bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation‐induced polymerization at high dose rate. III. Isoprene in bulk
Authors: Hayashi Kanae , Tachibana Michinori , Okamura Seizo
Published: April 2003

Radiation‐induced polymerization of isoprene in bulk state was studied at 25°C in a wide dose rate range. Variations of the rate of polymerization and molecular weight of the products were essentially the same as those observed in the monomers which were capable of both radical and cationic polymerizations. At low dose rate, 7.0‐230 rad/sec, radical polymerization took place. At high dose rate, 8.8 × 103‐2.2 × 105 rad/sec, radical and cationic polymerizations took place concurrently. The average molecular weight of the high‐dose‐rate product was about 850, independent of dose rate. The microstructure of the products at high dose rate consisted mainly of trans‐ 1,4 units with only about 7% of cis‐ 1,4 and 10% of 3,4‐vinyl units. The residual unsaturation in the high‐dose‐rate products was 90%. Decreases in cis units and residual unsaturation at high dose rate were accounted for by the change in predominant mechanism of polymerization with dose rate.
The solubility of cellulose in liquid ammonia/salt solutions
Authors: Hudson Samuel M. , Cuculo J. A.
Published: April 2003

The dissolution of cellulose in solutions of liquid ammonia and ammonium thiocyanate is discussed. Viscosity measurements on dilute solutions of cellulose in this solvent over a range of shear rates and shear stresses are reported. A four‐bulb Ubbelohde suspended level viscometer was used for the measurements. Plots of log [η] versus log M gave Mark‐Houwink coefficients of a = 0.95 and K = 6.686 × 10−5 at 25°C for [η] as dl/g. The Bloomfield equation was used to calculate effective bond lengths (b) from limiting viscosity numbers of cellulose in solutions of ammonia/ammonium thiocyanate and Cuene, respectively. Results indicate that cellulose may have similar configurations in both solvents and also that the ammonia solutions are true cellulose solutions. Miscibility of the cell‐ ulose/ammonia/ammonium thiocyanate solutions with organic solvents, such as glycerol, is also reported. Further, a few interesting characteristics of the liquid ammonia/ammonium salt solutions, discussed briefly, are the convenient boiling point, the rheological behavior, and the relatively high concentration of cellulose obtainable.
Polymerization of aromatic nuclei. XXVI. Poly(p‐phenylene): Friedel–crafts alkylation, molecular weight, and propagation mechanism
Authors: Jones Martin B. , Kovacic Peter , Lanska Douglas
Published: April 2003

Poly(p‐phenylene) was alkylated with n‐propyl bromide, n‐propyl chloride, and isopropyl bromide in the presence of aluminum chloride. Apparently, the reactions involve dialkylation with n‐propyl halides and alternating mono‐ and dialkylation with isopropyl bromide. Alkylation with ethyl or n‐butyl bromide was unsuccessful. The dialkylated polymer was sufficiently soluble to allow molecular weight determination. Mechanistic aspects of alkylation and propagation are treated.
Studies on the vinyl polymerization photoinitiated by p‐benzoylperoxybenzoic acid tert‐butylester
Authors: Gupta Satyendra N. , Gupta Ipsita , Neckers D. C.
Published: April 2003

p‐Benzoylperoxybenzoic acid tert‐butylester (BPE) undergoes an efficient photodecomposition producing cleavage of the peroxy bond. The excited triplet benzophenone carbonyl group of the perester is quenched by vinyl monomers (the degree of which depends on the type of monomer used) thus reducing the rate of decomposition of BPE when it is used as a photoinitiator. Radicals generated from the decomposition of BPE are highly efficient in initiating vinyl polymerization. The benzophenone‐containing end groups of the polymer chain can be estimated and the carbonyl function is useful for polymer modification.
Synthesis of aromatic polyamides having pyridine moiety and their lyotropic properties in solution
Authors: Ogata Naoya , Sanui Kohei , Koyama Takashi
Published: April 2003

Fully aromatic polyamide containing pyridine moieties (PPy) were successfully synthesized either by interfacial or solution polycondensation to prepare polyamide with inherent viscosity as high as 4. Solution properties of PPy in sulfuric acid were investigated in terms of solution viscosity and lyotropic behavior. The polyamide had a better solubility in sulfuric acid than in poly(p‐phenylene terephthalamide) (PT) and the PPy solution in sulfuric acid exhibited an optically anisotropic property in a wider range of concentrations at relatively low temperatures in comparison with the PT solution. Viscosities of the PPy solution and the film cast from the PPy solution indicated a phenomenon characteristic of a highly oriented rigid polymer molecule caused by a lyotropic behavior.
The synthesis of a macromolecular ligand by the modification of polystyrene
Authors: Phillips Hodge H. , Kinstle James F. , Adcock James L.
Published: April 2003

Uncrosslinked atactic polystyrene was chemically modified first by acetylation then by a Claisen condensation with ethyl perfluoropropanoate to produce three crosslinked chelating polymers that contained a phenyl, perfluoroethyl, beta‐diketone chelating group in 10, 20, and 63 mole % compositions. Cu(II), Ni(II), and uranyl chelates of the macromolecular ligands were prepared and analyzed. The macromolecular ligands and their chelates were compared with the model ligating species 4,4,5,5,5‐pentafluoro‐1‐phenyl‐1,3‐pentanedione with infrared and mass spectroscopy and proton nuclear magnetic resonance.
Electron transfer reactions to electroactive polymers
Authors: Funt B. Lionel , Hsu Li‐Chien , Hoang P. M.
Published: April 2003

In the electrochemical reduction of an electroactive polymer several thousand electrons may be transferred to a single molecule. For polymers with noninteracting centers, recently developed theory indicates that the current—potential response would be identical with that of the corresponding molecule solvation, structural change, and variation in ionic environment, and may be used to probe these factors. A series of model compound of poly(vinylbenzophenone) and of poly(vinylbenzophenone‐co‐styrene) were prepared and investigated. In this study samples of various constant chain length with differing spacing of electroactive centers were employed. The current—potential measurements corresponded to the ideal theoretical case. This indicates that the behavior of the electroactive groups attached to the polymer chain was not influenced by the macromolecular environment or by neighboring group interaction.
Polymerization of allyl esters of unsaturated acids. VII. Copolymerization of methyl allyl maleate and fumarate with styrene
Authors: Urushido Kunio , Matsumoto Akira , Oiwa Masayoshi
Published: April 2003

Radical copolymerizations of methyl allyl maleate (MAM) and methyl allyl fumarate (MAF) with styrene (St) are carried out in bulk using AIBN as an initiator at 60°C, and their copolymerization behaviors are compared in detail. The different rate features are observed with each other; thus in the MAF‐St copolymerization the rate was quite enhanced and, also, the maximum rate was found at the molar ratio of 1:1 in the monomer feed, whereas no maximum phenomenon of the rate was apparent for the MAM—St copolymerization. The copolymerizability of MAF with St was quite high, whereas that of MAM was very poor. The cyclization of MAM or MAF was hindered by the highly reactive St monomer. These results are discussed in terms of the formation of the charge—transfer complex between MAF and St and, furthermore, the cyclocopolymerization kinetics involving the 17 elementary reactions as the propagation reactions.
Catalysis by cationic polyelectrolytes and micelles in bisulfite oxidation
Authors: Kim O.‐K.
Published: April 2003

The oxidation of sodium bisulfite in the presence of cationic polyelectrolytes or micelles has been studied. The formation of cationic‐bisulfite complexes is indicated, and a kinetic analysis suggests the validity of the enzyme kinetics applied to determine the kinetic parameters. Distinct differences in the activity of cationics depend on the configuration of the cationics in solution; micelle‐forming cationics are more effective than nonmicellar polycationics, except in the case of poly(diallyldimethylammonium chloride), (PDADM). The oxidation rate is strongly affected by the presence of monomer in the system, especially where nonmicellar polycationics are involved.
NMR studies and conformations of asymmetric polyamides derived from cyclopropyl diacids and diamines
Authors: Overberger C. G. , Nishiyama T.
Published: April 2003

The synthesis and optical properties of the polyamides [poly(C3A˙C3B) and poly(C3A‐C3MB)] derived from asymmetric trans‐1,2‐cyclopropanedicarboxylic acids (C3A), asymmetric trans‐1,2‐diaminocyclopropanes (C3B), and asymmetric trans‐1,2‐bis(methylamino) cyclopropanes (C3MB) were reported in the preceding article. This paper describes the NMR studies and conformations of the polyamides. The NMR studies of the polyamides and their diamide models have suggested that the polyamides have about a 90° torsional angle for NH (or CH3) CH. This angle seems to be reasonable because of less steric interaction, especially for poly(+)C3A(+)C3MB. The NCH3 of the poly(+)C3A(+)C3MB in sulfuric acid‐d2 (D2SO4) is a singlet and is tentatively assigned to trans to the carbonyl oxygen of the amide group. In 2,2,2‐trifluoroethanol‐d3 (TFE‐d3) and chloroform‐d (CDCl3) it is also a singlet and is tentatively assigned to cis. The overall results obtained suggest that poly(+)C3A(+)C3MB exists in a compact helical conformation in TFE and TMS, while some conformational transition to a highly extended helical form with opposite handedness is induced by the addition of MSA. Likewise, poly(+)C3A(+)C3B must exist in some ordered conformation in the solvents studied. Possible ordered conformations of the polyamides have been proposed based on the experimental results and some assumptions.
Hydrolytically stable fluorocarbon ether bibenzoxazole polymers
Authors: Evers Robert C. , Abraham Tonson , Burkett Jerald L.
Published: April 2003

Hydrolytically and thermooxidatively stable fluorocarbon ether bibenzoxazole (FEB) polymers were synthesized by the acetic acid‐promoted polycondensation of fluorocarbon ether bis(o‐aminophenol) monomers with novel fluorocarbon ether dithioimidate ester monomers. The dithioimidate esters were derived from hexafluoropropylene oxide (HFPO) or, preferably, from a combination of HFPO and tetrafluoroethylene oxide (TFEO). The latter class of TFEO:HFPO‐derived dithioimidate esters imparted improved hydrolytic stability to the resultant FEB polymers while minimizing undesirable, concomitant increases in polymer glass transition temperatures. The polymers exhibited inherent viscosities in the range of 0.20 to 0.41 dl/g. Polymer structures were verified by elemental and infrared (IR) spectral analyses. Lower glass transition temperatures were obtained with increased fluorocarbon ether content, a minimum value of −48°C being achieved. High thermooxidative stability of the HFPO‐ and TFEO:HFPO‐based FEB polymers was substantiated by thermogravimetric analysis and isothermal aging studies in air. After isothermal aging in air for 200 hr at 288 and 260°C, representative polymers exhibited weight losses of 17 and 7%, respectively. Hydrolytic stability of the polymers was evaluated by exposure to a 95% relative humidity, 93°C environment for prolonged periods of time. Based on comparative glass transition temperature, inherent viscosity, and IR spectral data, the HFPO‐ and TFEO:HFPO‐based FEB polymers exhibited vastly improved hydrolytic stability over analogous TFEO‐based FEB polymers. Optimum hydrolytic stability and low‐temperature viscoelastic properties were achieved by the use of a TFEO:HFPO‐derived dithioimidate ester that did not contain structural isomers that would lead to sites of hydrolytic instability in the polymer backbone.
Solid‐state polymerization of long‐chain vinyl compounds. VI. In‐source polymerization of octadecyl acrylate by γ‐ray irradiation
Authors: Shibasaki Yoshio , Fukuda Kiyoshige
Published: April 2003

The in‐source polymerization of octadecyl acrylate in the lamellar crystal (hexagonal packing) by γ‐ray irradiation has been investigated, as compared with the two‐step and one‐step postpolymerizations. The viscosity‐average molecular weight is very high even in the initial stage and is practically saturated after 3–5 hr, although the conversion increases successively with time. The molecular weight distribution of poly(octadecyl acrylate) obtained by in‐source polymerization is very wide (Mw/Mn = 13.1, at 20°C). The results of in‐source polymerization of the long‐chain vinyl compounds can be interpreted using the cone model for polymerization probability, similar to those of one‐step and two‐step postpolymerizations.
Polymerization of acrylonitrile: Kinetics of the reaction initiated by the Fe2+/BrO3− redox system
Authors: Samal R. K. , Suryanarayana G. V. , Das D. P. , Samal S. , Nayak M. C.
Published: April 2003

The aqueous polymerization of acrylonitrile initiated by the bromate—ferrous redox system in aqueous sulfuric acid was studied under nitrogen atmosphere. The rate of polymerization increased with increasing concentration of ferrous in the range of 0.25‐1 × 10−2M. The percentage of conversion increased with increasing concentration of the catalyst, but beyond 2.5 × 10−3M there was a decreasing trend in the rate of polymerization. The rate varied linearly with [monomer]. The initial rate of polymerization as well as the maximum conversion increased within the range of 1–2.5 × 10−3M KBrO3, but beyond 2.5 × 10−3M the rate of polymerization decreased. The initial rate and limiting conversion increased with increasing polymerization temperature in the range 30–40°C; beyond 40°C they decreased. The effect of certain neutral salts, water‐miscible solvents, complexing agents, and copper sulfate concentration on the rate of polymerization was investigated.
Telomerization kinetics by redox catalysis: A study of reactions leading to telomers with low degrees of polymerization
Authors: Boutevin Bernard , Maubert Claude , Pietrasanta Yves , Sierra Pierre
Published: April 2003

An adaptation of the David and Gosselain formula for redox catalyzed telomerization was made. An equation was developed for transfer reactions between oligomer radicals and metallic ions. This equation was applied to data obtained in chlorotrifluoroethylene (CTFE)—carbon tetrachloride telomerizations catalyzed by a ferric chloride—benzoin mixture. It was found that the metal ion transfer constants (CMei) were the predominant parameters influencing the distribution of products obtained. These were found constant for degrees of polymerization greater than 2.
Synthesis and polymerization of the four 1,3‐di(cyano and/or carbomethoxy)‐substituted butadienes
Authors: Ahn Kwang‐Duk , Hall H. K.
Published: April 2003

The four 1,3‐di(cyano and/or carbomethoxy)‐substituted butadienes were synthesized. Their cyclopentadiene adduct precursors and, in one case, an anthracene adduct precursor were synthesized and pyrolyzed at 400–600°C (0.1–1.0 mm) to yield the four new dienes. Two crystalline precursors gave crystalline dienes 1,3‐dicyano‐1,3‐butadiene, mp 79°C, and 1‐carbomethoxy‐3‐cyanobutadiene, mp 45–46°C, in modest yields in small‐scale experiments, which were completely characterized by elemental analyses and spectra. The other two liquid precursors produced no isolable or detectable dienes but led directly to polymer. The two crystalline dienes were exceptionally reactive, polymerizing on storage or when deliberately initiated with AIBN, but were moderately stable in solution. All polymers possessed the trans‐1,4‐structure exclusively. Because of the favorable location of the electronegative substituents for stabilizing the growing radical, these new dienes are the most reactive di‐electronegatively substituted butadienes described.
Radiation‐induced cationic polymerization of β‐pinene
Authors: Adur Ashok M. , Williams Ffrancon
Published: April 2003

The radiation‐induced polymerization of β‐pinene carried out in bulk at ca. 25°C has been studied for different methods of monomer drying. It has been confirmed that the polymerization is sensitive to adventitious moisture and that substantial polymer yields (ca. 10% conversion per Mrad) can only be obtained under extremely dry conditions. Complete inhibition of the reaction by added tripropylamine corroborates the view that the polymerization is cationic. About half of the polymer formed is insoluble in the monomer. The number‐average molecular weights for the soluble poly(β‐pinene) fraction have been measured by vapor pressure osmometry and are in the narrow range from 1700 to 2400 with little or no dependence on the degree of monomer conversion to polymer, at least up to 80%. The results are compared with literature reports on the polymerization of β‐pinene by catalytic initiators.
Cationic oligomerization and polymerization of some propenylbenzene derivatives
Authors: Alexander R. , Jefferson A. , Lester P. D.
Published: April 2003

A comparative study was undertaken of the cationic oligomerization/polymerization of the natural propenylbenzene derivatives, anethole, isoeugenol, and isosafrole, together with synthetic o‐methoxypropenylbenzene and N,N‐dimethyl‐p‐propenylaniline using boron trifluoride diethyletherate as catalyst. Two (optimum) reaction temperatures were employed, −12 and −45°C, and only the (E) isomers of the monomers were studied. The order of reactivity of the monomers was found to be anethole > isoeugenol > isosafrole > o‐methoxypronylbenzene as measured by following the rate of loss of monomer by proton magnetic resonance spectrometry at −12°C. N,N‐dimethyl‐p‐propenylaniline only appeared to form a complex with the catalyst. Low‐molecularweight polymeric materials were prepared from anethole, isosafrole, and isoeugenol at −45°C using the same catalyst while o‐methoxypropenylbenzene formed oligomers. Isosafrole was recovered unchanged when treated with the boron trifluoride diethyl etherate initiator system at −78°C in an attempt to increase the molecular weight of the polyisosafrole.
Aqueous polymerization of methyl methacrylate catalyzed by copper metal and some of its compounds
Authors: Moustafa A. B. , El‐Ghaffar M. A. Abd , Badran A. S. , Rabie A. M.
Published: April 2003

The aqueous polymerization of methyl methacrylate (MMA) with sodium bisulfite as initiator was carried out in a nitrogen atmosphere with and without inorganic substances like copper metal, cupric and cuprous oxides, and cupric sulfide. It was also done in the presence of organocopper compounds like copper phthalocyanine and copper biphthalocyanine. The catalytic effect of these compounds was studied. Mildly heated cupric sulfide proved to have a small catalytic effect on the polymerization process that may be attributed to the retarding effect of the released elementary sulfur. The catalytic effect of the different copper compounds and the copper metal equivalent contained in them was studied. The polymerization process revealed that cuprous and cupric oxides possess the highest catalytic influence. An attempt was made to investigate the role of the different anions on the polymerization process. It was found that an increase on the concentration of the copper compounds leads to a corresponding increase in the catalytic effect. It was also observed that the behavior of insoluble copper catalysts is different from that of the soluble. The effect of these catalysts on the average molecular weight of the poly(methyl methacrylate) (PMMA) produced was also examined.
Synthesis and polymerization of p‐(p′‐vinylbenzoyl)‐peroxybenzoic acid tert‐butylester: A monomer containing a photodissociable radical source
Authors: Gupta Satyendra N. , Thijs Lambertus , Neckers Douglas C.
Published: April 2003

In a previous report we have shown that efficiently photodecomposable, but thermally stable, peresters can be made from a compound that contains both a triplet photosensitizer functionality and a perester group. This fundamental approach has been extended to make a novel vinyl monomer containing a triplet sensitizer and a perester group. Thus, the monomer p‐vinylbenzoyl‐p‐tert‐butyl perbenzoate (VBPE) has been synthesized and polymerized by normal procedures without loss of perester activity. The resulting polymer perester can be used as an efficient photolabile radical source by irradiating at the λmax of the benzophenone carbonyl moiety. The homopolymer (PVBPE) and copolymers with other monomers, such as styrene, could be photocrosslinked with high efficiency. Copolymers of VBPE and styrene containing low percentages of VBPE have been used to initiate graft chains of poly(methyl methacrylate) by irradiating a solution of the copolymer in methyl methacrylate at 366 nm.
Thermoxidative degradation of poly(vinyl alcohol) under dynamic thermogravimetric conditions. II. Influence of the hydrolysis degree
Authors: Vasile Cornelia , Călugăru Elena Maria , Bodonea Silvia Florica
Published: April 2003

The influence of the degree of hydrolysis on thermoxidative degradation of the poly(vinyl alcohol) was studied. The thermoxidative degradation was carried out under dynamic thermal conditions. Taking into account the dependence of the activation energy values on the heating rate, molecular weight, degree of conversion, and degree of hydrolysis, some conclusions were drawn about the decomposition mechanism and the variation of the thermal stability.
Hydrogen evolution from water by use of viologen polymers as electron transfer catalyst
Authors: Ageishi Kentaro , Endo Takeshi , Okawara Makoto
Published: April 2003

The behavior of viologen polymer (P‐V2+) as an electron transfer catalyst in the reaction of hydrogen generation was studied. In the photoirradiation system, which contains triethanolamine (TEA), Ru(bpy)3+3, and P‐V2+, the amount of hydrogen evolution was less than methyl viologen (MV2+); P‐V2+, however, was more effective in sodium dithionite as the electron donor and showed higher initial rates than MV2+.
Radical polymerization in the presence of complexing agents. III. Effect of low concentrations of ZnCl2 on the radical polymerization of methyl methacrylate
Authors: Madruga E. L. , Román J. San
Published: April 2003

The formation of complexes between ZnCl2 and methyl methacrylate (MMA) or between ZnCl2 and AIBN was tested at two different polymerization temperatures, taking into account the Haeringer and Riess treatment. For any concentration of ZnCl2 between 0.01 and 0.1 mole/liter the formation of ZnCl2−MMA complexes is favored, whereas AIBN−ZnCl2 complexes are hardly showed. The effect of zinc chloride on the stereostructure of poly(methyl methacrylate) was also investigated at both temperatures.
A study of structure formation processes occurring with the gelation of polysulfonamide solution in dimethylacetamide
Authors: Kochervinsky V. V. , Zagainov V. M. , Sokolov V. G. , Zelenev Yu. V.
Published: April 2003

This work investigates spontaneous gelatination of polysulfonamide in the solution of dimethylacetamide by nuclear magnetic relaxation, small‐angle light scattering, and refractive index measurement. Two stages of the gelatination process were found to occur. Spherulites are formed in the first stage while the mobility of the solvent molecules decreases sharply. The second stage is characterized mainly by perfection of the inside structure of spherulites without a change in their size. The degree of decreasing mobility of the solvent molecules is much less in this stage than in the first stage.
Agitation effect on the rate of soapless emulsion polymerization of methyl methacrylate in water
Authors: Arai Kunio , Arai Masahiko , Iwasaki Shigeo , Saito Shozaburo
Published: April 2003

In order to identify the factors causing an agitation effect on the rate of soapless emulsion polymerization, the polymerization of methyl methacrylate was carried out in water. Experimental results indicated the significance of monomer transfer from monomer droplets to water. A kinetic model was proposed which would take into account this monomer transfer. This model enabled the effect of monomer transfer on the rate of soapless emulsion polymerization to be evaluated for the present system and the experimental results to be interpreted qualitatively.
Polymerization of acrylonitrile by catalytic systems consisting of triphenylphosphine and a lewis acid
Authors: Kuran Witold , Borycki Jerzy
Published: April 2003

Polymerization of acrylonitrile in the presence of systems that consisted of triphenylphosphine (PPh3) and a Lewis acid RmMXn (ZnCl2, Me3Al, Et3Al, Et2AlCl, EtAlCl2, AlCl3) was studied. The systems that contained Me3Al and Et3Al (i.e., Lewis acid of moderate acidity) were the most efficient catalysts. Conductometric measurements carried out in the polymerization systems showed the presence of ions. The presence of phosphonium cation in the polyacrylonitrile chain formed by the PPh3–RmMXn catalytic systems was determined by IR, 1H‐NMR, and 31P‐NMR spectroscopy. The average molecular weight measurements and kinetic chain lengths of polyacrylonitrile formed within the reaction time in the presence of PPh3–Et3Al showed that transfer reactions occur. According to the results obtained, the polymerization reaction of acrylonitrile by PPh3–RmMXn involved a zwitterion formed by the attack of PPh3 on acrylonitrile complexed by Lewis acid [Ph3P⊕CH2C⊖HCN → MRmXn] and the anion [CH2C⊖CN] formed by the proton abstraction from the monomer.
Polymerization behavior of bistrimethylsilyloxycycloalkenes
Authors: Kondo Akihiro , Nakashima Masataka , Iwatsuki Shouji
Published: April 2003

The radical copolymerizations of bistrimethylsilyloxycycloalkenes, such as 1,2‐bistrimethylsilyloxycyclobutene (I), 1,2‐bistrimethylsilyloxycyclopentene (II), and 1,2‐bistrimethylsilyloxycyclohexene (III), were carried out with acceptor monomers, such as maleic anhydride, N‐phenylmaleimide, and methyl methacrylate. I and II gave alternating copolymers with maleic anhydride and random copolymers with N‐phenylmaleimide but no copolymer with methyl methacrylate. III gave no copolymer with the acceptor monomers. These polymerization behaviors of bistrimethylsilyloxycycloalkenes were explained primarily in terms of the electron donor–acceptor interaction between both monomers.
The identification of peroxy‐features at polymer surfaces by ESCA
Authors: Dilks A.
Published: April 2003

A preliminary investigation of the identification of peroxy‐features at polymer surfaces by ESCA is described. Oxidation of a hydrocarbon polymer in the effluent of a singlet molecular oxygen generator, based on a microwave discharge in oxygen, produces surfaces rich in peroxy‐features. By comparison with experimental and theoretical studies of model systems these features can be identified in ESCA spectra by their characteristic O1s binding energies. The oxygen atoms in the peroxy‐linkage have essentially the same binding energy, which is within a narrow range of 534.0 eV for simple peroxides and hydroperoxides and a narrow range of 535.2 eV for peroxy‐features in more highly oxygenated environments; for example, peracids and peresters. Peroxy‐linkages decompose rather rapidly under the typical x‐ray flux used in the ESCA experiment.
Anionic polymerization to high vinyl polybutadiene
Authors: Halasa Adel F. , Lohr D. F. , Hall J. E.
Published: April 2003

1,3‐Butadiene was polymerized anionically to polybutadiene which contained up to 100% 1,2‐addition product. The atactic 100% 1,2‐polybutadiene was prepared with n‐butyllithium modified with bis piperidino ethane. The polymerization was done in hexane solvent at −5 to +20°C polymerization temperature.
Reactions of poly(phenylene oxide)s with quinones. I. The quinone‐coupling reaction between low‐molecular‐weight poly(2,6‐dimethyl‐1,4‐phenylene oxide) and 3,3′,5,5′‐tetramethyl‐4,4′‐diphenoquinone
Authors: White Dwain M.
Published: April 2003

A bifunctional polymer is formed when low‐molecular‐weight poly(2,6‐dimethyl‐1,4‐phenylene oxide) (I) reacts with 3,3′,5,5′‐tetramethyl‐4,4′‐diphenoquinone (II). Infrared (IR), nuclear magnetic resonance (NMR), and gel permeation chromotography (GPC) measurements indicate that the quinone is bound covalently to the polymer chain as a biphenyl moiety which can be located at a terminal position (III, a = 0) or an internal position (III, a > 0):
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Acetylation of III produces a diacetate ester characterized by field desorption mass spectrometry to confirm the bifunctional nature of III. The reaction of I with II proceeds at 25°C but is faster at elevated temperatures or with amine catalysis. Oxidation of III with oxygen and a copper/amine catalyst of the type used initially to prepare I regenerates II from the biphenyl moiety in III in high yield and converts the remaining oxyphenylene units to high‐molecular‐weight polymer.
Preparation and properties of novel polyhydrazides
Authors: Mahadevan V. , Padma S. , Srinivasan M.
Published: April 2003

A new class of polyhydrazides having aromatic as well as aliphatic units has been synthesized by low‐temperature solution polycondensation from equimolar amounts of diacid chloride and dihydrazides in HMPT as solvent. These polyhydrazides have poor solubilities and their intrisnsic viscosities ranged from 0.2 to 0.6 dl/g. X‐ray diffractograms of these polyhydrazides show that the polymers having terephthalic acid dihydrazide unit were more crystalline and all the polymers have densities in the range of 1.2‐1.8 g/cm3. Thermogravimetric analysis of these polyhydrazides showed initial weight losses commencing at 220–300°C in both air and nitrogen.
A novel method for the synthesis of liquid crystalline polymers. Preparation by the interaction of poly(acryloyl chloride) with mesogenic compounds
Authors: Paleos C. M. , Filippakis S. E. , Margomenou‐Leonidopoulou G.
Published: April 2003

A new method for the synthesis of thermotropic liquid crystalline polymers, which is comprised of the interaction of reactive polymers with mesogenic compounds, was investigated. This method is illustrated by the interaction of poly(acryloyl chloride) withp‐hydroxybenzylidene‐p‐butylaniline orp‐aminobiphenyl on the preparation of poly(p‐acryloyloxybenzylidene‐p‐butylaniline and poly(N‐p‐biphenylacrylamide)), respectively. These polymers were subjected to characterization studies which included optical microscopy, x‐ray diffraction analysis, and differential scanning calorimetry. It was established that both polymers in the melt exhibit smectic mesomorphism.
Solvation of polymeric organolithium compounds. Stoichiometry and heats of interaction of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with poly(styryl)lithium and poly(isoprenyl)lithium
Authors: Quirk Roderic P. , McFay Dennis
Published: April 2003

The enthalpies of interaction of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with poly‐(isoprenyl)lithium and poly(styryl)lithium were measured as a function of R ([base]/[Li]) by using high‐dilution solution calorimetry at 25°C. Both polymeric organolithiums exhibit initial exothermic enthalpies of interaction with TMEDA (R ≃ 0.1) of ca. −13 kcal/mole. The concentration dependencies show a break (decrease) in the plot of ΔH vs. R at ca. R = 0.5 for poly(isoprenyl)lithium and at ca. R = 1.0 for poly(styryl)lithium.
Aqueous polymerization of methacrylamide
Authors: Shukla J. S. , Tiwari R. K.
Published: April 2003

The aqueous polymerization of methacrylamide (I) initiated by KBrO3–thioglycolic acid (TGA) has been studied at 30 ± 0.2°C in nitrogen. The rate is given by K[M]1.19 [thioglycolic acid]1 [KBrO3]0.53 for 10–15% conversion. Activation energy was found to be 53.96 kJ/mole (12.92 kcal/mole) in the investigated range of temperature 30–45°C. The role of addition of a series of aliphatic alcohols and some salts was also determined. The kinetics of polymerization was followed iodometrically.
γ Radiolysis of polyethylene grafted with styrene
Authors: Mitsui Hiroshi , Shimizu Yuichi
Published: April 2003

γ Radiolysis of polyethylene grafted with styrene of 0–76 wt % was carried out at 30–100°C in vacuo with a dose rate of 6.35 × 105 rad/hr. The formation of hydrogen and trans‐vinylene unsaturation decreased as the content of styrene unit in polymer increased and the rate of formation was described by zero‐order formation kinetics with respect to each concentration combined with first‐order disappearance. The gel fraction changed with the content of styrene unit according to irradiation time and temperature. The gel data were evaluated by using the Charlesby–Pinner equation. Kinetic analysis showed that in γ radiolysis of polyethylene grafted with styrene the formation of hydrogen is somewhat retarded, the crosslinking and main chain scission are accelerated, and the disappearance of hydrogen and formation and disappearance of trans‐vinylene unsaturation are almost entirely unaffected. On the basis of these results the reactions induced by γ rays in graft polymer were discussed in connection with the reaction mechanisms of the γ radiolyses of polyethylene and polystyrene.
Reactions of hydroxymethylated 2‐methoxy‐ and 2‐methyl‐4,6‐diamino‐s‐triazines with urea
Authors: Tashiro Tatsuo
Published: April 2003

The reactions of hydroxymethylated 2‐methyoxy‐ (MMT) and 2‐methyl‐4,6‐diamino‐s‐triazines (MAG) which had an average degree of formaldehyde (F) substitution (n) = 2, with urea were studied in acidic aqueous solution in the pH 5‐1.6 region. The observed facts were in fairly good agreement with the rate equations. The reaction rate constants of MMT with urea were greater than those of MAG with urea, but their activation energy was almost equal: MMT, 20.3; MAG, 20.2 kcal/mole. For reference summaries of earlier studies were provided.
Copolymerization of butadiene with vinyl chloride by radiation
Authors: Hayashi Kanae , Tachibana Michinori , Tanaka Yoshinori , Okamura Seizo
Published: April 2003

The copolymerization of butadiene with vinyl chloride was demonstrated in homogeneous phase by radiation. The reactivity parameters were r1 = 10 and r2 = 0.02 (M1 = butadiene) in bulk at −10°C. The average molecular weight of the product was about 1000–2500, depending reaction conditions.
Polyetherimides via nitro‐displacement polymerization: Monomer synthesis and 13C‐NMR analysis of monomers and polymers
Authors: White D. M. , Takekoshi T. , Williams F. J. , Relles H. M. , Donahue P. E. , Klopfer H. J. , Loucks G. R. , Manello J. S. , Matthews R. O. , Schluenz R. W.
Published: April 2003

The synthetic route to polyetherimides by displacement of nitro‐groups from disubstituted bis‐imides by the dianion of bisphenols are described. The prepration of bis‐imides and bisphenol dianions, their polymerization, and some of the properties of the polymers are presented in detail. The 13C‐NMR spectra of intermediates and products were used to establish compositions and determine molecular weights.
Gamma radiation‐initiated polymerization of styrene at high pressure. I. Kinetic parameters with intermittent irradiation
Authors: Moore P. W. , Clouston J. G. , Chaplin R. P.
Published: April 2003

By adapting the rotating sector technique to provide an intermittent source of cobalt‐60 radiation the activation volumes for all reaction steps of the bulk polymerization of styrene have been shown to be independent of pressure up to 208 MPa. The activation volumes determined for polymerization, initiation, propagation and termination were, respectively, ΔV≠pol = −20.5 ± 0.22, ΔV≠i = +2.0 ± 0.18, ΔV≠p = −18.6 ± 0.44, and ΔV≠t = +5.8 ± 0.55 cm3 mol−. The values for the effect of pressure on the degree of polymerization ΔDP and the radical lifetime Δτ were, respectively, −22.6 ± 0.16 and −3.9 ± 0.29. The average radical lifetime increased from 4.5 s at atmospheric pressure to 6.3 s at 208 MPa. Because ΔV≠t is less than ΔV≠t and both are positive, the molecular weight increased with pressure at a faster rate than the polymerization rate. Although fewer radical chains were initiated per second under pressure the macroradical concentration increased with pressure because of the longer average lifetime of the radicals.
ESR study of the effects of water, methanol, and ethanol on gamma‐irradiation of starch
Authors: Henderson Alex M. , Rudin Alfred
Published: April 2003

This investigation deals with the nature and relative abundance of stable radicals formed by gamma‐irradiation of wheat starch at room temperature. Additions of equal weights of water, methanol, and ethanol were equally effective in reducing the content of stable radicals in starch which contained about 12% water before the additions. When, however, the starting material was dried starch with 2.9% initial water content additional water and methanol were better radical scavengers than ethanol. This difference is attributed to the superior ability of water and methanol to permeate the starch structure. Superficially different ESR spectra were obtained in products made by irradiating starch and starch that contained added water or methanol. Computer simulation of these spectra showed that they could be matched by superposition of the spectra of the same four component radicals, with some adjustments of relative intensities and peak widths. The structures of these radicals have been dedueed from the spectral assignments and relative effects of the three solvents used on the intensities of the respective ESR spectra.
Solvolysis of 4‐acyloxy‐3‐nitrobenzoic acid substrates catalyzed by polyethylenimine derivatives
Authors: Pavlisko J. A. , Overberger C. G.
Published: April 2003

The solvolytic reactions of anionic activated esters (Sn−) catalyzed by dodecane‐block‐poly[ethylenimine‐graft‐4(5)‐methylimidazole] and related model compounds were investigated. Hydrolysis of 4‐acetyl‐3‐nitrobenzoic acid (S2−) as a function of pH suggested that electrostatic interactions are operative only in the higher molecular weight polymers. Apolar interactions were evident from the greater catalytic rates observed for the hydrolysis of a series of 4‐acetoxy‐3‐nitrobenzoic acid substrates (Sn−). The largest rate enhancements were reflected by catalysts that make effective use of the electrostatic interaction and also provide an apolar binding site. Dodecane‐block‐poly[ethylenimine‐graft‐4(5)‐methylimidazole], with a DP = 85, catalyzed hydrolysis of Sn−(n = 2, 4, and 7), in excess substrate, exhibited saturation kinetics and followed a simple Michaelis‐Menten‐type mechanism. Inhibition of the catalyst in the hydrolysis of S12− was observed and can be rationalized by analogy to certain multisite enzymatic reactions.
Preparation, characterization, and porperties of optically active poly(α‐methyl‐α‐ethyl‐β‐propiolactones)
Authors: Grenier Daniel , Prud'Homme Robert E. , Leborgne Alain , Spassky Nicolas
Published: April 2003

S(−) and R(+) enantiomers of α‐methyl‐α‐ethyl‐β‐propiolactone (MEEPL) were prepared in an eight‐step synthesis with respective optical purities of 99 and 97% determined by 1H‐NMR (250 MHz) spectroscopy. Polymers (PMEPL) of different enatiomeric compositions were prepared with an anionic‐type initiator. Substantial differences in physical properties were observed between the racemic and optically pure polymers; for example, the melting point of the latter is 42°C higher than that of the former. Chiroptical properties of PMEPLs are reported. The 13C‐NMR (100.62 MHz) spectra of the polymers indicated that the distribution of configurational units in the macromolecular chain is random.
Studies of inorganic precipitate membrane. Part XXX. Membrane selectivity from electrical potential and conductivity measurements
Authors: Beg M. Nasim , Shyam R. , Beg M. Mohtashim
Published: April 2003

Bi‐ionic and multi‐ionic potentials across parchment‐supported mercuric sulfide membrane with various combinations of 1:1 electrlytes at different concentrations were measured. Membrane conductivity in contact with a single electrolyte was experimentally determined to evaluate selectivity of the membrane with the predetermined values of intramembrane mobility ratio. The selectivity sequence of the membrane was K+>Na+>Li+, which on the basis of the Eisenman–Sherry model of membrane selectivity, points toward the weak field strength of the charge groups attached to the membrane matrix. The permeability ratio of ions within the membrane was also evaluated by use of the equation based on the macroscopic linear laws of nonequilibrium thermodynamics derived by Sandblom and Eisenman. Three different methods of various integrated forms of the Nernst‐Plank flux equation were used to derive the potentiometric selectivity constant Kijpot of the membrane. These values were close to one another.
Excluded volume effects on polymer reaction rates
Authors: Black P. E. , Worsfold D. J.
Published: April 2003

The rates of reaction of acid chloride groups with nitrophenol groups were measured with the groups attached to polymer chains. The average degree of substitution was kept low, near to one or less groups per chain. It was found that the interpolymer reaction rates decreased several fold in dilute solution for high polymers compared with the rates in more concentrated solutions or with those for low‐molecular‐weight polymers. The results were compared with the models proposed by Morawetz and the effect was of the predicted magnitude. The results also confirmed Morawetz' prediction that smaller effects could be expected for terminally substituted than for randomly substituted polymers.
Reaction of poly(vinyl alcohol) with superoxide anion
Authors: Osawa Zenjiro , Moriyama Chiharu , Nakano Hiroko
Published: April 2003

Reaction of pol(vinyl alcohol) (PVA) with superoxide anion was carried out in a dimethyl sulfoxide solution at 40°C under nitrogen and changes in the yield of recovered polymer, molecular weight, and chemical structure were examined. Appreciable decreases in the yield of recovered polymer and molecular weight were observed during the reaction, which indicated that a main chain scission of the polymer had occurred. Residual acetyl groups identified by the absorption peaks at ca. 1720 and 1250 cm−1 in infrared (IR) spectra were removed rapidly and β‐diketone groups identified by the peaks at ca. 1640 and 1560 cm−1 in IR spectra and at ca. 255 nm in ultraviolet (UV) spectra were formed during the reaction. Formation of carboxylate groups was also assumed. The reaction mechanism was discussed on the basis of the results obtained.
Liquid crystal polymers. IV. Thermotropic polyesters with flexible spacers in the main chain
Authors: Antoun S. , Lenz R. W. , Jin J.‐I.
Published: April 2003

Two closely related series of polyesters that contain mesogenic units interconnected by flexible spacers along the main chain were prepared and characterized for their liquid crystal properties. All of these polymers showed theotropic behavior, which was examined by DSC, hot‐stage microscopy on a polarizing microscope, small‐angle light and wide‐angle x‐ray scattering methods, and visual observation of stir‐opalescence of the polymer melts. The effect of the length of the flexible spacer and the nature of the substituent, which is on the central aromatic ring of the mesogenic unit, on the stability and molecular order of the mesophase for each of the polymers was investigated and the results are discussed on the basis of the thermodynamic data obtained.
Neighboring effect of thiol group in acyl transfer reaction on a polymer with a lipoic acid structure
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto
Published: April 2003

Reductive S‐monoacylation of lipoamide with some carboxylic acids and tri‐n‐butylphosphine was carried out in acetonitrile to obtain the corresponding S‐monoacylated compounds in excellent yield. This method was applied to the preparation of S‐monoacylated dihydrolipoyl polymer with a neighboring thiol group. The acyl transfer from the polymer to cyclohexylamine was enhanced as much as 64 times by adding silver perchlorate.
Combined environment aging effects: Radiation‐thermal degradation of polyvinylchloride and polyethylene
Authors: Clough Roger L. , Gillen Kenneth T.
Published: April 2003

Results are presented for a case of polymer aging in which powerful synergisms are found between radiation and temperature. This effect was observed with formulations of polyvinylchloride and polyethylene and occurred insimultaneousandSequentialradiation‐thermal experiments. Dose rate dependencies, which appear to be mechanistically related to the synergism, were also found. The evidence indicates that these aging effects are mediated by a thermally induced breakdown of peroxides initially formed by the radiation. Similar effects could be important to material degradation in a variety of other types of combined‐stress environment. A new technique, which uses PH3treatment of intact polymer specimens to test for the importance of peroxide is the pathway that leads to changes in macroscopic tensile properties, is described.
Degradation of lignin by ozone. II. Molecular weights and molecular weight distributions of the alkali‐soluble degradation products
Authors: Mbachu R. A. D. , Manley R. St. John
Published: April 2003

The molecular weights and molecular weight distributions of the alkali‐soluble degradation products from the ozonolysis of spruce periodate and cuoxam lignins and spruce protolignin have been studied by gel permeation chromatography and ultracentrifugation. The bimodal distribution previously reported for soluble lignins was found to be an artifact; the correct distribution has one broad lowmolecular‐weight maximum, with a long tail extending toward the high‐molecular‐weight end of the distribution. Weight‐average molecuar weights of the alkali‐soluble degradation products, obtained by sedimentation equilibrium measurements, increased with time of ozonization up to about 15 min. Beyond this time fragmentation of the partly degraded products results in a decrease in molecular weight. Lignin degradation followed the pattern expected of a three‐dimensional, infinite‐network polymer gel undergoing breakdown. Based on the molecular weights and the molecular weight distributions, a random stepwise mechanism is suggested as the mode of lignin degradation by ozone.
Preparation and properties of some cardopolyamides
Authors: Srinivasan P. R. , Mahadevan V. , Srinivasan M.
Published: April 2003

Several polyamides that contained cardo units were prepared. Thus 9,9‐bis(4‐aminophenyl)fluorene and 9,9‐bis(4‐aminophenyl)anthrone were condensed with 2,5‐dimethyl‐1,4‐benzenediacetyl chloride, 2,4‐dimethyl‐1,4‐benzendiacetyl chloride, and 2,5‐dimethoxy‐1,4‐benzediacetyl chloride. Lowtemperature solution polycondensation in dimethyl acetamide (DMAc) was used throughout. The polymers were obtained in 80–90% yield and possessed intrinisic viscosities in the range of 0.6–1.2. The polymers were characterized by infrared (IR) spectra and elemental analysis. The solubility, crystallinity, and thermal stability of the polyamides were also determined.
Solutions of nylon‐6 in antimony trichloride
Authors: Aharoni S. M. , Walsh E. K. , Cilurso F. G.
Published: April 2003

Dilute solution viscosity measurements of nylon‐6 in molten SbCl3 reveal a polyelectrolyte effect that becomes more pronounced with increased molecular weight of the polymer sample. Intrinisic viscosities result in a relationship of [η] = 2.35 × 10−6M1.45w for nylon‐6 in SbCl3 at 100°C, which indicates a high polymeric chain extension in molten SbCl3 in the limit of zero concentration. Infrared (IR) and nuclear magnetic resonance (NMR) spectra indicate that a substantial fraction of the amide groups in each polymer chain remains unaffected, whereas the rest is interacted, probably, with SbCl4‐ions originating from the self‐ionization of SbCl3.