bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural characterization of polybenzyls by high field 13C‐NMR spectroscopy
Authors: Ul Hasan Misbah , Tsonis Christos P.
Published: April 2003

13C‐NMR Spectroscopy has been used for the structural characterization of polybenzyls synthesized from the polymerization of benzyl chloride catalyzed by arene chromium tricarbonyls. The 13C‐chemical shifts for various mono‐, di‐, tri‐, and tetrasubstituted phenyl groups in a polybenzyl have been calculated by the use of additivity parameters and compared with their observed shifts. Although from a theroetical point of view, polysubstitution on a phenyl ring gives rise to a number of isomers, the results indicate the preferential formation of only a few of them due to steric and electronic considerations. Based on quantitative 13C‐NMR data, several important structural parameters including the percentage of mono‐, di‐, tri‐, and tetrasubstituted phenyl rings in the polybenzyl can be calculated. The extent of branching in a number of polybenzyls prepared under different experimental conditions was determined. The results indicate an increase in branching with the increase in reaction temperature.
The photopolymerization of isoprene with the use of hydrogen peroxide as photoinitiator
Authors: Tang D. K. , Ho S. Y.
Published: April 2003

The photochemical polymerization reactions of isoprene with the use of H2O2 as the photoinitiator have been studied in benzene, acetone, and tetrahydrofuran solutions. Hydrogen peroxide is photodecomposed to form hydroxyl radicals which may initiate the polymerization of isoprene with hydroxyl terminated polyisoprene as the product. Average molecular weight, microstructure, and the functionality of the hydroxyl terminated polyisoprene are determined. A suitable reaction mechanism and the polymerization rate equations are proposed. The overall activations energy is evaluated to be about 3.8 kcal/mol.
Polymeric arylsulfonylmethyl isocyanide, a novel polymer reagent
Authors: Kamogawa Hiroyoshi , Maeda Kazunori
Published: April 2003

p‐Vinylphenylsulfonylmethyl isocyanide (1M) was synthesized starting with sodium p‐styrenesulfinate via p‐vinylphenylsulfonylmethylformamide (4M). Free‐radical polymerization of 1M provided cross‐linked insoluble polymers (1), whereas 4M provided soluble polymers, which could be converted to soluble polymer 1. Conversions of carbonyl compounds to nitriles and Schiff bases to 1,5‐disubstituted imidazoles with both soluble and cross‐linked polymers 1 as reagents proceeded almost as efficiently as with their low molecular weight analog. Reusability of polymer 1 was fairly good.
Emulsion polymerization of styrene. III. Effect of Ti(III) and Cl(1) on the polymerization of styrene initiated by potassium persulfate
Authors: Bataille P. , Gonzalez A.
Published: April 2003

The emulsion polymerization of styrene initiated by potassium persulfate catalyzed by Ti+3 ions was studied. Two sources of Ti+3 ions were used: the titanium trichloride and titanium sulfate. It was found that the titanium ions used in conjunction with potassium persulfate decrease both the reaction rate and the average molecular weight. An even greater drop of reaction rate was noted when chlorine anions (TiCl3) were present. The presence of these ions had a stabilizing effect on the polydispersity.
Structure and properties of poly(ethylene terephthalate) crystallized by converging flow and high pressure
Authors: Ledbetter Marshall , Cuculo John , Tucker Paul
Published: April 2003

The structure and properties of a poly(ethylene terephthalate) extrudate, prepared by converging flow and high pressure, were examined. Relatively high levels of crystallinity and orientation were produced by the combination of an orienting flow and high‐pressure quench. The fine structure was examined in detail by x‐ray diffraction, negative staining–transmission electron microscopy, and amine etching–gel permeation chromatography. The morphology was directly relatable to this unique preparative technique. Modulus was determined by a compressive Rheovibron technique. Low shrinkage and the compressive modulus were related to the structure in the development of a structural model.
Mass spectroscopy of epoxylated novolac resin cured with phthalocyanine tetraamines
Authors: Achar B. N. , Fohlen G. M. , Hsu M. S. , Parker J. A.
Published: April 2003

Mass spectroscopy was done at different temperatures on epoxylated novolac resin DEN 438 (Dow Chemical Co.) alone, and after curing with various metal(II) phthalocyanine tetraamines (MPTA). Possible modes of fragmentation are given to explain the experimental results. Gas‐chromatographic/mass‐spectroscopic (GC–MS) analyses of MPTA derivatives indicated the presence of only trace quantities of benzene, aniline, cyanobenzene, and orthodicyanobenzene. The GC–MS studies of the cured DEN 438 epoxy resins indicated that the mechanisms of thermal degradation are qualitatively similar, and some common features were observed in their fragmentation in an electron beam and by thermal degradation. This study is a further assessment of the utility of these phthalocyanine derivatives for curing epoxy resins to produce heat‐resistant polymer systems.
Effect of structure on properties of polypyromellitimide films
Authors: Varma I. K. , Tripathi Anita , Goel T. C. , Murthy K. R. , Tripathi A. K.
Published: April 2003

Polypyromellitimides were prepared by the reaction of di(4‐aminophenyl) ether (E)/di (4‐aminophenyl) methane (M), and pyromellitic dianhydride in dimethylformamide, followed by thermal cyclization in a nitrogen atmosphere. Copolyimides were obtained by taking different molar ratios of diamines in the initial monomer feed. Differential scanning calorimetric, thermogravimetric analysis, and thermally stimulated current studies were carried out on these samples. It was concluded that the dielectric relaxation in these copolymers is due to trapping of the charge carriers. The dielectric relaxation parameters and activation energies were also calculated.
Polymerization of alkyl allyl oxalates in the evolution of carbon dioxide at elevated temperatures
Authors: Yamawaki Masataka , Matsumoto Akira , Oiwa Masayoshi
Published: April 2003

Radical polymerization of several alkyl allyl oxalates, including methyl allyl oxalate (MAO), ethyl allyl oxalate, propyl allyl oxalate, butyl allyl oxalate, and octyl allyl oxalate, was conducted in the evolution of carbon dioxide at elevated temperatures, and was compared with the anomalous polymerization behavior of diallyl oxalate (DAO) discussed in our earlier article

A. Matsumoto, I. Tamura, M. Yamawaki, and M. Oiwa, J. Polym. Sci. Polym. Chem. Ed., 17, 1419 (1979).

. The kinetic equations for the polymerization of alkyl allyl oxalate were derived following the kinetic treatment of the DAO polymerization by further consideration of the absence of cyclization of the growing polymer radical and the effective reinitiation by alkyl radical, and were then satisfactorily applied to the polymerization of MAO, as a representative alkyl allyl oxalate. The evolution of carbon dioxide in the polymerization of alkyl allyl oxalates was enhanced with the increase of bulkiness of the alkyl substituent, as a result of steric suppression of the propagation of the growing polymer radical.
Mechanisms of antioxidant action: Transformations of 4‐hydroxy‐2,2,6,6‐tetramethylpiperidinoxyl (HTMPO) in polypropylene during processing
Authors: Bagheri Rouhalla , Chakraborty Khirud B. , Scott Gerald
Published: April 2003

When 4‐hydroxy‐2,2,6,6‐tetramethyl piperidinoxyl (HTMPO) is processed in polypropylene in a closed mixer, almost 50% is converted to other products during the first few minutes whilst the applied torque in the mixer is high. There is associated formation of unsaturation and this fact, in conjunction with the almost complete regeneration of nitroxyl within five minutes, suggests that the corresponding hydroxylamine (HTMPOH), which can be qualitatively identified, is the major transformation product. A study of the UV stability of PP films fabricated from polymer processed for varying times shows that UV stability is related to the quantity of the redox couple (HTMPO + HTMPOH) remaining in the polymer. This is considerably reduced by severe processing. The redox capable has almost no thermal antioxidant (oven aging) activity.
Syntheses of poly[N‐(1‐pyrenyl)acetyl ethylenimine] [pyrene‐substituted linear poly(ethylenimine)] and poly[methyl 2‐(1‐pyrenyl)acetamidopropenoate] [pyrene‐substituted poly(dehydroalanine methyl ester)]
Authors: Arora Kartar S. , Overberger C. G.
Published: April 2003

The syntheses of two new pyrene‐containing monomers—2‐(1‐pyrenyl)methyl‐2‐oxazoline (6) and methyl 2‐(1‐pyrenyl)acetamidopropenoate (12)—and their polymerization are described. Cationic isomerization polymerization of 6 with ethylene glycol ditosylate initiator gave poly[N‐(1‐pyrenyl)acetyl ethylenimine] (7) and free‐radical polymerization of 12 with AIBN initiator gave poly[methyl 2‐(1‐pyrenyl)acetamidopropenoate] (15). The monomer model compounds of the two polymers, namely, N,N‐diethyl(1‐pyrenyl)acetamide (9) and methyl 2‐methyl‐2‐(1‐pyrenyl)acetamidopropanoate (14), were also synthesized. The polymers were characterized by elemental analysis, IR spectroscopy, and a comparison of their 1H‐NMR spectra with those of the respective monomer model compounds.
W/O microemulsions of styrene monomer and dimer
Authors: Friberg Stig E. , Liang Paul
Published: April 2003

The reason for the lower water solubility in W/O microemulsions of the styrene dimer, trans, trans‐1,4‐diphenyl‐1,3‐butadiene, in comparison with the monomer was investigated by determining the phase equilibria in the microemulsion system with pentanol as the cosurfactant and sodium dodecyl sulfate as the surfactant. The main factor for the low tolerance for water in the system was the incompatibility of the dimer with the cosurfactant and surfactant.
Fire‐ and heat‐resistant adhesive resins based on maleimido and citraconimido substituted 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes
Authors: Mikroyannidis John A.
Published: April 2003

A novel class of fire‐ and heat‐resistant bisimide resins was prepared by thermal polymerization of maleimido or citraconimido derivatives of 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (1). The neat bisimide resin prepared by curing 1‐[di(2‐chloroethoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐bismaleimidobenzene exhibited a limiting oxygen index 75% higher and smoke evolution about 30 times lower compared with the parent polymer obtained by curing m‐phenylenebismaleimide. The char yield of cured bisimide resins at 700°C was 58–70% in a nitrogen atmosphere and 35–60% in air. An increase in formula weight between the imide groups slightly reduced the char yield. The polymer precursors were synthesized by reacting the phosphorus‐containing diamines (1) (1 mol) with maleic anhydride/citraconic anhydride (2 mol) or by reacting the monomaleimido derivative of (1) with benzophenone tetracarboxylic dianhydride/methylenebis(4‐phenylisocyanate) in a 2:1 mole ratio. The monomers were characterized by elemental analysis, Fourier‐transform–infrared (FT‐IR), proton nuclear magnetic resonance (1H‐NMR) spectroscopy, and gas chromatography–mass spectroscopy (GC‐MS). Direct cleavage of the PC bond and inversion of the synthesis reaction may occur during their pyrolysis. The thermal polymerization of the monomers was investigated by differential scanning calorimetry (DSC). Biscitraconimides are thermally polymerized at a relatively lower temperature than the corresponding bismaleimides.
A novel photoinitiator of cationic polymerization: Preparation and characterization of bis [4‐(diphenylsulfonio)phenyl]sulfide–bis‐hexafluorophosphate
Authors: Watt W. R. , Hoffman H. T. , Pobiner H. , Schkolnick L. J. , Yang L. S.
Published: April 2003

Efforts to prepare triphenylsulfonium hexafluorophosphate by metathesis between commercially available “triphenylsulfonium chloride” and potassium hexafluorophosphate failed to yield the expected product but gave, instead, in approximately 50% yield, a crystalline substance with well‐defined properties readily distinguishable from triphenylsulfonium hexafluorophosphate. The unexpected substance is identified as bis‐[4(diphenylsulfonio)phenyl]sulfide–bis‐hexafluorophosphate, for which no previous reference has been found in the literature. Its identification is based on elemental analysis, NMR, mass spectrometry, and infrared analysis. Bis‐[4‐(diphenylsulfonio)phenyl]sulfide–bis‐hexafluorophosphate was also prepared by the reaction of benzene with sulfur monochloride in the presence of aluminum chloride and chlorine, followed by addition of potassium hexafluorophosphate. The product is an effective photonitiator for the crosslinking of epoxide resins.
Effect of γ radiation on certain non‐newtonian fluids
Authors: Roshdy M. H. , Haridi M. T. , Ibrahim I. A. , Yaacoub M. Sh.
Published: April 2003

The radiation degradation of viscoelastic solutions of a dialkyl monohydroxy aluminum polymer compound (AIR2OH)x is investigated. Radioactive cobalt‐60 is chosen for irradiation experiments. The viscosity of the polymer in six different solvents is measured after irradiation using a capillary viscometer at room temperature (25°C). The degradation effects on both the radiation dose and the solvent used.
Two‐component interpenetrating polymer networks (IPNs) from polyurethanes and epoxies. II. Effect of different charge groups in polyurethanes and epoxies on properties and morphologies of two‐component IPNs
Authors: Cassidy Edward F. , Xiao Han X. , Frisch Kurt C. , Frisch Harry L.
Published: April 2003

Two‐component interpenetrating polymer networks (IPNs) that contained charge groups in the backbones of the polyurethane and epoxy networks were studied. IPNs that contained opposite charge groups, similar charge groups, no charge groups, and corresponding pseudo‐IPNs were prepared. A comparison of mechanical properties, water‐resistance data, mechanical spectra, and electron microscopy showed that improved properties and morphologies resulted in IPNs that contained opposite charge groups. Presumably, interactions between the opposite charge groups in the constituent networks resulted in a forced compatibility between the two polymers which decreased the degree of phase separation.
Stereospecific polymerization of some methyl aryloxymethacrylates
Authors: Balakrishnan T. , Devarajan R. , Santappa M.
Published: April 2003

By exposure to ultraviolet and gamma radiation and by the usual methods of thermal polymerization, the stereospecific polymerization of methyl aryloxymethacrylates was carried out at different temperatures in several solvents. Triad tacticity values of the polymers obtained by free‐radical and ionic routes were computed from nuclear magnetic resonance spectral data. Results of this investigation support our earlier observation

See: K. Saunders, T. Balakrishnan, R. W. Lenz, and K. Hatada, Macromolecules, 12, 392 (1979).

that, under the conditions used, heterotactic content is the maximum in most of these polymers, thereby justifying the high steric effect of the bulky and polar aryloxy side chain which offers equal isotactic and syndiotactic placements.
Improved acetone‐adduct and acetylene‐terminated quinoxaline oligomers
Authors: Lin See , Marvel C. S.
Published: April 2003

A series of acetone‐adducts of acetylene‐terminated quinoxaline oligomers and polymers was synthesized by using 3‐(4‐ethynylphenoxy) benzil as endcapping agent for possible adhesives in airplane manufacturing.
Preparation and properties of N‐phenylated aromatic polyamide‐esters from anilinophenols and aromatic diacid chlorides
Authors: Imai Yoshio , Kakimoto Masa‐Aki , Hamaoka Nobuo
Published: April 2003

N‐Phenylated aromatic polyamide‐esters with high molecular weights were synthesized by the high‐temperature solution polycondensation in nitrobenzene at 200°C from combinations of m‐ and p‐anilinophenol and isophthaloyl and terephthaloyl chloride. Reaction variables such as monomer concentration, solvent, temperature, and time were studied to optimize the reaction conditions for the preparation of high molecular weight polymers. Some of the N‐phenylated aromatic polyamide‐esters have glass transition temperatures around 190°C and good solubility in chlorinated and amide solvents. These polymers gave transparent flexible films by solution‐casting. Copolymers from p‐anilinophenol and the two diacid chlorides were also synthesized and characterized.
Conformation of poly(S‐(2‐N‐carbazolylethyl)‐L‐cysteine) in the solid state
Authors: Oshima Ryuichi , Wada Tatsuo , Kumanotani Ju
Published: April 2003

The β‐forming characteristics of poly(S‐(2‐N‐carbazolylethyl)‐L‐cysteine), (CELC)n, were examined by infrared (IR) spectroscopy. The film of (CELC)39 cast from tetrahydrofuran (THF) showed the typical spectrum of the antiparallel β‐form with the amide I band at 1630 cm−1, whereas that of (CELC)200 from dimethylformamide (DMF) or pyridine exhibited the amide I band at 1640 cm−1 which shifted to 1630 cm−1 on heating at 100°C for 5 min. As a result of the examination of the spectral variation due to the degree of polymerization, casting solvents, casting temperatures, and heat treatment, together with the evaluation of interaction constants for intermolecular hydrogen bonds, the band at 1640 cm−1 was attributed to the antiparallel‐chain pleated sheet (designated as β′‐form) with weaker hydrogen bond strength than that of the usual antiparallel β‐form. The β′‐β‐transformation is discussed in terms of the rigidity of the side‐chain region.
Substituent effects of methoxy, methyl, and vinyl groups on glow discharge polymerization
Authors: Inagaki N. , Koyama M. , Igaki H.
Published: April 2003

Glow discharge polymerizations in systems of trimethoxymethylsilane, trimethoxyvinylsilane, tetramethylsilane, and trimethylvinylsilane were compared by elemental analysis, infrared (IR) spectroscopy, and ESCA to reveal effects of methoxyl, methyl, and vinyl substituents. The substituent effects appeared in the chemical composition of the polymers formed especially at low W/FM values. Methoxy groups depressed the C/Si and H/Si ratios of the polymers rather than the methyl groups, whereas vinyl groups increased the C/Si and H/Si ratios. On IR spectra the polymers formed from silanes that contained methoxy groups showed fewer absorptions due to SiH groups and strong absorptions due to SiOH groups. The polymers from those that contained no methoxy groups showed absorptions of SiH groups and no absorptions of SiOH groups. These differences in the environment of Si atoms of polymeric chains also appeared in the Si2p core level spectra, thus indicating the different fragmentation patterns of the starting materials in glow discharge.
An MNDO SCF MO investigation of some structural isomers of the perfluoro diazines (pyrimidine, pyrazine, and pyridazine) of relevance to their plasma polymerization
Authors: Clark D. T. , Johnson S. A. , Brennan W. J.
Published: April 2003

Extensive MNDO SCF MO calculations were made to determine the heats of formation of the ground state of geometry‐optimized perfluorodiazabenzenes (pyridazine, pyrimidine, and pyrazine) and some of their structural isomers (Dewar benzene, benzvalene, prismane, fulvene, and hexadienyne). The heats of formation of the cation, singlet, and triplet states, were derived for the ground‐state geometry of 1,3‐diaza isomers to gain some insight into the excited state manifolds. These results were used to interpret various experimental observations that relate to the plasma polymerization of the diazines. In particular, the interconversion of the parent heteroaromatic, the relative energies of interconversion and polymerization, and the possibility of the elimination of a small stable molecule were considered. Comparison is made with results reported for the tetrafluorobenzenes.
Selective separation of water–alcohol binary mixture through poly(maleimide‐co‐acrylonitrile) membrane
Authors: Yoshikawa Masakazu , Yokoi Hideto , Sanui Kohei , Ogata Naoya
Published: April 2003

Separation of various alcohols and water through a membrane was carried out by means of a hydrogen‐bonding interaction. A membrane obtained from poly(maleimide‐co‐acrylonitrile) was effective for a selective separation of water from aqueous alcohol solution by pervaporation technique. Spectroscopic analyses verified that this high selectivity was attributed to the hydrogen‐bonding interaction between water and maleimide units in the membrane.
Polymer‐ bound flavins. III. Effects of coil dimension and substrate structure on reaction kinetics in water/2‐propanol mixtures
Authors: Bootsma Jan P. C. , Rupert Leo A. M. , Challa Ger , Müller Franz
Published: April 2003

The strong influence of medium composition (water/2‐propanol mixtures) on the rate of oxidation of 1‐substituted dihydronicotinamides by a flavin‐containing polyelectrolyte was studied. We found that the coil dimensions of the corresponding copolymer of styrene and vinylbenzyltriethylammoniumchloride without flavin groups dramatically depend on the solvent. Viscometric measurements revealed compact coil conformations in solvents of both high water and high 2‐propanol content, but pronounced coil expansion in intermediate mixtures. These changes of polyelectrolyte coil dimensions are related to changes in electrostatic potential of the microreactors. Addition of 2‐propanol also results in decrease of substrate enrichments, caused by weakening of nonpolar polymer–substrate interactions, as was demonstrated for 1‐carbamoylmethyl‐, 1‐benzyl‐, and 1 decyl‐substituted 1,4‐dihydronicotinamide substrates. The enormous decrease in rate constant for oxidation of DNAH by 2 upon increasing the 2‐propanol content from 10 to 40% (v/v), from k = 3120 to 21 M−1 s−1, can thus be explained as a cooperation of both effects. Evidence for the formation of a charge transfer complex between the polyelectrolyte‐bound flavin and the dihydronicotinamide having a long‐wavelength absorption is also presented.
Radical‐initiated homo‐ and copolymerization of methoxymethyl methacrylate
Authors: Ueda Mitsuru , Ishibashi Setsuo , Suzuki Toshiyuki , Masuko Toru , Pittman Charles U.
Published: April 2003

The kinetics of methoxymethyl methacrylate (MOMA) homopolymerization has been investigated in benzene, using azobis(isobutyronitrile) as an initiator. The rate of polymerization (Rp) could be expressed by Rp = k[AIBN]0.5 [MOMA]1.19. The overall activation energy was calculated to be 73.2 kJ/mol. Kinetic constants for MOMA polymerization were obtained as follows: kp/kt1/2 = 0.091 L1/2 · mol−1/2 · s−1/2; 2fkd = 1.37 × 10−5 s−1. The values of K and a in the Mark–Houwink equation, [η] = KMa, where K = 5.89 × 10−5 and a = 0.82 when M = Mn and the solvent was benzene. The relative reactivity ratios of MOMA (M2) copolymerizations with styrene (r1 = 0.40, r2 = 0.58) were obtained. Applying the Q‐e scheme led to Q = 0.78 and e = 0.67. The glass transition temperature (Tg) of poly(MOMA) was observed to be 64°C by DSC. Thermogravimetry of poly(MOMA) showed a 10% weight loss at 230°C in air.
13C nuclear magnetic resonance studies of cellulose acetate
Authors: Miyamoto T. , Sato Y. , Shibata T. , Inagaki H. , Tanahashi M.
Published: April 2003

13C‐NMR spectra of ring carbons and O‐acetyl carbonyl carbons of cellulose acetate (CA) in dimethyl sulfoxide‐d6 were analyzed. The CA samples with the degree of substitution (DS) ranging from 0.84 and 1.91 were prepared by homogeneous acetylation of cellulose with acetic anhydride in a 10% LiCl/dimethyl acetamide solvent. It was found that the use of these low DS samples permitted easier assignments not only of the ring carbon but also of the O‐acetyl carbonyl carbon signals. The assignments were confirmed by comparing with the 1H‐NMR spectra of the samples obtained by complete acetylation of the corresponding CA samples with acetyl‐d3 chloride. Two methods for determining the distribution of O‐acetyl groups of CA, i.e., the relative DS at the three different types of hydroxyl groups, were developed. One is based on the measurements of the relative intensities of the signals for the ring carbons and the other is based on the measurements of the relative intensities of the signals for the O‐acetyl carbonyl carbons.
Direct synthesis of polyamides by N‐acyl phosphoramidites
Authors: Kawanobe Wataru , Yamaguchi Kazuo , Rokicki Gabriel , Mei Sha Kei , Yamazaki Noboru , Nakahama Seiichi
Published: April 2003

A variety of N‐acyl phosphoramidites were prepared from chlorophosphites and amide derivatives, and their structures were determined with the aid of 1H‐, 13C‐, and 31P‐NMR, and IR spectroscopies. These phosphoramidites were employed in direct polycondensation reaction of dicarboxylic acids and diamines under various conditions resulting in polyamides with inherent viscosities of 0.1 to 1.13. The best results were obtained when aliphatic dicarboxylic acids and aromatic diamines were condensed by 2‐(N‐methylacetamido)‐1,3,2‐dioxaphospholane in nitriles.
Synthesis of functionalized linear poly(divinylbenzene). II. Synthesis of poly(divinylbenzene) with hydroxyl pendants and/or endgroups
Authors: Aoshima Sadahito , Higashimura Toshinobu
Published: April 2003

Poly(divinylbenzene) [poly(DVB)] derivatives having hydroxyl terminals and/or pendants were synthesized by chemical modifications (hydration and hydroxylation) of unsaturated linear poly(DVB) (I), which was prepared by the polymerization of DVB catalyzed by acetyl perchlorate. Hydroboration of both terminal and in‐chain carbon–carbon double bonds in I with BH3.THF complex yielded a fully hydrated poly(DVB) II, in which hydrophilic and hydrophobic groups are placed alternately. Selective hydroboration of the vinyl endgroups in I with 9‐borabicyclo[3.3.1]nonane led to an α,ω‐dihydroxy‐poly(DVB) (III). Reaction of I with m‐chloroperbenzoic acid gave fully epoxidated poly(DVB) IV, which was subsequently hydrated to yield polymer V consisting of glycol repeat units and terminals. The physical properties and reactions (chain extension and crosslinking) of these polymers were also studied.
Poly(alkylene oxide) ionomers VIII. Synthesis of methyl ω‐alkenoates and methyl ω‐epoxyalkanoates
Authors: Muggee John , Vogl Otto
Published: April 2003

ω‐Alkenoic acids, either commercially available or synthesized, were esterified to their corresponding methyl esters. They were characterized by their infrared, 1H‐, and 13C‐NMR spectra. The ω‐alkenoates prepared were: propenoate (acrylic acid), butenoate, pentenoate, hexenoate, heptenoate, octenoate, nonenoate, and decenoate. These compounds were epoxidized with m‐chloroperoxybenzoic acid to the corresponding methyl ω‐epoxyalkanoates. The rate of epoxidation of the double bond is found to increase as the double bond is separated from the carbomethoxy group by increasing numbers of methylene groups. When at least three methylene groups are inserted, the rate of epoxidation becomes constant and is similar to the epoxidation of ω‐olefins. The methyl ω‐epoxyalkanoates were characterized by their infrared, 1H‐, and 13C‐NMR spectra. Methyl ω‐alkenoates and methyl ω‐epoxyalkanoates were prepared and characterized, and their purification was studied in preparation for their investigation as monomers for olefin or epoxide polymerization using corrdination initiators.
Controlled release by polyelectrolyte microcapsule membranes
Authors: Tsai Ming‐Fu , Levy Moshe
Published: April 2003

Polyelectrolyte submicron microcapsules were prepared by interfacial crosslinking of an aqueous salt solution of poly(ethyleneimine) and a toluene solution of brominated poly‐(2,6‐dimethylphenylene oxide). The two solutions were brought together and mixed by sonication. As a result, a stable emulsion was obtained, which was subsequently cast into a membrane in which the microcapsules were embedded. The salt solution contained in the microcapsules could be released under controlled conditions. The rates of release were measured. They could be controlled by applying osmotic pressures, by additional quaternization of the membrane, or by modification of the structure of the capsule wall by introduction of a surfactant.
An ESCA study of the inductively coupled RF plasma polymerisation of 2,4,6‐trifluoro‐1,3,5‐triazine
Authors: Munro H. S. , Allaker R. S. , Clark D. T. , Recca A.
Published: April 2003

ESCA has been used to investigate the composition and structural features of plasma‐polymerized 2,4,6‐trifluoro‐1,3,5‐triazine. Polymer formation was studied as a function of power and post‐polymerisation treatment. All the polymer films revealed an intense peak at a binding energy of ∼290.2 eV probably arising from groups. A high sensitivity towards hydrolysis was observed resulting in substantial loss of fluorine and increase in oxygen content of the plasma polymers.
Grafting onto cellulose. VIII. Graft copolymerization of poly(ethylacrylate) onto cellulose by use of redox initiators. Comparison of initiator reactivities
Authors: Misra B. N. , Mehta I. K. , Khetarpal R. C.
Published: April 2003

In an attempt to compare the relative reactivities of different redox systems in graft copolymerization of vinyl monomers onto cellulose, we studied grafting of ethylacrylate (EA) in aqueous medium by using the well‐known redox intiator, ferrous ammonium sulfate–potassium persulfate (FAS–KPS) system, and its reactivity was compared with that of Fenton's reagent (Fe2+ −H2O2) towards grafting of EA onto cellulose. Optimum conditions for affording maximum grafting were evaluated and percent grafting is expressed as functions of different reaction variables. Evidence of grafting was obtained from IR spectroscopic measurements, SEM, and TGA studies of the grafted and ungrafted cellulose. A plausible explanation for the observed reactivity pattern shown by (FAS–KPS) and (FAS–H2O2) redox systems is offered. Fenton's reagent (Fe2+ −H2O2) was found to be several times more reactive than (FAS–KPS) redox system.
Synthesis and polymerization of optically active N‐α‐methylbenzylmaleimide
Authors: Oishi Tsutomu , Fujimoto Minoru
Published: April 2003

Optically active N‐α‐methylbenzylmaleimide (MBZMI) was prepared with maleic anhydride and d‐(+)‐α‐methylbenzylamine. The polymerizations of MBZMI were carried out with α,α′‐azobisisobutyronitrile (AIBN) and n‐butyllithium (n‐BuLi) in tetrahydrofuran (THF). The specific rotations of the polymers obtained by AIBN and n‐BuLi initiator were +11.1° to +13.0° and −57.0° to −89.2°, respectively. The weight‐average molecular weights (Mw) for the polymers were between 4200 and 8000. Furthermore, MBZMI was copolymerized with styrene (ST) and methyl methacrylate (MMA) with AIBN in THF at 50°C to obtain optically active copolymers. The monomer reactivity ratios of MBZMI (M1) with ST (M2) were obtained as r1 = 0.027, r2 = 0.094 in the MBZMI–ST and r1 = 0.15, r2 = 1.54 in the MBZMI–MMA system. The Q‐e values for MBZMI were Q1 = 0.78, e1 = 1.62. All the polymers and copolymers were found to show a weakly negative circular dichroism (CD) peak at about 250 nm and a strongly positive CD peak at about 220 nm.
Compatibility in poly(ethylene oxide)–poly(methyl methacrylate) blends
Authors: Liberman Susana A. , Gomes Ailton De S. , Macchi Edgardo M.
Published: April 2003

The compatibility of poly(ethylene oxide)‐poly(methyl methacrylate) (PEO‐PMMA) blends were examined covering the complete composition range. Up to 20% of PEO content films were transparent and glass transition temperatures were determined by DSC and by refractive index vs. temperature measurements. Only one Tg was obtained for these samples and the relationship between Tg and composition has been evaluated. At higher PEO content crystallization took place and the films were opaque. Melting temperatuures of PEO in blends were determined by DSC. Melting point depression was observed for increasing proportion of PMMA and the binary interaction parameter has been calculated.
A convenient photochemical method to immobilize enzymes
Authors: Ichimura Kunihiro
Published: April 2003

A method to immobilize enzymes photochemically with use of photocrosslinkable poly(vinylalcohol) bearing stilbazolium groups is described. Irradiation of a film of the photosensitive polymer containing enzyme gave water‐insoluble, cellophane‐like transparent film demonstrating high enzyme activity. The dissolution of enzymes from the film was dependent upon the molecular weight of the proteins and the content of the photocrosslinking unit. It was found that various enzymes are sufficiently entrapped in the photocrosslinked polymer matrix when the content of the photosensitive group is more than about 1.0 mol%.
Superacid polymers from sulfonated poly(styrene‐divinylbenzene): Preparation and characterization
Authors: Dooley K. M. , Gates B. C.
Published: April 2003

Superacid polymers were prepared by bringing metal halides (AlCl3, SnCl4, TiCl4, BF3, or SbF5) in contact with macroporous sulfonic acid resins [sulfonated, crosslinked poly(styrene‐divinylbenzene)]. The resulting solids were characterized by chemical analysis, temperature‐programmed desorption, transmission electron microscopy, and X‐ray photoelectron spectroscopy. They were also tested as catalysts for n‐butane isomerization at 0.5 bar and 60 to 120°C. The polymers consist of supported metal oxyhalide particles, complexes of metal oxyhalides and sulfonate groups, and the remaining unreacted sulfonic acid groups. In the presence of HCl, these polymers were highly active catalysts for the butane isomerization reaction, the activity being a consequence of a high proton‐donor strength inferred to be associated with H2Cl+ groups stabilized on the polymer surface by negative charge delocalization over sulfonate–metal oxyhalide sulfonate groups.
Polyelectrolyte influences on the trans–cis isomerization of sodium m‐(4‐ethoxyphenylazo)benzene sulfonate
Authors: Ishiwatari Tsutomu , Tsuji Tadashi , Aoshima Kazuyuki , Mitsuishi Masaru
Published: April 2003

Influences of microenvironment of various polyelectrolytes, i.e., ionene polymers and polyamine sulfones, on the photo‐ and/or thermal isomerization between the trans and cis forms of sodium m‐(4‐ethoxyphenylazo)benzene sulfonate (SEPS) were studied. 6,6‐Ionene demonstrated larger enhancing effect on the cis–trans thermal isomerization than 3,3‐ionene, which indicated that the micropolarity or the pH around the polymer is important. In the Arrhenius plots for both photo‐ and thermal isomerizations, deviations from the linearity were observed. In the former case, a sharp bend and the negative apparent activation energy were obtained at the high temperature. Furthermore, they were sensitively affected by the polyelectrolytes.
A study of the mechanism of photocrosslinking polymers by quinones
Authors: Cha Younsik , Tsunooka Masahiro , Tanaka Makoto
Published: April 2003

Photocrosslinking of poly(methyl methacrylate) (PMMA) was studied in the solid state in the presence of various quinones. For the study of photocrosslinking mechanism, a PMMA film containing p‐benzoquinone (Q) was irradiated with UV light (λ > 370nm) and then purified by reprecipitation. It was found that the reprecipitated polymer has quinone‐type moieties, besides the hydroquinone‐type moieties, chemically bound to the polymer chain. The reprecipitated polymer film also crosslinking efficiency was higher than that of PMMA film containing Q. It was concluded that the formation of quinone‐type structure during irradiation played an important role in the photocrossing of PMMA containing Q.
Chemistry of alkenyl azlactones. IV. Preparation and properties of telechelic acrylamides derived from amine‐terminated oligomers
Authors: Heilmann Steven M. , Rasmussen Jerald K. , Krepski Larry R. , Smith Howell K.
Published: April 2003

The ring‐opening, nucleophilic addition of amine‐terminated oligomers to alkenyl azlactones was exploited to prepare reactive, that is, in free radical polymerizations, oligomers that could be used in 100% solids resin systems. Acrylamide‐functional oligomers resulted from the reaction that used 2‐vinyl‐4,4‐dimethylazlactone, whereas methacrylamide‐functional oligomers were produced with 2‐isopropenyl‐4,4‐dimethylazlactone. The overall reaction took place under mild conditions, for example, a few hours at room temperature, and was particularly free of side reactions. Examination of reaction rates with the two alkenyl azlactones revealed that the 2‐vinyl derivative reacted ca. four times faster. The (meth)acrylamide‐terminated resins were characterized by IR, NMR, and molecular weight analyses.
Kinetics of emulsion polymerization of methyl methacrylate
Authors: Ballard Mathew J. , Napper Donald H. , Gilbert Robert G.
Published: April 2003

The kinetics of the emulsion polymerization of methyl methacrylate at 50°C have been studied in seeded systems using both chemical initiation and γ‐radiolysis initiation. Both steady‐state rates and (for γ‐radiolysis) the relaxation from the steady state were observed. The average number of free radicals per particle was quite high (e.g., ∼0.7 for 10−3 mol dm−3 S2O28 initiator). The data are quantitatively interpreted using a generalized Smith–Ewart–Harkins model, allowing for free radical entry, exit, biomolecular termination within the latex particles, and aqueous phase hetero‐termination and re‐entry. From this treatment, there results (i) the dependence of the termination rate coefficient (kt) on the weight fraction of polymer (wp), (ii) lower bounds for the dependence of the entry rate coefficient on initiator concentration, and (iii) the conclusion that most exited free radicals undergo subsequent re‐entry into particles rather than hetero‐termination. The results for kt(wp) are consistent with diffusion control at temperatures below the glass transition point. Comparisons are presented of the behavior of methyl methacrylate, butyl methacrylate, and styrene in emulsion polymerization systems.
Radiation‐induced copolymerisation of trioxane with penta‐acetyl‐glucose
Authors: Sagu M. L. , Bhattacharyya K. K.
Published: April 2003

Copolymerisation of trioxane (TOX) with penta‐acetyl‐glucose (PAG) in the solid state was investigated by gamma radiation. Effects of radiation doses, PAG concentration, and related parameters were studied and compared with that of the homopolymerisation of TOX. The yield of copolymer was lower than homopolymer and only a fraction of the PAG taken entered into the polymer. Chemical properties of the copolymer were determined; after amine treatment the copolymer showed good thermal stability. The kinetics of homopolymerisation were similar to those of TOX‐homopolymerisation.
Styrylpyridine‐based epoxy resins: Synthesis and characterization
Authors: Yan Hoh‐Jiear , Pearce Eli M.
Published: April 2003

Polymers containing rigid aromatic structures in the chain backbone usually gave high thermal stability and good flammability resistance. Three glycidyl ethers of epoxy resins were prepared from 2,4‐di(p‐hydroxystyryl)pyridine (2,4‐DGESP), 2,6‐di‐(p‐hydroxystyryl)pyridine (2,6‐DGESP), and 2,4,6‐tri‐(p‐hydroxystyryl)pryidine (2,4,6‐TGESP) to study the relationships of structure to polymer degradation. To prepare a highly crosslinked material, trimethoxyboroxine (TMB) was used as the curing agent. The relative char yields of the three different resins, as measured by TGA, were 2,4‐DGESP ≈ 2,6‐DGESP > 2,4,6‐TGESP. The char yield of the cured 2,6‐DGESP varied with different amounts of the TMB curing agent, and was higher than the uncured 2,6‐DGESP. The oxygen index increased as a function of thermal curing time for the 2,6‐DGESP epoxy resin. An intermolecular Diels–Alder reaction with 2,6‐DGESP is proposed as a primary reaction during thermal curing.
n‐Butyllithium/α‐methylstyrene/benzene/diethyl ether: A suitable initiation system for anionic syntheses of model co‐ and homopolymers of styrene and isoprene
Authors: Podešva J. , Špaček P. , Sikora A. , Podol'Skii A. F.
Published: April 2003

An initiation system of the anionic polymerization, intended for the syntheses of homopolymers and block copolymers with narrow molar mass distribution, was tested with styrene and isoprene. The actual initiating species, viz., the oligomeric α‐methylstyryl anion, originates by the reaction of n‐butyllithium with α‐methylstyrene in a benzene/diethyl ether 1:1 (v:v) solvent mixture at room temperature. The homopolymers and two‐block copolymers of styrene and isoprene, prepared by using this system, were characterized by light scattering, membrance osmometry, GPC, and 1H NMR spectroscopy. By using the suggested initiation system, it is possible to synthesize well‐defined homopolymers and block copolymers with low polydispersity (as judged by the shape of the GPC peaks and by the values of the polydispersity index), especially in a molar mass region between 4 × 104 and 1.5 × 105 g/mol. Above the upper limit of this interval, an appropriate decrease of the diethyl ether/benzene volume ratio is recommended, though the polymerization time must then be prolonged.
Studies on plasma‐initiated polymerization of acrylamide in solid state and in solution
Authors: Akovali Güneri , Orhan Bilge
Published: April 2003

Plasma‐initiated polymerization is applied to acrylamide both in solid state and in solution. The effect of the amount of water, in addition to certain operational parameters such as applied vacuum, post polymerization period, and temperature, are well verified. Characteristics of polymers are determined by IR spectroscopy and X‐ray diffraction studies as well as by intrinsic viscosity determinations.
Correlation between macromolecular parameters and the average breaking strength of agave fibers
Authors: Patel A. , Prasad J. R. , Nayak S. K.
Published: April 2003

The small‐angle X‐ray scattering method was applied to evaluate macromolecular parameters of Agave fibers (Agave sisalana, A. cantala, A. hybrid, A. elongata, and A. ameniensis). The macromolecular parameters such as specific inner surface, percentage of void, length of coherence, range of inhomogeneity, and transversal lengths were evaluated. The correlation of macromolecular parameters with the average breaking strength of Agave fibers did not lead to a linear relation, however, the specific macromolecular organization in A. sisalana manifested higher breaking strength.
Synthesis and thermal characteristics of phosphorus‐containing polyureas and copolyureas based on 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes
Authors: Mikroyannidis John A.
Published: April 2003

The reactions of 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (1) with various diisocyanates such as tolylene diisocyanate, methylenebis(4‐phenylisocyanate), and hexamethylene‐1,6‐diisocyanate were studied for the synthesis of phosphorus‐containing polyureas. Furthermore, diamines 1 were used as comonomers for preparing fire‐resistant copolyureas. In addition, the corresponding common polyureas were synthesized for comparative purposes. All polymers were characterized by elemental analysis, inherent viscosity measurements, infrared (IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The relatively low chemical reactivity of 1 toward diisocyanates was interpreted on the basis of their structural features. The phosphorus‐containing polyureas showed a lower molecular weight, a lower polymer decomposition temperature, and a higher char yield than the corresponding common polyureas. Their fire‐resistance was evaluated by determining the limiting oxygen index value.
Water‐soluble copolymers. X. Copolymers of acrylamide with N‐(1,1‐dimethyl‐3‐oxybutyl)acrylamide and N,N‐dimethylacrylamide: Solution properties
Authors: McCormick C. L. , Chen G. S.
Published: April 2003

Dilute solution properties of copolymers of acrylamide (AM) with N‐(1,1‐dimethyl‐3‐oxybutyl)acrylamide (DAAM) and with N,N‐dimethylacrylamide (DMAM) have been studied as a function of composition, temperature, time, and added electrolytes sodium chloride and calcium chloride. Unlike the AM‐DMAM copolymers, the AM‐DAAM copolymers show solution viscosity increases in the presence of added NaCl and CaCl2 and decreases with increasing temperature which are related to copolymer composition. The unusual viscosity behavior of the DAAM‐AM copolymers is suspected to be due to chain extension resulting from intramolecular hydrogen bonding and other cooperative associations along the macromolecular backbone.
Membranes obtained by preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene–perfluorovinyl ether)
Authors: Hegazy El‐Sayed A. , Dessouki Ahmed M. , Rabie A. M. , Ishigaki I.
Published: April 2003

Some properties of the membranes obtained by preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene‐perfluorovinyl ether) copolymer (PFA) films have been investigated. The dimensional change caused by grafting and swelling behavior, water uptake, electrical conductivity, and mechanical properties of the grafted films were found to increase as the grafting proceeds. The influence of the preparation conditions (such as preirradiation dose, monomer concentration, grafting temperature, and film thickness) on those properties was studied. These properties were found to be dependent mainly on the degree of grafting regardless of grafting conditions, except at higher monomer concentration (>40 wt %). The electric conductivity and mechanical properties for the membranes obtained at higher AAc concentrations were lower than those obtained at lower ones. Analysis by x‐ray microscopy of the grafted films revealed that the grafting begins at the part close to the film surface and proceeds into the central part with progressive diffusion of monomer to give finally homogeneous distribution of the electrolytes in the whole bulk of the polymer. The membranes show good electrochemical and mechanical properties which make them acceptable for practical use as cation‐exchange membranes.
Synthesis and characterization of some aromatic polyamides containing double bonds
Authors: Sachindrapal P. , Nanjan M. J.
Published: April 2003

Ten polyfumaramides based on fumaric acid and aromatic diamines and six polystilbenediamides based on 4,4′‐stilbenedicarboxylic acid and aromatic diamines were synthesized and characterized by solubility, viscosity, density, infrared and UV‐visible spectroscopy, and thermal analyses. Variation in properties with structure is discussed here.
Copolymers containing alternating sequences of nucleic acid base pairs. III. Spectroscopic studies
Authors: Aponte Maria A. , Butler George B.
Published: April 2003

A study was conducted of the complementary base pair interactions between various pairs of electron‐donor monomers, electron‐acceptor monomers, homopolymers and alternating copolymers selected from the following group: (1) 9‐(2‐vinyloxyethyl)adenine; (2) 1‐(2‐vinyloxyethyl)thymine; (3) 1‐(2‐vinyloxyethyl)cytosine; (4) 9‐(2‐maleimidoethyl)adenine; (5) 6‐chloro‐9‐(2‐maleimidoethyl)purine; (6) 1‐(2‐maleimidoethyl)thymine; (7) 1‐(2‐maleimidoethyl)cytosine; (8) homopolymer of (4); (9) homopolymer of (6); (10) alternating copolymer of (2) and maleic anhydride; (11) alternating copolymer of (2) and (5); and (12) alternating copolymer of (2) and (4). By 1H‐NMR, in CDCL3, the base pair interactions between (1) and (2) were shown to be hydrogen bonding, the extent of which was shown by a calculated binding constant, K = 61.81 L/mol. The nature of this interaction was conformed by IR. Neither monomer pairs (1)/(2) nor (4)/(6) exhibited hydrogen bonding in DMSO‐d6. However, hydrogen bonding interaction was observed for DMSO‐d6 solutions of homopolymers (8) and (9) and for alternating copolymer (12). On the basis of an upfield chemical shift of the 2‐ and 8‐aromatic protons of ademine of (1) in D2O, a partial overlap stacking interaction is proposed. No charge‐transfer interactions could be observed by UV between donor‐acceptor monomer pairs.