bluuebunny/crossref_metadata_2025 huggingface dataset:
Free‐radical polymerization of vinylferrocene. II. Spectroscopic and physical properties
Authors: George M. H. , Hayes G. F.
Published: April 2003

The spectroscopic and physical properties of poly(vinylferrocene) prepared by free‐radical polymerization in benzene are discussed. The results obtained in these studies are in accord with the kinetic analysis of the polymerization reactions in benzene. ESR spectroscopy shows that the polymer is paramagnetic and contains a species which is identified by Mössbauer spectroscopy as an ionically bound complex of Fe(III) in a high spin (3d5) configuration. The concentration of this species is shown to be dependent upon kinetic parameters. Magnetic susceptibility measurements show that the polymer does not contain any oxidized ferromagnetic impurities. Infrared spectroscopy indicates that the polymer contains vinylidene groups. The presence of these groups is explained by chain transfer to monomer followed by reinitiation. Ultraviolet spectroscopy also suggests the presence of unsaturation in the polymer. Gel‐permeation chromatography indicates that poly(vinylferrocene) is branched even at low conversions. The effect of transfer reactions and the intramolecular electron transfer termination of the chain radical on the structure of poly(vinylferrocene) is discussed. The glass transition temperature and thermal stability of the polymer are also examined.
Application of ESCA to polymer chemistry. VIII. Surface structures of AB block copolymers of polydimethylsiloxane and polystyrene
Authors: Clark D. T. , Peeling J. , O'Malley J. M.
Published: April 2003

The surface morphology of a number of films of AB block copolymers of polydimethylsiloxane and polystyrene was examined by ESCA and contact angle measurements. In all cases the immediate surface is shown to consist of an essentially pure polydimethylsiloxane component. By comparing the intensities of elastic peaks corresponding to photoionizations from core levels without energy loss for polydimethylsiloxane and polystyrene with those for the block copolymers and by consideration of shake‐up phenomena specific to the polystyrene component, an estimate of the thickness of the polydimethylsiloxane outer layer of the latter may be obtained. This is shown to vary between ∼13 and 40 Å, depending on the method of formation of copolymer film.
Synthesis of light‐sensitive arenesulfonylazido polycarboxylic acids
Authors: Ulrich Henri , Stuber F. A. , Peters G. M. , Sayigh A. A. R.
Published: April 2003

Several light‐sensitive arenesulfonylazido polycarboxylic acids were synthesized by a one‐step reaction of a polymeric anhydride with a light‐sensitive monofunctional alcohol, or by the reverse reaction, i.e., reaction of a polymeric alcohol with a light‐sensitive monofunctional anhydride. The polycarboxylic acids are soluble in polar organic solvents and in aqueous base. Neutralization of part of the carboxyl groups gives rise to the formation of water‐soluble polymers. Coreaction of poly(maleic anhydride‐co‐methyl vinyl ether) with 2‐hydroxyethyl 4‐sulfonylazidocarbanilate and 2‐hydroxyethyl trans‐2,5‐dimethoxystilbene‐4′‐carbamate produces a light‐sensitive polycarboxylic acid with “built‐in” sensitizer.
Anionic polymerization. IV. Effect of crown ethers on alkylsodium initiator
Authors: Cheng Tai Chun , Halasa Adel Farhan
Published: April 2003

The polymerization of butadiene and copolymerization of butadiene‐styrene with alkylsodium catalyst modified by crown ethers in hydrocarbon solvent has been investigated. This catalyst system produced polybutadiene of high viscosity (2.0–5.0) and high vinyl content (80%) in high conversion (75–95%). These results are in contrast to those obtained with aliphatic ether‐modified alkylsodium polymerization which typically gives products of low molecular weight and at low conversion. The copolymerization of butadiene‐styrene with alkylsodium catalyst modified by crown ethers gave a copolymer which did not contain block styrene. Although the copolymer did not contain block styrene, there was an unusually high level of incorporation of styrene in the copolymer at low conversion. This behavior is quite different from either modified organolithium or unmodified organosodium initiators, in which the styrene is uniformly and randomly incorporated along the chain.
Polymerization of coordinated monomers. XI. Structure and reactivity of the ternary molecular complex composed of stannic chloride, methyl methacrylate, and styrene
Authors: Komiyama Makoto , Hirai Hidefumi
Published: April 2003

The time‐averaged orientation of styrene in the ternary molecular complex composed of stannic chloride, methyl methacrylate, and styrene was determined by use of the chemical shift changes of the protons in the methyl methacrylate on the ternary molecular complex formation. The observed chemical shift change for each of the protons in the methyl methacrylate is expressed by the weighted average of the shifts due to the anisotropic shielding of the benzene ring of styrene for conformations I and II, using the common statistical weight. Conformations I and II correspond to the cis and trans rotational isomers, respectively, of methyl methacrylate with respect to the rotation of the methoxymethyl group around the carbonyl carbon‐ether oxygen bond. Extended Hückel calculations were made on the methyl methacrylate monomer coordinated to stannic chloride and styrene monomer as well as the growing radicals corresponding to the monomers. The energy levels of the frontier orbitals of the species were determined by use of the ionization potentials, the absorption maxima, and the results of the extended Hückel calculations. The high reactivity of the ternary molecular complex is discussed in terms of the interactions between the frontier orbitals of the styrene and those of the coordinated methyl methacrylate.
Synthesis of polyphthalamides by ring‐opening polyaddition reaction of N,N′‐disubstituted bisphthalisoimides with diamines
Authors: Ueda Mitsuru , Kanno Susumu , Imai Yoshio
Published: April 2003

The ring‐opening polyaddition reaction of N,N′‐disubstituted bisphthalisoimides with various diamines in amide‐type solvents at room temperature afforded polyphthalamides having inherent viscosity of up to 0.26 in excellent yields. Some of the polymers thus obtained are a new class of ordered alternating copolyphthalamides. These polyamides were soluble in polar aprotic solvents, as well as in acidic solvents. They showed relatively low melt temperature in the range of 120–220°C and further low level of thermal stability.
Free radicals in γ‐irradiated poly‐α‐methylstyrene
Authors: Mawaziny Sheila , Arafa Salah , Iskandar Magdy F. , El‐Subee Maher Z.
Published: April 2003

Electron spin resonance (ESR) spectra were observed at −160°C and at room temperature for γ‐irradiated poly‐α‐methylstyrene. The spectrum observed at room temperature has been attributed to the radical species while that at −160°C results from the same radical and superposition of the spectrum due to the radical ĊH2‐C(CH3)(C6H5)‐. The radicals which are stable at room temperature could be used to graft vinyl acetate.
Chain scission efficiency of some polymers in γ‐radiation
Authors: Ouano A. C. , Johnson D. E. , Dawson B. , Pederson L. A.
Published: April 2003

The G values of poly(methyl methacrylates) (PMMA), polycarbonates, and a polylactone for γ‐radiation were determined by using a computer‐assisted GPC as the primary tool for the measurement of the number‐average molecular weights M̄n. The accuracy and precision of the automated GPC were found to have a normalized standard deviation (σ/M̄n) of less than 7%. The G value of PMMA was determined to be essentially independent of molecular weight. For low molecular weight polymers, some nonlinearity in the I/M̄n versus dosage plot was observed at low dosage, i.e., about 1 Mrad.
Polymerization of hexamethylcyclotrisiloxane with a biscatecholsiliconate. I. Nature of polymerization
Authors: Lee C. L. , Johannson O. K.
Published: April 2003

Polymerization behavior of hexamethylcyclotrisiloxane (D3) in toluene solution with the use of benzyltrimethylammonium bis(o‐p;henylenedioxy)phenylsiliconate as a catalyst, dimethyl sulfoxide as promoter, and adventitious moisture as initiator was investigated. The polymerization system gives a linear difunctional polymer, HO(Me2SiO)xH, with a molecular weight which is inversely proportional to the amount of water reacted rather than to the amount of catalyst employed. The polymerization in the presence of H2O gives rise to molecular weight distributions very close to Poisson distributions. The normalized experimental GPC curve agrees very well with the theoretical GPC curve calculated from the polymerization scheme:
\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm H}_2 {\rm O} + ({\rm Me}_2 {\rm SiO})_3 \to {\rm HO}({\rm Me}_2 {\rm SiO})_3 {\rm H}} \\ {{\rm HO(Me}_{\rm 2} {\rm SiO)}_{\rm 3} {\rm H} + {\rm N(Me}_{\rm 2} {\rm SiO)}_{\rm 3} \to {\rm HO}({\rm Me}_2 {\rm SiO})_{3(n + 1)} {\rm H}} \\ \end{array} $$\end{document}
Polymerization carried out in the combined presence of H2O and ROH, where R is Me or Me3Si, gives rise to bimodal molecular weight distributions. The resulting polymers consist of HO(Me2SiO)2xH and RO(Me2SiO)xH. The molecular weight of the former is twice that of the latter, and their proportion depends on the ratio of H2O to ROH. The system is a special type of “living” polymer.
Sulfur‐containing vinyl monomers. XII. Charge transfer complexes of thioethylene derivatives with π‐electron acceptors
Authors: Inoue Hiroshi , Otsu Takayuki
Published: April 2003

The absorption spectra of charge‐transfer (CT) complexes of thioethylene derivatives with p‐chloranil (CA), tetracyanoethylene (TCNE), and 7,7,8,8,‐tetracyanoquinodimethane (TCNQ) were measured in methylene chloride. Since the CT bands of alkyl vinyl sulfides having bulky substituents such as isopropyl, cyclohexyl and tert‐butyl were similar to that of methyl vinyl sulfide, the complexing site of these sulfides to acceptor was assumed to be the vinyl group rather than the sulfur atom. In the case of the TCNE complex of phenyl vinyl sulfide, however, a new second CT band at 378 nm was observed, and the first CT band was also close to that of ethyl phenyl sulfide, indicating that the TCNE formed a complex with this vinyl sulfide mainly at its phenyl group. To investigate further the conformation of the complex, CT spectra of bis‐, tris‐ and tetrakis (phenylthio) ethylenes were measured. These compounds showed markedly different CT bands, and the changes in these CT bands with the number of the phenylthio substituents appears to be attributable to the change in complexing site with the acceptors used.
Synthesis of polyenamines by vinylogous nucleophilic substitution polymerization of 2,2′‐disubstituted bis(4‐ethoxymethylene‐5‐oxazolone) with diamines
Authors: Ueda Mitsuru , Kino Kohsuke , Hirono Takeo , Imai Yoshio
Published: April 2003

A new class of polyenamines was synthesized by the vinylogous nucleophilic substitution polymerization of 2,2′‐p‐phenylenebis(4‐ethoxymethylene‐5‐oxazolone) with diamines in polar aprotic solvents under very mild conditions. The polymers derived from aliphatic diamines were soluble in these solvents and had inherent viscosities in the range of 0.3–0.9. The dilute solutions showed marked decrease in viscosity with time, presumably due to hydrolytic chain scission of the enamine structures in the polymer backbone. The polymers exhibited no melting temperature, and onset of breakdown under thermogravimetric analysis in a nitrogen atmosphere occurred at 250–300°C.
Synthesis and polymerization of (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐propiothiolactone
Authors: Jerman B. , Fleš D.
Published: April 2003

(R)‐(+)‐2‐Methyl‐2‐ethyl‐3‐propiothiolactone was synthesized by debenzylation and cyclization of (−)‐2‐methyl‐2‐ethyl‐3‐benzylmercaptopropionyl chloride under the conditions of Friedel‐Crafts synthesis, and by dehydration of (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐mercaptopropionic acid with dicyclohexyl carbodiimide. The configuration of the (+)‐propiothiolactone was determined by chemical interconversion with (−)‐2‐methyl‐2‐ethylsuccinic acid, the absolute configuration of which is known to be (R). The polymerization of (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐propiothiolactone was performed in bulk with tetrabutylammonium versatate as catalyst. The specific rotation of the polymer ([α]D +151.7°) compared with the rotation of the low molecular weight model compound (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐acetylmercapto‐thiolpropionic acid methyl ester ([α]D +55.0°) shows a significant enhancement, thus suggesting the possibility of the presence of rigid conformations in polymer chain.
Equilibrium anionic polymerization of n‐valeraldehyde
Authors: Hashimoto Kazuhiko , Sumitomo Hiroshi , Ohsawa Shinji
Published: April 2003

This paper describes an anionic polymerization of n‐valeraldehyde (VA) in tetrahydrofuran (THF) initiated by benzophenone‐monolithium complex in a high vacuum system. In spite of the deposition of the resulting polymer an equilibrium state between the monomer and the polymer was observed at a temperature range of −90 to −68°C. From the linear relationship between the equilibrium monomer concentration and the polymerization temperature, values of −5.3 ± 0.3 kcal/mole and −25.7 ± 1.4 cal/mole‐deg, respectively, were evaluated for the enthalpy change and the entropy change in the present system. The effect of polar substituents on the polymerizability of aldehydes is discussed from the comparison of these values with those in the case of β‐methoxypropionaldehyde.
Kinetics of anionic polymerization of α‐methylstyrene in tetrahydrofuran and toluene mixed solvents
Authors: Hui K. M. , Ong Y. K.
Published: April 2003

The kinetics of anionic polymerization of α‐methylstyrene with Na+ as counterion have been studied in mixed solvents of tetrahydrofuran (THF) and toluene in various compositions at −25 to 5°C. The ion‐pair rate constant k(±) increases by about a factor of 50 at −10°C, whereas the activation energy decreases from 5.1 to −2.2 kcal/mole, when THF in the mixed solvent increases from 30 to 100 vol‐%. The plot of log k(±) against (D − 1)/(2D + 1) is a curve, where D is the dielectric constant of the medium. This deviation from linearity is explained in terms of propagation by two types of ion‐pairs.
19F‐ and 1H‐NMR spectra of tetrafluoroethylene–propylene copolymers
Authors: Kojima Gen , Wachi Hiroshi , Ishigure Kenkichi , Tabata Yoneho
Published: April 2003

High resolution 94‐MHz 19F‐ and 100‐MHz 1H‐NMR spectra were measured on a series of tetrafluoroethylene (TFE)‐propylene (P) copolymers having a range of composition (TFE/P molar ratio = 37/63–55/45) and polymerized at different temperatures (−23, 25 and 65°C). The spectra were analyzed in relation to copolymer compositions. The assignment of 19F resonance in terms of tetrads proposed previously was confirmed, and the tentative assignment of 1H resonances was proposed in terms of triads. The spectra thus interpreted revealed the sequence distribution of the copolymers. Copolymer compositions calculated from NMR spectra and elemental analysis agreed rather well with each other. Monomer reactivity ratios were calculated from the sequence distributions and compared with those obtained from the elemental analysis. It was observed that highly alternating copolymers are obtained in this system over a wide range of monomer composition at lower temperatures and that a deviation from alternancy increases slightly with rising polymerization temperature.
Modification of poly(ethylene terephthalate) and nylon 66 surfaces by using organometallic polymerization catalysts
Authors: Dobbs B. , Jackson R. , Gaitskell J. N. , Gray R. F. , Lynch G , Thompson D. T. , Whyman R.
Published: April 2003

Zirconium hydrocarbyl catalysts react with nylon and poly(ethylene terephthalate) (PET) fibers to produce a supported species which may be used to polymerize a sheath of polyethylene around the fiber. Very high catalyst activities have been achieved over very short reaction periods on PET spinning threadlines. It is also possible to use these reagents to produce strongly adhered oxide and sulfide surface coatings. Infrared evidence is given for a mechanism in the case of reaction between catalyst and PET.
Kinetics and mechanism of the thermal reaction between tert‐butyl perbenzoate and n‐alkanes: A model system for the crosslinking of polyethylene
Authors: Van Drumpt J. D. , Oosterwijk H. H. J.
Published: April 2003

The thermal reaction between tert‐butyl perbenzoate and n‐alkanes has been studied under conditions as close as possible to those during actual crosslinking of polyethylene. Product analysis allowed a description of the fate of 90–95% of the peroxide fragments. Approximately 50–60% of the substrate radicals, formed upon hydrogen abstraction, were found to combine and give crosslinks, whereas about 30% showed disproportionation, thus leading to substrate unsaturation. The two competing reactions account for 85–90% of the generated substrate radicals. The model system provides a simple and convenient method for comparing the crosslink efficiencies of peroxides; these data are reported for some commercial peroxides. In order to facilitate an extrapolation of the results in liquid alkanes towards solid polyethylene (PE), the influence of substrate viscosity and temperature on the peroxide decomposition rate, product distribution, and crosslink efficiency was studied. In n‐alkanes peroxide decomposition follows first‐order kinetics well, with an Arrhenius activation energy of 32.9 ± 0.5 kcal/mole. In addition, the kinetics in the model system are compared with those calculated from Rheometer (torque vs. time) measurements on the curing of unfilled PE and ethylene‐propylene‐dicyclopentadiene terpolymer (EPDM). Only minor differences in peroxide decomposition rate and overall activation energy were found.
High‐resolution NMR studies on radiolytic reactions in polyethylene
Authors: Hayakawa N. , Kuriyama I.
Published: April 2003

High‐resolution NMR spectra was obtained for linear polyethylene powder irradiated by 60Co γ‐rays in vacuo or in air. For the sample irradiated in vacuo, the spectra consist of two components having different line width. The narrow component was assigned to soluble molecules and the broad one to gel. When samples are irradiated in air, their spectra show no broad component. The GPC curves obtained for the samples irradiated in air shift to high elution counts (low molecular weight) upon increase of the irradiation dose. It is concluded that oxidative degradation is the predominant reaction in the sample irradiated in air.
Polyimidines, a new class of polymers. II. Polyhexamethylenetetraphenyldithiopyromellitimidine
Authors: Cassidy Patrick E. , Lee Frankie W. C.
Published: April 2003

Polyimidines have been shown to be soluble, thermally stable polymers. In searching for an alternate synthetic method the thio analog of this system has been discovered. The brightly colored (red‐orange) perthio derivatives of 3,3‐diphenylphthalide and 3,3,5,5‐tetraphenyipyromellitide were synthesized from their oxo analogs with P2S5. The model compound thioimidines were synthesized by reacting 3,3‐diphenyldithiophthalide with aniline and with 1,6‐hexane diamine and by reacting 3,3,5,5‐tetraphenyltetrathiopyromellitide with aniline and n‐hexylamine. The polymerization of tetraphenyltetrathiopyromellitide occurred readily with 1,6‐hexanediamine in boiling carbon tetrachloride with complete cyclization. This reaction gave an 80% yield with inherent viscosities up to 0.89 and molecular weights up to approximately 11,000. Thermogravimetric analysis showed a 2% weight loss at 200°C and 10% weight loss at 300°C with rapid decomposition above 300°C. Although the polythioimidine was less thermally stable than its oxo analog, it was much more soluble in common solvents (aromatic and chlorinated aliphatic hydrocarbons) and more readily synthesized in higher yield.
Préparation de polyesteramides alternés
Authors: Akçatel P. , Jasse B.
Published: April 2003

The polycondensation of hydroxyamido acids of general formula HO‐R1‐CO‐NH‐R2‐COOH provides alternating polyesteramides only when R1 and R2 are alkyl groups. These aliphatic alternating polyesteramides, according to their structural high regularity, possess a more important content of interchain hydrogen bonds than the random copolymers. The higher melting point of the random copolymers is attributed to the heterogeneity of amide group partition in the chain. The existence of a benzyl group in the structure of the hydroxyamido acids reduces the polycondensation ability and the molecular weights of the products are low. These aromatic monomers are thermally degraded, p‐toluic acid evolving; ester and amide functions stoechiometric ratio is not maintained, but infrared and differential thermal analysis show that these aromatic polyestermides keep a reasonable structural regularity.
Vinyl chloride–propylene copolymerization
Authors: Ravey M. , Waterman J. A. , Shorr L. M. , Kramer M.
Published: April 2003

Because of the allylic nature of propylene, the vinyl chloride–propylene system exhibits polymerization behavior markedly different from that of vinyl chloride, even at relatively low propylene concentrations. Propylene acts as a degradative chain‐transfer agent, and as a result, both the polymerization rate and the molecular weight of the resultant copolymers are lower than those of the homopolymer, decreasing with increasing propylene content. Even at propylene concentrations as low as 10% the rate of polymerization is proportional to the initiation rate, indicating kinetic control by the propylene. The reactivity ratios of these monomers given by Cain were verified. The reciprocal intrinsic viscosity of the copolymer was found to be linearly related to the monomer feed composition.
Applications of ESCA to polymer chemistry. X. Core and valence energy levels of a series of polyacrylates
Authors: Clark D. T. , Thomas H. R.
Published: April 2003

The core and valence levels of a series of poly(alkyl acrylates) have been studied by ESCA. From an analysis of the individual component peaks for the C1s and O1s core levels and from comparison of relative area ratios it is shown that ESCA may be applied to the study of surface compositions. The evidence presented strongly suggests that on the ESCA depth‐profiling scale the technique statistically sample the repeat units with no evidence for preferential orientation of side chains at the surface. For some samples, ESCA provides evidence for a degree of surface oxidation and hydrocarbon contamination. The valence energy levels are shown to be characteristic of the polymer system. The measured absolute and relative binding energies of the core levels have been compared with model calculations using the charge‐potential model in the CNDO/2 SCF MO formalism.
Synthesis of monomers that expand on polymerization. Synthesis and polymerization of 3,9‐dimethylene‐1,5,7,11‐tetraoxaspiro[5.5]undecane
Authors: Bailey William J. , Endo Takeshi
Published: April 2003

A spiro ortho‐carbonate containing two double bonds, 3,9‐dimethylene‐1,5,7,11‐tetraoxaspiro[5.5]undecane (III) was prepared from 2‐methylene‐1,3‐propanediol (VI). The structure of the monomer was indicated by its elementary analysis as well as its infrared and NMR spectra. When the crystalline monomer was polymerized with Lewis acids such as trifluoride etherate as catalysts, soluble polymer with a high molecular weight was obtained. The infrared and NMR spectra indicated that the polymer was an alternating copolymer of ether and carbonate having double bonds. When the usual monomers such as vinyl chloride and styrene polymerize, shrinkage occurs. However, this monomer underwent expansion on polymerization.
Study of radiation‐induced polymerization of vinyl monomers adsorbed on inorganic substances. VII. Effect of pretreatment temperature of silica gel on styrene–silica gel system
Authors: Fukano Kazuyuki , Kageyama Eiichi
Published: April 2003

To investigate the reaction mechanism of radiation‐induced polymerization of styrene adsorbed on silica gel, the effect of pretreatment temperature of silica gel was studied. Preheating of silica gel was carried out at 200, 500, and 800°C. The number of silanol groups of silica gel surface decreased as preheating temperature increased. The rate of polymerization on the silica gel preheated at 500°C was faster than that at 200°C, but the polymerization rate on the silica gel preheated at 800°C was the lowest. These results suggest that rate of polymerization on the silica gel is affected by the conditions of silica gel surface such as the number of silanol groups and the pore size. At the same monomer conversion, percent grafting decreased as preheating temperature of silica gel increased. The GPC spectra of both graft polymers and homopolymers have two peaks at all preheating temperatures. The monomer conversion of low molecular weight peaks of graft polymers decreased as preheating temperature of silica gel increased. This result suggests that there is a probability that the grafting sites of low molecular weight peaks of graft polymers somehow interact with silanol groups.
Effect of surface swelling on diffusion on polymers. II. Delamination
Authors: Sefton Michael V. , Merill Edward W.
Published: April 2003

Swelling in chloroform resulted in delamination of surface‐hydroxylated styrene‐butadiene‐styrene block copolymers, with the formation of three fractions: crosslinked gel, reacted sol, and unreacted chloroform‐soluble material. From the relative weights of these fractions, the depth of penetration of the reaction and the shape of the reaction front were determined. The weight of the gel fraction gave directly an estimate of the depth of penetration, λx which decreased with increasing film thickness. This was attributed to the increased amount of reacted polymer being noncrosslinked material (sol) in the interior compared to the 100% crosslinked nature of the surface region and to a reduction in the penetration of the reaction front resulting from the effect of stress transfer in lowering the permeation rate of peracetic acid. Comparison of the depth of penetration estimates λx and λs determined from the weight of the unreacted polymer demonstrated that, for the conditions used, the reaction front is quite broad. (For example, at 40°C, in 71% acetic acid for 80 min, the fully crosslinked portion is 15 μm thick and the partially reacted region extends for another 8.5 μm.) The combined influences of the increase in penetration of the reactants in the polymer and the relief of stress secondary to this increase in penetration were reflected in the time dependence of the depths of penetration λx and λs.
Interaction of several polymers with p‐substituted phenols in aqueous solution
Authors: Inoue Masami , Otsu Takayuki
Published: April 2003

The interactions between several water‐soluble polymers, i.e., polyethyleneimine (PEI), poly‐(ethylene glycol) (PEG), polyacrylamide (PAM), and poly(methacrylic acid) (PMAA), and p‐X‐substituted phenols (X = CH3O, CH3 C2H5, H, Cl, Br and NO2) in aqueous solution at 30°C were investigated by means of equilibrium dialysis. By applying the Klotz equation to the results obtained, the bonding constants between these polymers, including poly(vinylpyrrolidone) (PVP) which was reported previously, and phenol were determined; they decreased in the following order: PVP > PMAA > PEI > PAM > PEG. This order was in agreement with that reported from the solubility of naphthalene, biphenyl, and alkyl halides in aqueous solution of these polymers caused by a hydrophobic bonding interaction. In this case, therefore, a hydrophobic bonding seemed to be significant. The bonding constants of these polymers with p‐substituted phenols were also determined, and they were found to be approximately correlated with Hamett σ constants of the para substituents in phenols. Therefore, it was concluded that the interactions due to electrostatic and hydrogen‐bonding forces were also important.
Liquid crystal polymers. I. Preparation and properties of p‐hydroxybenzoic acid copolyesters
Authors: Jackson W. J. , Kuhfuss H. F.
Published: April 2003

High molecular weight copolyesters were prepared by the acidolysis of poly(ethylene terephthalate) with p‐acetoxybenzoic acid and polycondensation through the acetate and carboxyl groups. The mechanical properties of the injection‐molded copolyesters containing 40–90 mole‐% p‐hydroxybenzoic acid (PHB) were highly anisotropic and dependent upon the PHB content, polyester molecular weight, injection‐molding temperature, and specimen thickness. As the injection‐molding temperature increased and the specimen thickness decreased, the tensile strength, stiffness, and Izod impact strength increased when measured along the direction of flow of the polymer melt, and the coefficient of thermal expansion was zero. In some compositions these properties were superior to those of commercial glass fiber reinforced polyesters. Maximum tensile strengths, flexural moduli, notched Izod impact strengths, and minimum melt viscosities were obtained with polyesters containing 60–70 mole‐% PHB. Higher oxygen indicies (39–40) and heat deflection temperatures (150–220°C) were obtained with 80–90 mole‐% PHB.
Poly‐N‐methyliminotetrafluoro‐1,4‐phenylene
Authors: Koppang Rolf
Published: April 2003

Poly‐N‐methyliminotetrafluoro‐1,4‐phenylene has been prepared. The polymer was insoluble in organic solvents, but dissolved in concentrated H2SO4. It started to melt at approximately 360°C with decomposition. The structure of the polymer is discussed on the basis of synthesized oligomers.
Kinetic study of the alternating copolymerization of butadiene and methyl methacrylate
Authors: Furukawa Junji , Arai Yoshihiro , Kobayashi Eiichi
Published: April 2003

A kinetic investigation of the alternating copolymerization of butadiene and methyl methacrylate with the use of a system of ethylaluminum dichloride and vanadyl chloride as a catalyst was undertaken. The relation between the polymer yield and the molar fraction of methyl methacrylate in the feed was examined by continuous variation of butadiene and methyl methacrylate, the concentrations of total monomer, ethylaluminum dichloride, and vanadyl chloride being kept constant. This continuous variation method revealed that the polymer yield attains its maximum value with a monomer feed containing less than the 0.5 molar fraction of methyl methacrylate. This value of the molar fraction of methyl methacrylate affording the maximum polymer yield decreased on increasing the total monomer concentration but was not changed on varying the concentration of ethylaluminum dichloride. The number of active species estimated from the relation between yield and molecular weight of the polymer was almost constant, regardless of the molar fraction of methyl methacrylate in the feed. Consequently, it can be said that the maximum polymer yield depends mainly on the propagation reaction, not on the initiation reaction or the termination reaction. Three types of the mechanism have been discussed for this alternating copolymerization: polymerization via alternating addition of butadiene and methyl methacrylate complexed with ethylaluminum dichloride by the Lewis‐Mayo scheme; polymerization via the ternary intermediate of butadiene, methyl methacrylate, and ethylaluminum dichloride; polymerization via the complex formation of butadiene and methyl methacrylate complexed with ethylaluminum dichloride occurring only at the growing polymer radical. From the kinetic results obtained, it was shown that the first and third schemes are excluded, and polymerization by way of the ternary intermediate is compatible with the data.
Ring‐opening polymerization. V. Hydroxyl‐initiated polymerization of phenyl‐substituted 1,3‐dioxolan ‐2,4‐diones: A model study
Authors: Smith I. J. , Tighe B. J.
Published: April 2003

The reaction of C(5) phenyl‐substituted 1,3‐dioxolan‐2,4‐diones with a series of alcohols has been studied in order to obtain quantitative information relating to the role of hydroxyl initiation in the polymerization of these compounds. Results relating to both the effect of C(5) substitution and the structure of the attacking alcohol are presented. The reactions are secondorder (first‐order with respect to each component) and show some of the kinetic features associated with monosubstituted 1,3,2‐dioxathiolan‐4‐one‐2‐oxides. Structural effects are adequately represented in terms of Taft σ* and Es substituent constants. Of the parameters describing the properties of the reaction medium, the donicity concept was found to give the best correlation with rate data. It is considered that hydroxyl initiation will contribute to a relatively small extent in the polymerization of 5,5‐diphenyl‐1,3‐dioxolan‐2,4‐dione and 5‐methyl, 5‐phenyl‐1,3‐dioxolan‐2,4‐dione but will form the basis for the major chain‐growth process in 5‐phenyl‐1,3‐dioxolan‐2,4‐dione.
Correlation between the effect of sonic irradiation on the microfibrils of chitin and cellulose and the polarity of their chains
Authors: Colvin J. Ross
Published: April 2003

The effect of sonication on the morphology of microfibrils of chitins and celluloses was correlated with the polarity of their constituent chains. For given conditions, fibrillation of the microfibrils takes place when the polarity of the chains is antiparallel but not when it is parallel. If this correlation may be extended to cases of unknown structure, it permits an inference about the parallelity or antiparallelity of the chains of samples of both polymers where polarity cannot be determined directly.
Formation of free radicals in photoirradiated cellulose. VIII. Mechanisms
Authors: Hon Nyok‐Sai
Published: April 2003

Photoinduced free radicals in cellulose were studies by means of ESR spectroscopy. Plausible mechanisms have been suggested for each type of intermediate radical to account for the ESR spectra observed and for the product balances. Based on the principles of photochemistry of cellulose, coupled with the findings of the ESR spectra, it becomes evident that localization of the energy absorbed in the cellulose molecule leads to formation of free radicals in terms of chain scission, dehydrogenation, dehydroxylation, and dehydroxymethylation. Emphasis has been placed on the correlation of the mechanisms of photodegradation and the mechanisms of photoinduced graft copolymerization.
220‐MHz NMR spectra of acrylic monomer–2‐substituted 1,3‐diolefin alternating copolymers
Authors: Furukawa Junji , Kobayashi Eiichi , Arai Yoshihiro , Suzuki Toshimitsu , Takegami Yoshinobu
Published: April 2003

An investigation by 220‐MHz NMR spectroscopy was carried out on the alternating copolymers of acrylic monomer with 2‐substituted 1,3‐diolefin. The chain structures were determined. The acrylic monomers used were methyl methacrylate (MMA), acrylonitrile (AN), and methacrylonitrile (MAN); isoprene (IP) and chloroprene (CLP) were the 1,3‐diolefins. In the MAN–IP alternating copolymer, the 1‐position methylene protons of IP showed an AB quartet peak, confirming the α‐1 linkage structure. Similarly, in the MMA–CLP and AN–CLP copolymers, the 1‐position methylene protons of CLP showed and AB quartet and an ABX pattern, respectively, confirming the α‐1 linkage structure in both these cases also. The α‐1 linkage structure was also revealed by the decoupling technique in the MAN–CLP alternating copolymer. The AN–IP and MMA–IP alternating copolymers also possess a bond between the α‐position of the acrylic monomer and the 1‐position of IP. The monomeric units in the alternating copolymers of acrylic monomers with 2‐substituted 1,3‐diolefins were generally linked at the α‐position of acrylic monomer and the 1‐position of 1,3‐diolefin. On the other hand, in the Diels‐Alder adducts of acrylic monomer with 2‐substituted 1,3‐diolefin, the reaction takes place between the α‐position of acrylic monomer and the 4‐position of 1,3‐diolefin.

The regioselectivity of the alternating copolymers and the Diels‐Alder adducts is quite compatible with the expectations from molecular orbital theory.
Phenylethynyl‐pendant polyphenylquinoxalines curable by an intramolecular cycloaddition reaction
Authors: Hedberg F. L. , Arnold F. E.
Published: April 2003

Polyphenylquinoxalines containing 2,2′‐bis(phenylethynyl)diphenylene moieties along the polymer backbone have been synthesized. As anticipated, these polymers were found to undergo a novel curing reaction consisting of an intramolecular cycloaddition (IMC) of pendant groups to a dibenzoanthracene backbone structure. The IMC reduces chain mobility, and the fused ring structure increases the glass transition temperature of the polymer. The potential of this approach to curing high‐temperature polymers was demonstrated in the processing of one such polymer having an initial Tg of 215°C. Curing at 245°C with no evolution of volatiles produced a Tg of 365°C. This very significant increase in potential use temperature via a volatiles‐free IMC cure provides promise for a tough phenyiquinoxaline resin system which can be used to fabricate reinforced composites that have use temperatures far exceeding processing temperatures.
Vinyl polymerization. CCCXXXIX. Effect of chain length of nylon 3 on the polymerization of methyl methacrylate initiated with the system of nylon 3, copper(II) ion, and water
Authors: Ouchi Tatsuro , Nishimura Tamio , Imoto Minoru
Published: April 2003

It was found recently that the system of nylon 3, copper(II) ion, and water could initiate a radical polymerization of methyl methacrylate(MMA). In the present paper, the effect of average chain length of the molecules of nylon 3 on the rate of polymerization of MMA was studied. The rate increased with the chain length of nylon 3. This result was explained well by the fact that the shorter nylon 3 forms a complex with copper (II) ion more easily than longer nylon 3. It was assumed that the shorter nylon 3 fills three or four coordination sites of copper(II) ion and loses the ability to initiate the polymerization. The efficiency of grafting of MMA and the degree of polymerization of MMA homopolymer were independent of the chain length of nylon 3.
Rotating ring‐disk electrode studies of the reaction of stable radical cations with styrene and isobutyl vinyl ether
Authors: Funt B. Lionel , Severs Wendy , Glasel Arnold
Published: April 2003

An electroanalytical technique has been utilized in a new method for the study of reactive intermediates in polymerization reactions. A ring‐disk electrode system generated persistent carbocation radicals whose stability decreased in the order: 1,3,6,8‐tetraphenylpyrene (TPP), rubrene (Ru), 9,10‐diphenylanthracene (DPA), and 9,10‐dimethylanthracene (DMA). Radical cations from these parent compounds flowed to a collecting ring which was controlled potentiostatically to reduce unreacted cations. When styrene or isobytyl vinyl ether was added to the solution, the concentration of carbocation radicals reaching the electrode was reduced. Current collection efficiencies N were determined as a function of rotation speed ω for each monomer concentration. Plots of N−1 as ω−1 in the absence of monomer show no dependence on ω (indicative of stable intermediates), but a linear dependence is found with each concentration of monomer. This indicates a first‐order dependence on radical cation concentration. The rate constants show a trend in cation reactivities which is in agreement with that obtained by other methods. This technique, however, extends the range of investigation to a much shorter time scale.
Oligomeric polyaromatic ether‐ketone‐sulfones with acetylenic end groups. X
Authors: Huang Frank , Marvel C. S.
Published: April 2003

Two new oligomeric polyaromatic ether‐ketone‐sulfones with acetylenic end groups have been synthesized. These acetylene‐terminated oligomers are soluble in common organic solvents and can be cured under thermal conditions to give the crosslinked polymers which do not soften below 240°C. In the case of oligomer which is incorporated with terephthaloyl chloride, the cured polymer shows almost no penetration below 400°C. Isothermal aging studies show that the cured polymers are stable in circulating air at 300°C with less than 10% weight loss in 3 days.
Photochemistry of fiber‐forming polymers. II. Ketone‐containing poly(ethylene terephthalates)
Authors: Alexandru L. , Guillet J. E.
Published: April 2003

Poly(ethylene terephthalate) copolymers were prepared containing minor amounts of comonomers containing backbone and side‐chain ketone groups. The photochemistry of these polymers was studied at 313 nm, both in film and fiber form. It was demonstrated that only the comonomer, dimethyl‐γ‐ketopimelate (DMKP), gave a copolymer with enhanced sensitivity to ultraviolet degradation in air. Since this sensitivity is reduced in a nitrogen atmosphere, it is suggested that the mechanism involves main‐chain scission to form two free radicals by the Norrish type I mechanism, and that recombination of these radicals is reduced by reaction with oxygen. The use of copolymers of this type provides a method for the controlled photodegradation of polyester fibers.
Applications of ESCA to polymer chemistry. XII. Structure and bonding in commercially produced fluorographites
Authors: Clark David T. , Peeling James
Published: April 2003

A series of fluorinated graphites, Fluorographites, of varying fluorine content has been examined by ESCA, and the chemical shifts and relative intensities of the core electron lines yield a consistent picture of the compositions and structures in the surface regions of the materials. Fluorographites of composition (C1F0.81)n to (C1F1.00)n are fully fluorinated in the outermost ∼40 Å and consist of a bulk structure composed of tertiary →CF groups with CF2 groups at the prismatic edges of the fluorinated graphite layers. This is also the case for (C1F1.05)n, but, in addition, some of the CC bonds involving edge →CF carbons are broken and replaced by CF bonds, giving a higher concentration of CF2 groups at the outermost surfaces of the particles of this material. The ESCA data for (C1F0.25)n are consistent with a structure comprising six‐membered aromatic rings in which each ring carbon is attached to a →CF group acting as a bridge among three similar rings, with the CF bonds alternately pointing up and down with respect to the plane defined by the carbon atoms. At the immediate surface the valence requirements of the carbon atoms at the prismatic edges of the graphite‐like layers are satisfied by bonding with oxygen. This is also the apparent structure of (C1F0.37)n, but in addition there exist discrete regions of composition (C1F1)n distributed uniformly throughout this material. The Fluorographites (C1F0.34)n, and (C1F0.40)n, and (C1F0.63)n consist of blocks of C1F1 stoichiometry and blocks of unreacted graphite. The presence of CF2 groups and the complete absence of oxygen in the surface regions of these Fluorographites suggests that the prismatic edge sites are fully fluorinated. The inhomogeneous block‐like structures of (C1F0.37)n, (C1F0.37)n, and (C1F0.34)n, (C1F0.40)n, and (C1F0.63)n, give rise to differential sample charging, resulting in apparent shifts in the binding energy scales between the spectral components originating from different regions of the samples. Such differential sample charging is also described for a number of mixtures of the Fluorographites and of graphite with the Fluorographites. It is pointed out that in view of these results it is necessary to exercise considerable caution in using the ESCA lines of an added compound as a reference in measuring core electron‐binding energies.
Synthesis of polystyenes with different stereoregularities by anionic polymerization
Authors: Uryu Toshiyuki , Seki Toshiyuki , Kawamura Tokiji , Funamoto Akashi , Matsuzaki Kei
Published: April 2003

The stereoregularity of polystyrene prepared by anionic polymerization was determined by means of 13C‐NMR spectroscopy. The stereoregularity changed with such polymerization conditions as catalyst, solvent, and temperature. Sodium naphthalene as catalyst gave a syndiotactic‐rich polystyrene of 66–68% syndiotactic dyads independently of solvent and temperature, while potassium and cesium naphthalenes as catalyst produced polystyrenes with different stereoregularities ranging from syndiotactic‐rich to isotactic‐rich configurations, depending on solvent and temperature. The mechanism of anionic polymerization which caused the difference in stereoregularity was discussed from the viewpoint of growing ionic species.
ESCA studies of polymers. XIII. Shake‐up phenomena in substituted polystyrenes
Authors: Clark D. T. , Dilks A.
Published: April 2003

Shake‐up phenomena in a series of para‐substituted polystyrenes have been studied by ESCA. Comparison with other spectroscopic data and with theoretical calculations within the sudden approximation, equivalent cores model, and CNDO SCF MO formalism identifies the shake‐up structures as arising predominantly from π*← π transitions involving the highest occupied and lowest unoccupied orbitals of the pendant phenyl groups.
Thermodynamics of binding of methyl orange and its homologs by poly(vinylpyrrolidone): The effect of inorganic electrolytes
Authors: Takagishi Toru , Imajo Koichi , Nakagami Kimio , Kuroki Nobuhiko
Published: April 2003

The extent of binding of methyl orange, ethyl orange, propyl orange, and butyl orange by poly(vinylpyrrolidone) has been measured in aqueous solutions of inorganic electrolytes such as NaCl, LiCl, NaSCN, and NaClO4 by an equilibrium dialysis method. The effect of the salts on the first binding constants and the thermodynamic functions which are accompanied by the dye—polymer association process was investigated relative to the corresponding values in the absence of such salts. It was found that in aqueous solutions of NaCl and LiCl the enthalpy change accompanying the binding is small and the largest contribution to the free energy of binding is from the positive entropy gain. For NaSCN and NaClO4, the values of ΔF° and ΔH° were both large and negative and the value of ΔS° was small and negative. Thus, the favorable free energy for the complex formation was due entirely to the negative enthalpy term. These characteristics of the thermodynamic quantities are discussed in terms of changes in structural properties of water in the vicinity of the binding entities and conformational changes of the polymer to which the dye is bound due to the added foreign electrolytes.
Reactivity ratios for acrylonitrile–vinyl chloroacetate copolymerization systems
Authors: Miller Andrzej , Szafko Jerzy , Turska Eligia
Published: April 2003

Reactivity ratios for acrylonitrile—vinyl chloroacetate systems have been determined for radical copolymerization at 60°C in dimethylformamide. The values of the ratios calculated by the linear graphical method of Kelen and Tüdös were as follows: r1 = 4.05 ± 0.1 and r2 = 0.001 ± 0.001 for acrylonitrile (AN)—vinyl monochloroacetate (VCAc), r1 = 7.0 ± 0.25 and r2 = 0.05 ± 0.015 for acrylonitrile—vinyl dichloroacetate (VDAc), r1 = 7.13 ± 0.25 and r2 = 0.06 ± 0.015 for acrylonitrile—vinyl trichloroacetate (VTAc). The penultimate model of the copolymerization and the effect of the vinyl chloroacetate structure were discussed.
Chemiluminescence from polytetrafluoroethylene
Authors: Mendenhall G. David , Hassell John A. , Nathan Richard A.
Published: April 2003

The chemiluminescence emission from commercial samples of polytetrafluoroethylene, PTFE (Halon G‐80 and Halon G‐10), was studied at temperatures between 25 and 172°C. The emission intensity decreased on extended heating, removal of the surface layer, solvent extraction, or changing from an atmosphere of oxygen to an inert atmosphere. Films of PTFE deposited from the vapor phase showed comparatively little chemiluminescence under these conditions. Ozone‐induced chemiluminescence was observed at 37°C from G‐10 but not from G‐80, or from films deposited from the vapor phase. The chemiluminescence intensity from ozone and G‐10 was not reduced by solvent extraction.