bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization and chemistry of polyaldehyde microspheres
Authors: Margel Shlomo
Published: April 2003

The chemical composition of polyacrolein (PA) microspheres of various types as well as polyglutaraldehyde (PGL) microspheres was elucidated. Nephelometric measurements were used for studying the stability properties of the polyaldehyde microspheres in different pH and salt concentrations. The stability of the aldehyde groups themselves at various pH and temperature was also determined. The polyaldehyde microspheres covalently bind amino ligands, e.g., proteins, antibodies, enzymes, and drugs in a single step. The effect of temperature and the influence of thiol compounds on the reaction between the polyaldehyde microspheres and amino ligands was examined. The reaction of the polyaldehyde microspheres with sodium hydrogen sulfite is also described.
Aqueous polymerization of methacrylic acid initiated by Ce4+ ‐glycolic acid redox pair
Authors: Misra G. S. , Arya B. D.
Published: April 2003

The aqueous polymerization of methacrylic acid (MAA) initiated by a Ce4+ ‐glycolic acid (GA) system was observed in a sulfuric acid medium at 35 ± 0.2°C in a nitrogen atmosphere. The rate of monomer disappearance was proportional to [MAA]1 and the rate of ceric ion disappearance was proportional to [GA][Ce4+]. An increase in the reaction temperature from 30 to 45°C raised the rate and the overall activation energy was 63 kJ/mol. The molecular weight increased with a rise in [MAA] and a reduction in [Ce4+]. The effect of varying [H2SO4] was also studied.
Photoinduced reversible pH change in aqueous solution of azoaromatic poly(carboxylic acid)
Authors: Ishihara Kazuhiko , Matsuo Tohru , Tsunemitsu Katsuaki , Shinohara Isao , Negishi Naoki
Published: April 2003

To regulate the pH value of an aqueous solution containing polyelectrolyte by photoirradiation, an azoaromatic poly(carboxylic acid), acrylic acid(AA)‐p‐phenylazoacrylanilide (PAAn) copolymer was synthesized and the photoresponse of the polymer solution was investigated. AA‐PAAn copolymer, which takes a compact form in the ordinary state owing to the presence of azoaromatic side chains, is transformed into an extended form when azoaromatic moieties are isomerized by photoirradiation. Thus, the pH value of the solution can be reversible regulated by irradiation and interruption of light through a change in polymer conformation. The range of the pH change was about 0.15. These phenomena can be explained on the basis of polarity change induced by the photoisomerization of azoaromatic side chains.
Synthesis and characterization of soluble aromatic polyazomethines from 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene and aromatic dialdehydes
Authors: Imai Yoshio , Maldar N. N. , Kakimoto Masa‐Aki
Published: April 2003

New soluble aromatic polyazomethines with inherent viscosities of 0.4–0.8 dL/g were prepared by the solution polycondensation of 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene, bis(4‐aminophenyl) ether, and aromatic dialdehydes in o‐chlorophenol at 20°C. The copolyazomethines are generally soluble in chlorinated hydrocarbons, amide‐type or phenolic solvents. The thermal stability of the polymers, which showed no weight loss up to 400°C in both air and nitrogen atmospheres.
A warning about structures of thiophene polymers
Authors: Gutierrez Mario H. , Ford Warren T. , Pohl Herbert A.
Published: April 2003

2,5‐Dichlorothiophene, 2,5‐dibromothiophene, and tetrabromothiophene have been polymerized with anhydrous sodium sulfide in N‐methylpyrrolidone (NMP) at 250°C to insoluble products which contain structural fragments derived from both the starting thiophene and the NMP. The copolymers absorb 0.5 to 1.0 times their weights of iodine to give materials with electrical conductivities of about 10‐5 (ohm cm)‐1 at 16 kbar and 10‐7 (ohm cm)‐1 at atmospheric pressure.
Kinetics of oligomerization of methyl ester of dehydrated castor oil fatty acid over molybdenum oxide on silica–alumina catalyst in comparison with the thermal oligomerization process
Authors: Venkatachalam S. , Kumar V. G. , Rao K. V. C.
Published: April 2003

A process is described for the oligomerization of methyl ester of dehydrated castor oil fatty acid over molybdenum oxide on silica–alumina catalyst. The process is compared with thermal oligomerization. The nature of the reaction in both the processes are shown to be the same from the structural elucidation of the product despite the variation in product composition. The percentage of dimer in the product in both the processes is observed to attain an equilibrium value at around 270°C. The catalytic process is shown to follow a second‐order kinetics with respect to the monomer, whereas the thermal reaction follows a first‐order kinetics. The kinetic scheme derived for the catalytic process is shown to be consistent with the steps of the general mechanism proposed for oligomerization reactions over transition metal catalysts [V. G. Kumar, S. Venkatachalam, and K.V.C. Rao, J. Poly. Sci. Polym. Chem. Ed., 22, 3850 (1984)].
Titanium and rare earth chloride catalysts for ethylene polymerization
Authors: Martin Joel L.
Published: April 2003

Anhydrous chlorides of Mg, Mn, Y, and selected lanthanides were reacted with tri‐n‐butylphosphate and finally TiCI4 to prepare ethylene polymerization catalysts. With triethylaluminum as cocatalyst the highest activities were observed with Mg, Nd, and Pr, which correlate with the peak activity for Nd and Pr in diene polymerization catalysts prepared from the lanthanides. At a given hydrogen concentration molecular weights and molecular weight distributions and catalyst activities were similar for these three metals. The high activity for Nd and Pr is surprising because NdCI3 and PrCI3 adopt the UCI3 structure rather than a layer lattice structure common to MgCI2 and TiCI3.
Hydroperoxides as intermediates responsible for wavelength effects in photooxidation reactions
Authors: Bousquet J. A. , Fouassier J. P.
Published: April 2003

A quantitative study of a model elastomer was performed to gain a deeper insight into photooxidation processes. Since the twofold role of hydroperoxides as excited sensitizer quenchers, and radical initiators has been amply demonstrated, we described the mechanism of energy transfer to repulsive excited states of these substances and quantitatively determined their distribution in the polymeric material, according to their reactivity. In addition, two irradiation wavelengths (λ = 254 nm and λ = 313 nm) were used to demonstrate that behavior of hydroperoxides depends on the nature and the concentration of excited chromophoric groups and accounts for the macroscopic wavelength effect usually observed in the photooxidation of polymers.
Functional monomers and polymers. CXXI. Methylation and interaction studies on adenine containing polymethacrylate derivatives
Authors: Fang Shi‐Bi , Inaki Yoshiaki , Takemoto Kiichi
Published: April 2003

Studies of the methylation of polymethacrylate derivatives with adenine bases were made in comparison to those with uracil bases. The polymethacrylate derivatives with adenine bases were methylated by using methyl iodide in dimethyl sulfoxide solution to produce polymers that contained N1‐methyladenine and N1, N6‐dimethyladenine units. The products were identified by spectroscopic data and by preparing their model compounds. The methylated polymers obtained were further applied in a study of polymer complex formation with uracil‐base polymers.
Characteristics of microemulsion polymerized styrene with water‐soluble versus oil‐soluble initiators
Authors: Johnson P. L. , Gulari Esin
Published: April 2003

The effect of oil‐soluble versus water‐soluble free‐radical generators in the polymerization of styrene in oil‐in‐water (O/W) micromulsions were investigated by photon correlation spectroscopy. The microemulsions were formed by styrene, brine, sodium dodecyl sulfate (SDS), and pentanol. The polymerizations were carried out in two microemulsions that contained droplets differing by a factor of 2.4 in volume. Under the conditions of ϕ = 0.019 and NaCl/SDS > 2 the microemulsions were stable and the droplets were independent of one another. Both oil‐soluble and water‐soluble initiators produced polystyrene that contained fractions of two different sizes. In the case of the oil‐soluble initiator the droplet size in the microemulsion seemed to be correlated to the size of the product whereas in the case of the water‐soluble initiator, there seemed to be little relation.
Aromatic polyamides. XII. Effect of the polymeric unit linkage position on the thermal decomposition and flammability of the unsubstituted and halogen‐substituted aromatic polyamides
Authors: Kapuscinska M. , Pearce E. M. , Chung H. F. M. , Ching C. C. , Zhou Q. X.
Published: April 2003

The synthesis, thermal characterization, and oxygen index of aromatic polyamides varying with polymeric unit linkage positions (meta and/or para units) and halogen substitution have been reported. It has been found that polyamides containing para units are more thermal stable than those containing meta units. There is no significant effect of the main chain structure studied here on either the pyrolysis pathways or flammability of similarly halogen substituted polyamides.
Reaction epoxy‐amine: Suivi du mecanisme reactionnel et de la cinetique par RMN 13C, 15N et HPLC
Authors: Grenier‐Loustalot Marie‐Florence , Grenier Philippe
Published: April 2003

The curing reaction of diglycidyl ether of bisphenol A (DGEBA) with metaphenylene diamine (mPDA) was investigated with high performance liquid chromatography (HPLC) and Fourier transform nuclear magnetic resonance spectroscopy (FT NMR 13C and 15N). With the results obtained from a series of models a mechanism was proposed and the cure kinetics were obtained at 100°C. The major conclusion is that the cure proceeded mainly by chain extension, whereas crosslinking occurred in the reaction of hydroxyl groups with epoxides and resulted in the formation of ether linkages.
Short‐chain model studies on emission properties of poly(9‐vinylphenanthrene‐co‐p‐N,N‐dimethylaminostyrene): Exciplex quenching and subsequent formation of another fluorescent exciplex
Authors: Iwai Kaoru , Takemura Fukuo , Furue Masaoki , Nozakura Shun‐Ichi
Published: April 2003

The emission properties of 1‐(4‐dimethylaminophenyl)‐3‐(9‐phenanthryl)propane, Ph(CH2)3 DMA, and 1,3‐di‐(9‐phenanthyrl)propane, Ph(CH2)3Ph, were studied in comparison with those of poly(9‐vinylphenanthrene‐co‐p‐N,N‐dimethylaminostyrene). Ph(CH2)3DMA showed an intense intramolecular exciplex fluorescence in dioxane. Ph(CH2)3Ph did not exhibit a clear intramolecular excimer fluorescence. The quenching of the intramolecular exciplex by several electron acceptors was studied. As a result moderate electron acceptors, such as cyanobenzene, methyl benzoate, and acrylonitrile, selectively quenched the intramolecular exciplex, and in the case of cyanobenzene the subsequent formation of another fluorescent exciplex was observed. The results were discussed in terms of the reduction potentials of electron accepting quenchers.
Cationic polymerization of 1‐phenyl‐4‐ethyl‐2,6,7‐trioxabicyclo[2.2.2]octane
Authors: Uno Hitomi , Endo Takeshi , Okawara Makoto
Published: April 2003

Cationic polymerization of bicyclo ortho ester, 1‐phenyl‐4‐ethyl‐2,6,7‐trioxabicyclo[2.2.2]octane, was carried out with Lewis acids and cation sources to obtain the polyether containing ester group in the side chain. It was found that boron trifluoride etherate was the most active initiator in the Lewis acids. Magnesium perchlorate and triphenylcarbenium tetrafluoroborate, which have lower nucleophilic counter ions, initiated effectively the polymerization of bicyclo ortho ester.
Polymeric catalysis: Imidazoles grafted onto poly(vinylamine). II. Kinetics of the esterolysis of activated phenyl esters
Authors: Tomko Richard , Overberger C. G.
Published: April 2003

In the previous paper, some ω‐(1‐imidazolyl) and ω‐[4(5)‐imidazolyl]alkanoic acids were synthesized and grafted onto poly(vinylamine). These water soluble catalysts of varying apolarity contain both hydrophobic and electrostatic binding sites for neutral and charged substrates. The influence of side chain length, percent graft, and the substitution in the imidazole ring are described. The grafts possessing the longer side chains and lesser apolar weight were more efficient catalysts than the grafts containing numerous short side chains and greater apolar weight. These grafts exhibited slower rates than poly[4(5)‐vinylimidazole].
Grafting onto wool. XXV. Effect of acids on γ‐radiation‐induced graft copolymerization of methyl methacrylate onto wool fiber
Authors: Misra B. N. , Rawat B. R.
Published: April 2003

Graft copolymerization of methyl methacrylate (MMA) onto Himachali wool fiber has been investigated in aqueous medium by using γ irradiation from a 2100 Ci60CO source as means of initiation. Graft copolymerization was carried out by the mutual method in nitrogen atmosphere as well as in air. Effect of mineral acids and acetic acid on percentage of grafting was studied. Percentage of grafting was determined as functions of total dose, concentration of monomer, and concentration of acids. Maximum percentage of grafting in the presence of acids occurred in nitrogen atmosphere at a total dose of 1.05 MR. All the acids were found to influence grafting and the reactivity of different acids towards graft copolymerization was found to follow the order: H2SO4 > HCl > HNO3 > HC1O4 > HOAc. An attempt has been made to explain the reactivity order of different acids in the light of the mechanism proposed for γ‐irradiation‐induced graft copolymerization of vinyl monomer onto wool fiber.
Study on triazine thiols. VI. Selective graft copolymerization of MMA on modified copper plates
Authors: Mori Kunio , Nakamura Yoshiro
Published: April 2003

Graft copolymerization of MMA on copper surface which is initiated by Na2S2O8 in an aqueous solution proceeded selectively when copper plates are modified by 6‐unsaturated group‐1,3,5‐triazine‐2,4‐dithiol monosodium salts (UTD) and 6‐dimethylamino‐1,3,5‐triazine‐2,4‐dithiol monosodium salt (DMTD). Grafting weight was influenced by the molar ratio of UTD to DMTD in the aqueous solution that copper plates are treated. The former on copper surface is a coupling component of MMA radicals and initiator radicals. The latter is a catalyst which accelerates the formation of radicals acting with Na2S2O8. Selective graft copolymerization is due to the reason that radicals generate selectively in the neighborhood of copper surface and in this place there are monomers such as MMA and UTD.
Graft copolymerization. II. Grafting of benzyloxyethyl methacrylate on poly(vinyl alcohol)
Authors: Silberman Ruth , Kohn David H.
Published: April 2003

New graft copolymers were produced by grafting benzyloxyethyl methacrylate, the benzyl ether of HEMA, on high‐molecular‐weight poly(vinyl alcohol) in dimethyl sulfoxide solution with Ce4+ as initiator. The effects of the concentration of the initiator, the concentration of the monomer, the total concentration of the reactants, the temperature, and the duration of reaction on the percentages of grafting and conversion were investigated. Further, also the relationships between the initiator concentration and the percentages of grafting and of conversion in the reaction with poly(vinyl alcohol)s of lower molecular weight and of different degrees of hydrolysis were studied.
Molecular design of multicomponent polymer systems. VII. Emulsifying effect of poly(ethylene–b–styrene) copolymer in high‐density polyethylene/polystyrene blends
Authors: Fayt R. , Hadjiandreou P. , Teyssie Ph.
Published: April 2003

Poly(butadiene–b–styrene) copolymers containing a pure, 1,4‐PB block have been synthesized by a “living” coordination process. The complete hydrogenation of the PB chain leads accordingly to a high‐density polyethylene (HDPE) block. The emulsifying efficiency of such a copolymer (H‐7) in HDPE/PS blends is compared with that of a previously reported poly(ethylene–butene–b–styrene) copolymer (SE‐7) obtained by the PB hydrogenation of an anionically prepared PB–b–PS. Microscopy examinations demonstrate unambiguously the interfacial activity of both copolymers in HDPE/PS blends. The tensile mechanical properties of the blends are significantly but also differently modified by the two emulsifiers. The copolymer H‐7 gives rise to the highest strengths, but, contrary to the copolymer SE‐7, provides a poor ductility to the blends. This different behavior is assumed to result in part from the different characteristics of the hydrogenated PB blocks. The elastomeric HPB chain of SE‐7 should form at the interface a more or less extended soft zone whereas a rigid interface would result from the cocrystallization of the HPB chain of H‐7 with the HDPE homopolymer.
Heterogeneous oxidative degradation in irradiated polymers
Authors: Clough R. L. , Gillen K. T. , Quintana C. A.
Published: April 2003

In the presence of oxygen, polymeric materials may undergo diffusion‐limited heterogeneous degradation with significant oxidation occurring only near the surfaces. It is important in studying polymer degradation (and in designing accelerated aging experiments) to be able to determine under what conditions heterogeneous degradation occurs, and to estimate the extent of significant oxidative penetration under those conditions. We describe here the use of several techniques for identification of oxidative degradation gradients. A rapid determination of oxidation depth is accomplished by optical examination of metallographically polished cross‐sectioned samples; oxidized and nonoxidized regions are distinguished by differences in surface reflectivity. A more detailed determination of the shapes of degradation gradients is accomplished by performing a series of sensitive determinations of relative hardness changes across the surface of cross‐sectioned, polished samples. Typical oxidation depths for the commercial polymers examined are on the order of fractions of millimeters over a dose‐rate range of 104–106 rad/h. Significant variations among different materials are found, as would be expected given differences in oxygen consumption and permeation rates. A detailed example is given of the tensile property behavior of a Viton material over a range of dose rates where the degradation is seen to change from strongly heterogeneous at high dose rates to homogeneous as the dose rate is lowered. Degradation differences in this material are very pronounced: at high dose rates the polymer undergoes primarily crosslinking to give a hard brittle material, whereas under lower dose rates, where oxygen permeation is complete, the polymer undergoes predominantly scission to yield a soft, easily stretchable material.
Synthesis and characterization of styrene/isoprene/ethylene oxide block copolymers
Authors: Benson R. S. , Wu Q. , Ray A. R. , Lyman D. J.
Published: April 2003

Poly(ethylene oxide/isoprene/styrene/isoprene/ethylene oxide) block copolymers were synthesized using potassium–napthalene catalyst in tetrahydrofuran. The dynamic and thermal properties and water absorption of these tri‐block copolymers were determined and related to their bulk morphology.
Nature and ESR anisotropy of trapped radicals in UV‐irradiated isotactic polypropylene at 4.2 K and 77 K
Authors: Faucitano A. , Buttafava A. , Martinotti F. , Gratani F. , Bortolus P.
Published: April 2003

A comparative ESR study of low‐temperature photolysis at 77 and 4.2 K of isotactic polypropylene, preoxidized under controlled conditions, and of 2.6.8 trimethylnonane‐4‐one as a model compound of the inchain PP ketones CH2COCH2 is presented. The results show conclusively that the ESR spectra of low‐temperature PP photolysis reported in the literature arise from the decomposition of tertiary hydroperoxides, whereas the contribution by the Norrish I photolytic cleavage of ketones is of minor importance; the relative efficiency of radical production at 77 K (λ ≥ 300 nm) by both types of photoactive compound has been measured by ESR and found to be about 15 times greater for the hydroperoxides. The mechanism of solid‐state photolysis of PP hydroperoxides is dominated by the nearly complete decay of excited alkoxyls during the photolytic events that yield the chain end radicals CH(CH3)CH2· by β scission (87.8%) and the inchain radicals CH2C(CH3)CH2 by hydrogen abstraction (10.4%). The low yield of methyl radicals detected (1.8%) and their delayed appearance strongly suggest that these species are of secondary origin and that the decomposition of alkoxyls via CCH3 scission is of negligible importance. From the ESR anisotropy of the deliberately prepared peroxyradicals CH(CH3)CH2O2· and CH2C(CH3)(O2)CH2 evidence of the misalignment of terminal chain segments following scission of alkoxyls at 77 K was obtained. An unexpected result of the measurements at 4.2 K is represented by the identification of a clear signal by H atoms: the H atoms apparently are not trapped in perprotiated matrices, even at 4.2 K, because of their unusually high reactivity toward the hydrogen abstraction assisted by tunneling effects.
Poly(alkylene oxide) ionomers. X. Copolymerization of methyl ω‐epoxyalkanoates and characterization of the polymers
Authors: Muggee John , Vogl Otto
Published: April 2003

Selected methyl ω‐epoxyalkanoates ranging from methyl 3,4‐epoxybutanoate to methyl 7,8‐epoxyoctanoate were copolymerized with a number of oxiranes and with oxetane. Tetrahydrofuran did not take part in the attempted methyl ω‐epoxyalkanote–tetrahydrofuran copolymerization, but acted only as the solvent. The oxirane copolymers had polymer compositions similar to the comonomer feed ratio. Oxirane comonomers used were propylene oxide (1,2‐epoxypropane), butylene oxide (1,2‐epoxybutane), 1,2‐epoxyhexane, epichlorohydrin, and phenylglycidyl ether. The initiator system used was triethylaluminum/water/acetylacetone (1.0/0.5/1.0) in about 5 mol %. In the copolymerizations using methyl 3,4‐epoxybutanoate as a comonomer, only small yields of polymer (in the range of 1 to 2%) were realized, while for methyl 4,5‐epoxypentanoate the yields were generally in the range of 20 to 60%. Methyl 7,8‐epoxyoctanoate copolymerized readily and gave yields of copolymers of 50 to 90%.
Poly(alkylene oxide) ionomers. XI. Polymerization and copolymerization of methyl ω‐epoxyundecanoate and characterization of the polymers
Authors: Bansleben Donald A. , Vogl Otto
Published: April 2003

Methyl 10‐undecenoate was epoxidized in nearly quantitative yield with m‐chloroperoxy‐benzoic acid to methyl 10,11‐epoxyundecanoate. The functional epoxide monomer was polymerized by the reaction product of triethylaluminum/water/acetylacetone (1.0/0.5/1.0) to a high molecular weight elastomer having pendent carboxyl groups, and a molecular weight distribution near the most probable distribution. With the same initiator system, methyl 10,11‐epoxyundecanoate was copolymerized with ethylene oxide, propylene oxide, 1‐butene oxide, 1‐hexene oxide, phenyl glycidyl ether, epichlorohydrin, and 4,4,4‐trichloro‐1‐butene oxide. The copolymers were typically high in molecular weight, elastomeric, and had methyl 10,11‐epoxyundecanoate incorporations similar to the initial feed ratio of comonomers. The new family of functional polymers were characterized by their infrared and NMR spectra, dilute solution viscosity and thermal transitions.
Polyesters derived from 1,4‐oxathian‐2‐ones
Authors: Huffman K. R. , Casey D. J.
Published: April 2003

1,4‐Oxathian‐2‐one (1a) was prepared in high yield by oligomerization of methyl(2‐hydroxyethyl)mercaptoacetate (3) followed by catalytic depolymerization in vacuo. A similar sequence starting with methyl(2‐hydroxyethyl)sulfonylacetate (5) afforded the corresponding sulfone, 1,4‐oxathian‐2‐one‐4,4‐dioxide (1c), however, 1,4‐oxathian‐2‐one‐4‐oxide (1b) could not be obtained by this procedure. Ring opening melt polymerization of 1a and 1c afforded low molecular weight crystalline polyesters 2a and 2c. Oxidation of 2a with m‐chloroperoxybenzoic acid produced the corresponding polyester 2b containing sulfoxide groups. Thermogravimetric analyses and visual observations indicated 2b to be thermally unstable relative to 2a and 2c.
Preparation of soluble and fusible poly(2,5‐dimethoxy‐1,4‐phenylene)
Authors: Mukai Katsuya , Teshirogi Takuma , Kuramoto Noriyuki , Kitamura Taku
Published: April 2003

Poly(2,5‐dimethoxy‐1,4‐phenylene) was prepared by oxidative polymerization of p‐dimethoxybenzene with aluminum chloride and copper(II) chloride in nitrobenzene under reduced pressure. The polymers obtained were soluble in sulfuric acid and fusible at 320°C. The intrinsic viscosity of the polymer was ca. 0.07 in sulfuric acid. Demethylation of methoxy groups did not occur during the polymerization.
Polymeric catalysts. IX. Cobalt complexes of polyureas based on bipyridine pyridine and crown ether for aldol condensation
Authors: Zhang Keda , Kumar G. Sudesh , Neckers D. C.
Published: April 2003

We report herein studies of Co(OAc)2 and related transition metal compounds which serve as catalysts for aldol condensations when complexed with bipyridine, triphenyl phosphine, and crown ether. A comparison has been made with polymeric complexes of cobalt(II), which serve the same purpose. Cobalt complexes of built‐in polyureas based on bipyridine and crown ether as well as those immobilized to polystyrene by triphenylphosphine and poly(4‐vinyl pyridine) are also reported.
Synthesis of N‐substituted polyethylenimines with polarizable side chain pendent groups
Authors: Litt Morton H. , Kim Jinbaek , Rodriguezparada José M.
Published: April 2003

Two new N‐substituted polyethylenimines containing carbazole and acridone groups on the side chains were prepared. The polymers were obtained by cationic ring opening polymerization of the corresponding 2‐oxazoline monomers. The carbazole containing oxazoline was low melting and could be polymerized in bulk; however the acridone containing monomer had a high melting point and solution polymerization had to be used. This paper describes the synthetic procedures used to obtain these polymers.
Polychloroprene. I. Etude de la microstructure par RMN 1H
Authors: Petiaud Roger , Pham Quang Tho
Published: April 2003

The microstructure of polychloroprenes was studied by 1H‐NMR at high field (350 MHz). An examination with two solvents, CDCl3 and C6D6, was necessary to show all the addition modes. The complementary information obtained made possible the quantitative determination of head‐to‐tail, head‐to‐head, tail‐to‐tail, trans‐1–4, and cis‐1–4, 1–2, and 3–4 additions.
Direct synthesis of aromatic polyesters by use of a sulfonium salt derived from tosyl chloride and N‐methylimidazole
Authors: Higashi Fukuji , Ozawa Michihide , Chang Teh‐Chon
Published: April 2003

A sulfonium salt derived from tosyl chloride and N‐methylimidazole was successfully used as an effective condensing agent for the preparation of high‐molecular‐weight aromatic polyesters by the direct polycondensation of aromatic dicarboxylic acids and bisphenols. Conditions for the formation of the sulfonium salt and of the reaction of the salt with dicarboxylic acids favorable for the polycondensation were examined. Thermal property of a polymer was investigated in terms of random sequences of monomer in the polymer backbone. Preparation of a polyamide and a polyesteramide was attempted with limited success.
Selective chemical modifications of dextran
Authors: Yalpani Manssur , Brooks Donald E.
Published: April 2003

Specific modification of the reducing end group of dextran has been achieved using the reductive amination procedure and solvent systems designed to optimize polymer reactivity. Dextran fraction (with Mw ranging from 10,000 to 500,000 daltons) were derivatized with [14C]‐octadecylamine in yields of up to 60% to afford the corresponding alkyl dextrans which are of interest as affinity ligands. Reactive dextran intermediates with terminal amine, carboxyl, and aldehyde functions were prepared using sodium cyanoborohydride and ammonium acetate, glycine, and glucosamine, respectively. The dextran glucosamine derivative was further modified by reductive amination with octadecylamine. Similarly, condensation of dextran with streptomycin produced a new type of cationic derivative bearing a terminal, branched saccharide residue. Other reducing‐end modifications included nitroxide‐spin labelling, covalent attachment to aminopropyl‐activated glass beads, and a carbodiimide‐mediated amidation of carboxyl—dextran. The reductive amination method was also applied to guar gum and locust bean gum.
Soluble magnesium–titanium catalysts for ethylene polymerization. I
Authors: Yano Takefumi , Ikai Shigeru , Shimizu Michimasa , Washio Katsutoshi
Published: April 2003

A study has been made of a catalyst system comprising the heptane‐soluble magnesium and titanium compounds in combination with an organoaluminum compound for ethylene polymerization at a high temperature. The productivity for ethylene polymerization of the catalyst system, n‐butylethyl magnesium (BEM)‐2‐ethyl hexanol (C8H17OH)‐tetra‐n‐butoxytitanium[Ti(OBu)4]/diethyl aluminum chloride (DEAC) is higher than for MgCl2‐Cl2‐C8H17 OHTi(OBu)4/DEAC and much higher than MgCl2‐Ti(OBu)4/DEAC. The nature of the three different catalyst systems have been discussed in comparison with experimental data on polymerization behavior and the data of the elemental and x‐ray diffraction analysis of the solid products obtained from the reactions between the catalyst components.
Synthesis and polymerization of 4‐o‐vinylbenzyl‐2,2,6,6‐tetramethylpiperidine
Authors: Miyazawa Takeo , Endo Takeshi , Okawara Makoto
Published: April 2003

Some hindered amine polymers containing 2,2,6,6‐tetramethylpiperidine structure were synthesized. A new monomer, 4‐O‐vinylbenzyl‐2,2,6,6‐tetramethylpiperidine, was homopolymerized and copolymerized with some vinyl monomers in the presence of AIBN as an initiator. The obtained amine polymers were oxidized with hydrogen peroxide to obtain the polymers having nitroxyl radical moiety.
Polymerization of methyl methacrylate by resin containing polyethylenepolyamine side chain–peroxide system
Authors: Nonaka Takamasa , Abe Takashi , Egawa Hiroaki
Published: April 2003

Macroreticular resins (RST) bearing polyethylenepolyamine side chain were prepared by the amination of the chloromethylated macroreticular styrene—divinylbenzene copolymer beads. The polymerization of methyl methacrylate (MMA) was carried out in a water—organic solvent mixture containing hydroperoxide and RST. The polymerization of MMA proceeded smoothly in the presence of both hydroperoxide and RST. The presence of water was indispensable for this polymerization. 1,4‐Dioxane hydroperoxide showed a high activity for the polymerization of MMA. The polymerization of MMA by this system was greatly affected by the structure of the resins. It was especially accelerated by using macroreticular resins with appropriate porosities.
Thermal treatment, spectroscopic analyses, and electrical properties of poly(copper 2,3,9,10,16,17,23,24‐octacyanophthalocyanine)
Authors: Lin John W‐P. , Dudek Les P.
Published: April 2003

Thermal treatment of novel poly(copper 2,3,9,10,16,17,23,24‐octacyanophthalocyanine), PCOCP, has been carried out at different temperatures in an inert atmosphere. As polyacrylonitrile, the polymer can be thermally cyclized through the cyano groups to produce semiconductive and conductive materials. Polymeric copper octacyanophthalocyanine material with a conductivity as high as 5–8 (Ω cm)‐1 was prepared. Weight loss, electrical data, infrared, and photoacoustic results of the thermally treated copper octacyanophthalocyanine polymer are discussed.
Electropolymerization potential—FMO relations
Authors: Akbulut U. , Toppare L. , Türker L.
Published: April 2003

Electroinitiated polymerizations can be carried out by direct electron transfer if the anodic (Ep,a) and cathodic (Ep,c) potentials of monomers are known. Peak potentials of various halostyrenes were measured by cyclic voltammetry in acetonitrile for the first time. Polymerizations were carried out at measured peak potentials, on Pt0 electrode versus Ag0/Ag+, in dichloromethane in which chain transfer is negligible. Frontier molecular orbital energies εm and εm+1 of monomers were calculated by Hückel molecular orbital considerations. Measured Ep,a and Ep,c values were correlated to calculated HOMO and LUMO energies, respectively. Linear equations have been developed for the above correlations as well as for Ep,a — Ep,c versus εm — εm+1.
An electrically conductive plastic composite derived from polypyrrole and poly(vinyl chloride)
Authors: De Paoli Marco‐A. , Waltman R. J. , Diaz A. F. , Bargon J.
Published: April 2003

An electrically conductive plastic material was obtained by the electrochemical polymerization of pyrrole in a poly(vinyl chloride) matrix. The transmission electron microscopy shows that polypyrrole is uniformly distributed in the matrix. The conductivity of the composites fall in the range of 5 to 50 S/cm, and their mechanical properties, as measured in a stress—strain test, are very similar to those of pure poly(vinyl chloride). These can be further improved by addition of poly(chloroprene) rubber as a plasticizer.
Polymer‐immobilized lipoamides—iron(II) system as a reducing catalyst for the reduction of nitrobenzenes to anilines by sodium borohydride
Authors: Kijima Masashi , Nambu Yoko , Endo Takeshi
Published: April 2003

Based on a redox function of 1,2‐dithiolane ⇌ 1,3‐dithiol, lipoamide (LAm), and polymers having lipoamide structure were found to work as reducing catalysts for the reduction of p‐substituted nitrobenzenes to corresponding anilines with sodium borohydride in the presence of ferrous chloride in ethanol. Polyallylamine having lipoamide structure (PAA—LAm) showed a good reactivity for the reduction and was easily separated from the reaction mixture.
Direct mass spectrometry of polymers. XIII.. Thermal fragmentation processes in copoly‐α‐amino acids
Authors: Ballistreri Alberto , Giuffrida Mario , Maravigna Pietro , Montaudo Giorgio
Published: April 2003

The thermal fragmentation processes in L‐Proline—Sarcosine and in L‐Proline—L‐Alanine copolymers have been investigated by direct pyrolysis—mass spectrometry. The mass spectral data show that proline—sarcosine copolymers decompose in three steps, yielding cyclic oligomers. The first step is characterized by the presence of the Sar—Sar, Sar—Pro, and Pro—Pro cyclic dimers. In the second step the formation of several series of cyclic oligomers up to nonamers—decamers can be observed, while the third step of thermal decomposition process leads to the almost exclusive formation of Pro—Pro cyclic dimer. The proline—alanine copolymers, instead, show a single‐step thermal degradation process leading to the formation both of cyclic oligomers and compounds with olefin and nitrile end‐groups. Our results show that the thermal decompostion of alanine units is affected by the neighboring units along the polymer chain. Sarcosine units act as thermally labile probes, causing the selective thermal cleavage of the Pro—Sar copolymer.
Substitution and elimination reactions of poly(epichlorohydrin) and poly(2‐chloroethyl vinyl ether) using phase transfer catalysis
Authors: Iizawa Takashi , Nishikubo Tadatomi , Ichikawa Midori , Sugawara Yoshihiko , Okawara Makoto
Published: April 2003

The reactions of poly(epichlorohydrin) (PECH) and poly(2‐chloroethyl vinyl ether) (PCEVE) with various reagents were investigated using phase transfer catalyst (PTC) such as tetra‐n‐butylammonium bromide (TBAB), 18‐crown‐6 (CR6), and dicyclohexyl‐18‐crown‐6 (DCHC) is a solid—liquid two‐phase system. Although the reactions of these polymers hardly occurred without PTC in nonpolar solvents such as toluene and diglyme under mild conditions, the addition of PTC caused the reactions to proceed smoothly under the same conditions. In addition, the reactions of PECH and PCEVE with a strong base such as potassium hydroxide proceeded selectively through β‐elimination reaction to produce the polymers with pendant vinyl groups. These results suggested this method is useful for the syntheses of functional polymers. On the other hand, it turned out that quaternary ammonium salts such as TBAB have higher catalytic activity than crown ethers such as CRG and DCHE in these reactions. Furthermore, the catalytic activity of quaternary ammonium salts was strongly influenced by their chain length and the structure of the polymers.
Effect of carboxyl end groups on hydrolysis of polyglycolic acid
Authors: Huffman K. R. , Casey D. J.
Published: April 2003

Dye interaction analysis in hexafluoroisopropanol was used to determine end carboxyl groups in polyglycolic acid (PGA). The rate of heterogeneous hydrolysis of purified PGA in water at 37°C shows a first‐order dependence on carboxyl end group concentration at levels above 12 meq/kg. Reaction of molten PGA with a tetraarylorthocarbonate or a triarylketenimine gave end‐capped PGA with carboxyl levels as low as 1 meq/kg. These samples were somewhat more resistant to hydrolysis than untreated PGA despite an increased initial rate at the lower carboxyl levels.
Polymeric arylsulfonylnitromethane: A novel polymer reagent
Authors: Kamogawa Hiroyoshi , Sueki Toshiyuki
Published: April 2003

p‐Vinylphenylsulfonylnitromethane (3) was synthesized by the reaction of sodium p‐styrenesulfinate with nitromethane. Free radical copolymerizations of 3 with styrene and N‐vinyl‐2‐pyrrolidone provided soluble copolymers. Conversions of RCH2X (X = Br, OAc) with the copolymers as reagents proceeded in a different manner from the corresponding lowmolecular‐weight compound, phenylsulfonylnitromethane, to afford RCOOH in addition to the expected RCH2CH2NO2 and RCH2COOH; no nitriles were formed.
Spectroscopic studies of poly(N‐acyldehydroalanines) containing asymmetric nucleic acid base derivatives as pendant groups
Authors: Brandt K. A. , Overberger C. G.
Published: April 2003

Water‐soluble polynucleotide analogs having a poly(N‐acyldehydroalanine) {poly(α[–(N‐acylamino)acrylate])} backbone were studied by 360‐HMz1H‐NMR, UV, and CD spectroscopies. Significant UV hypochromicity values for the polymers versus monomer model compounds as well as peak shifts in the NMR spectra implied a high degree of base stacking in these systems. The CD spectrum of poly{(‐)‐2‐[2‐(thymin‐l‐yl) propanoamido] propenoic acid} (p(‐)TDHA), having an optically active side chain, was remarkably insensitive to the degree of neutralization of the polymer, but was very sensitive to the ionic strength of the solution. Continuous variation mixing experiments revealed no base‐pairing interactions between complementary charged polymers, and weak interactions between charged and uncharged polymers and model compounds. These results suggest that the polymers are conformationally restricted in solution.
The anionic polymerization of butadiene in the presence of dipiperidinoethane
Authors: Bywater S. , Mackerron D. H. , Worsfold D. J. , Schué F.
Published: April 2003

The polymerization of butadiene by lithium‐based initiators in aliphatic hydrocarbon solvents in the presence of dipiperidinoethane gives a highly 1,2 structure. This system was studied to determine the factors that govern the structure. The effect of this complexing agent on the kinetics of propagation, the microstructure of the polymer, and the ultraviolet spectrum of the active chain end was measured. The results suggest that more than one solvated species form, all giving highly 1,2 polymer structures, but that a solvate containing one chain end with one dipiperidinoethane molecule is the principal reacting species which gives close to 100% 1,2 structure. This reacting center has a high proportion of trans‐structure in the allyllic ion, únlike most complexed active chain ends, which are often highly cis. It is this transstructure in the ion that is thought to be responsible for the polymer structure.
Synthesis and cation‐binding properties of poly‐and bis(thiacrown ether)s
Authors: Oue Masatoshi , Ishigaki Akira , Kimura Keiichi , Matsui Yousuke , Shono Toshiyuki
Published: April 2003

Poly‐ and bis(thiacrown ether) derivatives in which some oxygen atoms of benzocrown ether moiety are replaced by sulfur atoms have been synthesized. Their cation‐binding abilities were investigated by using the solvent extraction method. The poly‐ and bis(benzothiacrown ether)s showed great affinity for silver ion, being more excellent in the affinity than the corresponding monocyclic analogs. They, however, possess very poor cation‐binding ability for alkali and alkaline‐earth metal ions. The poly‐ and bis(thiacrown ether)s also bind mercuric ions effectively, whereas the corresponding monomeric analogs do not at all.
Binding of metal ions by polyethylenimine and its derivatives
Authors: Takagishi Toru , Okuda Sadatsugu , Kuroki Nobuhiko , Kozuka Hiroshi
Published: April 2003

Measurements have been made of the binding of divalent metal ions, Cu2+, Ni2+, Co2+, and Zn2+ ions, by polyethylenimine (PEI) and its acetyl or alkyl derivatives by the equilibriumdialysis technique. These metal ions, in particular the Cu2+ ion, exhibited tremendously remarkable binding affinity toward PEI. The extent of complexation of the polymer with the metal ions was decreased markedly by acetylation or alkylation of the polymer. PEI with no primary amine showed an appreciable decrease in its affinity for the metal ion. These results indicate the participation of the primary amine of the polymer in the formation of the complex. A cooperative binding isotherm was observed in PEI–metal ion complex formation, suggesting swelling or conformational change of the polymer induced by this coordination process. Binding of the Cu2+ ion by PEI was found to be essentially independent of temperature over the range 5–35°C.
A regenerable immobilized nadh model IV: Reduction of pyridine‐2‐carbaldehyde by immobilized 1,4‐dihydronicotinamide in the presence of Mg2+ ions
Authors: Eling Berend , Challa Ger , Pandit Upendra K.
Published: April 2003

Dihydronicotinamide, anchored to a macroreticular polystyrene resin, reduces pyridine‐2‐carbaldehyde (PCA) in the presence of Mg2+ ions in acetonitrile. The reactions are clean at room temperature, the high rate precluding complications arising from slow side reactions. The influence of Mg2+ concentration on the rate of reduction of PCA by polymer‐bound reagent and BNAH (1‐benzyl‐1,4‐dihydronicotinamide; low‐molar‐mass analog) has been studied. Analysis of the kinetic data showed that of the processes contributing to the overall reduction, the reaction between the reductant and the complexed substrate proceeded at the highest rate. In the polymer‐bound reagent, “site isolation” on the rigid matrix was observed to prevent bimolecular disproportionation of the neighboring dihydronicotinamides. Regeneration of the polymeric reagent was achieved with an efficiency of 98% per cycle.
A simplification of the terpolymerization equation
Authors: Chien James C. W. , Finkenaur Amy L.
Published: April 2003

The terpolymerization composition equation has been modified to eliminate the consideration of interactions between monomers 2 and 3 when they are present in low concentration in the feed mixture relative to monomer 1. Terpolymers with a wide variety of comonomers and compositions have been synthesized and used to demonstrate that a simplified terpolymerization equation accurately predicts terpolymer composition.
Analysis of products of the thickening reaction between polyesters and magnesium oxide
Authors: Rao K. Balakoteswara , Gandhi K. S.
Published: April 2003

The products of the reaction between MgO and polypropylene‐glycol adipates of different acid values and water contents were analyzed for the water generated and the magnesium reacted into the resin by means of Karl Fischer titration and atomic absorption spectroscopy, respectively. The results conclusively show that both basic and neutral salts are present in the products. The ratio of the amounts of basic and neutral salts present in the mixture, rB/N, could also be calculated from the results. It was found that as R, the moles of MgO added per mole of acid groups, is increased both the amount of oxide reacted and rB/N increase while these are relatively unaffected by the water content of the resin. The minimum value of R at which basic salt exists in the reaction products was found to increase with decreasing acid value. It is proposed that diffusional effects account for these observations as well as those reported in literature.
Synthesis of isotactic, syndiotactic, and heterotactic poly(tributyltin methacrylate) and poly(tributyltin methacrylate‐co‐styrene)
Authors: Zeldin M. , Lin J. J.
Published: April 2003

Pure isotactic and enriched syndiotactic poly(tributyltin methacrylate) were synthesized by the reaction of the respective poly(methacrylic acid) with tributyltin oxide. The heterotactic polymer was prepared in a similar manner and from free radical initiated (AIBN or BPO) polymerization of tributyltin methacrylate. In each case, polymer configuration was confirmed by 1H‐NMR of the hydrolyzed/esterfied product. The relatively large 119Sn‐NMR linewidth of the isotactic tributyltin containing polymer suggests an intra‐molecular exchange of the pendant tin groups. Tg, Td, and Mv data are also reported. Poly(tributyltinmethacrylate‐co‐styrene) was prepared by free radical polymerization and reactivity ratios [r(styrene) = 0.51, r(TBTM) = 0.49] and Q‐e values for TBTM (0.78, 0.38) were determined.
Molecular structure and photosensitivity of polyesters with conjugated double bonds
Authors: Iwata Kaoru , Hagiwara Tsuneo , Matsuzawa Hiroshi
Published: April 2003

Photocrosslinkable polyesters of m‐ and p‐phenylenebis(α‐cyanoacrylic acids) (I‐a and I‐b), m‐ and p‐phenylenebis(α‐cyanobutadiene carboxylic acids) (I‐d and I‐e), p‐phenylenebis(acrylic acid) (I‐c), and p‐phenylenebis(butadiene carboxylic acid) (I‐f) were prepared, and their photosensitivities were investigated. The spectral sensitivities of I‐a, I‐c, I‐d, and I‐e ranged up to 365, 385, 510, and 560 nm, respectively. This order corresponds to that of λmax due to the π‐π* transition in their absorption spectra. I‐e was sensitive to the visible part of argon ion laser even in the absence of photosensitizer. The highest sensitivity observed with I‐e was estimated to be 1.5 mJ/cm2. In contrast, the sensitivity of I‐c was low (> 105 mJ/cm2) and that of I′‐d, a modified I‐d, was 1300 mJ/cm2, respectively. Addition of 2,6‐di(4′‐methoxyphenyl)‐4‐(4′‐n‐amyloxyphenyl)thiapyrylium perchlorate to them extended their sensitivity range, improving their sensitivity values to 35 and 110 mJ/cm2, respectively.
Electrochemical polymerization of acetylene on a surface of platinum
Authors: Chen Show‐An , Shy Hsiou‐Jeng
Published: April 2003

Polyacetylene (PA) deposited on a platinum surface is synthesized by electrochemical polymerization of acetylene in a cell with platinum strip as cathode, nickel strip as anode, and nickel bromide in acetonitrile as electrolyte. The electrolytic solution is presaturated with acetylene. The PA so produced has a granular morphology and high surface area (79 m2/g), and is insoluble. Polymerization at lower temperature gives higher content in cis units. It has the same chemical structure as that produced using the Shirakawa method as examined by elemental analysis, infrared spectroscopy, x‐ray diffraction, and differential scanning calorimetry.