bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complexation of poly(ethyleneimine) with copper(II) and nickel(II) ions in 0.5 M KNO3 solution
Authors: Fujimori Kiyohisa 
Published: April 2003

AbstractComplexation of poly(ethyleneimine) (PEI) with copper(II) and nickel(II) ions was studied in a 0.5M aqueous KNO3 solution. The potentiometrically determined logarithm of the three successive formation constants (log kJ) were 8.14, 7.96, and 7.37 for Cu+2‐PEI complexation and 6.74, 6.52, and 6.23 for Ni+2–PEI complexation at 25°C, according to Bjerrum's modified method. The maximum average coordination number was 3.2 for the Cu+2–PEI system and 3.7 for the Ni+2–PEI system. An entropy effect was observed in the third coordination. The wavelengths of maximum absorption of the complexes and the continuous variation method showed that at least two coordination sites of Cu+2 ion and three coordination sites of Ni+2 ion were occupied immediately by PEI as the solutions of PEI and the metal ions were mixed.
Microstructural order in the developing cotton fiber based on availabilities of hydroxyl groups
Authors: Rowland Stanley P. , Howley Phyllis S. 
Published: April 2003

AbstractThe relative availabilities of accessible O(2)H, O(3)H, and O(6)H in the cellulose of developing cotton fibers were measured by conducting a reaction to a low degree of substitution under mild conditions in an aqueous medium. Raw cotton fibers from unopened bolls and from mature, opened bolls were studied. Correction was made for the presence of a β‐1,3‐glucan that was detected by substitution at the abundant O(4)H of this polysaccharide. The order of decreasing availability of hydroxyl groups of cellulose was O(2)H > O(6)H > > O(3)H. Results indicate that cellulose in the secondary wall of the cotton fiber is laid down with a high degree of order and that this order decreases with opening of the boll.
Preparation of a polymeric membrane with lipoamide structure and its application to electron transport across membrane
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto 
Published: April 2003

AbstractA lipoamide (LAm) structure was introduced into a polymeric membrane by chemical modification of poly(γ‐methyl‐D‐glutamate) (PMG). A. redox reaction proceeded across the membrane mediated by pendant LAm groups as solid carriers. It is suggested that the electron transport process in the membrane is derived from the exchange reaction between reduced LAm (thiol) and LAm (disulfide).
Synthesis of polymeric crown ethers and thermoregulated ion complexation effects
Authors: Kahana N. , Deshe A. , Warshawsky A. 
Published: April 2003

AbstractThe alkylation of catechol with (chloromethyl)styrene–divinylbenzene copolymer 1 produces the polymer‐bound catechol 2, which upon reaction with a series of polyglycol dihalides affords macrocyclic polymeric benzo crown ethers 3, in fair yields. The alkylation of polybenzylamine 4 with polyglycol dihalides leads to diazapolymeric pseudocrown ethers 5. The degree of conversion of the catechol groups into macrocyclic ether groups and the residual concentration of diol groups were estimated from elemental analysis, weight‐gain data, and the analysis of bis‐2,4‐dinitrophenyl derivatives of the residual diol groups. The ion‐coordination patterns for the polymeric crowns were determined using distribution and column techniques. Equilibrium distribution values in methanol in the temperature range 20–60°C, for the perchlorate, thiocyanate, or bromide salts, have led to the following conclusions: (1) The spheric recognition patterns, typical of crown ethers in solution, are fully reproduced in the polymeric analogs. (2) The order of binding constants is K > Cs > Na > Li for polymeric benzocrown‐6 (3Hc) and benzocrown‐8 (3Hd) and K > Cs ≅ Na > Li for polymeric benzocrown‐4 (3Ha) and benzocrown‐5 (3Hb). (3) The polymers bind alkali metal cations by two mechanisms: the residual diol groups by ion exchange mechanism, and the crown groups by a salt‐coordination mechanism; the second mechanism is temperature‐dependent. Consequently, a thermal increase of 40°C causes a spontaneous elution, by “thermal shock,” and a three‐fold increase in the eluent of the original ion concentration. (4) Quantitative release of all the bound salt is observed.
Polymeric catalysis: Imidazoles grafted onto poly(vinylamine). I. Synthesis and grafting of imidazolylalkanoic acids
Authors: Tomko Richard , Overberger C. G. 
Published: April 2003

AbstractSome ω‐(1‐imidazolyl) and ω‐[4(5)‐imidazolyl]alkanoic acids were synthesized and grafted onto poly(vinylamine) with an amide bond. These water‐soluble grafts were used to study the kinetics of the esterolysis of activated phenyl esters. The 1‐substituted imidazoles were prepared by the reaction of the sodium salt of imidazole with the ethyl ω‐bromoalkanoates. The 4(5)‐substituted imidazoles were prepared from urocanic acid or 4(5)‐hydroxymethylimidazole. The ω‐(1‐imidazolyl)alkanoic acids were grafted onto poly(vinylamine) via their acyl–guanidine derivatives; the 3‐[4(5)‐imidazolyl]propanoic acid was grafted with a water‐soluble carbodiimide.
Effects of potential on electroinitiated copolymerization of styrene and β‐bromostyrene
Authors: Toppare L. , Eren S. , Akbulut U. 
Published: April 2003

AbstractCopolymerization of styrene and β‐bromostyrene, by constant potential electrolysis, in 1,2‐dichloroethane was achieved at various applied potentials. Effect of polymerization potential on the copolymer composition and the reactivity ratios was studied. Monomer reactivity ratios were determined by integrated Lewis–Mayo equation.
Multiphoton infrared laser‐induced degradation of polydimethylsiloxane and hexamethyldisiloxane
Authors: Manders W. F. , Bellama J. M. 
Published: April 2003

AbstractThe IR laser‐induced degradations of liquid polydimethylsiloxane (PDMS) vapor and of hexamethyldisiloxane vapor have been studied in order to determine whether the high temperature thermal properties of the dimethylsiloxane unit is best represented by SiO bond rearrangement (the conventional pyrolysis mechanism) or SiC bond cleavage (the thermodynamic reaction pathway). The volatile products of these pulsed laser experiments with various viscosities of PDMS are methane, ethane, ethylene, and hydrogen. These results are consistent with SiC bond cleavage to form methyl radicals, which can then recombine to form ethane or abstract a hydrogen atom from a matrix molecule to form methane. The presence of ethylene and hydrogen can be explained by the decomposition of hot ethane molecules. No evidence of SiO bond cleavage was observed. Reaction temperatures are estimated with computer modeling using heat capacity data.
Laser‐initiated polymerization of epoxies in the presence of maleic anhydride
Authors: Sadhir R. K. , Smith J. D. B. , Castle P. M. 
Published: April 2003

AbstractLaser‐initiated polymerization of cyclohexene oxide in the presence of maleic anhydride was investigated. The influences of solvents laser irradiation time and the monomer feed ratio on the polymer yield and composition were evaluated. The rate of polymerization increased with an increase in the molar concentration of maleic anhydride in the monomer feed. Short irradiation times of 1–3 min duration gave very high yield of epoxy polymer (>80% conversion). Infrared spectral studies of the polymer product indicated the formation of polyether linkage at lower levels of conversion and an adduct of polyether and maleic anhydride at higher polymer conversions. The quantitative chemical analyses results also showed similar results. The results indicated that the polymerization was initiated by the excited charge transfer complex between the electron donor, cyclohexane oxide, and the electron acceptor–maleic anhydride. In the initial stages of polymerization, cyclohexene oxide undergoes a cationic polymerization in the presence of the radical anion of maleic anhydride. Laser‐initiated polymerization of cyclohexene oxide/maleic anhydride is several hundred times more efficient than UV‐initiated polymerization, as measured by the energy absorbed by the polymer system.
Block copolyurethanes based on polyoxytrimethylene glycols
Authors: Conjeevaram S. V. , Benson R. S. , Lyman D. J. 
Published: April 2003

AbstractTrimethylene oxide was polymerized to polyoxytrimethylene glycol by two synthetic routes. High molecular weight polytrimethylene oxide was synthesized using a coordination catalyst system consisting of triethylaluminum, acetylacetone, and water, then ozonized and reduced with lithium aluminum hydride in anhydrous ether to form hydroxyl end‐capped polyoxytrimethylene glycol. In the second route, the polyoxytrimethylene glycols were synthesized directly by the cationic polymerization of trimethylene oxide with boron trifluoride/ethyl ether as catalyst and 1,4 butanediol as co‐initiator. (AB)n block copolyether–urethane–ureas based on these polyoxytrimethylene glycols were synthesized and characterized by differential scanning calorimetry, and dynamic mechanical and stress–strain measurements.
Synthesis and morphology of BAB type poly(styrene‐b‐2‐methyl‐2‐oxazoline) block copolymers
Authors: Ishizu Koji , Ishikawa Satoshi , Fukutomi Takashi 
Published: April 2003

AbstractWell defined BAB‐type poly[styrene(ST)‐b‐2‐methyl‐2‐oxazoline(MeOz)] was prepared by the cationic polymerization of α,ω‐p‐toluenesulfonic acid ester‐terminated PST (PST‐BTs) as an initiator. Alkaline hydrolysis of this block copolymer was carried out under various reaction conditions to obtain BAB‐type poly[ST‐b‐ethylene imine(EI)]. Morphologies of these block copolymer specimens cast from several solvents were observed by electron microscope. The results are discussed in some detail.
Cation binding properties of poly(crown ethers) with photodimerizable groups
Authors: Shirai Masamitsu , Orikata Takao , Tanaka Makoto 
Published: April 2003

AbstractPolymers that have crown ether groups as cation binding sites and cinnamic acid ester groups as photodimerizable groups were prepared by the cationic polymerizations of 2‐vinyloxyethyl 4′‐(2,3‐benzo‐1,4,7,10,13‐pentaoxa‐2‐cyclopentadecene)acrylate and 2‐vinyloxyethyl 4′‐(2,3‐benzo‐1,4,7,10,13,16‐hexaoxa‐2‐cyclooctadecene)acrylate. When irradiated with ultraviolet (UV) light the cinnamic acid ester groups of the polymers caused dimerization in dilute solution without the formation of insoluble materials. The irradiation was carried out in a dioxane solution and an aqueous solution in the presence and absence of salts. The effect of phototransformation of polymers on the cation binding properties was investigated by a method of picrate salts extraction. The binding ability of the phototransformed polymers for alkali and alkaline earth metal cations was higher than that of the native polymer. Furthermore the cation binding ability of the phototransformed polymers was less sensitive to temperature than that of the native polymer. The effect of the degree of photodimerization of the polymers and the concentration of KCl that exists during irradiation on the cation binding ability was also investigated.
Polymerization of 2‐azabicyclo[2,2,1]heptan‐3‐one and its copolymerization with 2‐pyrrolidone
Authors: Cho Hyun‐Nam , Choi Kil‐Yeong , Choi Sam‐Kwon 
Published: April 2003

AbstractThe anionic polymerization of a bridged bicyclic lactam, 2‐azabicyclo[2,2,1]heptan‐3‐one (ABHO), was carried out in bulk and in solution under various reaction conditions. In general bulk polymerization of ABHO was superior to solution polymerization in conversion and degree of polymerization. The resulting polymer exhibited good thermal stability at temperatures up to 300°C. The melting point and decomposition temperature of this polyamide, poly(cyclopentane‐1,3‐diyliminocarbonyl), were about 307 and 335°C, respectively. Copolymerization of ABHO with 2‐pyrrolidone was also made at 30°C and a varying weight percentage of ABHO with potassium pyrrolidonate as catalyst and CS2 as activator. Copolyamides that contained 15 w % of ABHO decomposed at a temperature higher than the melting point by almost 30°C. Thus the thermal stability of copolymers compared with that of nylon‐4, was greatly improved. Moisture sorptions of homopolymers and copolymers were always larger than those of other polyamides (nylon 4 and 6) at any relative humidity. Tenacity and elongation at the break of melt‐spun fibers obtained from copolyamides that contained 15 w % of ABHO without the drawing and annealing process were 1.25 g/den and 13.1%, respectively.
Magnesium chloride supported high mileage catalyst for olefin polymerization. VII. Determinations of concentrations of titanium–polymer and aluminum–polymer bonds
Authors: Chien James C. W. , Kuo Chi‐I 
Published: April 2003

AbstractTwo methods were used in an attempt to determine by radioquenching the active site concentration, [Ti*], in a MgCl2 supported high activity catalyst. For the reactions of tritium labelled methanol, the kinetic isotope effects were first determined: kH/kT = 1.63 for the total polymer and 1.67 for the isotactic polypropylene fraction. Polymerizations were quenched with an excess of isotopic CH3OH after various lengths of time, at different A/T (amount of AlEt3 with 0.33 equivalent of methyl‐p‐toluate to amount of Ti in the catalyst) ratios, and temperatures. From the known specific activity of tritium in CH3OH and radioassay of the polymer, value of the total metal polymer bond, [MPB], can be obtained. [MPB] increases linearly with polymerization time. Extrapolation to t = 0 gives [MPB]0, which should be close to [Ti*] because chain transfer with aluminum alkyls to produce Al–P bonds is negligible during very early stage of the polymerization. The values of [MPB]0 range from 7–30% of the total Ti; the number of MPB is nearly equally distributed in the amorphous and isotactic fractions of polypropylene in most runs. The rate of incorporation of radioactive CO into polymers produced by the MgCl2 supported high mileage catalyst is far slower than that claimed by some investigators for TiCl3 type catalysts. There is an initial rapid phase of incorporation of CO which lasts for about 1 hr of contact time. The subsequent rate of CO incorporation steadily declines, yet there is no constant maximum value of radioactivity even after 48 h of reaction in the absence of monomer. Radioquenching of polymerizations with CO was also performed at several temperatures and A/T ratios. In all cases, the maximum [Ti–P] was reached after 30–40 min of polymerization, whereas the maximum rates of polymerization, Rp,m, occurred within 3–10 min. In fact, the rate of polymerization decays to a small fraction of Rp,m after 30–40 min. Furthermore, this maximum value of [Ti–P] remains constant until the end of polymerization (t = 90 min). Therefore, isotopic CO is not reacting with the initially formed active sites Ti1*, but only with those sites, Ti2*, which predominate during the later stage of polymerization.
Synthesis of poly[S‐(2–9′‐acridinylethyl)‐L‐cysteine] and its TCNQ salt
Authors: Oshima Ryuichi , Sato Tadanori , Kumanotani Ju 
Published: April 2003

AbstractPoly[S‐(2–9′‐acridinylethyl)‐L‐cysteine] (5) was synthesized by the N‐carboxy anhydride procedure. It was converted to the trifluoroacetic acid salt (6), which was treated with LiTCNQ in methanol to give the TCNQ anion radical salt (7). 7 showed electrical conductivity of 10−8 S/cm at 295 K.
Mechanochemical reactions of elastomers with metals
Authors: Gent A. N. , Rodgers W. R. 
Published: April 2003

AbstractMetal powders were incorporated into various elastomers and the mixtures were subjected to intense shearing in air or a nitrogen atmosphere. The molecular weight after shearing was still relatively high, however; greater than 100 kg/mol. The elastomer was then dissolved and centrifuged to remove the metal particles and the solution was analyzed for reaction products. A strongly ultraviolet (UV)‐absorbing species was formed by shearing a styrene–butadiene copolymer (SBR) with iron powder. The concentration increased with the concentration of iron powder in the mixture and the extent of shearing, and it was greater after shearing in a nitrogen atmosphere. These results are attributed to the direct reaction of macromolecular radicals, formed by shearing, with iron powder to yield an iron–polymer compound. Natural rubber (cis‐polyisoprene), which absorbed 100–200 μg of iron per gram of polymer, was about as reactive as SBR. Polybutadiene was less reactive, and an ethylene–propylene copolymer did not react with or solubilize a significant amount of iron. Zinc was, in general, solubilized to a somewhat lesser degree than iron, whereas aluminum powder appeared to undergo virtually no reaction with sheared elastomers. The maximum extent of reaction (solubilization) was of the order of one metal atom per final polymer molecule, which was consistent with the proposed mechanism. Moreover, an analogous reaction took place between simple organic radicals and iron particles in suspension.
Synthesis of poly(vinyl alcohol) containing asymmetric nucleic acid base derivatives as grafted pendants
Authors: Overberger C. G. , Lu Chengxun 
Published: April 2003

AbstractThe preparations of new model polymers of polynucleotides with linear poly(vinyl alcohol) (PVA) backbones and an optically active nucleic acid base derivative as a pending side chain are described. (±)‐, (+)‐, and (−)‐2‐(thymin‐1‐yl)propionic acid were grafted onto PVA through ester bonds by direct coupling with dicyclohexylcarbodiimide (DCC) in the presence of highly active catalyst 4‐pyrrolidinopyridine (PPY) to give optically active graft polymers. The corresponding monomer and dimer models have been prepared.
Polychloroprene. II. Etude comparée de la microstrusture par RMN 1H et 13C. Thermodynamique de propagation des différentes unités structurales
Authors: Petiaud Roger , Pham Quang Tho 
Published: April 2003

AbstractA microstructure analysis of polychloroprenes by 1H and 13C NMR produced slightly different results which, however, are in good agreement. The main uncertainty concerned the assignment of the 1,4‐cis and trans head‐to‐head and tail‐to‐tail additions. In the (+ 12, +70°C) region of polymerization temperatures the principal addition mode was 1,4. An increase in the polymerization temperature to 70°C increased the abnormal head‐to‐head, tail‐to‐tail additions, and 1,4‐cis additions (6–7%), and all vinyl structures that were not higher than 2–3% were equally distributed between 1,2 and 3,4. Under the experimental conditions used in this study no isomerized vinyl structures were found. As in all radical polymerizations the influence of temperature on the propagation mechanisms, namely, the addition modes, was relatively weak, but because of the great number of possible addition modes in microstructure—physicomechanical relationships variations in the microstructure must be taken into account. Only 1H and 13C NMR are capable of determining these variations quantitatively.
Benzophenone‐sensitized photopolymerization of methyl methacrylate using dimethyl aniline–maleic acid combination as photoinitiator
Authors: Ghosh Premamoy , Chowdhury Dilip Kumar 
Published: April 2003

AbstractBenzophenone (BP)‐sensitized photopolymerization of methyl methacrylate (MMA) in near UV/visible light was studied at 40°C using dimethylaniline maleic acid (DMA—MA) combination as the photoinitiator. An instantaneous 1:1 complexation between DMA and MA takes place when they are mixed together in acetonitrile. Also, instantaneous complex formation occurs between DMA and MMA and between MA and MMA when they are dissolved in MMA in low concentrations, separately. Interestingly, when equimolar proportions of DMA and MA are mixed together in MMA, there is indication for further instantaneous complexation between (DMA—MMA) complex and (MA—MMA) complex forming the actual initiating species in the photopolymerization system. Initiator exponent was 0.28 and monomer exponent varied between 0.0 to 1.8 depending on the nature of the solvent and range of dilution used. Analysis of kinetic data indicates a free radical mechanism for the polymerization with initiator‐dependent termination. Chain termination via degradative initiator transfer is quite significant; but the degradative effect becomes much less prominent in the higher range of initiator concentration indicating that the reinitiation reaction following the initiator transfer process assumes more proportionate significance as the initiator concentration is increased, probably as a result of higher reinitiation efficiency. Polymers obtained gave evidence for the incorporation of aromatic (amine) end groups in them.
Friedel–Crafts polymerization of fluorene with methylene chloride, methoxyacetyl chloride, and chloromethyl methyl ether
Authors: Nystuen Natalie J. , Jones Martin B. 
Published: April 2003

AbstractThe polymerization of fluorene with various chloromethylating reagents (methylene chloride, methoxyacetyl chloride, and chloromethyl methyl ether) in the presence of aluminum chloride was studied. The products that were obtained were insoluble, infusible, colored powders which contain a low concentration of aromatic radicals. Each of the polymers is composed predominantly of fluorene nuclei bridged at the 2 and 7 positions by methylene groups. In addition, the materials possess varying amounts of crosslinked and ring‐fused moieties. Based on physical and spectral properties and reaction stoichiometry, the fluorene/methylene chloride polymer is the most highly crosslinked of the three. The fluorene/methoxyacetyl chloride and fluorene/chloromethyl methyl ether polymers are similar to each other in most respects.
Photostabilizing activity of tertiary hindered amines
Authors: Kurumada Tomoyuki , Ohsawa Hisayu , Oda Osamo , Fujita Takashi , Toda Toshimasa , Yoshioka Takao 
Published: April 2003

AbstractThe influence of the N‐alkyl group of tertiary hindered amines on the photostabilization of polymers was studied. The photostabilizing effects of the tertiary amine derivatives of 4‐benzoyloxy‐2,2,6,6‐tetramethylpiperidine (1a) in polypropylene were compared. All tertiary amine derivatives having α‐H to hindered N showed higher effectiveness than 1a. Model liquid phase photoxidations were carried out by irradiating (UV‐lamp) the solutions of tertiary hindered amines containing tert‐butyl hydroperoxide as a photoinitiator. The tertiary hindered amines were oxidized more easily than corresponding parent hindered amine and converted to the parent amine, which was identified as its salt, resulting from the carboxylic acid produced from the N‐alkyl group by oxidation. The thermal reaction of the tertiary hindered amines with tert‐butyl hydroperoxide was also studied in the liquid phase. The tertiary hindered amines decomposed tert‐butyl hydroperoxide more rapidly than the parent secondary hindered amine, and generated the parent amine. It was also found that the photostabilizing effects of tertiary hindered amines for polyolefins were higher than that of the parent secondary hindered amine.
Chemical release control: Sulfonate esters from perfume and herbicide alcohols and p‐styrenesulfonyl chloride
Authors: Kamogawa Hiroyoshi , Haramoto Yuichiro , Misaka Yukihiro , Asada Yasuhiro , Ohno Yumiko , Nanasawa Masato 
Published: April 2003

Abstractp‐Styrenesulfonate esters of primary and secondary perfume alcohols and phenols, including citronellol, 1‐menthol, borneol, β‐phenethyl alcohol, eugenol, p‐anisyl alcohol, cinnamyl alcohol, and geraniol, and herbicide alcohols such as 2,4‐dichloro‐ and 2,4,5‐trichlorophenoxy‐ethanols were synthesized using p‐styrenesulfonyl chloride in the presence of bases such as pyridine, triethylamine, sodium hydrogen carbonate, and sodium hydride. The hydrolytic behavior of sulfonate ester monomers and their copolymers with N‐vinyl‐2‐pyrrolidone to liberate perfume and herbicide alcohols was structure‐dependent, thereby affording chemical release control.