bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism of alternating copolymerization of methyl methacrylate with styrene in the presence of diethylaluminum chloride
Authors: Zubov V. P. , Lachinov M. B. , Ignatova E. V. , Georgiev G. S. , Golubev V. B. , Kabanov V. A.
Published: April 2003

A kinetic study of the propagation mechanism of the alternating copolymerization of styrene (St) with methyl methacrylate (MMA) in the presence of a complexing agent (diethylaluminum chloride, DEAC) in bulk and in tetrachloroethylene solutions at a molar ratio DEAC/MMA = 0.5 has been carried out. It has been shown that the copolymerization is a chain radical process characterized by a short active‐center lifetime, bimolecular termination, and high rate of chain transfer to the complexed MMA. A kinetic scheme has been proposed for the propagation mechanism of alternating copolymerization in the presence of a complexing agent not requiring independent measurements of the equilibrium constant of complexation. It has been found that spontaneous and UV‐initiated copolymerizations in the system have different mechanisms of initiation and a common mechanism of propagation. The propagation proceeds by addition of single monomers as well as donor‐acceptor complexes of the comonomers to the propagation radicals, with the first mechanism being predominant. Inclusion of the monomers in the complex leads to an increase of the St reactivity and to a decrease of the MMA reactivity in propagation to the corresponding macroradicals in comparison with the reactivity of the free monomers. A number of kinetic and statistical parameters of the propagation reaction have been calculated.
Plasma polymerization. VI. An ESCA investigation of the RF plasma polymerization of perfluoro‐2‐butyl tetrahydrofuran
Authors: Clark D. T. , Abrahman M. Z.
Published: April 2003

Perfluoro‐2‐butyl tetrahydrofuran was polymerized by an RF glow discharge technique and detailed ESCA studies were made of the resultant films. The rate of film deposition was sensitively dependent on the W/FM parameter and the site of deposition. The ESCA data show that the molecular rearrangement accompanying plasma polymerization and the oxygen functionality is at a significantly lower level than the starting material. Under appropriate conditions plasma polymerization produces material with a C:F stoichiometry of 1:2, although the ESCA data show that the polymer is drastically different from PTFE. ESCA studies are also reported on thin films of the monomer studied at low temperature.
The chemistry and kinetic behavior of Cu‐Cr‐As/B wood preservatives. II. Fixation of the Cu/Cr system on wood
Authors: Pizzi A.
Published: April 2003

The kinetic behavior of a Cr6+/Cu2+ system in its reaction with wood has been elucidated. The same reactions with carbohydrates and lignin of wood for CrVI alone are still present. Approximately 20% of the copper is fixed to the guaiacyl units of lignin in the form of copper chromate; the remaining copper forms complexes with cellulose and mainly with the guaiacyl units of lignin. The CrVI/lignin guaiacyl unit complexes already found for the treatment of wood with CrO3 are still the main CrVI complexes formed. Copper chromate is present as [Cu(H2O)2(guaiacol)]CrO4(guaiacol) complexes, and CuCrO4 bridges between different guaiacyl units of the lignin network appear to be likely. Substantial interference of the Cu2+ ions in the second‐zone reactions of CrVI with wood occurs. The amount of CrVI and CrIII fixed onto lignin and cellulose compares well with experimental values. Rate constants, energies of activation, and Arrhenius equations of the various reactions have been obtained. The amount of Cu2+ interference in the reaction has also been calculated.
Quantitative NMR measurements in copolymers of vinylidene chloride and acrylonitrile: The effect of saturation and varying nuclear Overhauser enhancements
Authors: Henrichs P. M. , Hewitt J. M. , Schwartz L. J. , Bailey D. B.
Published: April 2003

Spin‐lattice relaxation times and nuclear Overhauser enhancements (NOE) for 13C nuclei in copolymers of acrylonitrile and vinylidene chloride were measured at 20.1 and 67.9 MHz. In the CCl2 region of the spectrum T1 and NOE values of the various resonances are equal within experimental error and are invariant to changes in composition. The T1 and NOE values of the CCl2 region, however, are not equal to those of the CH or CN region. As a result compositions cannot be calculated by direct comparison of the areas in the CCl2 region and either the CH or the CN region. Discrepancies can be corrected for the CH resonances by multiplication of the area by an empirical constant. A similar constant for the CN region is composition‐dependent at 20.1 and 67.9 MHz. A chemical shift anisotropy mechanism is postulated as important for relaxation of the CN resonances. The overall influence of variable T1 and NOE values on quantitative determination of polymer composition is considered.
Water‐soluble copolymers. IV. Random copolymers of acrylamide with sulfonated comonomers
Authors: McCormick C. L. , Chen G. S.
Published: April 2003

Random copolymers of acrylamide with sodium‐2‐sulfoethyl methacrylate and with sodium‐2‐acrylamido‐2‐methylpropane sulfonate were synthesized in aqueous solutions utilizing persulfate initiators. Copolymer compositions were determined by elemental analysis and by infrared spectroscopic methods. Monomer reactivity ratios were calculated using Fineman–Ross, Kelen–Tüdos, and/or Mayo–Lewis techniques at appropriate conversions. The copolymer microstructure, including mean sequence length distributions, was calculated from reactivity ratios. Membrane osmometry and viscometry measurements were utilized to estimate molecular weight and size. The large dimensions of these polyelectrolytes in aqueous solutions, as well as their inherent hydrogen bonding capacity and pseudoplasticity, make these copolymers excellent candidates for application as mobility control agents in enhanced oil recovery.
Exactly alternating silarylene–siloxane polymers. II. The condensation polymerization of arylenedisilanols and bisureidosilanes
Authors: Dvornic Petar R. , Lenz Robert W.
Published: April 2003

A new method for the preparation of exactly alternating silarylene–siloxane polymers by the low temperature step‐growth condensation polymerization reaction of arylenedisilanols and bisurei‐dosilanes in chlorobenzene was investigated. To obtain high molecular weight products 1H NMR spectroscopy and gel permeation chromatography were used to monitor the polymerization reaction. By using these procedures 12 different polymers were prepared from 1,4‐bis(dimethylhydroxysilyl)‐benzene, 4,4′‐bis(dimethylhydroxysilyl)phenyl ether, bis(1,1‐tetramethylene‐3‐phenylureido)‐dimethylsilane, and bis(1,1‐tetramethylene‐3‐phenylureido)‐methylvinylsilane monomers. The polymers were obtained in high yields, purities, and molecular weights.
Alternating copolymerization of α‐methylstyrene and maleic anhydride
Authors: Javni I. , Fleš D. , Vuković R.
Published: April 2003

Alternating copolymers of α‐methylstyrene (α‐MeSt) and maleic anhydride (MAn) were prepared by free‐radical‐initiated polymerization in bulk, benzene, or butanone as solvents. By applying the generalized model described by Shirota and co‐workers, the reactivity ratios k1c/k12 and k2c/k21 were calculated from the change of copolymerization rate with monomer feed at constant total monomer concentration. From the equation Rp = Rp(f) + Rp(CT) were calculated Rp(f) and Rp(CT), and it was found that in benzene the reaction proceeds predominantly by the addition of CT‐complex monomers, while in butanone, cross propagation of free monomers predominates. Termination occurs predominantly by homotermination of α‐MeSt macro free radicals, kt22, although the cross termination kt21 is also operative.
Soapless emulsion polymerization of methyl methacrylate in water in the presence of calcium sulfite
Authors: Arai Masahiko , Arai Kunio , Saito Shozaburo
Published: April 2003

A kinetic study performed on the polymerization of the MMA‐K2S2O8‐CaSO3‐H2O system shows that two different shapes of the time‐conversion curve were obtained according to the presence or absence of calcium sulfite powder in the reaction mixture. In the absence of the powder, the polymerization behavior is similar to that of the MMA‐K2S2O8‐H2O system reported earlier. An attempt was made to apply the kinetic model of the rate of polymerization and the self‐nucleation model of polymer particle formation in soapless emulsion polymerization to the present system. One is able to express the experimental time‐conversion curves reasonably well. The other can account for the number of polymer particles formed in polymerizations initiated with potassium persulfate alone or calcium sulfite alone but not that in polymerization initiated by both. In the latter case the rate of radical generation and the ionic strength were appreciably enhanced compared with the former. These enhancements might affect the mechanism of polymer particle formation; certain nucleations, such as an aggregative nucleation, might occur simultaneously in addition to the self‐nucleation. In the presence of the solid phase the time‐conversion curves were similar to that of emulsion polymerization rather than soapless emulsion polymerization, and the molecular weight of polymer formed was smaller than in the absence of the solid phase. It was shown experimentally that the rate of polymerization was remarkably enhanced by an increase in the solid content, whereas the molecular weight of polymer was only slightly affected. As a result, it is considered that calcium sulfite solid provides an important polymerization locus and probably also plays a significant role in radical generation.
Adhesive interface interactions between primary aliphatic amine surface conditioners and polyamic acid/polyimide resins
Authors: Linde H. G.
Published: April 2003

The interface reactions of 3‐aminopropyltriethoxysilane treated surfaces, with the polyamic acid/polyimide resin formed from pyromellitic dianhydride and oxydianiline, were defined in bulk reactant systems and by FTIR analysis on the surface layers of germanium internal reflection plates. Adhesion between these interfacial layers is the result of chemical bonding, which proceeds through initial carboxylate salt formation between the amino function of the silylated surface and the car‐boxylic acid present in the polyamic acid. Heating results in dehydration and amide formation, which is followed by preferential incorporation of the alkyl, surface‐bound amine (stronger base), over the aromatic polymer amine, in an imide linkage. Aromatic imides formed before or during thermal curing may also be preferentially opened in a modified Ing‐Manske reaction and reclosed to the more stable surface‐bound alkylimide. Apparently polymer scission at the aromatic amide linkages occurs in this adhesion process, preferentially bonding surface‐bound alkyl amines to one end of a shortened polymer chain.
Coenzyme models. 32. Catalytic activity of polymer‐bound thiazolium ions as estimated by flavin trapping technique
Authors: Shinkai Seiji , Hara Youichiro , Manabe Osamu
Published: April 2003

Three thiazolium‐containing polymers, Th‐7, Th‐33, and Th‐18‐Py [where Th‐x and Py mean x mol % thiazolium unit and pyridinium unit (54 mol %), respectively], were synthesized from partially p‐chloromethylated polystyrene. The catalytic activities of these polymer catalysts in acyloin condensation of aldehydes and decarboxylation of α‐keto acids were estimated kinetically by oxidative trapping of the key intermediate by flavin (flavin‐trapping technique). In aqueous solution at 30°C, the catalytic activity of Th‐18‐Py and Th‐33 in condensation of p‐chlorobenzaldehyde was comparable with that of the cationic‐micelle‐bound thiazolium ion, whereas Th‐7 and a monomeric thiazolium compound (N‐benzylthiazolium bromide) scarcely exhibited any catalytic activity. The catalysis of the polymer‐bound thiazolium ions was sensitively suppressed by increased ionic strength. These results suggest that the pendent thiazolium ion is activated by the relatively high charge density along the polymer chain: the cationic environment is able to facilitate dissociation of the thiazolium ion to the ylid form and deprotonation of the thiazolium‐aldehyde adduct to the key intermediate.
Synthesis and properties of poly(imide‐sulfonate)s
Authors: Choi Kil‐Yeong , Choi Sam‐Kwon
Published: April 2003

Polycondensations of N,N′‐bis(hydroxyalkyl)pyromellitic diimides, N,N′‐bis(hydroxyphenyl)‐pyromellitic diimides, N,N′‐bis(hydroxyalkyl)‐3,3′,4,4′‐benzophenonetetracarboxylic diimides and N,N′‐bis(hydroxyphenyl)‐3,3′‐4,4′‐benzophenonetetracarboxylic diimides with aromatic disulfonyl chlorides were carried out in pyridine to produce poly(imide‐sulfonate)s. The resulting polymers had inherent viscosities in the range of 0.25–0.38 dL/g. These poly(imide‐sulfonate)s were insoluble in common organic solvents and had relatively good thermal stability. The TGA data showed 10% weight losses at 253–365°C and residual weights at 500°C were 22–72% in nitrogen.
Studies on the kinetics of ceric–thiourea‐initiated aqueous polymerization of methyl methacrylate. I. Mechanistic features in moderately acid solution
Authors: Pramanick D. , Chatterjee A. K.
Published: April 2003

The kinetics of the aqueous polymerization of methyl methacrylate by a ceric‐thiourea initiator system in moderately acid solution (pH 2.15) was studied. The rate of polymerization was proportional to 0.41 power of ceric concentration, 0.32 power of thiourea concentration, and 1.18 power of monomer concentration. The degree of polymerization was smaller than expected from the rate of polymerization. Initiation efficiency was less than one. There was no evidence of any ceric ion termination in the concentration range of 2.50 × 10−4–2.00 × 10−3M studied. The results are explained in terms of partial primary radical termination; the principal mode of termination, however, was bimolecular.
Diffusion‐controlled vinyl polymerization. II. Limitations on the gel effect
Authors: Soh S. K. , Sundberg D. C.
Published: April 2003

It is frequently observed that the gel effect in vinyl polymerizations decreases in intensity at about the 50‐70% conversion level. This is apparent in both rate and molecular weight data. It is postulated that there should be a limitation on the decrease in the termination rate constant to explain this effect. As an extension of the general theory of chain length dependent termination behavior, a general treatment of the gel effect with a limiting value of the termination rate constant is presented. A specific model is proposed for this limited rate constant which is based on the simple consideration that as translational movement of macroradicals becomes increasingly difficult the contributions made by segmental motion derived solely from the propagation reaction will be the prevailing mechanism. The termination reaction changes from chain length dependent to chain length independent during this transition period.
Preparation and characteristics of photocross‐linkable poly(vinyl alcohol)
Authors: Ichimura Kunihiro , Watanabe Shoji
Published: April 2003

The reaction of poly(vinyl alcohol) with styrylpyridinium and quinolinium salts which contain formyl group produced water‐soluble photosensitive polymers. The sensitivity was high, although the content of the styryl groups was extraordinarily low. Spectroscopical studies revealed that the high sensitivity is due to the aggregation of photofunctional group in the polymer matrix which leads to cyclodimerization on exposure to ultraviolet (UV) light.
Mechanisms of pyrolysis for a specifically labeled deuterated urethane
Authors: Voorhees Kent J. , Lattimer Robert P.
Published: April 2003

The pyrolysis products of a model urethane prepared from trimethylolpropane (TMP) propoxylated with 3, 3, 3‐d3‐propylene oxide and PAPI have been extensively studied by gas chromatography in conjunction with electron‐impact, chemical‐ionization, and field‐ionization mass spectrometry. The isotope distributions for some of the lower‐molecular‐weight species (determined by electron‐impact and/or field‐ionization mass spectrometry) showed a greater amount of H/D mixing than was expected from previously postulated concerted mechanisms. The deuterium distributions of the higher‐molecular‐weight TMP species were, in general, consistent with previously described mechanisms. The results from this study support the proposal that pyrolytic degradation of urethanes occurs mainly by a systematic sequence of concerted reactions. However, the deuterium distributions in some compounds indicate that free‐radical reactions are important in the formation of some pyrolyzates.
Synthesis of aromatic polyamide‐phthalimidines from chloroformylphthalides and aromatic diamines
Authors: Imai Yoshio , Takahashi Takeyoshi , Ueda Mitsuru
Published: April 2003

New polymer‐forming monomers, 3‐benzylidene‐5‐chloroformylphthalide and 3‐benzylidene‐6‐chloroformylphthalide, were synthesized by the Perkin reaction of trimellitic anhydride with phenylacetic acid, followed by chlorination. The polycondensation of these monomers with aromatic diamines in N‐methyl‐2‐pyrrolidone at 200°C afforded aromatic polyamide‐phthalimidines having inherent viscosities of 0.2‐0.5 dL/g. All the polymers were readily soluble in m‐cresol, pyridine, dimethylformamide, and dimethyl sulfoxide. Glass transition temperatures of some of the polymers were in the range of 255–282°C. The polyamide‐phthalimidines began to lose weight at around 300°C in both air and nitrogen atmospheres, with 10% weight losses being recorded at 435–475°C in nitrogen by thermogravimetry.
Vinyl polymerization by lithium organocuprates
Authors: Han Y. K. , Park J. M. , Choi S. K.
Published: April 2003

Vinyl polymerizations initiated by lithium organocuprates under several conditions were investigated. It was observed that this catalyst was effective in the polymerization of specific monomers such as α,β‐unsaturated nitrile and carbonyl analogues. The rate of polymerization was rapid but retarded by the addition of pyridine, nitrobenzene, or hydroquinone. Polymerization of methyl methacrylate (MMA) with lithium di‐n‐butylcuprate as initiator produces predominantly isotactic poly(methyl methacrylate) (PMMA) in toluene. The overall activation energy was estimated as 3.5 kcal/mol deg. Lithium di‐n‐butylcuprate exerts a higher stereoregulating effect on the addition of monomers than other organolithium initiators. It is proposed that polymerization proceeds via a coordinated anionic mechanism.
Solvent effects on the synthesis of ion‐exchange membranes by radiation‐induced graft polymerization of methyl α,β,β‐trifluoroacrylate
Authors: Omichi Hideki , Okamoto Jiro
Published: April 2003

Methyl α,β,β‐trifluoroacrylate (MTFA) was grafted onto polyethylene (PE) film and fluorine‐containing films to make ion‐exchange membranes. In the case of PE the grafting yield was not influenced by the presence of trifluorotrichloroethane (Freon 113) in the reaction mixture, while the presence of methanol decreased the grafting yield. The transversal distribution of graft chains in the film observed by electron‐probe x‐ray microanalysis showed that when the grafting was carried out in the presence of Freon the amount of graft chains in the central part of PE film was much larger than that at the film surface and that the grafts obtained in the absence of Freon were located mainly at the film surface. The electric resistance of the graft PE film obtained in the presence of Freon decreased more than that of the one obtained in the absence of Freon. The weight loss of the graft films in H2O2 solution was negligibly small.
Characterization of aromatic polymers (benzenoid and heterocyclic) by cross‐polarization, magic‐angle 13C‐NMR spectroscopy
Authors: Brown Charles Eric , Khoury Issam , Bezoari Massimo D. , Kovacic Peter
Published: April 2003

The cross‐polarization, magic‐angle 13C‐NMR spectra of solid samples of poly(p‐phenylene), its nitro derivative, polymerized biphenyl, poly(p‐phenylene sulfide), poly(1‐methyl‐2,5‐pyrrolylene), poly(1‐phenyl‐2,5‐pyrrolylene), poly(2,5‐thienylene), and poly(2,5‐selenienylene) and the high‐resolution 13C‐NMR spectrum of poly(m‐phenylene) in solution are presented and assigned. In all cases the chemical shifts are similar to those of model compounds in solution. In most instances the resonances of the nonprotonated carbon atoms in the solid polymers are more intense than those of the protonated carbons and appear to depend on the charge distribution in the molecular orbitals.
Plasma polymerization. VIII. A comparative study of the plasma polymers produced from inductively coupled plasmas excited in the fluorobenzenes
Authors: Clark D. T. , Abrahman M. Z.
Published: April 2003

An ESCA investigation has been made of the plasma polymers produced from the isomeric tri‐, di‐, and monofluorobenzenes in inductively coupled plasmas. Comparison is drawn with other published data on perfluoro‐, pentafluoro‐, and isomeric tetrafluorobenzenes. The data reveal that extensive molecular rearrangement accompanies polymerization and that proportionately the C:F stoichiometry shows a decrease in fluorine content relative to the monomer in going from perfluoro‐ to monofluorobenzene. Internal stress, critical surface tensions, and coefficients of friction are compared for the plasma polymers.
Functional monomers and polymers. XCVII. Synthesis of oligomer models of polyethyleneimine derivatives containing pendant thymine bases
Authors: Inaki Yoshiaki , Sakuma Yo , Suda Yasuo , Takemoto Kiichi
Published: April 2003

A series of oligomer models of polyethyleneimine derivatives having pendant thymine bases were prepared by the reaction of carboxyethyl derivatives of thymine with oligomer amines using an activated‐ester method. It was found that the hypochromicity values obtained from UV spectra and pKa values obtained from spectrophotometric titrations depend on the chain length of the oligomers and the thymine content of the polymers.
Longitudinal volume viscosity of epoxide prepolymers
Authors: Lesbats J. P. , Legros R. , Aleman J. V.
Published: April 2003

Volume flow of epoxide prepolymers and the effect of compression rate, temperature, and molecular weight on it are described. An increase in longitudinal volume viscosity with decreasing volume deformation, increasing compression rate, and increasing temperature has been observed. The molecular weight seems to have no influence.
Emulsion copolymerization of styrene and methyl methacrylate
Authors: Goldwasser J. M. , Rudin Alfred
Published: April 2003

Chain transfer constants to monomer have been measured by an emulsion copolymerization technique at 44°C. The monomer transfer constant (ratio of transfer to propagation rate constants) is 1.9 × 10−5 for styrene polymerization and 0.4 × 10−5 for the methyl methacrylate reaction. Cross‐transfer reactions are important in this system; the sum of the cross‐transfer constants is 5.8 × 10−5. Reactivity ratios measured in emulsion were r1 (styrene) = 0.44, r2 = 0.46. Those in bulk polymerizations were r1 = 0.45, r2 = 0.48. These sets of values are not significantly different. Monomer feed compcsition in the polymerizing particles is the same as in the monomer droplets in emulsion copolymerization, despite the higher water solubility of methyl methacrylate. The equilibrium monomer concentration in the particles in interval‐2 emulsion polymerization was constant and independent of monomer feed composition for feeds containing 0.25–1.0 mole fraction styrene. Radical concentration is estimated to go through a minimum with increasing methyl methacrylate content in the feed. Rates of copolymerization can be calculated a priori when the concentrations of monomers in the polymer particles are known.
Magnesium chloride supported high‐mileage catalysts for olefin polymerization. I. Chemical composition and oxidation states of titanium
Authors: Chien James C. W. , Wu Jiun‐Chen , Kuo Chi‐I
Published: April 2003

The chemical composition of a MgCl2‐supported, high‐mileage catalyst has been determined at every stage of its preparation. Ball milling of MgCl2 with ethyl benzoate (EB) resulted in the incorporation of 95% of the EB present to give MgCl2·EB0.15. A mild reaction with a half‐mole equivalent of p‐cresol (PC) at 50°C for 1 h resulted in near quantitative retention of p‐cresol by the support. The composition is now approximately MgCl2·EB0.15P̌0.5. Addition of an amount of AlEt3 corresponding to half‐mole equivalent of p‐cresol liberated one mole of ethane per mole of p‐cresol, thus signaling quantitative reaction between the two components. The support contains on the average one ethyl group per Al. Further reaction with TiCl4 resulted in the incorporation of titanium of approximately 8, 38, and 54% in the oxidation states of +2, +3, and +4, respectively. The ratio of Al to Ti in the catalyst lies in the range of 0.5–1.0. Only 19% of all the Ti+3 species in the catalyst can be observed by electron paramagnetic resonance (EPR); these are attributable to isolated Ti+3 complexes. The remaining EPR silent Ti+3 species are believed to be bridged to another Ti+3 by Cl ligands. The total Cl content is equal to the sum of 2 × Mg + 3 × Al + 3.5 × Ti. Most of the p‐cresol moiety apparently disappeared from the support, leaving much of ethyl benzoate in the catalyst. Activation with AlEt3/methyl‐p‐toluate complex reduces 90% of the Ti+4 in the catalyst to lower oxidation states. The ester apparently moderates the alkylating power of AlEt3 to avoid excessive formation of divalent titanium sites. There appears to be a constant fraction of 1/4–1/5 of the titanium which is isolated and the remainder is in bridged clusters independent of the oxidation states of titanium.
Synthesis and characterization of a new conjugated polymer: Polytrifluoromethylacetylene
Authors: Rubner Michael , Deits Walter
Published: April 2003

Polytrifluoromethylacetylene (PTFMA) was synthesized from trifluoromethylacetylene (TFMA) using a PdCl2/DMF catalyst solution or the anionic initiator n‐butyl lithium. Although PdCl2 proved to be an effective catalyst for the polymerization of TFMA, long reaction times and poor yields made characterization of the resultant polymer difficult. The use of n‐butyl lithium, on the other hand, resulted in high yields of PTFMA in relatively short reaction times. The results of thermal analysis and the effects of n‐ and p‐type doping on the electrical conductivity of the polymer are discussed.
Polymerization ability of cis‐ and trans‐4,5‐epoxy‐2‐pentenal with ionic and free radical initiators. Cyclopolymerization of the cis isomer
Authors: Yokoyama Y. , Hall H. K.
Published: April 2003

The behavior of the readily available cis‐ (1) and trans‐ (2) 4, 5‐epoxy‐2‐pentenals toward classical cationic, anionic, and free radical initiators has been examined. Only the cationic polymerization of 1 gave soluble polymer of moderate molecular weights. This polymer possessed predominantly the cyclopolymerized furanose structure 12. Cationic initiation of 2 and anionic initiation of both 1 and 2 gave only crosslinked materials, and free radical initiators with 1 and 2 gave no polymer.
Reaction of poly(vinyl chloride) with electrogenerated superoxide anion
Authors: Osawa Zenjiro , Uchida Yoshihito
Published: April 2003

Reaction of poly(vinyl chloride) (FVC) with electrogenerated superoxide anion was carried out in a mixed solvent of tetrahydrofuran (THF) and dimethylformamide (DMF), mostly at 40°C, under a nitrogen stream. The results obtained were compared with those in an earlier article,1 in which the use of potassium superoxide was described. Reaction of PVC with electrogenerated superoxide anion took place easily and the yield and molecular weight of the recovered polymer decreased appreciably. Functional groups formed in PVC treated with electrogenerated superoxide anion were similar to those in PVC treated with potassium superoxide; that is, hydroxy (ca. 3400 cm−1), conjugated carbonyl groups (ca. 1675 cm−1), and polyene structures (ca. 1600 cm−1) were observed. In addition, a new peak, probably due to nonconjugated aldehyde groups, was observed at 1725 cm−1. Ultraviolet (UV) spectra of PVC treated with electrogenerated superoxide anion showed that the polyene sequences formed in the polymer were shorter than octaene and that the octaene and that the octaene was formed only in the reaction at 60°C.
13C‐NMR sequence analysis. 19. Anionic copolymerization of γ‐butyrolactam, δ‐valerolactam, and caprolactam at low temperatures
Authors: Kricheldorf Hans R. , Coutin Bernard , Sekiguchi Hikaru
Published: April 2003

Copolymerizations of pyrrolidone‐2 (γ‐butyrolactam) with piperidone‐2 (δ‐valerolactam) and azepinone‐2 (ε‐caprolactam) and the copolymerization of piperidone‐2 with azepinone‐2 were studied in bulk at 30 or 45°C. The sodium salt and the tetramethylammonium salt of pyrrolidone‐2 were used as catalysts and N‐acetylpyrrolidone‐2 as cocatalyst. The sequences of the resulting copolyamides were analyzed by means of 22.63‐MHz 13C‐NMR spectra. All sequences were nearly random in nature, yet copolymerizations of pyrrolidone‐2 favor slightly the formation of alternating sequences. Furthermore, the rate of incorporation of pyrrolidone is higher than that of the two comonomers in contrast to experiments at temperatures above 100°C. The influence of transamidation reactions on the sequences is discussed. Propagation/degradation equilibria involving N‐acyllactam chain ends were found to modify the initially formed, kinetically controlled sequences in direction of thermodynamically controlled ones.
Acidic peroxo salts: A new class of initiators for vinyl polymerization. III. Kinetics of polymerization of methyl methacrylate initiated by potassium monopersulfate catalyzed by Co(II)
Authors: Samal Rajani K. , Satrusallya S. C. , Nayak B. L.
Published: April 2003

Kinetics of the polymerization of methyl methacrylate by an acidic peroxo salt like potassium monopersulfate catalyzed by Co(II) have been investigated in aqueous medium, over the range of 35–50°C. The rates of polymerization (Rp) have been studied at various concentrations of monomer and initiator. The efficiencies of various metal salts in catalyzing the polymerization have been evaluated from the observed value of Rp. The effects of catalyst (CoSO4), initiator, monomer, and various concentrations of FeCl3 on Rp and percentage conversion have been studied. The end groups of the recovered polymers have been studied using standard methods. From the observed end groups and kinetic results, a reaction scheme has been proposed involving initiation by SO4· or OH· radicals, generated by the interaction of the initiator with cobalt sulfate and termination of the polymer chains by mutual combination.
Head‐to‐head vinyl polymers. VI. Preparation and characterization of head‐to‐head poly(allyl alcohol) and its esters
Authors: Quach Loc , Otsu Takayuki
Published: April 2003

Head‐to‐head (H–H) poly(allyl alcohol) (PAA) was prepared by the LiAlH4reduction of H–H poly(methyl acrylate) obtained from the methylation of alternating copolymer of ethylene with maleic anhydride. H–H poly(allyl acetate) (PAAc) and H–H poly(allyl benzoate) (PABz) were further derived by means of its acylations. All of these three H–H polymers were characterized by IR, NMR, TGA, and PGC measurements. The corresponding head‐to‐tail (H–T) polymers were also prepared by a similar method from the conventional H–T polymer of methyl acrylate, and characterized to allow comparison with the H–H polymers. The softening temperatures of all H–H polymers were somewhat higher than those of the respective H–T polymers, probably suggesting that the H–H placements increased the stiffness of the polymers. Unlike poly(acrylic esters) reported previously, these H–H allyl polymers were found to degrade at temperatures slightly lower than the H–T polymers. On pyrolysis at 430°C, both PAAc and PABz were also observed to release predominantly acetic acid and benzoic acid, respectively, and small quantities of the corresponding allyl ester monomers. The molar ratios of acid to ester were substantially larger for H–H polymers.
Studies of the polymerization of diallyl compounds. XXXVII. Copolymerizations of diallyl phthalate with dialkyl fumarates
Authors: Matsumoto Akira , Kamigaki Hiroyuki , Oiwa Masayoshi
Published: April 2003

Diallyl phthalate (DAP) was copolymerized with dialkyl fumarates, including diethyl fumarate (DEF), di‐n‐butyl fumarate (DBF), and di‐n‐octyl fumarate (DOF) by using 2,2′‐azobisisobutyronitrile as an initiator at 60°C. Both rate and degree of copolymerization were quite enhanced compared with the homopolymerization of DAP and the maximum rate was found at the molar ratio of 1:1 in the monomer feed. The cyclization of DAP was almost exclusively suppressed in the Copolymerization. Gelation was promoted from 25% of the gel‐point conversion for the DAP homopolymerization to 9% of the minimum one observed. Copolymerizability of DAP (M1) with dialkyl fumarates (M2) was quite high, with the following monomer reactivity ratios M2, r1, r2: DEF, 0.01, 1.25; DBF, 0.02, 1.01; DOF, 0.02, 0.96. These results are discussed in mechanistic detail.
Photoinitiated polymerization of methyl methacrylate with benzoin methyl ether. III. Independent photogeneration of the ether radical
Authors: Pappas S. Peter , Asmus Robert A.
Published: April 2003

Evidence is presented for initiation of MMA polymerization by the α‐methoxybenzyl (ether) radical, photogenerated by H abstraction from benzyl methyl ether, utilizing benzophenone as the H‐ab‐stracting agent. The results support previous reports on the initiating ability of ether radical, photogenerated from 14C‐labeled benzoin methyl ethers. Independent generation of one or both of the radicals derived from unsymmetrical initiators is more broadly applicable. The potential utility of this technique for providing insights into the photoefficiencies of commercially important photoinitiators, which produce initiator radicals by intramolecular bond cleavage, is discussed.
Reactivities of monomers toward the 2‐cyano‐2‐propyl radical by NMR study of end groups in copolymers
Authors: Bevington J. C. , Huckerby T. N. , Hutton N. W. E.
Published: April 2003

Copolymerizations of styrene (S) with methyl methacrylate (MMA) and methacrylonitrile (MAN) at 60°C were performed with azoisobutyronitrile as initiator, enriched in its methyl groups with 13C. From the NMR spectrum of a copolymer it is possible to compare the numbers of initiator fragments attached to the two types of monomer unit; this information can be used to study the competition between the monomers for capture of the radicals formed from the initiator. The velocity constants for addition of the 2‐cyano‐2‐propyl radical to S, MMA, and MAN are in the proportions 1:0.56:0.34; it is concluded that polar effects are of some importance in the reactions of the radical.
Radiation degradation of copolymers of methyl methacrylate and 3‐oximino‐2‐butanone methacrylate
Authors: Bowmer T. N. , Reichmanis E. , Wilkins C. W. , Hellman M. Y.
Published: April 2003

Copolymers of methyl methacrylate and 3‐oximino‐2‐butanone methacrylate (OM) were investigated as deep‐UV and e‐beam resists. Their increased sensitivity relative to PMMA (up to 50 times) was correlated with the radiation chemical yields of the volatile products and main chain scissions. The degradation of these copolymers, activated by the 3‐oximino‐2‐butanone entity, is discussed in terms of energy absorption mechanisms and the subsequent scission reactions.
Microstructure and electric properties of elastomeric ionene‐TCNQ salts
Authors: Watanabe Masayoshi , Toneaki Nobuhiro , Takizawa Yoshio , Shinohara Isao
Published: April 2003

The elastomeric ionene polymers characterized by the alternating structure of the rigid polycation segments that contained 4,4′‐bipyridilium rings and the flexible polypropyleneoxide (PPO) segments were prepared as a function of chain length of the PPO segments. From the measurements of dynamic mechanical properties and x‐ray diffraction patterns of these ionenes and their 7,7,8,8‐tetracyanoquinodimethane (TCNQ) salts, a microheterogeneous structure of the PPO segments and the polycation‐TCNQ salts segments in the TCNQ salts was estimated. On the basis of this microstructure a change in the conductive and dielectric properties with an increase on the weight fraction of the PPO segments the TCNQ salts (Wf) were discussed. For the simple salts the values of resistivity (ρ) and activation energy of conduction (Ea) were increased with the increase in the value of Wf. The values of ρ for the complex salts also increased with the increase in the value of Wf, whereas the values of Ea were nearly constant (ca. 0.07 eV) until the value of Wf reached 0.8. Strong interaction between \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm TCNQ}^{-\atop\cdot}$\end{document} and TCNQ° molecules facilitated the formation of the continuous conduction columns and did not change their structure and properties. Dielectric constant (ε) of the TCNQ salts attained 102−104. The dielectric behavior was consistent with the conductive behavior, and the appearance of the high ε values was caused by polarization of carrier electrons of the TCNQ salts in the conductive paths isolated or interrupted by the PPO segments. As the Wf value increased, the ε values of the TCNQ salts decreased. The decrease in the number of these paths accompanied by the increase in the Wf value led to reduced ε values.
Effect of pressure on free‐radical copolymerization kinetics. III. An improved method of measuring monomer reactivity ratios under high‐pressure conditions
Authors: Schrijver J. , Ammerdorffer J. L. , German A. L.
Published: April 2003

To investigate high‐pressure copolymerizations a sampling technique has been developed enabling continual on‐line GLC analysis of the reaction mixture. As a result more reliable kinetic data are obtained. This new “sequential sampling” method, allowing the use of gaseous monomers, has been tested for the copolymerization of ethylene with vinyl propionate at 118 MPa and 335 K with tert‐butyl alcohol as solvent. The results are compared with those obtained with the “quenching” method used so far, which yields compositional data on the reaction mixture before and after the high‐pressure stage, only. It is shown that the “sequential sampling” method is the most adequate method of determining high‐pressure monomer reactivity ratios. Furthermore, it is an important safety feature that the present procedure can be easily remote controlled. The present experimental method is neither restricted to copolymerization nor to gas‐chromatographic analysis of the reaction mixture.
Dispersion photopolymerization of styrene
Authors: Mayoral Joaquin F. , Levy Moshe
Published: April 2003

Photopolymerization of styrene was carried out in a dispersed system to obtain 10 μm particles, using d‐t‐butylperoxide as initiator and poly(vinyl alcohol) as protective colloid. It was shown that particles typical for latex polymerization are also formed and interfere with the dispersion polymerization when excess protective colloid is used.
Charge transfer interaction and electrical conductivity of poly(vinyl acetals) containing dispersed TCNQ radical anion salts
Authors: Kim O.‐K. , Fox R. B.
Published: April 2003

Charge transfer (CT) interaction is described in semiconducting dispersions of TCNQ complex salt \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Et}_3 {\rm NH}^+ ({\rm TCNQ})_2^{\cdot^{\hskip-3.7pt\hbox{--}}}$\end{document} with and without added TCNQ°, in poly(vinyl acetal) matrices in which the electron‐donor moiety is varied. The extent of CT interaction was determined in films and in solution (DMF, acetonitrile, or methylene chloride) through the absorbances at 398 nm (\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm TCNQ}{\ }^{\cdot^{\hskip-3.7pt\hbox{--}}}$\end{document} and TCNQ°) and 857 nm \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm TCNQ}{\ }^{\cdot^{\hskip-3.7pt\hbox{--}}}$\end{document}. Resistivity of the conductive films was related to the stoichiometry of TCNQ species in the films and found to have a minimum at \documentclass{article}\pagestyle{empty}\begin{document}$[{\rm TCNQ}^\circ]/[{\rm TCNQ}{\ }^{\cdot^{\hskip-3.7pt\hbox{--}}}]\simeq 1$\end{document}. Lower resistivities were attained with films having a uniform, densely packed dispersion of microcrystallites which were obtained at a relatively slow solvent removal rate. With this particular complex salt, strong electron‐donor polymers are found to be better matrices for semiconductivity.
Poly[(2‐chloroethyl)oxirane], poly[(3‐chloropropyl)‐oxirane] and poly[(4‐chlorobutyl)oxirane]: New polyether elastomers of improved chemical reactivity
Authors: Shih J. S. , Brandt J. F. , Zussman M. P. , Tirrell D. A.
Published: April 2003

(2‐Chloroethyl)oxirane, (3‐chloropropyl)oxirane, and (4‐chlorobutyl)oxirane were prepared from the corresponding alkenols and polymerized using a triethylaluminum‐water‐acetylacetone initiator system. Copolymerizations with propylene oxide and epichlorohydrin were also accomplished; the copolymerization activities of the (chloroalkyl)oxiranes were similar to the activity of epichlorohydrin. Poly[(2‐chloroethyl)oxirane], poly[(3‐chloropropyl)oxirane], and poly[(4‐chlorobutyl)oxirane] exhibit elastomeric properties and are highly reactive in nucleophilic substitution reactions.
Ground‐state dynamics of α‐methylstyrene. I. Thermally induced oligomerization in bulk
Authors: Kauffmann H. F. , Harms H. , Olaj O. F.
Published: April 2003

α‐Methylstyrene (α‐Me‐St) in bulk undergoes a variety of thermally induced processes which we investigated in detail by product‐distribution analysis. The oligomeric products, shown by GC–MS coupling techniques and independent syntheses, consisted of nine dimers and nine trimers with no detectable higher oligomers or polymers. Two isomeric cyclobutanes and one of the open‐chain unsaturated dimers were formed by a conventional two‐step cycloaddition; a Flory‐type diradical was the common intermediate. In contrast to these 2π + 2π products, the majority of the remaining oligomers could not be interpreted on the basis of π‐electron interaction between closed shell molecules. Their structures, however, were compatible with a free radical process in which cumyl(MH·) and 1,4‐dimethyl‐1‐phenyl‐tetrahydronaphthalene‐yl(THN·), which are consecutive products of 4π + 2π and 2π + 2π interactions, respectively, were involved in addition and transfer reactions. Because of the small rate of initiation and the obvious lack of free radical recombination products, a mechanism was suggested in which MH· and THN· radicals react predominantly in a closed sequence of elementary processes and to a rather small extent only by bimolecular free radical termination. Two sorts of stabilization steps, hydrogen transfer to monomer (RnH· + M → Rn + MH·) and hydrogen abstraction from a hypothetical 4π + 2π intermediate I (RnH· + I → RnH2 + THN·), are attributed to the high rates of unsaturated and saturated oligomer formation.
The effect of the purity of ingredients, oxygen, and inorganic particulate dispersion on the course of styrene emulsion polymerization
Authors: Hasan Syed Mahmud
Published: April 2003

A study of the effects of ingredients on styrene emulsion polymerization kinetics showed that the purity of sodium dodecyl sulfate emulsifier affected the rate of polymerization (Rp) in the absence of added initiator. Below a critical concentration oxygen accelerated the Rp; above the critical concentration it inhibited the Rp. The effect of distilling styrene, compared to washing it with alkali to deinhibit, was minimal. Indications are that particulate dispersions of silica and titanium dioxide are encapsulated in situ by the growing polymer chains during styrene emulsion polymerization.
Mechanism of styrene emulsion polymerization during interval II
Authors: Hasan Syed Mahmud
Published: April 2003

A systematic study of the kinetics of styrene emulsion polymerization in the postnucleation stage by the way of seed particle growth of monodisperse latices was undertaken, in which the colloidally important parameters were varied: Rp was independent (within limits) of (a) ionic strength, (b) pH, (c) initiator concentration (potassium persulfate), and (d) surfactant (sodium dodecyl sulfate) concentration; Rpp was independent (within limits) of (a) seed particle number concentration N, (b) oil:water phase ratio, and (c) monomer:polymer ratio; Rp was directly proportional to seed‐particle surface area. The viscosity average molecular weight of the polymer formed during interval II, Mv(i–j), was approximately constant and increased linearly with N. Log Mv(i–j) was inversely proportional to reaction temperature; Mv(i–j) was inversely proportional to initiator concentration. The overall activation energy of polymerization E′p was equal to the activation energy of propagation Ep during interval II. The value of kp at 60°C was 615 dm3 mol−1 s−1. Trace of oxygen seems to affect the average number of radicals per particle ī during interval II polymerization.
Polymers containing hydrogen bonding rings. Synthesis and thermal properties of poly(enamine‐ketones)
Authors: Pavlisko J. A. , Huang S. J. , Benicewicz B. C.
Published: April 2003

The synthetic route to poly(enamine‐ketones) by vinylogous nucleophilic substitution of aromatic bis(1,3‐diketones) with aromatic and aliphatic diamines is described. The preparation of aromatic bis(1,3‐diketones), their polymerization, and thermal properties of the polymers are presented in detail. The polymers exhibited anisotropic melts and representative model compounds were shown to be thermotropic liquid crystals.
Properties of low‐molecular‐weight polyethylene treated with gas plasma
Authors: Ashida Michio , Ikada Eiji , Ueda Yasukiyo , Aizawa Hideki
Published: April 2003

Polyethylene films were evaporated in gas plasmas of Ar, N2, O2, and H2O. The deposits were analyzed by infrared (IR) spectroscopy to determine the concentration of characteristic functional groups. The deposit prepared in Ar‐atmosphere had a rather high concentration of methyl group and many double bonds were produced in the film. The deposits prepared in Ar‐ and N2‐plasmas produced similar spectra, which showed twice the concentration of methyl group than the deposit in Ar‐atmosphere and also contained a few carbonyl and hydroxyl groups. The film treated in O2‐plasma contained the largest amount of carbonyl group and the lowest number of double bonds among the plasma‐treated deposits. Dielectric loss curves against temperature for the deposits treated in these plasmas showed a broad peak near 20°C. For O2‐plasma‐treated film the loss tangent curves showed a sharp maximum. The activation energy for the relaxation of Ar‐, O2‐, and H2O‐plasma‐treated films had the same value of 50.6 kcal/mol. The observed relaxation in the films prepared in gas plasmas was considered due to the β process and was attributed to the motion of oxidized branched polyethylene.
Interaction of poly(vinyl acetate) radical with iron (III) complexes
Authors: Begum S. S. , Dass N. N.
Published: April 2003

The polymerization of vinyl acetate in N,N‐dimethylformamide (DMF) at 60°C initiated by AIBN in the presence of [Fe(DMF)6](ClO4)3 and Fe(N3)3 had been studied. Fe(N3)3 was produced in situ by mixing solid sodium azide (NaN3) and hexakis(N,N‐dimethylformamide) iron (III) perchlorate, [Fe(DMF)6](ClO4)3, in the ratio of 3:1. The velocity constant kx for the interaction of poly(vinyl acetate) radical with [Fe(DMF)6]3+ was found to be 1.44 × 103L mol−1 s−1 and that for the interaction of poly(vinyl acetate) radical with Fe(N3)3 to be 3.44 × 105 L mol−1 s−1 at 60°C.
Chemical release control—Schiff bases of perfume aldehydes and aminostyrenes
Authors: Kamogawa Hiroyoshi , Mukai Hiroshi , Nakajima Yoichi , Nanasawa Masato
Published: April 2003

Schiff bases of p‐ and m‐aminostyrenes with perfume aldehydes such as citral, cinnamaldehyde, piperonal, vanillin, and ethyl vanillin were synthesized in ethanol in more than 50% yield. Water‐soluble copolymers of these Schiff bases with N‐vinyl‐2‐pyrrolidone or with N,N‐dimethylacrylamide were obtained. The hydrolytic behavior of Schiff base monomers and copolymers to liberate perfume aldehydes was structure dependent, thereby affording chemical release control.