bluuebunny/crossref_metadata_2025 huggingface dataset:
Resacetophenone oxime–formaldehyde resin and its metal chelates. III
Authors: Parmar J. S. , Patel M. R. , Patel M. M.
Published: April 2003

In this paper the synthesis and properties of resacetophenone oxime–formaldehyde resin are described. The number‐average molecular weights of the resin determined by vapor‐pressure osmometry and nonaqueous conductometric titration are 2200 ± 10% and 2500 g/mol, respectively. Cu(II), Ni(II), and Co(II) chelates of the resin were prepared. Elemental analysis of the chelates indicates a metal to ligand ratio of 1:2. The diffuse reflectance spectra and magnetic moments of Ni(II) and Co(II) chelates show tetrahedral structure, whereas Cu(II) chelate shows a square planar structure. Infrared spectral studies show that the metals are coordinated through the nitrogen of the oximino group and oxygen of the phenolic group. The presence of methylene bridges is also indicated by IR spectral studies. The thermal behavior of the resin and its metal chelates are also discussed.
Cross‐linked polyvinylpyrrolidones with increased affinity and specificity for methyl orange and its homologs
Authors: Takagishi Toru , Hayashi Akiyo , Kuroki Nobuhiko
Published: April 2003

Polyvinylpyrrolidones of various degrees of cross‐linkage have been prepared by radical polymerization of N‐vinylpyrrolidone with methylenebisacrylamide to regulate the fraction of cross‐linkage. The insoluble polymers obtained were examined for their ability to bind methyl orange and its homologs, methyl orange, ethyl orange, propyl orange, and butyl orange at 5, 15, 25, and 35°C, respectively, in an aqueous solution. The first binding constants and the thermodynamic parameters that accompanied the binding were calculated. For any particular dye the extent of binding, the absolute magnitude of ΔF°, and the value of ΔS° increased as the degree of cross‐linkage increased, starting with water‐soluble polyvinylpyrrolidone (zero cross‐linkage) and proceeding to the polymer with high cross‐linking density. This behavior can be accounted for in terms of more extensive hydrophobic domains in the cross‐linked polymeric matrix that enhances hydrophobic interactions in the binding process. Moreover, the cross‐linked macromolecule polymerized in the presence of methyl orange and then stripped of the bound methyl orange shows substantially stronger binding for this small molecule than the polymer cross‐linked in the absence of methyl orange. In contrast, the cross‐linked polymer prepared similarly in the presence of the larger molecule, butyl orange, exhibits decreased affinity toward the smaller consolute, methyl orange, than either of the other polymers described. It seems, therefore, that the polymeric matrix provides favorable binding sites or pockets that can accommodate a specific small molecule. The preparative procedure, which uses a small‐molecule template, molds into the polymer some structural specificity in the binding of small molecules.
Vinyl polymerization initiated by peroxydiphosphate. VII. Polymerization of acrylonitrile initiated by peroxydiphosphate–ascorbic acid redox system
Authors: Lenka Subasini , Dhal Akshaya K.
Published: April 2003

The polymerization of acrylonitrile was studied with a peroxydiphosphate–ascorbic acid redox system as the initiator. The rate of polymerization increased with increasing peroxydiphosphate concentration and the initiator exponent was computed to be 0.5. It also increased with increasing monomer concentration and the monomer exponent was computed to be unity. The reaction was carried out at three different temperatures and the overall activation energy was computed to be 4.6 kcal/mol. The effect of certain surfactants on the rate of polymerization was investigated and a suitable kinetic scheme is described.
Exactly alternating silarylene‐siloxane polymers. 4. Step‐growth polymerization reactions with dichlorosilane monomers
Authors: Lai Yu‐Chin , Dvornić Petar R. , Lenz Robert W.
Published: April 2003

A series of alternating silarylene‐siloxane polymers of moderate molecular weights was prepared by the step‐growth polymerization reactions of 1,4‐bis(dimethylhydroxysilyl) benzene and three different dichlorosilanes: methylphenyldichlorosilane, dimethyldichlorosilane, and methylvinyldichlorosilane. The reactions were monitored by gel permeation chromatography (GPC). The polymers were characterized by 1H‐and 13C‐NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Polymers with number‐average degrees of polymerization ranging from 90 to 350, based on the use of polystyrene standards in GPC analysis, were obtained. For the two homopolymers and a series of copolymers that contained either or both dimethylsiloxyl and methylphenylsiloxyl units, the glass temperatures and thermal stabilities increased substantially with increasing methylphenylsiloxyl unit content.
γ‐Radiation‐produced supported metal complex catalysts. 3. Phosphinated polypropylene supports
Authors: Hartley Frank R. , Murray Stephen G. , Nicholson Philip N.
Published: April 2003

p‐Styryldiphenylphosphine was grafted onto polypropylene by γ‐radiation. However, olefinic phosphines in general do not readily undergo such grafting. Among the many other olefinic phosphines examined only 1‐(4‐diphenylphosphinophenyl)‐prop‐1‐ene and vinyldiphenylphosphine were grafted successfully and both had low grafting yields. The optimum conditions for grafting involve low dose rates and high total doses of γ‐radiation in dimethylsulfoxide as solvent. This grafting is sensitive to impurities and inhomogeneity in the product readily results, especially at high grafting yields. Oxygen must be rigorously excluded if oxidation of grafted phosphorus(III) to phosphorus (V) is to be avoided. Phosphine oxides can be reduced to phosphines when grafted to the polymer with trichlorosilane. Mass spectrometry has shown that more than one olefinic phosphine binds to a single site in the polymer. Solid‐state, high‐resolution 31P‐NMR is a valuable technique for characterizing the grafted polymer. The preparation and characterization of the following hitherto unreported phosphines is described:
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In addition, the precursor halides
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none of which has been reported, were prepared and characterized.
Reaction rate of crosslinkings by using a metallated polymer. II. Intermolecular and intramolecular crosslinkings at the second state
Authors: Ishizu Koji , Ino Kazuhide , Fukutomi Takashi , Kakurai Toshio
Published: April 2003

Lithium‐metallated styrene–p‐benzylstyrene copolymer was reacted with the branched polymer with chlorine groups at the pendant chain ends (multifunctional branched polymer) in tetrahydrofuran (THF) at 25°C. The rate constant was estimated from the changes in the concentration of metallated polymer by using photometrical measurements. The various reaction conditions were chosen and it became clear that the rate constants of intermolecular (k20) and intramolecular (k3intra) crosslinkings were derived separately at the second stage. k20 showed a constant value in spite of the molecular weight of crosslinker chains and was about equal to the rate constant of the grafting. The rate of intramolecular crosslinking at the second stage increased with decreasing the molecular weight of pendant chains of multifunctional branched polymer.
Polymerization of oriented monomers. VI. Polymerization of monomeric di(undecenyl) phosphate vesicles to stable polymeric vesicles
Authors: Paleos C. M. , Christias C. , Evangelatos G. P. , Dais Photis
Published: April 2003

The synthesis of a novel vesicle‐forming surfactant monomer, i.e., of di(undecenyl) phosphate is reported. Vesicles formed from this monomer were irradiated by γ rays for the production of polymeric vesicles. Polymerization was studied in conjunction with the model of the monomeric vesicles and the structure of the polymers was primarily studied with 1H‐NMR spectra. It was further established that polymerized vesicles retain the structure of their monomeric counterparts while exhibiting higher stability than the unpolymerized vesicles.
13N‐NMR spectroscopy. XXXV. Sequence analysis of alternating and random copolyamides made up of aliphatic and aromatic ω‐amino acids
Authors: Kricheldorf Hans R. , Joshi Sharda V. , Hull William E.
Published: April 2003

Alternating copolyamides of various ω‐amino acids were synthesized by base‐catalyzed polycondensation of N‐isothiocyanatoacyl ω‐amino acids in solution. Derivatives of the following amino acids were used: glycine, β‐alanine, γ‐aminobutyric acid, δ‐aminovaleric acid, ε‐aminocaproic acid, D,L‐β‐aminobutyric acid, trans‐4‐aminocyclohexane 1‐carboxylic acid, 4‐aminophenyl acetic acid, 3‐aminobenzoic acid, 4‐aminobenzoic acid, 3‐amino‐4‐methyl benzoic acid, and 4‐amino‐3‐methyl benzoic acid. The base‐catalyzed polycondensation at lower temperatures gave purer products than the bulk condensation at 180–200°C. 13C‐NMR and natural‐abundance 15N‐NMR spectra measured in trifluoroacetic acid demonstrate that in most cases undisturbed alternating sequences were obtained. Strong neighboring residue effects and long‐range sequence effects were found in the 15N‐NMR spectra, and structure/shift relationships are discussed. The sequences of copolyamides obtained by copolymerizations of lactams or β‐amino acid N‐carboxyanhydrides were investigated by both 15N‐NMR and 13C‐NMR spectroscopy. 13C‐NMR spectroscopy was found to be more useful if the copolyamides consist of ω‐amino acid units of different chain length. However, 15N‐NMR spectroscopy is more suited if the monomer units differ exclusively by their substituents.
Grafting polyesters onto carbon black. I. Polymerization of β‐propiolactone initiated by alkali metal carboxylate group on the surface of carbon black
Authors: Tsubokawa Norio , Funaki Akira , Hada Yukio , Sone Yasuo
Published: April 2003

By use of carbon black that contained alkali metal carboxylate (COOM; MLi, Na, K, Rb, or Cs) group as catalyst the anionic polymerization of β‐propiolactone (PL) was carried out at 50°C and the grafting of polyester onto the carbon black surface was investigated. Carbon black that contained COOM group was prepared by the reaction of carboxyl group on the surface with corresponding alkali metal hydroxide and was able to initiate the anionic ring‐opening polymerization of PL. The carbon black obtained from the reaction gave a stable colloidal dispersion in an organic solvent. It was confirmed that the polyester formed was grafted effectively onto the surface; for instance, by using carbon black that contained COOK group as catalyst the grafting ratio was increased to 145% (viz., 1.45 g of polyester was grafted/1 g of carbon black) with an increase in conversion. Furthermore, the effect of alkali metal countercation (M+) on the polymerization was studied. The initiating activity of COOM group on the surface increased in the following order: COOLi < COONa < COOK < COORb < COOCs. This order was in agreement with that of increasing electropositivity of these alkali metals.
Study of the curing of an acetylene‐terminated polyphenylene resin with thermal expansion measurements
Authors: Baise A. I.
Published: April 2003

The curing of an acetylene‐terminated polyphenylene resin (Hercules H‐Resin) was followed by thermal expansion measurements. This approach proved useful in optimizing the curing conditions of the resin. Curing the polymer in air led to the formation of carboxyl groups, whereas curing under nitrogen did not. The thermal expansion coefficient is a minimum (32 ppm deg−1) for a cure cycle of 250°C for 30 min, followed by 350°C for 30 min. Heating at temperatures above 350°C led to degradation of the crosslinked polymer and an increase in the thermal expansion coefficient.
Influence of monomer composition on certain factors affecting the light‐transmitting properties of MBS terpolymers
Authors: Karaenev S. S. , Chilingirjan M. K.
Published: April 2003

This article is a report of the investigation of the influence of monomer composition within optimum limits on the light‐transmitting properties of MBS terpolymers obtained by the mass‐suspension method. The high and nearly constant light‐transmitting properties of the MS copolymer matrix have no effect on the light‐transmitting properties of MBS with a MMA content up to about 20 mol % higher than that at the azeotropic point. The refractive index of the MS copolymers decreases uniformly as the mole ratio of MMA increases and becomes equal to the index of the SBR. Particle concentration in sizes up to 0.6μm increases as the MMA content increases to a given point at which the concentration remains constant as MMA continues to increase. The light‐transmitting properties of MBS with a MMA content of 57 mol % are improved significantly. This fact is explained by a decrease in variation on the refractive index between the two phases to 0.0014 and by the increasing percentage of particles with sizes smaller than 0.6 μm up to 70%.
Comparisons of glow‐discharge polymerizations among tetramethylsilane, dimethyldimethoxysilane, and tetramethoxysilane
Authors: Inagaki N. , Koyama M.
Published: April 2003

Glow‐discharge polymerizations among tetramethylsilane, dimethyldimethoxysilane, and tetramethoxysilane were compared by elemental analyses and infrared spectroscopy. The elemental composition of the polymers prepared from the three monomers depended strongly on the operational conditions necessary to sustain a glow discharge, i.e., the W/FM parameter, where W is the rf power, F is the flow rate of the monomer, and M is the molecular weight of the monomer. Methoxy groups were more susceptible to glow discharge than methyl groups. Differences in chemical structure among these monomers appeared in the polymer structures formed when the glow‐discharge polymerization was carried out at a low value of the W/FM parameter, while the differences disappeared at high values of the W/FM parameter, for analogous polymers. Substitution with methoxy groups was favorable for the formation of polymers of low carbon content only when the glow‐discharge polymerization was performed at low values of W/FM.
Preparation of viologen polymers from alkylene dipyridinium salts by cyanide ion
Authors: Ageishi Kentaro , Endo Takeshi , Okawara Makoto
Published: April 2003

Polymers of viologen structure were prepared by oxidation of quinoid polymers obtained by the dimerization of alkylene dipyridinium salts with cyanide ion as catalyst. These polymers showed the behavior of polyelectrolytes and redox polymers that turn a deep blue when reduced chemically or electrically.
Siloxane‐containing polyenaminoesters
Authors: Moore J. A. , Mitchell T. D.
Published: April 2003

Polyenaminoesters were prepared by condensation of succinyl succinic ester (SSE) and p‐bis‐carbomethoxy diacetyl benzene (CDB) with 1,3‐bis(3‐aminopropyl)‐1,1,3,3‐tetramethyldisiloxane. Conditions of solvent and temperature were discovered which yielded soluble polymer from SSE after heat treatment. CDB yields only tough, rubbery, insoluble products.
Distributions in nonself‐condensing polycondensations: A kinetic approach
Authors: Stafford J. W.
Published: April 2003

The size distributions of a number of different polycondensations with nonself‐condensing monomers were calculated by a kinetic method. The results of linear polycondensations with and without reversibility or stoichiometry and of multifunctional polycondensations are exactly the same as those obtained by Flory with probability methods and do not differ, when comparable, from the size distributions produced by the polycondensation of self‐condensing monomers. Size distributions were also obtained for reactions in which the order of reaction changes with conditions or during reaction. These results clearly show that a Flory distribution is obtained as long as the principle of equal reactivity applies at any given instant, although this reactivity may vary in the course of the reaction.
Metal‐containing coordination polymers. XIV. Relations between the structure and the melt viscosity of polyesters containing Mg ions
Authors: Vancsó‐Szmercsányi I. , Székely‐Pécsi Zs.
Published: April 2003

Rheological properties of coordination polymers formed in the reaction of low‐molecular‐weight (about 1000) polyesters with MgO were studied. The melt viscosity and activation energy of viscous flow were measured as functions of Mg content and temperature. Rheological behavior was discussed in view of the chemical structure of these systems and correlated with qualitative and quantitative conditions of the coordination bonds. Melts of Mg complexes of amorphous and semicrystalline polyesters showed identical rheological results.
HCN evolution from thermal and oxidative degradation of poly(diphenyl methane pyromellitimide) at high temperatures
Authors: Jellinek H. H. G. , Dunkle S. R.
Published: April 2003

HCN evolution from thermal and oxidative degradation of poly(diphenyl methane pyromellitimide) has been investigated over a range of temperatures from 500 to 1000°C; rate constants and Arrhenius equations have been determined. Kinetics and mechanisms have been proposed and quantitatively evaluated. They account well for the experimental results. The rate determining steps are CN scission for thermal degradation and H abstraction from the methylene bridge by O2 for oxidative degradation, respectively. At high temperatures, oxidation and thermal decomposition of the evolved HCN take place on its passage through the hot zone of the furnace in the highest range of temperatures (800–1000°C). Additional HCN is produced (>800°C) from the char obtained during thermal and oxidative degradation.
Gamma radiation‐initiated polymerization of styrene at high pressure. III. Emulsion polymerization with anionic emulsifiers
Authors: Moore P. W. , Clouston J. G. , Chaplin R. P.
Published: April 2003

Values calculated for the activation volume for chain propagation, ΔV, for the polymerization of styrene in emulsions under a variety of conditions agree closely with that previously obtained in pure styrene (ΔV = −18.6 cm3 mol−1). The rate of initiation of emulsion polymerization by radicals produced in the water phase was independent of pressure; therefore ΔV is zero. This differs from initiation in pure styrene which is slightly retarded by pressure (ΔV = 2.0 cm3 mol−1). The activation energy for the reaction in emulsion, as in pure monomer, decreases slightly with pressure. Chain transfer to monomer occurs to a much greater extent in emulsions than in pure monomer under similar temperature and pressure conditions. Values for the dependence of the polymerization rate on the initiator (i.e., the irradiation dose rate) and emulsifier concentration are consistent with Smith–Ewart, Case II kinetics.
Diaminobipyridine‐TDI polyureas: Synthesis, metal complexes, and catalytic activity
Authors: Zhang Keda , Neckers D. C.
Published: April 2003

In this article we report the synthesis of a polyurea containing the chelating ligand bipyridine and concentrate on some of the catalytic properties of its palladium complexes.
Preparation of aromatic polyesters by the direct polycondensation reaction with diphenyl chlorophosphate in pyridine
Authors: Higashi Fukuji , Hoshio Atsushi , Kiyoshige Jun
Published: April 2003

The direct polycondensation reaction of diphenyl chlorophosphate (DPCP) as a new condensing agent in pyridine was used for the preparation of polyarylene esters. High‐molecular‐weight polymers can be prepared by reacting a pyridine solution of dicarboxylic acids and DPCP in the presence of LiCl, followed by treating with a pyridine solution of bisphenols. About an equivalent of LiCl, and 30 mol % excess of DPCP were most favorably added. Effects of the initial reaction of the acids and DPCP, and of dropwise addition of bisphenols on the polycondensation were investigated. Polycondensations of several hydroxybenzoic acids were also carried out with limited success.
Radical copolymerization of acrylic monomers. V. Copolymerization of ortho‐ and para‐chlorophenyl acrylates with methyl methacrylate
Authors: San Román J. , Madruga E. L. , Del Puerto M. A.
Published: April 2003

The radical copolymerization of phenyl, ortho‐chlorophenyl, and para‐chlorophenyl acrylates with methyl methacrylate has been studied at low conversions. The reactivity ratios of these comonomeric pairs have been determined by the application of Fineman–Ross and Kelen–Tudös methods, and the inherent reactivities of phenyl acrylate derivatives toward methyl methacrylate radicals seem to be related to their availability of forming π complexes with methyl methacrylate. The scheme Q‐e for these systems clarifies that the higher the polar factor e of the phenyl acrylate derivative, the higher reactivity of the corresponding monomer. The stereochemistry of the prepared copolymers has been studied by NMR spectroscopy. In the analysis of the α‐CH3 resonance signals, considering methyl‐methacrylate‐centered triads, it becomes apparent that the introduction of ring aromatic substituents in the copolymer chains changes appreciably the tacticity of poly(methyl methacrylate).
Grafting of living poly(ethylene oxide) onto polystyrene via aromatic nucleophilic displacement of activated nitro groups
Authors: Shalati Mohamad D. , Overberger C. G.
Published: April 2003

Polystyrene of M̄ω = 2.2 × 104 was alkylated with 4‐nitrophthalimidomethyl groups as grafting sites. Several backbone polymers with various degrees of grafting sites (G = 2–100%) were prepared and characterized by elemental analysis, IR, 1H‐ and 13C‐NMR, and viscosity measurements. “Living” poly(ethylene oxide) with narrow molecular‐weight distribution was prepared in the presence of 15‐crown‐5, and grafted onto the 4‐nitrophthalimidomethylated polystyrene. The nitro displacement reaction was fast and the grafting yield was quantitative (100%). The graft copolymers are highly soluble in water and in organic solvents. The intrinsic viscosities of the graft copolymers are higher than those of the backbone polymers. The intrinsic viscosities show an initial increase followed by a decrease as the degree of grafting increase.
Photopolymerization initiated by charge‐transfer complex. VI. Photopolymerization of methyl methacrylate with the use of isoquinoline–chlorine charge‐transfer complex
Authors: Lenka Subasini , Nayak Padma L. , Nayak Sanjay K.
Published: April 2003

Polymerization of methyl methacrylate in visible light was studied at 30°C using the isoquino‐line–chlorine charge‐transfer complex as the photoinitiator. Analyses of kinetic and other data indicate that the polymerization proceeds via a radical mechanism and the termination is initiator dependent. Chain termination via degradative chain (initiator) transfer appears to be significant.
300‐MHz 1H‐NMR spectra of p‐cresol‐formaldehyde condensates having regular repeating structures
Authors: Tong S. N. , Park Kyung Y. , Harwood H. James
Published: April 2003

Model p‐cresol‐formaldehyde condensates having regular sequences of methylene ether and methylene linkages were prepared by the self‐condensation of dimethylol derivatives of p‐cresol‐formaldehyde condensates (2‐hydroxy‐5‐methyl‐1,3‐benzenedimethanol, 3,3′‐methylene‐bis[2‐hydroxy‐5‐methylbenzenemethanol] and 3,3′‐[(2‐hydroxy‐5‐methyl‐m‐phenylene)dimethylene]‐bis[2‐hydroxy‐5‐methylbenzenemethanol]). 300‐MHz 1H‐NMR spectra of these polymers and of their acylated derivatives were recorded and used to develop resonance assignments for the various types of protons present in these polymers. The spectra were found to be sensitive to end‐group and sequence distribution effects.
Plasma polymerization of trifluoromethyl substituted aromatic compounds
Authors: Diaz A. F. , Hernandez R.
Published: April 2003

Thin film coatings were prepared by polymerizing trifluoromethyl‐substituted aromatic compounds in a glow discharge with low power levels and medium pressures. Smooth, continuous films which are adherent and insoluble in conventional solvents were produced. A significant amount of the fluorine content from the monomer was retained in the polymer. The trifluoromethyl group was not removed by the plasma conditions and appeared in the film as trifluoromethyl and difluoromethylene groups. The films were slightly less wettable than those of the unfluorinated films.
Preparation and properties of N‐phenylated aromatic polyamides from N,N′‐diphenyl‐p‐phenylenediamine and aromatic diacid chlorides
Authors: Imai Yoshio , Hamaoka Nobuo , Kakimoto Masa‐Aki
Published: April 2003

N‐Phenylated aromatic polyamides and copolyamides derived from N,N′‐diphenyl‐p‐phenylenediamine, isophthaloyl, and terephthaloyl chloride were prepared by high‐temperature solution polycondensation in anisole at 155°C. Factors that influenced the reaction, such as monomer concentration, solvent, temperature, and time, were studied to determine the optimum conditions for the preparation of high molecular weight polymers. Compared with analogous unsubstituted aromatic polyamides, the N‐phenylated polymers exhibited better solubility in chlorinated and amide solvents, reduced crystallinity, and lower glass transition temperatures (above 200°C). All polymers except the polyterephthalamide could be solvent‐cast, as well as hot‐pressed, into transparent flexible films.
Preparation and some properties of nylon‐4,2
Authors: Gaymans R. J. , Venkatraman V. S. , Schuijer J.
Published: April 2003

An attempt was made to produce a new short‐chain alphatic polyamide nylon‐4,2. This polyoxamide can be prepared by polycondensation of tetramethylene diamine and diethyl oxalate. A high molecular weight polymer (ηinh = 1.9 from 0.5% solutions in 96% sulphuric acid) has been obtained by employing a two‐step polycondensation method; the precondensation was carried out in solution at low temperatures (20–140°C) and the postcondensation in the solid state at high temperatures (250–300°C). The effect of solvent composition and reaction temperature on the prepolymerization and the effect of reaction time and temperature on the postcondensation was studied. We also investigated the influence of moisture during washing, storing, and the solid‐state reaction on the polymerizability by the postcondensation. Nylon‐4,2 is soluble only in highly polar solvents such as trifluoroacetic acid (TFA), dichloroacetic acid, and 96% sulphuric acid. Films were cast from TFA. With these films we studied the IR spectrum, WAXS pattern, water absorption, and melting behavior. Nylon‐4,2 was found to melt at 388–392°C, has a crystallinity of 70%, and a low water absorption (3.1% at 50% RH). The glass transition temperature of the dry sample was found to be at ∼120°C and for the wet sample at −15°C.
Vinyl polymerization. 422. Initiation mechanism of uncatalyzed polymerization by polyethyleneglycol
Authors: Ouchi Tatsuro , Hosaka Yoshifumi , Imoto Minoru , Konaka Ryusei
Published: April 2003

The initiation mechanism on the radical polymerization of vinyl monomers by polyethyleneglycol (PEG‐300) in aqueous solution was studied. The initiating radical species were determined by means of the spin trapping technique. They were concluded to be generated by the hydrogen atom transfer from the monomer adsorbed at the ether group of PEG‐300 to the free monomer.
Preparation of silicon containing polymers. II.. Effect of structure on the thermal stability of organosilicon aramids
Authors: Ghatge N. D. , Jadhav J. Y.
Published: April 2003

Two silicon‐containing acid dichlorides, bis(4‐chlorocarbonylphenyl)dimethylsilane and bis(4‐chlorocarbonylphenyl)diphenylsilane, were synthesized and reacted with 1,3‐phenylene diamine, 1,4‐phenylene diamine, 4,4′‐diaminodiphenyl, 4,4′‐diaminodiphenyl methane 4,4′‐diaminodiphenyl ether, and 4,4′‐diaminodiphenyl sulfone in the preparation of 12 structurally different high molecular weight aromatic polyamides. A low‐temperature interfacial polycondensation technique was used. Most of the polyamides formed tough, transparent, flexible films and were characterized by solubility, solution viscosity, infrared spectroscopy (IR), and glass transition temperature (Tg). The thermal behavior of these aramids was studied by dynamic thermogravimetry. The effect of diamine and acid dichloride structure on the aramids properties is also discussed.
Polymerization of trimethylsilylacetylene by WCl6‐based catalysts
Authors: Okano Yoshimichi , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

The polymerization of trimethylsilylacetylene was investigated by using W and Mo catalysts. Mixtures of WCl6 with appropriate organometallic cocatalysts such as n‐Bu4Sn and Et3SiH at 1:1 molar ratio provided poly(trimethylsilylacetylene) in high yields. On the other hand, MoCI5 gave mainly methanol‐soluble oligomers even in the presence of these cocatalysts. The polymer formed was a partly insoluble yellow powder, and the molecular weight of the soluble fraction was about 7000. The IR, 1H‐NMR, and 13C‐NMR spectra supported the polymer structure, (CH = CSiMe3)n. Protodesilylation of poly(trimethylsilylacetylene) afforded a new polymer containing both acetylene and trimethylsilylacetylene units.
Preparation and characterization of p‐toluene sulfonyl ester and amino derivatives of tri‐ and poly(ethylene glycol)
Authors: Swamikannu A. Xavier , Litt Morton H.
Published: April 2003

Methods described in the literature are inadequate for the preparation of pure polyethylene glycol (PEG) tosylate. Therefore an improved method is presented. The hydroxyl groups on PEG can be quantitatively converted into the tosylate and isolated from the reaction medium free from impurities with no chain cleavage or reduction in molecular weight. 1,2‐Di(N‐phenyl 2‐aminoethoxy) ethane, α,ω‐di(N‐phenyl 2‐aminoethyl) poly(oxyethylene), and α,ω‐di(N‐phenyl, N‐benzyl 2‐aminoethyl) poly(oxyethylene) were prepared from the tosylates of tri‐ and poly(ethylene glycol)s and the corresponding primary and secondary aromatic amines.
Polymerization initiated by ylide: Polymerization of ethyl methacrylate with the use of 4‐picolinium p‐chloro phenacylide as initiator
Authors: Tewari R. S. , Awasthi A. , Srivastava A. K. , Kumar M.
Published: April 2003

The ylide 4‐picolinium, p‐chloro phenacylide‐initiated thermal polymerization of ethyl methacrylate (EMA) was studied. 4‐Picolinium p‐chloro phenacylide induces the thermal polymerization of ethyl methacrylate at 65°C. The rate of polymerization (Rp) rose as the initiator concentration increased from 2 × 10−3 to 4 × 10−3 M and the initiating exponent was computed as 1.9. The Rp decreased as the concentration of ylide increased from 6 × 10−2 to 1M. The greater initiator concentration also affected the molecular weight inversely. The polymerization was carried out at different temperatures and the overall activation energy was computed as 4.08 Kcal/mol. Polymerization was inhibited in the presence of hydroquinone as a radical scavenger. Kinetic studies and other data show that the overall polymerization takes place in a radical mechanism. The various kinetic parameters, such as the rate and average degree of polymerization, molecular weight, and energy of activation of the present system, were evaluated.
Ring‐opening polymerization of anhydro‐deoxy‐sugar derivative and chemical synthesis of stereoregular 2‐deoxy‐(1 → 6)‐α‐D‐arabino‐hexopyranan
Authors: Hatanaka Kenichi , Kanazawa Shuji , Uryu Toshiyuki , Matsuzaki Kei
Published: April 2003

The cationic, ring‐opening polymerization of 1,6‐anhydro‐3,4‐di‐O‐benzyl‐2‐deoxy‐β‐D‐arabino‐hexopyranose (ABDA) (=1,6‐anhydro‐3,4‐di‐O‐benzyl‐2‐deoxy‐β‐D‐glucopyranose) was investigated with Lewis acid as catalyst. Phosphorus pentafluoride at −78°C caused polymerization to a highly stereoregular (1 → 6)‐α‐linked polysaccharide. Effects of C‐2 substituent on the polymerization of 1,6‐anhydro sugar are discussed. In addition, copolymerization of ABDA (M1) with 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐β‐D‐glucopyranose (LGTBE, M2) was studied. The monomer reactivity ratios calculated by the Kelen‐Tüdös method were r1 = 4.46 and r2 = 1.66. Debenzylation of the polymer produced 2‐deoxy‐(1 → 6)‐α‐D‐arabino‐hexopyranan in which every repeating unit contained two free hydroxyl groups.
Polymerization of vinylcarbazole on copper(II)‐13X molecular sieves: Role of copper(II) salts
Authors: Biswas Mukul , Banerjee Madhusudan , Maiti Mrinal M.
Published: April 2003

Copper(II)‐exchanged‐13X molecular sieves, prepared from four copper(II) salts, namely, sulfate, nitrate, chloride, and acetate, and their activities in the polymerization of N‐vinylcarbazole at a fixed copper ion exchange level were studied. From the kinetic characteristics of polymerization it was established that the variation in activities of the Cu‐exchanged sieves is due primarily to the difference in the pH of the original salt solution, which is responsible for the varying degree of proton exchange with the zeolite during copper ion exchange. A first‐order dependence of the rate of polymerization was observed with respect to H+ ion concentration of the original copper‐salt solution. It was further established that the rate of polymerization of exchanged copper ion, at a hypothetical zero proton concentration, is low. A mechanism of polymerization of NVC on copper‐exchanged‐13X zeolite was suggested on the basis of the results obtained.
Differential scanning calorimetry studies of irradiated polyethylene: II. The effect of oxygen
Authors: Zoepfl F. J. , Markovic V. , Silverman Joseph
Published: April 2003

The effect of absorbed doses of ionizing radiation up to 2MGy in the presence of air on the melting behavior of high‐ and low‐density polyethylene was analyzed from data obtained by differential scanning calorimetry. Thermal measurements were made during the first melting after irradiation. The first melting temperature of polyethylene irradiated in air decreased with increasing absorbed dose. Above approximately 0.6 MGy bimodal endotherms were observed for high‐density polyethylene. The heat of fusion remained unchanged after irradiation in air for absorbed doses of less than 2 MGy. Bimodal endotherms were not obtained for low density polyethylene samples irradiated in air. The changes in melting temperature and the appearance of bimodal endotherms are related to the radiation chemistry of polyethylene in the presence of oxygen.
Functional monomers and polymers. CIV. Synthesis and properties of oligomer models of polyethyleneimine derivatives with spacer‐separated nucleic acid bases
Authors: Sakuma Yo , Inaki Yoshiaki , Takemoto Kiichi
Published: April 2003

A series of polyethyleneimine derivatives and their oligomer models with pendant thymine or adenine bases separated by β‐alanyl groups as spacers were prepared by an activated ester method. To elucidate the nature of intramolecular interaction of thymine and adenine bases ultraviolet (UV) spectrophotometric studies were undertaken for the series of compounds and the results were compared with those obtained for the corresponding oligomers without spacers. In the thymine derivatives, the nature of the intramolecular interaction resembled that of the corresponding compounds without β‐alanyl units, although larger hypochromicities were found in the series with β‐alanyl units. In the adenine derivatives, contrary to the corresponding thymine systems, UV hypochromicities of the compounds decreased by incorporation of the spacer group into side chains. It became evident that the intramolecular interaction of adenine bases was due to stacking neutral species, hydrogen bonding, and residual hypochromicity for the protonated species.
Reactive crystals. IV. Crystalline state photopolymerization of 5,5′‐1,4‐phenylene‐bis(2‐cyano‐2,4‐pentadienoic acid) derivatives
Authors: Nakanishi Fusae , Arai Masami , Nakanishi Hachiro
Published: April 2003

5,5′‐1,4‐Phenylene‐bis(2‐cyano‐2,4‐pentadienoic acid) derivatives were prepared. Many of this series of compounds were found to be polymerizable in the crystalline state by irradiation with light of wavelength λ > 340 nm. The polymers obtained contain a benzene and a cyclobutane ring in the main chain and have a cyanoacrylate as the side chain. They are crystalline and some of them are soluble in organic solvents. Photopolymerization was found to follow a stepwise mechanism. The polymerization process is separable into an oligomerization and a subsequent polymerization by controlling the wavelength of the irradiating light; an oligomer was obtained by an irradiating light; an oligomer was obtained by an irradiating light of wavelength λ > 430 nm.
Core‐shell emulsion copolymerization of styrene and acrylonitrile on polystyrene seed particles
Authors: Dimonie Victoria , El‐Aasser Mohamed S. , Klein Andrew , Vanderhoff John W.
Published: April 2003

Seeded emulsion copolymerization of an azeotropic composition of styrene (St) and an acrylinitrile (AN) comonomer mixture in polystyrene (PS) seed at different polymerization temperature of 55–75°C were investigated. The kinetic data showed a transition temperature at 65°C, above which the activation energy of polymerization is low, 6.1 Kcal/mol, compared with 9.8 Kcal/mol below it. The particle‐size results and thin layer chromatographic (TLC) data showed two types of particle of different composition and morphology in the final latex system: a smaller size of (St–AN) copolymer and a larger size of core‐PS and (St–AN) copolymer shell, with a zone of PS grafted (St–AN) copolymer in between. Various polymerization parameters, that is emulsifier concentration, type of seed particle and its size, and monomer/polymer ratio, were studied and their effects on particle size and particle morphology were examined. The percent of grafted core‐PS was 10% below a polymerization temperature of 65°C and 40% above that temperature. By adjusting the size and number of the seed particles, monomer‐polymer ratio, and emulsifier concentration conditions were established in which a final copolymer latex with “perfect” core‐shell morphology was achieved.
Insitu dehydro‐oligomerization of castor oil, fatty acid ester into esters of dimer and oligomer acids over molybdenum oxide on silica‐alumina catalyst
Authors: Kumar V. G. , Venkatachalam S. , Rao K. V. C.
Published: April 2003

A process is described for the conversion of methylricinoleate, the major castor oil, fatty acid ester, directly into esters of dimer and oligomer acids by using molybdenum oxide on a silica–alumina catalyst. The dehydration of the methylricinoleate into a corresponding mixture of conjugated and nonconjugated olefins and the oligomerization reaction took place side by side in a continuous column, fixed‐bed reactor. The products are characterized by IR, 1H NMR, and MS. The fragmentation pattern in the mass spectrum of the dimeric species distilled from the mixture reveals that the product contains cyclic and acyclic isomeric structures. The mechanism of dimerization and oligomerization reactions to transition metal complexes and transition metal oxide catalyst systems is reviewed briefly and the possibility of a common mechanism for all similar systems is suggested. A general mechanism for oligomerization reactions to similar catalysts is proposed and the products of the present reaction are explained on the basis of the proposed mechanism.
Preparation and characterization of plasma‐polymerized styrene thin films
Authors: Prohaska G. W. , Johnson E. D. , Evans J. F.
Published: April 2003

Plasma‐polymerized styrene (PPS) thin films (several hundred to several thousand Å thick) have been prepared under a variety of discharge conditions in a tubular reactor inductively coupled to a radio frequency (13.56 MHz) power supply. Studies have focussed on the correlation of deposited polymer structure, evidenced both at the film surface (via XPS analysis) and in the bulk polymer (via transmission FT–IR analysis) with controllable plasma parameters (coupled rf power, monomer flow rate, monomer pressure). It has been determined that the relative number of phenyl rings incorporated into the film intact is an inverse function of the power per styrene molecule ratio. Polymer deposition rate was found to be a strong function of styrene flow rate and substrate temperature. Plausible elements of the styrene plasma polymerization mechanism will be considered.
Dual functional catalysis for ethylene polymerization to branched polyethylene. I. Evaluation of catalytic systems
Authors: Beach David L. , Kissin Yury V.
Published: April 2003

Synthesis of low‐density polyethylene, that is, a density of less than 0.925 g/cm3, has traditionally been accomplished by the use of free‐radical initiators at high ethylene pressures or of an alpha olefin comonomer such as 1‐butene at lower pressures. We investigated an alternative route to branched, low‐density polyethylene with a single monomer, ethylene, as the feed in conjunction with multicomponent catalyst systems capable of in situ dimerization of ethylene and subsequent copolymerization to produce low‐density polyethylene. This article discusses the details of the evaluation of a number of dual‐functional systems based on Ziegler‐Natta catalysts. Specific, well defined, dual‐functional catalyst systems which could easily produce branched, low‐density polyethylene with levels of 20–30 branches per 1000 carbon atoms were developed. Variations in the relative number of component catalysts resulted in systematic, predictable changes in the properties of the polyethylene produced, which demonstrated the utility of the dual‐functional catalyst concept.
Thermal stability of the silica‐aminopropylsilane‐polyimide interface
Authors: Linde H. G. , Gleason R. T.
Published: April 2003

Thermal degradation of the silica–aminopropylsilane–amic acid/imide interface was studied by modifying a high‐surface‐area, neutral silica gel with a number of substituted aminopropylsilanes (APS). These substrates were reacted further with phthalic anhydride or aromatic amic acid monomers and the thermal decomposition of the adsorbed/reacted materials was monitored by thermogravimetric analysis (TGA) and infrared (IR) spectroscopy. The 3‐aminopropyltriethoxysilane/poly[N,N′‐(p,p′‐oxydiphenylene)pyromellitimide] interface was also evaluated by this method.

Comparison clearly distinguishes the thermal decomposition of surface‐bound APS from surface‐bound alkylphthalimides, the adhesion product of alkylamines and aromatic amic acids. Alkylamine imidization with the elimination of aromatic amine (analogous to polymer scission) and the decomposition of the surface‐bound imide are shown in the amic acid TGA profiles. This imidization and the accompanying aniline elimination begin at about 130°C, under nitrogen, to form the surface alkyl imide which slowly decomposes at 400°C. TGA analysis indicates that the surface‐bound imide undergoes minimal degradation under nitrogen at 370 ± 10°C; temperatures above this threshold range produce changes in the APS–imide interface.
Synthesis and characterization of nadimidized 1‐[(dialkoxyphosphinyl)methyl1]‐2,4‐ and ‐2,6‐ diaminobenzenes and their polymerization to fire‐resistant laminating resins
Authors: Mikroyannidis John A.
Published: April 2003

A series of nadimidized 1‐[(dialkoxyphosphinyl1)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes was prepared and polymerized thermally to yield highly crosslinked fire‐resistant laminating resins. Bisnadimides were characterized by elemental analysis and Fourier‐transform‐infrared (FT–IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. Curing behavior of the polymer precursors was studied by differential scanning calorimetry (DSC). Char yield of polymers at 700°C was 64–69% and 30–60% in nitrogen and air atmospheres, respectively. The pyrolysis behavior of some bisnadimides was investigated by gas chromatography–mass spectroscopy (GC–MS). Cyclopentadiene was evolved by retrograde Diels–Alder reaction during processing, but most was captured by copolymerization. The fire‐resistance of some polymers was evaluated by determining their limiting oxygen index and smoke evolution.
Preparation and luminescence properties of tris(bipyridine) ruthenium(II)‐containing vinyl polymers: Ru(bpy)2 (poly‐6‐vinyl‐2,2′‐bipyridine)Cl2 and Ru(bpy)2(poly‐4‐methyl‐4′‐vinyl‐,2,2′‐bipyridine)Cl2
Authors: Sumi Katsuhiro , Furue Masaoki , Nozakura Shun‐Ichi
Published: April 2003

Ruthenium (II) complex‐containing polymers were prepared and characterized by absorption and luminescence spectra, luminescence quantum yield, and luminescence lifetime. The polymers are Ru(bpy)2(poly‐6‐vinyl‐2,′2‐bipyridine)CI2 (1) and Ru(bpy)2(poly‐4‐methyl‐4′‐methyl‐4′ ‐vinyl‐2,2′‐bipyridine)CI2 (2). The absorption spectra and luminescence spectra of polymers 1 and 2 were substantially the same as that of Ru(bpy)3CI2. The lifetime of polymers 1 and 2 was similar to that of the respective monomer model compounds. The lifetime of polymer 1 was very short (ca. 13 ns) in comparison to Ru(bpy)3CI2 (660 ns), whereas the lifetime of polymer 2 (660 ns) was similar to that of Ru(bpy)3CI2. The temperature‐dependency of the lifetime was discussed in terms of Watts' model.
Polymerization of vinyl monomers in the water–1,4‐dioxane system containing peroxide and water‐soluble polymer
Authors: Nonaka Takamasa , Tagawa Rikiichi , Nishida Haruo , Egawa Hiroaki
Published: April 2003

Water‐solube polymer (PST) containing triethylenetetramine side chain was prepared by the amination of chloromethylated polystyrene with triethylenetetramine in 1,4‐dioxane. The polymerization of vinyl monomers was carried out in the water–organic solvent system containing PST and a very small amount of peroxide. The polymerization of methyl methacrylate proceeded smoothly in the presence of both peroxide and PST. It was found that the polymerization was initiated with the radicals generated by the interaction between hydroperoxide and amino groups of PST. 1,4‐Dioxane hydroperoxide showed a high activity for the polymerization of methyl methacrylate. The maximum rate of the polymerization was observed at 60°C and in an approximately neutral solution. The addition of suitable amount of Cu(II) accelerated the polymerization of methyl methacrylate. The selective polymerization of vinyl monomers was observed in this system.
ESCA studies of metal‐containing plasma polymers. Part I. Incorporation of mercury into plasma‐polymerized perfluorobenzene
Authors: Munro H. S. , Till C.
Published: April 2003

ESCA was used to examine the structure and bonding of mercury‐containing, plasma‐polymerized perfluorobenzene. A maximum Hg:C stoichiometry, independent of distillation temperature and power but dependent on substrate temperature, was obtained. Comparison of the plasma polymers of perfluorobenzene and mercury‐containing perflurobenzene formed as a function of power, revealed that the C1s structure of the latter system was not due to the level of mercury incorporated but to sensitized reactions that developed from energy absorption by the mercury in the gas phase.
Hexakis(arylisocyano) derivatives of chromium(0) as initiators of vinyl polymerization: Steric effects
Authors: Hargreaves K.
Published: April 2003

The free radical polymerization of methyl methacrylate initiated by the hexakis (arylisocyano)chromium(0)‐CCl4 system has been studied for a number of derivatives in which both chlorine and methyl groups have been introduced into the benzene ring. It has been found that single substituents in the benzene ring, irrespective of position, have little effect on the activity of the system other than that which can be explained by the electronic effects of these substituents. However, where steric overcrowding occurs it has been shown that the rate of initiation is reduced considerably. This confirms the established mechanism of initiation for this type of derivative.
Radiation polymerization of acrolein at low temperatures
Authors: Kumakura Minoru , Kaetsu Isao
Published: April 2003

Radiation polymerization of acrolein in the presence of the additives such as 2‐hydroxyethyl methacrylate, acrylic acid, and water at low temperatures (0–78°C) was studied. The polyacrolein resulting from the polymerization gave a small particlelike microsphere (0.5–5 μm in diameter). The rate of the polymerization reaction of acrolein appeared to be accelerated by the addition of a small amount of 2‐hydroxyethyl methacrylate or acrylic acid. The particle size of the polyacrolein particle varied with the condition of the polymerization and increased or decreased with an increase in the addition concentration of 2‐hydroxyethyl methacrylate or acrylic acid.