chatfield Dale A.
Published: April 2003

The thermal degradation of poly(vinylfluoride) (PVF) was studied under slow heating conditions to 1000°C with and without the presence of air. The degradation products, classified as low‐boiling volatiles, high‐boiling volatiles, and nonvolatile residues, were analyzed quantitatively by gas chromatography—mass spectrometry and several spectroscopic methods. Initial stages of degradation begin at 420°C with the evolution of HF and benzene and rapidly reach a maximum in sample weight loss by 450°C. One‐third of this weight loss was in the form of hydrofluoric acid (HF) and at least 70 low‐boiling volatile compounds that consisted of substituted aromatics, unsaturated hydrocarbons, and multiple‐ring compounds, many of which contained a fluorine atom. The high‐boiling volatile fraction contained compounds with more aliphatic but less aromatic character than the low‐boiling. The nonvolatile residue retained 4% of the original fluorine content and exhibited strong unsaturated character. In the presence of oxygen HF, CO, and H2O were the major constituents of the low‐boiling volatiles; the organic fraction was essentially unchanged in composition but reduced in overall concentration. The overall weight‐loss process was bimodal in air and produced a thermally resistant residue that degraded by 650°C. A comparison of degradation products from poly(vinylchloride) with this work demonstrates that PVF forms more lower‐molecular‐weight, halogen‐containing compounds, whereas the former produced more HCl and nonvolatile residue containing a lower halogen content.
Conformational studies of poly(cis‐5‐ethyl‐D‐proline)
Authors: Yang Wayne W.‐Y. , Overberger C. G. , Venkatachalam C. M.
Published: April 2003

Two possible conformations for poly(cis‐5‐ethyl‐D‐proline) have been identified and characterized by using combinations of 1H‐ and 13C‐NMR, CD, and ORD spectroscopic techniques. Both forms have helical conformations similar to those of poly(L‐proline) characterized by different amide bonds (cis and trans). However, the carbonyl group of the amide in poly(cis‐5‐ethyl‐D‐proline) form II (trans) seems to be closer to perpendicular orientation with respect to the helical axis than in poly(L‐proline) form II. The pyrrolidine ring conformation of form I (cis) is probably β+γ−‐puckered, whereas for form II it is probably β+‐puckered in nature. The side‐chain ethyl groups prefer to adopt anti conformations to the C5H bond, or prefer to have χ = 180°, regardless which of the two forms poly(cis‐5‐ethyl‐D‐proline) may like to assume. The experimental results agree well with our previous theoretical conformational energy calculations.
The effect of methanethiol on the radiation chemistry of low‐density polyethylene
Authors: Zoepel F. J. , Silverman Joseph
Published: April 2003

The effect of methanethiol (CH3SH) on the radiation chemistry of low‐density polyethylene was examined by using intrinsic viscosity measurements, low‐angle laser light scattering, and infrared spectrophotometry. Radiation‐induced intermolecular linking was found to be almost completely inhibited in low‐density polyethylene by the presence of less than one weight percent of CH3SH during irradiation. The net yield of transvinylene was also reduced, probably by reaction of transvinylenes with methylthiyl radicals (CH3S). The inhibition of radiation‐induced intermolecular linking by CH3SH demonstrates that linking is a relatively slow process involving reactions of alkyl free radicals, and that prompt intermolecular links caused by rapid ionic, ion–molecule, or “hot hydrogen” processes are not significant in the radiation chemistry of low‐density polyethylene.
1H‐NMR study of structure and tacticity in p‐t‐butylstyrene/methyl methacrylate copolymers
Authors: Uebel J. J. , Dinan F. J.
Published: April 2003

Copolymers prepared by the bulk copolymerization of p‐t‐butylstyrene (S) and methyl methacrylate (M) were analyzed by 1H‐NMR. The spectra showed fine structure in the δ 2.2–3.6 region similar to that reported for styrene/methyl methacrylate copolymers. Reactivity ratios for S‐M copolymers determined by classical composition measurements differed markedly from the same ratios determined by NMR when it was assumed that NMR peak‐triad assignments could be made by analogy with published styrene/methyl methacrylate assignments. A new set of peak‐triad assignments was proposed that reconciles this difficulty and gives good agreement between triad fractions measured by NMR and those calculated from theory.
Aromatic bisvinyl ethers: A new class of highly reactive thermosetting monomers
Authors: Crivello J. V. , Conlon D. A.
Published: April 2003

Aromatic bisvinyl ethers, prepared by the condensation of bisphenols with 2‐chloroethyl vinyl ether in the presence of sodium hydroxide, are a new class of thermosetting monomers. These new materials can be polymerized cationically by using diaryliodonium salts as photo and thermal initiators to produce crosslinked resins whose physical and thermal characteristics resemble those of epoxy resins.
The condensation of trimethylolphenol
Authors: Jones Robert T.
Published: April 2003

The intermolecular condensation reactions of 2,4,6‐trimethylolphenol (TMP) have been studied. The rate of disappearance of TMP from aqueous solutions at 40°C was measured over a range of pH 2–11. Concentrations of TMP were determined by HPLC. Major products, separated on the chromatograph and identified by PMR, were the o,p‐ and p,p‐dimers and a trimer. Reaction kinetics were second order in TMP concentration at low pH. At high pH kinetics were first order in total TMP concentration, contrary to the findings of earlier investigators. The reaction rate varied with pH in a complex manner. The variation is explained by separate acid‐catalyzed and base‐catalyzed mechanisms. A kinetic model is proposed in which the rate constants are independent of pH.
Polymeric catechol derivatives. IV. Polymerization behavior of 4‐vinylcatechols and some properties of their polymeric derivatives
Authors: Iwabuchi Susumu , Nakahira Takayuki , Inohana Akira , Uchida Hideki , Kojima Kuniharu
Published: April 2003

The polymerization and copolymerization of 4‐vinylcatechols, such as 2‐(0‐methyl)‐4‐vinylcatechol (I), 3,4‐dimethoxystyrene (II), and 3,4‐methylenedioxystyrene (III), were investigated in cyclohexanone at 30°C, using tri‐n‐butylborane as an initiator. The reactions yielded vinyl polymers and copolymers. The copolymerization parameters of I–III were determined; their Q and e values were found to be similar to those of styrene and vinylhydroquinone. The copolymerization of I–III gave copolymers of a highly alternating character. The thermal stability of the polymers and copolymers so obtained was also studied. The redox potentials of hydroloyzed poly(I) were examined; the reverse “polymer effect” was observed.
Synthesis and polymerization of methyl 3‐methylenecyclobutene‐1‐carboxylate and dimethyl 3‐methylenecyclobutene‐1,2‐dicarboxylate
Authors: Hall H. K. , Snow L. Glen
Published: April 2003

The two title monomers were synthesized. In both cases the key cyclobutane intermediates were obtained by cycloaddition of allene to acrylonitrile or chloromaleic anhydride. These two new monomers proved to be highly reactive in free radical polymerization, and each polymerized spontaneously in air at room temperature. Linear polymers were prepared in dimethyl sulfoxide solution at 35° with AIBN and UV light. At higher temperatures crosslinking became a problem in some instances. The structure of the polymers derived from 1,4 polymerization in the diene portion of the monomers was confirmed by 13C‐NMR, 1H‐NMR and IR spectra. Copolymers were prepared with methyl methacrylate, styrene, and p‐methoxystyrene and were always rich in the methylene‐cyclobutene monomers used. Films of homopolymers and copolymers could be cast from chloroform solution.
Syndiotactic 1,2‐polybutadiene with Co‐CS2 catalyst system. IV. Mechanism of syndiotactic polymerization of butadiene with cobalt compounds–organoaluminum–CS2
Authors: Ashitaka Hidetomo , Jinda Kazuya , Ueno Haruo
Published: April 2003

A mechanism is proposed for the polymerization of syndiotactic 1,2‐polybutadiene (s‐PB) with soluble cobalt‐organoaluminum‐CS2. The proposed active species have structures which consist of side‐on coordination of CS2 to cobalt, anti‐π‐allyl growing end, cisoid bidentate coordination of butadiene, and activation by complex formation with organoaluminum at the nonbonded sulfur of the coordinated CS2. This proposal is based on findings for the aluminum‐free catalyst Co(C4H6)(C8H13)‐CS2. It is tentatively interpreted that syndiotactic 1,2 polymerization proceeds under the influence of the side‐on coordinated CS2, by which the reactivity between the terminal carbons of butadiene and the C3 of the π‐allyl end is enhanced.
The use of the error‐in‐variables model in terpolymerization
Authors: Duever T. A. , O'Driscoll K. F. , Reilly Park M.
Published: April 2003

The error‐in‐variables model (EVM) is a mathematical description of experiments in which there is error in all measured variables. This contrasts with ordinary least‐squares methods in which it is assumed that error is only present in the dependent variable or variables. EVM leads to statistical procedures which are able to obtain more efficient estimates of unknown parameters from data with error in all the variables than can be obtained by using least‐squares methods. One type of experiment to which EVM is applicable is the measurement of copolymer reactivity ratios. It has been applied recently to the binary case, but the only known method for estimating reactivity ratios in ternary systems is that of Rudin et al. which is based on ordinary least squares. The application of EVM to the problem is described in this article and the results are compared with those of Rudin et al.
Emulsion polymerization of vinyl acetate
Authors: Trivedi M. K. , Rajagopal K. R. , Joshi S. N.
Published: April 2003

Emulsion polymerization of vinyl acetate with sodium laryl sulfate as emulsifier and potassium persulfate as initiator was studied and found to follow the rate equation suggested by Harriot:
Study of photopolymer. XVII. Synthesis of novel photosensitive polymers with pendant photosensitive group and photosensitizer groups
Authors: Nishikubo Tadatomi , Iizawa Takashi , Yamada Minoru , Tsuchiya Koichi
Published: April 2003

Novel photosensitive polymers with pendant photosensitive group, such as cinnamic ester, and photosensitizer groups, such as N‐carbamoyl‐p‐nitroaniline and N‐carbamoly‐4‐nitro‐1‐naphthylamine, were synthesized from radical copolymerizations of (2‐cinnamoyloxy)ethylmethacrylate with photosensitizer monomers, such as p‐nitrophenylmethacrylamide and 4‐nitro‐1‐na‐phthylmethacrylamide, by using asobisisobutyronitrile (AIBN) in benzene and from the copolymerizations of (2‐hydroxy)ethylmethacrylate or (2‐hydroxy)ethylacrylate with photosensitizer monomers by using AIBN in DMF. This procedure was followed by condensation reactions of the copolymers with cinnamoyl chloride with pyridine as HCL acceptor in the same reaction flask. The photoreactivities of the polymers obtained were influenced by the concentration of photosensitive group and photosensitizer groups and their ratio in the polymer matrix. In addition, the photosensitivity of cinnamic ester groups attached to a soft polymer segment was higher than that of cinnamic ester group attached to a hard polymer segment when these polymers had the same pendant N‐carbamoyl‐p‐nitroaniline group as photosensitizer. Furthermore, the spacer length between the polymer chain and photosensitizer group was important for increasing the photoreactivity of the photosensitive group in the polymers with pendant cinnamic ester and N‐carbamoyl‐p‐nitroaniline groups.
Vinyl polymerization. 413. Polymerization of vinyl monomer initiated by poly(vinylbenzyltrimethyl)‐ammonium chloride
Authors: Ouchi Tatsuro , Izumi Tsutomu , Inaba Masaya , Imoto Minoru
Published: April 2003

The polymerization of vinyl monomer initiated by an aqueous solution of poly(vinylbenzyltrimethyl)ammonium chloride (Q‐PVBACI) was carried out at 85°C. Styrene, p‐chlorostyrene, methyl methacrylate, and i‐butyl methacrylate were polymerized, whereas acrylonitrile and vinyl acetate were not. The effects of the amounts of vinyl monomer, Q‐PVBACI, and water on the conversion of vinyl monomer were studied. The overall activation energy in the polymerization of styrene was estimated as 79.1 kJ mol−1. The polymerization proceeded through a radical mechanism. The selectivity of vinyl monomer was discussed by “a concept of hard and soft hydrophobic areas and monomers.”
Synthesis of stereoregular heteropolysaccharides having amino‐groups by ring‐opening copolymerization of 1,6‐anhydro‐azido‐sugar derivatives
Authors: Uryu Toshiyuki , Hatanaka Kenichi , Matsuzaki Kei , Kuzuhara Hiroyoshi
Published: April 2003

The cationic, ring‐opening copolymerization of 1,6‐anhydro‐2‐azido‐3,4‐di‐0‐benzyl‐2‐deoxy‐(2‐ABG), ‐3‐azido‐2,4‐di‐0‐benzyl‐3‐deoxy‐ (3‐ABG), ‐4‐azido‐2,3‐di‐0‐benzyl‐4‐deoxy‐β‐D‐glucopyranose (4‐ABG) with 1,6‐anhydro‐2,3,4‐tri‐0‐benzyl‐β‐D‐glucopyranose (LGTBE) was investigated with phosphorus pentafluoride as catalyst at low temperatures, giving highly stereoregular, (1→6)‐α‐linked copolymers with number‐average molecular weights of 3.90 × 104−9.27 × 104. Structure and composition of the copolymers were determined by 1H‐ and 13C‐NMR spectroscopies and elemental analysis, which indicated that copolymerization occurred in a stereoregular manner to give azido groups containing (1→6)‐α‐linked glucopyranan derivatives. The differences in polymerizability among the three azido monomers are discussed. Regioselective reduction of three kinds of heteropolysacharide derivatives which had different quantities of azido groups at C‐2, ‐3, or ‐4 position with lithium aluminum hydride and subsequent debenzylation of the copolymers with sodium in liquid ammonia produced amino‐group‐containing heteropolysaccharides.
Study of photopolymer. XIX. Novel syntheses of the polymers with pendant ester and chloromethyl groups by addition reactions of the copolymer of glycidyl methacrylate with acid chlorides
Authors: Nishikubo T. , Iizawa T. , Saito Y.
Published: April 2003

Polymer with pendant cinnamic ester and chloromethyl groups was synthesized by the addition reaction of poly(glycidyl methacrylate–co–methyl methacrylate) (PGMA) with cinnamoyl chloride. Also, polymers with pendant benzoic esters and chloromethyl groups were synthesized by reaction of PGMA with the corresponding benzoyl chlorides. Furthermore, polymers with cinnamic or benzoic esters and alkylazide groups were prepared by the substitution reaction of the obtained polymers with sodium azide.
Batch and semicontinuous emulsion copolymerization of vinyl acetat–butyl acrylate. I. Bulk, surface, and colloidal properties of copolymer latexes
Authors: El‐Aasser M. S. , Makgawinata T. , Vanderhoff John W. , Pichot C.
Published: April 2003

Vinyl acetate (VAc)–butyl acrylate (BuA) comonomer mixtures with various composition were polymerized by batch and semicontinuous emulsion polymerization processes. PVAc and PBuA homopolymer latexes as well as the (VAc‐BuA) copolymer latexes were characterized with respect to particle size, molecular weight, acid end groups on particle surfaces, and colloidal stability against electrolytes. The surface and colloidal properties of these latexes were also compared before and after aging and acid hydrolysis. The average particle size of batch latexes was independent of copolymer composition, whereas for semicontinuous latexes it decreased with increasing BuA content and was always lower than that of the corresponding batch latex. The molecular weight distribution (MWD) for batch latexes was narrower and much less dependent on composition than that of the semicontinuous latexes; bimodal MWD was found in most semicontinuous latexes with a substantial amount of low MW fraction. The total weak and strong acid end groups on particle surfaces for semicontinuous latexes is higher, and more dependent on composition, than the batch latexes. Acid‐induced hydrolysis results in a drastic change in the type and concentration of the surface groups of the semicontinuous latex particles. Colloidal stability against electrolytes showed that both electrostatic (due to surface acid groups) and steric [due to surface poly(vinyl alcohol)] mechanisms are contributing. However, for semicontinuous latexes, increasing PVAc content above 50 mol % resulted in a proportional increase and ultimately dominant role of steric stabilization. The results were interpreted in terms of differences in reactivity ratios and water solubilities of the two monomers and their effects on the locus of initiation and growth in the two polymerization processes, as well as the monomer sequence within the polymer chain and degree of homogeniety of the copolymer composition within the particle.
Batch and semicontinuous emulsion copolymerization of vinyl acetate–butyl acrylate. II. Morphological and mechanical properties of copolymer latex films
Authors: Misra S. C. , Pichot C. , El‐Aasser M. S. , Vanderhoff J. W.
Published: April 2003

Vinyl acetate/(VAc)‐butyl acrylate/(BuA) copolymer latex films of various copolymer compositions were investigated for their morphological properties by electron microscopy techniques, and for their mechanical properties by dynamic mechanical spectroscopy (DMS), differential scanning calorimetry (DSC), and tensile strength measurements. Batch copolymer latex films showed domains of PBuA dispersed in PVAc matrix; the domain sizes were increased with increased BuA content. Semicontinuous latex films were homogeneous in composition. Glass transition temperatures Tg determined from DMS and DSC indicated the presence of two, low and high, transition temperatures for batch latex films. The two temperatures approached the individual homopolymers, with increased PBuA content up to 51 mol %. Semicontinuous latex films showed only one single Tg. Tensile properties of the batch copolymer films showed a higher ultimate tensile strength, higher Young's modulus, and lower percent elongation to break compared to semicontinuous latex films. These differences were found to reflect the effect of mode of monomer addition during the emulsion copolymerization process on the particle morphology, and confirmed earlier data on bulk, colloidal, and surface properties of the same copolymer latexes.
Anisotropic electrical conductivity of drawn elastomeric ionene–TCNQ salts
Authors: Watanabe Masayoshi , Takizawa Yoshio , Shinohara Isao
Published: April 2003

Elastomeric ionene–TCNQ salts with favorable electrical, mechanical, and processing characteristics were drawn mechanically. The electrical conductivity parallel and perpendicular to the drawing axis was investigated. Correlation between anisotropic conductivity and the change in microstructure was discussed. The resistivity ρ at 25°C of the simple salt (EI‐TCNQ0) and the complex salt (EI‐TCNQ0.5) were on the order of 105 and 102 Ω cm, respectively. In the drawn TCNQ salts, the ρ parallel to the drawing axis increased greatly; on the other hand, the ρ perpendicular to this axis increased slightly or was similar to the ρ of the undrawn TCNQ salts. The anisotropy in the ρ of EI‐TCNQ0.5 between the two directions reached 40 times. The activation energy also increased in the direction parallel to the drawing axis. In the undrawn TCNQ salts, the continuous conduction paths exist isotropically. With drawing, the continuous conduction paths, particularly in the direction parallel to the drawing axis, break or make a structural change. The anisotropic conductivity disappeared with time in EI‐TCNQ0; however, it was present in EI‐TCNQ0.5 even after 200 days under ambient conditions.
A reassessment of the 1H‐NMR spectra of styrene/methyl methacrylate copolymers
Authors: Uebel J. J. , Dinan F. J.
Published: April 2003

The methoxy 1H‐NMR assignments in the 2.1–3.7δ region for styrene/methyl methacrylate copolymers have been assessed in terms of pentad sensitivity. Several of the methoxy resonances suggested by this study differ from literature assignments. The evidence in support of these reasignments is based on a comparison of calculated and observed triad distributions and on the good agreement of the value of the reactivity ratio rM calculated from individual triads with that obtained by classical methods. A new procedure for the determination of the tacticity coefficient σ is applied.
The use of acrylic acid‐co‐nylon substrates for immobilizing enzymes
Authors: Abdel‐Hay F. I. , Beddows C. G. , Gil M. H. , Guthrie J. T.
Published: April 2003

A number of poly(acrylic acid)‐co‐nylon graft copolymers were prepared. Two approaches were used. The first involved the direct, radiation‐induced grafting of acrylic acid onto the nylon, while the second involved the hydrolysis of polyacrylonitrile‐co‐nylon graft copolymers. All the resulting poly(acrylic acid)‐co‐nylon graft copolymers coupled large amounts of protein when the carbodimides CMC and EDAC were used as coupling agents. However, when the enzymes β‐galactosidase and trypsin were immobilized, the retention of activity was relatively low. A number of reasons for this effect can be postulated, some of which were investigated. From the evidence, it would appear that the major reason is that the carboxylic acid groups are fixed to a “rigid” backbone, which allows them to interact with the enzyme after the establishment of an initial covalent attachment. Additionally, with acid phosphatase, it was observed that the enzyme interacted with immobilized carboxylic acid groups before coupling occurred.
Ziegler–Natta polymerization of butadiene: Kinetic and molecular weight study
Authors: Honig J. A. J. , Burford R. P. , Chaplin R. P.
Published: April 2003

The effect of reaction conditions on conversion and molecular weight in the polymerization of butadiene initiated by cobalt octoate/diethylaluminum chloride/water was studied. The polymerization exhibited complex kinetics with respect to cobalt concentration. The molecular weight, as a function of conversion, was investigated. Chain transfer to aluminum alkyl was of only minor importance.
Liquid crystal polymers. 14. Synthesis and properties of thermotropic poly(1,4‐alkylphenylene terephthalates)
Authors: Dicke Hans‐Rudolf , Lenz Robert W.
Published: April 2003

A series of terephthalate polyesters was prepared from substituted hydroquinone monomers that contained a single cyclic or branched alkyl group. All the polymers were crystalline with melting points well below 400°C that decreased as the size of the cycloalkyl substituent increased. Most of the polymers had clearing temperatures below 400°C and all formed nematic melts. Copolyesters that contained equimolar amounts of two different substituted hydroquinone monomers, which were crystalline and had broad temperature ranges for nematic phase formation, were also prepared.
Synthesis of polyester by direct polycondensation with triphenylphosphine
Authors: Yasuda Satoshi , Wu Guo‐Chuang , Tanaka Hozumi , Sanui Kohei , Ogata Naoya
Published: April 2003

Direct polycondensation reactions of various dicarboxylic acids and diols were carried out at room temperature with triphenylphosphine and polyhalo compounds to obtain polyesters in good yield. Reaction conditions including solvent, temperature, concentration of monomer, amount of reagents, and effect of matrix on direct polycondenation were investigated. A combination of triphenylphosphine and hexachloroethane was found to be satisfactory for the polyester synthesis. The addition of matrix polymers such as poly(4‐vinylpyridine) in the reaction system enhanced the direct polycondensation reaction, and a polyester with a solution viscosity of 2.24 was obtained from bisphenol A and isophthalic acid under the optimum condition.
Etude par RMN 13C à 62,89 MHz des branchements éthyles dans les copolymères ethylène‐butène et polyéthylène basse densité
Authors: Grenier‐Loustalot Marie‐Florence
Published: April 2003

Carbon 13 nuclear magnetic resonance spectra (at 62,89 MHz) were obtained for a series of branched heavy alcanes (12‐ethyl tricosane, 11,20‐diethyl tricontane, 11,18‐diethyl octacosane, 11,17‐diethyl heptacosane, 11,16‐diethyl hexacosane, 9,12‐diethyl heneicosane, 5,7‐diethyl docosane, 6,7‐diethyl docosane, 2 éthyl‐hexyl‐12 tricosane), which provide a model set for describing the ethyl branched sequences in ethylene butene copolymers and low‐density polyethylene (LDPE). For ethylene‐butene copolymers we do not detect any head‐to‐head polymerization of butene as reported recently (the existence of a 1,2‐ethyl pair has not been confirmed by the low‐field signal at 41,3 ppm), but only isolated ethyl and 1‐3‐diethyl branches. The three peaks observed in the methyl region (broad signal) of the spectrum are assigned to butene centered triads, as opposed to branches in positions having different tacticities as reported earlier. Carbon 13 nuclear magnetic resonance spectra of high‐pressure polymerized low‐density polyethylene have been measured at 62,89 MHz. On the basis of Willbourn's double back biting mechanism, two kinds of complex branches, the 1,3‐ethyl pair and 2‐ethyl‐hexyl, have been assigned. Finally, these results suggest that the ethyl branches in low‐density polyethylene are not isolated branches.
Etude par RMN 13C à 62,89 MHz de ramifications longues d'alcanes lourds branchés. Modèles de PEbd et des copolymères éthylène‐α oléfines
Authors: Freche Patrick , Grenier‐Loustalot Marie‐Florence
Published: April 2003

A series of 12‐alkyl tricosanes (four compounds) was examined by use of 13C nuclear magnetic resonance at 62,89 MHz as model compounds for isolated short‐ and long‐chain (C5, C6, C7, C8) branches in low‐density polyethylene and ethylene‐α olefin copolymers. An array of 13C resonances was observed and we note that the 13C chemical shifts became insensitive to branch length with octyl and longer branches at this field.
Photocycloaddition of cis‐cyclooctene to low‐molecular‐weight polystyrene and some aromatic model compounds
Authors: Beckewitz F. , Heusinger H.
Published: April 2003

The product formation of 1,3 cycloaddition of cis‐cyclooctene to a low‐molecular‐weight polystyrene as well as to some monoaromatic and diaromatic model compounds is investigated. Information on the structure of the products mainly with respect to the number of phenyl rings attacked within the molecules is obtained by mass spectrometry.
Morphology and grafting in polybutylacrylate‐polystyrene core‐shell emulsion polymerization
Authors: Min T. I. , Klein A. , El‐Aasser M. S. , Vanderhoff J. W.
Published: April 2003

The morphology of polybutylacrylate–polystyrene (PBA–PS) core‐shell latex particles prepared by seeded emulsion polymerization was investigated as a function of the addition method of styrene (St). The thin layer chromatography/flame ionization detector (TLC–FID) technique was used to characterize the morphology of the core‐shell latexes. It was found that grafting PS to the PBA core occurs during seeded emulsion polymerization. The percentage of grafting depended on the method of addition of St, being greatest for the batch reaction, less for the preswollen batch reaction, and least for the semibatch reaction. Upon aging the PBA core‐polymer migrated out of the latex particles with a low degree of grafting to form dumbellshaped particles, whereas the PBA–PS core‐shell particles with a high degree of grafting remained spherical because of the emulsifying ability of graft copolymer.
Vinyl polymerization. 416. Polymerization of vinyl monomer initiated by polyethyleneglycol
Authors: Ouchi Tatsuro , Hosaka Yoshifumi , Beika Nobuaki , Imoto Minoru
Published: April 2003

The polymerization of vinyl monomer initiated by polyethyleneglycol (PEG) in aqueous solution was carried out at 85°C with shaking. Acrylonitrile (AN), methyl methacrylate (MMA), and methacrylic acid were polymerized by PEG–300 (M̄n = 300), whereas styrene was not. The effects of the amounts of monomer and PEG, the molecular weight of PEG, and the hydrophobic group at the end of PEG molecule on the polymerization were studied. The selectivity of vinyl monomer and the effect of the hydrophobic group are discussed according to “the concept of hard and soft hydrophobic areas and monomers.” The kinetics of the polymerization was investigated. The overall activation energy in the polymerization of AN was estimated as 37.9 kJ mol−1. The polymerization was effected by a radical mechanism.
Plasma polymerization. IX. A systematic investigation of materials synthesized in inductively coupled plasmas excited in perfluoropyridine
Authors: Clark D. T. , Abu‐Shbak M. M.
Published: April 2003

The RF plasma polymerization of perfluoropyridine was investigated for a range of operating parameters. The stoichiometries of the resulting thin films indicated a predominance of rearrangement mechanisms in their formation in which both nitrogen and fluorine were retained at approximately the same level as in the starting monomer. In appropriate cases a comparison was drawn with plasma polymers produced under comparable conditions from perfluoro and pentafluorobenzenes. Although the plasma polymer films from the benzenes have a low critical surface tension, that for the pyridine system changes with time, and the surface becomes completely wettable with water. This is attributed to surface hydrolysis of the plasma polymer films produced from perfluoropyridine.