bluuebunny/crossref_metadata_2025_split huggingface dataset:
p‐Vinylbenzoic acid: A convenient preparation, copolymerization, and examination as dye receptive modifier for acrylic fibers and as ion exchange resin component
Authors: Ōsawa E. , Wang K. , Kurihara O. 
Published: April 2003

AbstractA convenient preparation of p‐vinylbenzoic acid from β‐haloethylbenzene with 67% overall yield was described. Monomer reactivity ratio of p‐vinylbenzoic acid (1) to acrylonitrile (2) was determined:

p‐Vinylbenzoic acid increased the affinity of acrylic fibre toward cationic dye when copolymerized with acrylonitrile, but was less effective than sulfonic acids as dye receptive site. Acid ion exchange resins based on p‐vinylbenzoic acid possessed a high selection factor of Ca2+ over Mg2+.
Über die bildung und struktur von polymeren des α‐cyanstyrols und des p‐phenylendiacrylnitrils. II
Authors: Funke Von W. 
Published: April 2003

AbstractBei der Reaktion von p‐Phenylendiacetonitril (p‐Xylylendicyanid) mit Formaldehyd in Gegenwart von Alkaliverbindungen bilden sich vernetzte Polymere. Versuche mit Phenylacetonitril (Benzylcyanid) und Formaldehyd sowie mit monofunktionellen Modellverbindungen weisen darauf hin, daß diese vernetzten Polymerendurch anionische Polymerisation intermediär entstehender Phenylenacrylsäurenitrileinheiten gebildet werden. Als Endgruppen konnten Methoxyl‐, Hydroxymethyl‐, und Imidoestergruppen nachgewiesen werden. Die Bildung von Hydroxymethyl‐ und Imidoestergruppen stellt eine Gleichgewichtsreaktion dar. Imidoestergruppen entstanden nur aus solchen Nitrilgruppen, deren benachbarte C‐Atome noch H‐Atome besitzen.
Zur charakterisierung der copolymerketten und der netzwerkdichte in polyesterharzen
Authors: Nollen Von K. , Funke W. , Hamann K. 
Published: April 2003

AbstractEs wurden die Molekulargewichts‐ und die Konstitutionsverteilungen der Copolymerketten verschiedener Polyesterharze bestimmt. Hierbei zeigte sich eine systematische Änderung der Molekulargewichts‐ und der Konstitutionsverteilung mit der Zusammensetzung der Polyesterharze. Das Molekulargewicht der Copolymer ketten ist im allgemeinen so groß, daß die Netzwerkdichte der Polyesterharze durch die endliche Länge der Copolymerketten nicht wesentlich beeinflußt wird.
Infrared studies of polymer chain folding I. Linear polyethylene
Authors: Koenig J. L. , Witenhafer D. E. 
Published: April 2003

AbstractAn infrared method has been developed for studying folding in linear polyethylene utilizing the assignment of the 1350 cm−1 and 1304 cm−1 bands to gauche methylene units. Gauche methylenes can occur in the disordered regions or as a part of the fold; their absorption coefficients are different in the two regions and allow one to determine their contribution to each region by simultaneous solution of the absorbance equations.The results indicate the fold structure of slow‐cooled bulk polyethylene is essentially the same as the folds of solution crystallized polyethylene and no disordered regions containing gauche methylenes exist. Rapidly cooled samples contain gauche methylenes in anomalous structures which tend to disappear during annealing. Annealing at 120°C. produces no change in the fold structure of single crystals.
Activation of poly[N‐(2‐hydroxypropyl)methacrylamide] for the binding of bioactive molecules, 2. Activation with cyanogen bromide
Authors: Chytrý Vladimír , Kopeček Jindřich 
Published: April 2003

AbstractThe amount of chymotrypsinogen linked to poly[N‐(2‐hydroxypropyl)methacrylamide], which was activated by cyanogen bromide, under various conditions was determined. The optimal activation time was found to be indicated by the beginning of an invariable base consumption during the reaction of the polymer with cyanogen bromide. The degree of activation increased with the concentration of cyanogen bromide and with the pH, and the yield of coupling can be increased by variation of the temperature, concentration of the reaction components, and pH. At room temperature and pH 9,3, the coupling reaction was completed in less than 24 h. The stability of the activated polymer depends strongly on temperature and pH. The analysis of the active moieties on the polymer carrier revealed that the application of the generally accepted mechanism for cyanogen bromide activation of polysaccharide carriers to the activation of poly[N‐(2‐hydroxypropyl)methacrylamide] remains to be proved.
A general method for the determination of “monomolecular property versus molar mass relationships” from measurements on polymolecular polymers
Authors: Bareiss Rolf E. 
Published: April 2003

Abstract“Monomolecular property (p) versus molar mass (M) relationships” of the type p = Kp · Map as would result from an experimental determination of p and M of a polymer‐homologous series of strictly monomolecular polymers can also be obtained from a polymer‐homologous series of polymolecular samples or fractions, provided their correct corresponding averages p and M are determined (Principle of Corresponding Averages). In order to obtain the monomolecular intrinsic viscosity [η] vs. M relationship (Mark‐Houwink relationship), the corresponding averages weight‐average intrinsic viscosity ([η]w ≡ [η]) and viscosity‐average molar mass (M[η]) of a series of polymer‐homologous, polymolecular polymer samples or fractions have to be determined experimentally. Accordingly, the corresponding monomolecular relationships sedimentation coefficient s vs. M, diffusion coefficient D vs. M, and mean‐square radius of gyration 〈r2〉 vs. M are obtained by the determination of a series of couples of the corresponding averages s vs. M, D vs. M, and 〈r2〉 vs. M, respectively. The experimental determination of the corresponding averages presented is possible by different methods, including the determination of the molar mass distribution.
Oligo(thiophénylènes‐1,4) α,ω‐difonctionnalisés, 3. Oligomères α,ω‐diaminés et copolyamides qui en dérivent
Authors: Daccord Gérard , Sillion Bernard 
Published: April 2003

AbstractPolyamides 7a and 7b were prepared from α‐(4‐aminophenyl)‐ω‐aminopoly(thio‐1,4‐phenylene)s (3a) by reaction with 1,12‐dodecanedioic acid (6), tribloc copolymers 9 from 3a and 11 aminoundecanoic acid (8), and multibloc copolymers 10 from 3a, 6, and 8. The properties of these copolymers were studied by DSC and compared with those of N, N'‐lauroyl derivatives of 3a as model compounds. Phase separations were observed with products containing at least four phenylene units in the thiophenylene blocs. However, the Tg was found to increase with increasing number of phenylene units.
Studies on the CHCL3‐soluble fraction of polythiophene and its conductivity on doping with iodine
Authors: Cao Young , Wu Quihui , Guo Kezhen , Qian Renyuan 
Published: April 2003

AbstractThe CHCl3‐soluble fraction of polythiophene, prepared by catalytic coupling of thienyl Grignard reagent, was characterized by VPO, GPC, TLC, 1 H NMR, and WAXS measurements. Iodine doping of this polymer shows a maximum conductivity of the order of 5 Ω−1· cm−1, much higher than that of I2‐doped compact powder pellets of the insoluble polymer. IR spectra of slightly I2‐doped polythiophene show two new strong absorption bands, one at 1360–1380 cm−1 and the other at 1140 cm−1. XPS results indicate that the C 1st peak does not change after doping while the profile of the S 2p peak changes markedly. This suggests that in I2‐doped polythiophene the positive charge is localized on the S atom. Combined results of the change of the I 3d XPS peak profile and the Raman spectrum in the low frequency region suggest that iodine in doped polythiophene is present in the form of the I2 moleculre and the I‐ion, in contrast to polyacetylene where iodine exists in the form of I3− and I5− anions.
Thermisch und UV‐photochemisch initiierte hochdruckpolymerisation des ethylens, 1. Molmassen‐mittelwerte
Authors: Buback Michael , Choe Chul‐Rim , Franck Ernst‐Ulrich 
Published: April 2003

AbstractEthylene is polymerized with thermal and with UV‐photochemical initiation at temperatures between 130°C and 255°C up to pressures of 2500 bar. The conversions are between two and five percent. The degrees of polymerization as obtained from viscosity experiments are dependent on reaction temperature and pressure, but are insensitive to the kind of initiation, thermal or photochemical. These observations are explained by an equation which relates the degree of polymerization to kinetic parameters of the system which have partly been determined by independent experiments. From this equation, the activation energy and the activation volume of the transfer constant with the monomer, cm, are determined to be Ea(cm) = 43,9 ± 4 kJ · mol−1 and ΔV≠ (cm)=20,1 ± 3 cm3 · mol−1, respectively.
Photoinitiators and photoinitiation, 5. Photodecomposition of some α‐hydroxymethylbenzion derivatives: Sulfonic esters
Authors: Gaur Hardew Angad , Groenenboom Cornelis J. , Hageman Hendrik J. , Hakvoort Gerard T. M. , Oosterhoff Pieter , Overeem Ton , Polman Romkina J. , van der Werf Sake 
Published: April 2003

AbstractThe photodecomposition of several sulfonic esters of α‐hydroxymethylbenzion (1a) was studied by means of ESR and 1H NMR‐CIDNP techniques. An exclusive α‐cleavage into benzoyl and α‐hydroxy‐α‐sulfonyloxymethylbenzyl radicals (6 and 7) through a triplet excited state was observed. Radicals (7) were found to undergo elimination of sulfonic acid to give benzoylmethyl radicals (9) in an extremely fast process. Chemical confirmation was provided by naphthalene quenching and radical‐trapping experiments using 1‐dodecanethiol and 2,2,6,6‐tetramethylpiperidin‐1‐oxyl, respectively. Photodecomposition of the sulfonic esters in the presence of 1,1‐diphenylethylene as a model substrate for vinyl monomers indicated that both benzoyl and benzoylmethyl radicals are highly reactive towards the carbon‐carbon double bond.
Precursors of hydrophilic polymers, 3. The potentiometric behaviour of isotactic and atactic poly(2‐dimethylaminoethyl methacrylate) in water/ethanol solutions
Authors: Přádný Martin , Ševčík Stanislav 
Published: April 2003

AbstractThe dissociation constants of partially ionized isotactic and atactic poly(2‐dimethylaminoethyl methacrylate) in water/ethanol solutions were measured. The strong dependence of the apparent dissociation constant on the degree of ionization of the macromolecule is discussed using viscometric data and compared with the properties of low‐molecular‐weight model compounds. The values of the internal dissociation constants at various ionic strength in various water/ethanol solutions were obtained by extrapolation of the apparent dissociation constants to zero ionization degree of the macromolecule. The conformational structures of macromolecules in solution are discussed.
Precursors of hydrophilic polymers, 5. Activation parameters of quaternization of poly(2‐dimethylaminoethyl methacrylate) with methyl iodide
Authors: Přádný Martin , Ševčík Stanislav 
Published: April 2003

AbstractThe paper deals with the quaternization reaction of isotactic and atactic poly(2‐dimethylaminoethyl methacrylate) with methyl iodide in three water‐ethanol solutions at different temperatures. Using the temperature dependence of the rate constants extrapolated to zero conversion, the activation quantities at the beginning of the reaction were calculated (activation energy, enthalpy, entropy, free enthalpy, and the frequency factor). The reactivities of the two polymers are compared with each other and then also with that of a low‐molecular weight model compound, 2‐dimethylaminoethyl pivalate (DAEP). Reactivity of all compounds under investigation increases with increasing water content in the solvent: that of DAEP due to the decreasing negative activation entropy, that of the two polymers as a result of decreasing activation energy. Using the measured activation energies and entropies, polarity of the transient state of the polymers is discussed in comparison with the low‐molecular weight model, along with polymeric effects which may become operative in the quaternization reaction.
DSC studies of linear low density polyethylene. Insights into the disrupting effect of different comonomers and the minimum fold chain length of the polyethylene lamallae
Authors: Burfield David R. , Kashiwa Norio 
Published: April 2003

AbstractThis paper reports a DSC examination of a series of linear low density polyethylenes (LLDPE) prepared variously with propylene, 1‐butene or 4‐methyl‐1‐pentene comonomers. The enthalpy of fusion of the crystalline regions of the LLDPE decreases progressively with increasing comonomer content and is effectively independent of the comonomer type. Disruption of polymer crystallinity is thus determined principally by the number and distribution of the chain irregularities. A sequence length of n = 14 was calculated as the critical chain dimension below which polyethylene segments cannot be readily packed into a stable crystal lattice.
Formation of large cyclic amides by catalytic depolymerization of polyamides
Authors: Langhammer Monika , Lüderwald Ingo , Weingärtner Michaela 
Published: April 2003

AbstractNylon 8, nylon 12, nylon 6.6, nylon 11.6 and nylon 12.12 were thermally converted into cyclic oligomers at 280 to 330°C within one to three hours. The reaction is catalyzed by small amounts of salts of different carboxylic acids and is supposed to take place by an anionic depolymerization mechanism.
Conformational analysis of higher poly(oxyalkylenes) using empirical force field calculations
Authors: Miyasaka Taira , Yoshida Takaichi , Imamura Yoshio 
Published: April 2003

AbstractThe conformational energies for the various rotational isomers of model compounds for poly(oxytrimethylene), POM3, and poly(oxytetramethylene), POM4, were calculated by means of the empirical force field method, and statistical mechanics calculations were made for the configuration‐dependent properties of POM3 and POM4. Although the dipole moment ratios of these polymers directly calculated from the results of the force field calculations agreed well with the observed ones, the estimated characteristic ratios did not agree with the observed ones. When the two geometric parameters of POM3 were changed, excellent agreement between the experimental values and the estimated ones was obtained. In case of POM4, when only geometric parameters were changed, the agreement was less satisfactory. The value for the interaction energy Eσ, which is directly derived from the result of the force field calculation for the model compound of POM4, seems to be overestimated because of a fault minimum. The value for the interaction energy Eσ is estimated to be the same as for POM3. Moreover, when the four geometric parameters were changed, the estimated values agreed well with the experimental ones. The direct use of the results of the force field calculations is not always satisfactory, but the parameters obtained are a good initial set of parameters to reproduce the observed configuration‐dependent properties.
Precursors of hydrophilic polymers, 7. Potentiometric properties and structure of copolymers of 2‐dimethylaminoethyl methacrylate
Authors: Přádný Martin , Ševčík Stanislav 
Published: April 2003

AbstractThe study concerns the potentiometric behaviour of statistical copolymers of 2‐dimethylaminoethyl methacrylate with 2‐hydroxyethyl methacrylate, acrylamide, methacrylamide, 2‐methacryloyloxyethyltrimethylammonium methylsulfate, and of copolymers arising by the partial quaternization of poly(2‐dimethylaminoethyl methacrylate) with methyl iodide in various water‐ethanolic solutions. The potentiometric properties of poly(4‐dimethylaminobutyl methacrylate) and poly(6‐dimethylaminohexyl methacrylate) are also reported. The course of modified titration curves and the differences between pK0 values of copolymers and pK values of low‐molecular weight model compounds are discussed. Side chains of copolymers of 2‐dimethylaminoethyl methacrylate have a cyclic conformation (similarly to the homopolymer); the carbonyl and amine group interact with each other. Copolymers formed by the partial quaternization of poly(2‐dimethylaminoethyl methacrylate) with methyl iodide in a water‐ethanolic medium (Menshutkin's reaction) have a block structure, which suggests a zip mechanism of the quaternization reaction.
Metathesis degradation of poly(butadiene‐alt‐propene)
Authors: Hummel Klaus , Lechner Hildegard , Zekoll Haimo , Chemelli Ronald 
Published: April 2003

AbstractPoly(butadiene‐alt‐propene) (1) was degraded by metathesis reaction using symmetric olefins (3‐hexene and 4‐octene) in chlorobenzene solution in the presence of WCl6/(CH3)4Sn as catalyst. Identification of the degradation products by means of a combination of gas chromatography (GC) and mass spectrometry (MS) revealed small amounts of “defects” in the almost ideally alternating copolymer 1. These were non‐alternating sequences of 2‐butenylene and methylethylene units, vinylethylene units and branching points. In addition, the metathesis degradation of 1 with 4‐octene was investigated kinetically between 15 and 40°C. The measurements confirm that the thermodynamically stable 4‐methylcyclohexene is the final product. This can be formed directly from the polymer and via oligomeric products. The formation of these intermediates is preceded by an induction period. Their concentrations pass maxima, the positions of which depend on the size of the molecules and on the temperature.
Electrochemical synthesis of poly(1,4‐phenylene) films
Authors: Fauvarque Jean‐Francois , Petit Michel‐Alain , Digua Abdelouafi , Froyer Gérard 
Published: April 2003

AbstractHomogeneous films of poly(1,4‐phenylene) (PPP) can be deposited on various materials by electro‐reduction of 4,4′‐dibromobiphenyl in presence of a nickel complex catalyst. UV and IR spectra indicate that the polymer has a regular structure (exclusively 1,4‐phenylene units) and an unusual average molecular weight. The nascent PPP films are obtained in their neutral from and can be either reduced or oxidized.
Combined liquid‐crystalline polymers with chiral phases, 1 2‐octanol as chiral end of the mesogens
Authors: Bualek Sauvarop , Zentel Rudolf 
Published: April 2003

AbstractCombined liquid‐crystalline polymers containing azobenzene and azoxybenzene as the mesogenic groups and 2‐octanol as the chiral end‐group were synthesized and characterized. These polymers exhibit cholesteric, smectic A, and chiral smectic C* phases with monolayer and doublelayer structures. The polymers with azoxy groups do not crystallize upon cooling. Therefore, some of the liquid‐crystalline phases can be frozen in in the glassy state.
Copolymerisation von acetylen mit acetylenderivaten, 1. Copolymerisation von acetylen mit phenylacetylen
Authors: Kanischka Gerd , Höcker Hartwig 
Published: April 2003

AbstractCopolymers were obtained from acetylene and phenylacetylene by coordinative polymerization with MoCl5 as a catalyst in toluene as solvent. The copolymers were characterized by spectroscopic methods as well as by means of differential scanning calorimetry and gel permeation chromatography. The fraction of phenylvinylene units in the copolymers was determined by means of UV spectroscopy as well as the conjugation length of planar double bonds which increases with increasing fraction of vinylene units. The fraction of vinylene units in the copolymers was determined by IR spectroscopy. DSC measurements indicate the transformation temperature for isomerization, cyclization, aromatization and chain scission to decrease with increasing fraction of vinylene units. At high contents of vinylene units in the copolymers a trans‐cisoide configuration is realised, while for pure polyphenylacetylene and copolymers with a low vinylene fraction the cis‐transoide configuration is favoured. With increasing content of vinylene units the solubility of the copolymers decreases, while oxidizability and degradation reactions increase. These reactions are favoured at higher temperatures and upon light irradiation. The oligomeric fractions of the copolymers indicate the presence of biphenyl o,‐ m‐ and p‐terphenyl, 1,1′:2′,1″:4′,1 ‴‐ and 1,1′:3′,1″:5′,1 ‴‐quaterphenyl.
Initiation of polymerization with substituted ethanes, 11 Chromatographic separation of methyl methacrylate oligomers and NMR analysis of the diastereoisomers
Authors: Bledzki Andrzej , Balard Henri , Braun Dietrich 
Published: April 2003

AbstractThe free radical oligomerization of methyl methacrylate using different tetraphenylethane initiators [1,2‐diphenoxy‐1,1,2,2‐tetraphenylethane (4), tetraphenylsuccinonitrile (5), and 1,1,2,2‐tetraphenyl‐1,2‐bis(trimethylsiloxy)ethane (6)] gives telechelics 1 – 3 with end groups originating from the initiator. These telechelics were characterized by gel permeation, thin layer, and high performance chromatography. By adsorption chromatography, the separation does not only proceed in accordance with the molecular weight of the oligomers, but also with their tacticity as well. The free radical oligomerization is a process in which syndiotactic structures are favoured above isotactic ones.
Preparation and properties of polymerizable ferroelectric liquid‐crystalline acrylate and methacrylate derivatives
Authors: Shiraishi Kohei , Sugiyama Kazuo 
Published: April 2003

Abstract(+)‐2‐Methylbutyl 4‐[4‐(11‐acryloyloxyundecyloxy)benzylideneamino]cinnamate (3a) and (+)‐2‐methylbutyl 4‐[4‐(11‐methacryloyloxyundecyloxy)benzylideneamino]cinnamate (3b) were synthesized. 3a possesses a chiral smectic C (S*c) phase. From electro‐optical measurements of 3a, the rise time of the surface director (τsr) and the rise time of the bulk director (τbr) are found to be 0,32 ms and 110 ms, respectively.
Synthesis and properties of macromonomers carrying phosphatidylcholine analogous and azobenzene moieties
Authors: Sugiyama Kazuo , Shiraishi Kohei 
Published: April 2003

AbstractMacromonomers 6a, b, carrying phosphatidylcholine analogous and azobenzene moieties as a photoresponsive pigment, were prepared from the reaction of 2‐oxo‐1,3,2λ5‐dioxaphospholane derivatives 2 and poly[2‐dimethylaminoethyl methacrylate] macromonomer 5. 6b shows a nematic phase. The mesogenic group is connected with the chromophore via a flexible spacer group. Phase transition temperatures were determined by measurement of the rapid change in conductivity of the solutions of the amphiphiles with the temperature. From the result of photoreversible cis‐trans isomerization it can be concluded that 6b can possibly be used as a photoresponsive material of a membrane.
Poly(ether/ester)s based on poly(tetramethylene terephthalate) and poly(ethylene glycol), 4. Modification with 2‐butyne‐1,4‐diol
Authors: Gogeva Tanya , Fakirov Stoyko 
Published: April 2003

AbstractA series of poly(ether/ester)s derived from dimethyl terephthalate, 1,4‐butanediol, 2‐butyne‐1,4‐diol (2‐BD‐1,4) and α‐hydro‐ω‐hydroxypoly(oxyethylene) (molecular weight 1000) is synthesized. The mole ratio of the starting components is selected to result in copolymers with constant hard : soft segment weight ratio (59:41). The amount of 2‐BD‐1,4 is varied from 0 to 20 wt.‐% referred to the total amount of the short‐chain diols used. The incorporation of 2‐BD‐1,4 in the macrochains is proved by 1H NMR measurements. A small increase of the oxygen index is found with increasing the amount of 2‐BD‐1,4. It is established that the poly(ether/ester) containing 10 wt.‐% of 2‐BD‐1,4 behaves as known poly(ether/ester)s. Data from differential scanning calorimetry suggest a three‐phase structure, two amorphous and one crystalline one. Small‐angle X‐ray studies of the annealed samples reveal a strong tendency to phase separation with increasing the annealing temperature. The latter is in agreement with density measurements.