bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional monomers and polymers, 118. Asymmetric syntheses of 2‐alkylcyclohexanones using chiral polymers containing aminobornanol moieties
Authors: Liu Jui Hsiang , Kondo Koichi , Takemoto Kiichi 
Published: April 2003

AbstractCis‐endo‐3‐amino‐endo‐2‐bornanol (5) and exo‐5‐amino‐endo‐2‐bornanol (2) (prepared from endo‐2‐hydroxy‐5‐bornanone (1)) were reacted with chloromethylated polystyrene. With the resulting chiral polymers 4 and 6 asymmetric syntheses of 2‐alkyl‐cyclohexanones were carried out. These reactions showed a high enantioselectivity particularly with the chiral polymer 6, which suggests a specific restricted transition state to be important for the asymmetric alkylation reaction.
Block copolymers with broad interphase. Determination of morphological parameters and interphase width by electron microscopy and small angle X‐ray scattering
Authors: Annighöfer Frank , Gronski Wolfram 
Published: April 2003

AbstractPoly(isoprene‐b‐(isoprene‐co‐styrene)‐b‐styrene) three‐block copolymers with a random copolymer centerblock and an over‐all 50 wt.‐% styrene content were analysed by electron microscopy (EM) and small angle X‐ray scattering (SAXS) in the range of 0 to 33 wt.‐% random copolymer content, where these systems possess a two‐phase lamellar morphology with enhanced broadening of the transition region between the pure isoprene and styrene phases. By evaluation of EM micrographs of ultra‐thin sections stained with osmium tetroxide and by analysis of the total meridional SAXS intensity distribution by means of a one‐dimensional paracrystalline model, the variation of the mean long period, fluctuation of lamellar thicknesses, and of the interphase width were obtained in dependence of the copolymer content. The analysis shows that the volume fraction of the interphase in variable in the range between 8,5 wt.‐% and 65 wt.‐%. In addition the SAXS analysis provides information about the functional form of the density profile in the interphase.
Polyether‐segmented polyamides as a new designed antithrombogenic material: Microstructure of poly(propylene oxide)‐segmented nylon 610
Authors: Yui Nobuhiko , Tanaka Junko , Sanui Kohei , Ogata Naoya 
Published: April 2003

AbstractA series of segmented polymers based on poly(propylene oxide) (PPO) and nylon 610 was characterized. Transmission electron microscopic observations revealed spherulitic structures similar to those of semicrystalline homopolymers. Dynamic mechanical measurement and thermal analysis suggested distinct phase separation between the PPO and polyamide segments, which is generally observed for amorphous block copolymers systems. Moreover, density and X‐ray diffraction measurements indicated that the crystallization of the polyamide segments is promoted by the introduction of PPO segments in the copolymer. This is probably correlated with unique growth of crystalline lamellae in the PPO‐segmented polyamides.
Carboxyl‐terminated poly(vinyl alcohol). Chain transfer of methyl propionate to vinyl acetate
Authors: Meinander Gunilla , Charlton James L. 
Published: April 2003

AbstractPoly(vinyl acetate) was prepared at 60°C with benzoyl peroxide by using methyl[carbonyl‐14C] propionate as chain transfer agent and solvent. The resulting polymer was hydrolysed to poly(vinyl alcohol) (PVAL) having carboxyl end groups and the average number of carboxyl groups per chain was unambiguously determined by comparing the activity of the polymer to that of the methyl propionate. An average density of 1,5 carboxyl groups per chain was found for poly(vinyl alcohol) prepared from poly(vinyl acetate) of DP 80 – 90. Other methods of end group analysis for carboxyl groups in PVAL are discussed.
Study of the functionalization of new acrylic polymers with ethylenediamine
Authors: Balieux Françoise , Clavelin Véronique , Daunis Jacques , Jacquier Robert , Calas Bernard , Parello Joseph 
Published: April 2003

AbstractNew cross‐linked polyacrylic supports, functionalized with methoxycarbonyl groups (from 0,2 to 6,0 mmol · g−1), were prepared. The reaction with ethylenediamine was realized in two ways: action of neat ethylenediamine or use of coupling agents. The yield depends on the initial loading with methoxycarbonyl groups and on the length of the spacer group. The percentage leading to the formation of side reactions of bridges, and that of unreactive methoxycarbonyl residues depends on steric factors. These results are of importance for the preparation of supports adapted to the solid phase peptide synthesis.
Functional polymers and sequential copolymers by phase transfer catalysis, 3. Syntheses and characterization of aromatic poly(ether sulfone)s and poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) containing pendant vinyl groups
Authors: Percec Virgil , Auman Brian C. 
Published: April 2003

AbstractA method for the syntheses of α,ω‐dibenzyl aromatic poly(ether sulfone)s (PSU) and poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) (POP) containing pendant vinyl groups is presented. The first step of the synthetic procedure involves the chloromethylation of PSU and POP to provide polymers with chloromethyl groups. POP, containing bromomethyl groups, was obtained by radical bromination of the methyl groups. Both chloromethylated and bromomethylated starting materials were transformed into their phosphonium salts, and then subjected to a phase transfer catalyzed Witting reaction to provide polymers with pendant vinyl groups. A PSU, containing pendant ethynyl groups, was prepared by bromination of the PSU, containing pendant vinyl groups, followed by a phase transfer catalyzed dehydrobromination. Differential scanning calorimetry of the thermal curing of the polymers containing pendant vinyl and ethynyl groups showed that the curing reaction is much faster for the polymers containing vinyl groups. The resulting network polymers are flexible when the starting polymer contains pendant vinyl groups, and very rigid when it contains pendant ethynyl groups.
A new synthetic approach for the preparation of polymer supports based on beaded copolymers of styrene and 2,4,5‐trichlorophenyl acrylate: Synthesis and swelling behaviour of poly(styrene‐co‐acrylamide) resins
Authors: Arshady Reza 
Published: April 2003

AbstractA new synthetic approach for the preparation of polymer supports/polymeric reagents is reported. The method is based on the chemistry of activated esters, and it is generally simpler than the methods conventionally employed for the preparation of funcationalized resins. Thus, the details of a series of beaded, and predominantly alternate, poly(styrene‐co‐2,4,5‐trichlorophenyl acrylate)s is given. These activated resins were readily converted into highly functionalized poly(styrene‐co‐acrylamide) resins by aminolysis with a functional groups carrying amine. Resins with low degrees of functionality were obtained by partial aminolysis of the activated resins with a simples amine, and subsequent reaction with a functional group carrying nucleophile, or vice versa. A number of the new resins were examined for their swelling behaviour in a wide range of solvents and were found to show a considerably more general solvent compatibility than either styrene‐ or N,N‐dimethylacrylamide‐based resins. The relatively general solvent compatibility of the new resins is briefly discussed in terms of their copolymer structure and its is suggested that the dual “hydrophobic‐hydrophilic”, character of these resins may be of important practical implications in, among others, solid phase peptide synthesis.
The role of CT monomer complexes in radical copolymerization
Authors: Rätzsch Manfred , Steinert Volker 
Published: April 2003

AbstractThe mechanism of the copolymerization of monomers forming a charge‐transfer complex in the reaction mixture was investigated. A condition for establishing a certain mechanism consists in the determination of the elementary rate constants of the copolymerization; the results are in good agreement with well‐known elementary rate constants for radical polymerization. We could prove the mechanism by the method of Giese producing radicals in high concentrations. The radicals react either with monomers or monomer pairs, and the initiating radicals obtained are subsequently transferred into the hydrogenated form. The initial reaction products were identified by gas chromatography. Only addition to the radicals of either maleic anhydride or styrene and not of the CT‐complex was established by the reaction products in the mixture of styrene with maleic anhydride.
The adsorption of divalent metallic ions by polyamides having oligo(oxyethylene) segments in the repeating unit
Authors: Iwabuchi Susumu , Nakahira Takayuki , Yoshikawa Masahiko , Sato Yukitoshi , Kojima Kuniharu 
Published: April 2003

AbstractPolyamides 1a – d having 1 to 4 oxyethylene units in the repeating unit were prepared from α‐(2‐aminoethyl)‐ω‐aminooligo(oxyethylene)s (2a – d) and sebacoyl chloride. The adsorption of divalent metallic ions by the polyamides 1 was found to be in general in the order: Cu2+ > H ≫ Zn2+ ∼ Cd2+. Polyamides with longer oligo(oxyethylene) units exhibit better adsorption capacities. The adsorption of Hg2+ by a polyamide with four oxyethylene units in the repeating unit follows a Langmuir adsorption isotherm, with a binding constant of K = 146 1 per mol of repeating units and a maximum Hg2+ adsorption of ws = 0,36 mol per mol of repeating units.
Metathesis degradation of partially cyclopropanated 1,4‐polybutadiene: Consideration of side reactions in the calculation of block size distribution
Authors: Hummel Klaus , Martl Michael G. , Chemelli Ronald , Grießer Herbert , Wukovnig Siegfried , Zekoll Haimo 
Published: April 2003

Abstract(Z)‐1,4‐Polybutadiene was partially cyclopropanated with bis(iodomethyl)zinc and the polymer was degraded with (E)‐4‐octene in the presence of WCl6/(CH3)4Sn as catalyst. The products were identified by gas chromatography/mass spectrometry and determined by gas chromatography. The block size distribution in the partially cyclopropanated polymer was calculated from these products. A method is described by which the decrease in yield of the modified degradation products, caused by side reactions during the olefin metathesis, can be taken into account in this calculation. It is concluded that under the given experimental conditions the block size distribution is random.
Phase transfer catalysed reaction between chloromethylated poly(styrene‐co‐divinylbenzene) and the superoxide radical anion
Authors: Kolarz Bozena N. , Rapak Andrzej 
Published: April 2003

AbstractThe reaction of chloromethylated poly(styrene‐co‐divinylbenzene) (1 wt.‐% of divinylbenzene) with potassium superoxide in the presence of phase‐transfer catalysts was studied. It was found that in dimethyl sulfoxide and in the presence of 18‐crown‐6, the hydroxymethylated polymer is the main product with a yield of 45%. In dimethylformamide the transformation of chloromethyl groups was found to be the highest, but only 60% of alcohol groups are present in the resulting product. In benzene the transformation reaches only 25%. With Bu4NI as catalyst in a mixture of solvents, the transformation of chloromethyl groups proceeds with 85% yield and the product contains 80% hydroxyl groups.
Systèmes réactifs polyuréthannes bloqués, 2. Cinétique de réaction en présence d'un allongeur de chaînes. Structure et propriétés des polyuréthannes‐urées obtenus
Authors: Viollaz François , Pascault Jean‐Pierre , Camberlin Yres 
Published: April 2003

AbstractPoly(urethane‐urea)s, were prepared from α‐hydro‐ω‐hydroxypoly(oxytetramethylene) (4 or POTM), 2‐butanone oxime (9) as blocking agent and diamines (5, 6) as chain extenders. By DSC the kinetics of reactions of the blocked system with the two chain extenders 3‐aminomethyl‐3,5,5‐trimethylcyclohexylamine (5) and 4‐4′ methylenedicyclohexylamine (6) were studied. With the two chain extenders similar results were obtained. The enthalpy of the reaction was found to be about 40 J/g and the kinetic order is unity. Thermal analysis shows the amorphous character of the hard segments. The phase segregation degree is higher with 6 as chain extender. With 6, better mechanical properties at high temperature were obtained, but ultimate elongation and tensile strength are higher with chain extender 5.
Polymerisation of 1,3,5‐trioxane in presence of maleic anhydride, 2. An example of cationic living polymerisation
Authors: Atreyi Mahalakshmi , Vasudevan Balakrishnan Ashok , Kumar Surendra 
Published: April 2003

AbstractEvidence is presented for the possible existence of ‘living’ ends in the cationic polymerisation using ZnCl2, BF3 · OEt2, and γ‐rays as initiators of 1,3,5‐trioxane to polyoxymethylene in presence of maleic anhydride (1 : 1 by mole), where this binary system exists as a melt.
Functional metal porphyrazine derivatives and their polymers, 14. Synthesis and properties of [bis‐ or tetrakis(decyloxycarbonyl)phthalocyaninanto]metal complexes
Authors: Shirai Hirofusa , Hanabusa Kenji , Kitamura Mitsutoshi , Masuda Etsuko , Hirabaru Okikazu , Hojo Nobumasa 
Published: April 2003

AbstractA novel class of [bis‐ and tetrakis(decyloxycarbonyl)phthalocyaninato]metal complexes (metal = Fe(III), Co(II), Ni(II), or Cu(II)) (6a, b and 2a – d) was synthesized by condensation of the corresponding acid chloride derivatives (5 and 1) with 1‐decanol. The electrical conductivities of polystyrenes, containing these complexes as dispersions, were measured.
Intrinsic viscosity versus molecular weight relationship of polystyrene in cis‐decahydronaphthalene
Authors: Kulicke Werner‐Michael , Prescher Michael 
Published: April 2003

AbstractIntrinsic viscosities [η] and mean‐square radii of gyration 〈R〉 of a polymer homologous series of commercially available narrow‐molecular‐weight‐distribution polystyrene (PS) samples in a molecular‐weight range of 800 up to 24 · 106 were determined in cis‐decahydronaphthalene at 25°C by light‐scattering and viscosity measurements. These dilute solution properties were compared with those for PS in the good solvent toluene, in the constitutional isomer trans‐decahydronaphthalene both at 25°C and in cyclohexane at 34,5°C as a theta‐system.
On the temperature dependence of the elasticity of agarose gels
Authors: Nishinari Katsuyoshi , Watase Mineo , Ogino Kazuyoshi 
Published: April 2003

AbstractThe elastic modulus E of agarose gels with different molecular weights are determined as a function of temperature. E increases slowly from 5°C up to a certain temperature Tmax, which depends on the molecular weight, and then decreases gradually at first and then rapidly. Tmax is shifted to higher temperatures with increasing molecular weight. E is discussed in terms of an entropic and an energetic contribution. The entropic part decreases while the energetic part increases with increasing temperature.
Polymeric sulfoxides as liquid‐liquid phase transfer catalysts
Authors: Kondo Shuji , Ohta Kunihiro , Ojika Ryoko , Yasui Haruhiko , Tsuda Kazuichi 
Published: April 2003

AbstractSoluble polymeric sulfoxides were prepared by free‐radical polymerization of methyl 4‐vinylphenyl sulfoxide and methyl 4‐vinylbenzyl sulfoxide, and copolymerization of these monomers with styrene. These polymers serve as effective phase transfer catalysts for several reactions under liquid‐liquid biphase conditions. The catalytic activity of copolymers containing styrene units is generally higher than that of homopolymers. On the other hand, copolymers with acrylonitrile co‐units do not exhibit catalytic activity. It was found that polymeric sulfoxides extract all alkali metal cations examined here more efficiently than their monomeric analogs, and that the binding ability increases with increasing density of active sites, suggesting a cooperative effect of sulfoxide groups. It is reasonable therefore to assume that the catalytic activity is due to both cation binding on the polymers and activation of the anions caused by desolvation in the hydrophobic region of the polymers.
The kinetics of acid hydrolysis of polymeric ketone acetals
Authors: Hudeček Slavko , Otoupalová Jaroslava , Světlík Jan , Čefelín Pavel , Ryska Miroslav 
Published: April 2003

AbstractThe kinetics of acid hydrolysis of poly[(2,2‐dimethyl‐1,3‐dioxolane‐4‐yl)methyl methacrylate] and of its copolymers with methyl methacrylate in homogeneous phase was investigated by means of mass spectrometry using perdeuterated acetone as the internal standard. It was found that under conditions of a pseudomonomolecular reaction the homopolymer is capable of an acceleration process with respect to the splitting‐off of acetone according to the content of the syndiotactic dyads. The respective rate constants K0 and K1 were calculated. Characterization of the steric situation by means of models of polymeric ketonacetals and the absence of acceleration in the case of copolymers even containing only a small amount of methyl methacrylate units lead to the conclusion that the reported phenomenon is due to steric effects combined with a neighbouring group effect.
13C NMR investigation of crosslinked polyethylenes
Authors: Hortling Bo , Levon Kalle , Soljamo Kari , Pellinen Jukka , Lindberg J. Johan 
Published: April 2003

AbstractCrosslinked polyethylenes (PEX) with different degrees of crosslinking were separated in sol and gel fractions by extractions with hot o‐dichlorobenzene. The distribution of branches was determined by 13C NMR‐spectroscopy, according to the method of Randall et al. The relative amounts of butyl branches decrease in the gel fraction and increase in the sol fraction with increasing degree of crosslinking. For the other branches the changes were small or not observable. In addition, the activation energies for a sol and a gel fraction were determined by measurements of the spin‐lattice relaxation times T1 at temperatures between 303 and 403 K. The activation energy was higher for the gel fraction, suggesting a restricted motion of the polymer segments in the gel.
The molecular structures of 1,1‐diphenylethyl methacrylate and triphenylmethyl methacrylate
Authors: Kageyama Hiroyuki , Hayashi Yoko , Harada Shigeharu , Kai Yasushi , Kasai Nobutami , Okamoto Yoshio , Hatada Koichi 
Published: April 2003

AbstractThe molecular structures of 1,1‐diphenylethyl methacrylate (1,1‐DPEMA) and triphenylmethyl methacrylate (TrMA) were determined by means of X‐ray diffraction. 1,1‐DPEMA: monoclinic, space group P21/a,a = 9,666(6), b = 19,94(2), c = 8,132(6) Å, β = 104,49(7)°, and Z = 4; TrMA: monoclinic, space group P21/n, a = 17,349(3), b = 9,487(2), c = 11,254(2) Å, β = 102,30(2)°, and Z = 4. Both structures were solved by the direct method and refined by the block‐diagonal least‐squares procedure to R = 0,175 and 0,056 for non‐zero reflections, respectively. In both molecules, conformations about the C(1)C(2) and C(1)O(1) bonds are all synperiplanar and one of the two or three phenyl groups attached to the C(5) atom is in trans to the O(2).
Reactive latex studies, 2. Kinetics and retention of enzymatic activity in the covalent protein bonding to a polymer latex
Authors: Suen Chih‐Her , Morawetz Herbert 
Published: April 2003

AbstractBovine serum albumin (BSA) was coupled to the reactive chloromethyl groups of poly(vinylbenzyl chloride) latex following the process both by the amount of BSA covalently bound and the chloride ion released. The primary bond formation is very insensitive to temperature with protein adsorption probably rate determining. Subsequent bond formation has an unusually high temperature coefficient and may depend on the deformability of the BSA molecule. On covalent bonding of ribonuclease 10% of the enzyme activity is retained.
Cationic degradation of poly(thio‐1,1‐dimethylethylene) [poly(isobutylene sulfide)]
Authors: Bhatti Saqlain A. , Goethals Eric J. 
Published: April 2003

AbstractHigh molecular weight poly(thio‐1,1‐dimethylethylene) [poly(isobutylene sulfide)] obtained by anionic polymerization of 2,2‐dimethylthiirane (isobutylene sulfide) was degraded to a mixture of low molecular weight compounds when treated with a catalytic amount of methyl trifluoromethanesulfonate. The following degradation products were found: 2,2,5,5‐tetramethyl‐1,4‐dithiane (3), 2,2,6,6‐tetramethyl‐1,4‐dithiane (4), 2‐isopropyl‐4,4‐dimethyl‐1,3‐dithiolane (2), and an equimolar mixture of 3,3,6,6‐tetramethyl‐1,2,5‐trithiepane (5) and 2‐methylpropene (isobutylene). The formation of dithiolane 2 is explained by a hydride transfer to a transient carbenium ion.
Block copolymers by metathesis polymerisation
Authors: Amass Allan J. , Bas Suleyman , Gregory Denis , Mathew Mathew C. 
Published: April 2003

AbstractA transformation reaction from anionic to metathesis was used to prepare block copolymers of styrene and cyclopentene. The composition of the products was established by elemental and UV analysis. A mechanism for the formation of the propagating centre in the olefin metathesis reaction was postulated that will account for the incorporation of the alkyl group of the cocatalyst in the first formed metal carbene.
Kinetic investigations of the free radical crosslinking copolymerization in the pre‐gel state, 2. Styrene/ethylene dimethacrylate and styrene/diisopropenylbenzene systems
Authors: Hild Gérard , Okasha Rouzi 
Published: April 2003

AbstractA kinetic investigation of the free radical crosslinking copolymerization was carried out using the following monomer systems: styrene/ethylene dimethacrylate, styrene/m‐diisopropenyl‐benzene and styrene/p‐diisopropenylbenzene. The conversion curves of each individual monomer and the instantaneous composition of the copolymer formed were determined from vapor phase chromatography measurements. The rate of consumption of each monomer follows first order kinetics except for the system styrene/p‐diisopropenylbenzene in which strong deviations can be observed. The reactivity ratio of styrene, determined by VPC, is compared with the value obtained by the Kelen‐Tüdős linearization method. As for the system styrene/divinylbenzene, the fundamental role of the pendant bonds in the process has been established. Their ability to react with incoming radicals to form crosslinks determines the formation of interchain linkages and thus the gelation of the system.
Synthesis of water‐soluble branched polysaccharides and their antitumor activity, 1. Branched polysaccharides from cellulose acetate
Authors: Matsuzaki Kei , Yamamoto Iwao , Sato Takaya , Oshima Ryuichi 
Published: April 2003

AbstractBranched polysaccharides of cellulose having β‐glycosidically linked D‐glucose branches were synthesized by condensation of 3,4,6‐tri‐O‐acetyl‐(1,2‐O‐ethylorthoacetyl)‐α‐D‐glucopyranose with activated cellulose acetates (DS ≈ 2) in boiling chlorobenzene in the presence of a catalytic amount of 2,6‐dimethylpyridinium perchlorate. The branched polysaccharides were converted into water‐soluble polysaccharides by saponification and then tested for their antitumor activity. Synthetic, branched polysaccharides with 30% or more branching were found to be completely soluble in water. The structure of branched polysaccharides was determined by methylation analysis, and it was found that branching occurred preferentially at the Cxyh6 positions by β‐glucosidic linkages. The antitumor activity for Sarcoma 180 transplanted to mice was high for polysaccharides with a high DP. Cellulose did not react with acetyl glucose orthoester even after activation.
Preparation of polyamides containing α‐diketone moieties and their transformation into 1,2,4‐triazine rings with amidrazones
Authors: Akutsu Fumihiko , Takeyama Hidekazu , Miura Masatoshi , Nagakubo Kuniharu 
Published: April 2003

AbstractPolyamides 3–5 containing 1,2,4‐triazine rings in the main chain were prepared by condensation of amidrazones 2 with polyamides 1 containing α‐diketone moieties, with conversions between 10 and 87%. The thermal stabilities and the solubilities of the resulting polymers 3–5 were enhanced by the introduction of the 1,2,4‐triazine rings in the main chain.