bluuebunny/crossref_metadata_2025 huggingface dataset:
Condensation polymerization of 2,2′‐diiodobiphenyl‐4,4′‐dicarbonyl dichloride with some mono‐ and diamino compounds
Authors: Banihashemi Ahmad , Oboodi Mohammad Reza
Published: April 2003

Several potentially thermostable polyamides were prepared. 2,2′‐Diiodobiphenyl‐4,4′‐dicarboxylic acid and its diacid chloride 1 were synthesized. The latter was condensed with several amines, e.g., aniline, p‐toluidine, p‐chloroaniline, and 2‐aminopyridine, to prepare model compounds of polyamides testing the reactivity of the diacid dichloride 1 towards various amines, and to compare their spectra with those of the polymers. The polyamides themselves were prepared by solution and melt condensation of diacid chloride 1 with the following diamines: p‐phenylenediamine, m‐phenylenediamine, 2,6‐diaminotoluene, benzidine, bis(4‐aminophenyl)‐methane, 4,4′‐diaminobiphenyl sulfone, and 3,3′‐diaminobenzophenone. The solubility of the polyamides in different solvents and their inherent viscosities were also measured. The values of the inherent viscosity were in the range of 0,1–1,9. The UV, IR, and 1H NMR spectra of the prepared polyamides were recorded. The melting points of the polymers were found to be higher than 360°C and the thermogravimetric curves showed that the polymers are stable up to 400°C in air.
Vinyl polymerization, 367. Polymerization of methyl methacrylate initiated with sodium polyethylenephosphate in the presence of an aqueous solution of copper(II) chloride
Authors: Imoto Minoru , Ouchi Tatsuro , Sakae Masatoshi , Yamamoto Hiroyuki
Published: April 2003

Polymerization of methyl methacrylate (MMA) initiated with the system of sodium polyethylenephosphate (PEP‐Na), copper(II) chloride, and water was carried out. The effect of the mass of each component on the conversion of MMA was studied. The polymerization proceeded through a radical mechanism. The overall activation energy was found to be 54,5 kJ·mol−1. The formation of a complex of Cu(II)‐ion with PEP‐Na and water was confirmed by electronic absorption spectra. The initiation mechanism was discussed.
Präparative Mehrschritt‐Trennverfahren mit entmischenden Flüssigkeiten
Authors: Kuhn Rainer
Published: April 2003

Multi‐step fractionation methods using demixing solvents have been used to determine the chemical distribution of binary copolymers as well as block‐ and graft‐copolymers. Four variations of these multi‐step fractionation methods are described: Cumulative fractionation, successive fractionation, semicumulative fractionation, and head‐tail type of fractionation. The ability of these fractionation methods is demonstrated by investigating two‐block copolymers of styrene and butadiene which have different chemical compositions and by fractionating a chlorinated polyethylene. Using the head‐tail fractionation procedure, one obtains a middle fraction with a compositional heterogeneity of less than 2%. The results show that the chemical compositional distributions of all chemical heterogeneous copolymers can be determined by the method of fractionation with demixing solvents provided the corresponding homopolymers can be separated into different phases. This type of separation procedure has been applied to 60 different polymer systems and should be applicable to many more polymer systems.
Distinction entre les phénomènes d'agrégation et de micellisation présentés par des copolymères amphipathiques. Cas des copolymères polystyrène/polyvinylpyridinium en milieu aqueux
Authors: Selb Joseph , Gallot Yves
Published: April 2003

Hydrophobic‐hydrophilic polystyrene/poly(4‐vinyl‐N‐ethylpyridinium bromide) (poly‐(l‐phenylethylene)/poly[l‐(N‐ethyl‐4‐pyridinio)ethylene bromide]) block or graft copolymers were synthesized. These copolymers are well defined products, and are homogeneous in mole‐ cular weight and composition. They were obtained by quaternization, with ethyl bromide, of the nitrogen atoms of pyridine units of polystyrene/poly(4‐vinylpyridine) block or graft copolymers. In dilute solution in a selective solvent for polyelectrolytic polyvinylpyridinium moities (water + salt), there is multimerization, i. e. presence of particles constituted by several macromolecules. Light scattering and ultracentrifugation measurements show that this multimerization is not the expected “micellization”, i.e. an “association” phenomenon due to the amphiphilic character of the copolymer, but corresponds Lo an “aggregation” phenomenon, resulting from incomplete dissolution of the product at the molecular scale.
The polymerization of isobutyl vinyl ether by trifluoroacetic acid
Authors: Bolza F. , Treloar F. E.
Published: April 2003

The polymerization of isobutyl vinyl ether (IBVE) initiated by trifluoroacetic acid (TFA) in 1,2‐dichloroethane and in 1,2‐dichloroethane/carbon tetrachloride mixtures has been studied over the temperature range −2,5°C to 35°C. Provided that the ratio [IBVE]/[TFA] did not exceed 88 and that 2·10−4 mol·1−1 < [TFA] < 4·10−3 mol·1−1 polymerization was the only detectable reaction, and the initial rate of reaction R0 was equal to k[IBVE]2[TFA]. The activation energy of the rate = (34 ± 2) kJ · mol−1 and the activation energy of the molecular weight = − (11,9 ± 0,5) kJ · mol−1. When [TFA] < 1·10−4 mol/l, no reaction was detectable. The polymers produced had molecular weights less than 4400; the only transfer is by monomer and this is the main chain‐breaking step. The reaction was unaffected by the addition of water for [H2O] < [TFA]. The rate depended on the solvent dielectric constant, but in a manner suggestive of a dipole‐dipole reaction. A mechanism is proposed for the reaction in which the reactive intermediates are trifluoroacetate esters solvated by monomer.
Die thermische polymerisation von methylmethacrylat, 3. Verhalten des ungesättigten dimeren bei der polymerisation
Authors: Brand Elisabeth , Stickler Manfred , Meyerhoff Günther
Published: April 2003

The thermal polymerization of methyl methacrylate is accompanied by the formation of appreciable amounts of an unsaturated dimer (H‐1). The behaviour of H‐1 during homopolymerization in presence of an initiator at 60, 80 and 100°C and during copolymerization with MMA in presence of an initiator at 60°C are investigated. The rate of (H‐1)‐homopolymerization is very low. The transfer constant to monomer H‐1 is about CH‐1 = 3·10−3 at 80°C as received from Pn‐determinations. The termination is essentially by disproportionation. The copolymerization parameters as resulting from polymerizations with labeled MMA at 60°C are rMMA = 1,8 and rH‐1 = 0,33, respectively.
Functional metal‐porphyrazine derivatives and their polymers, 5. Peroxidatic oxidation of guaiacol by Fe(III)‐3,4,3′,4′,3″,4″,3‴,4‴‐octacarboxyphthalocyanine (Fe(III)‐oaPc) and Fe(III)‐oaPc/polyelectrolyte systems
Authors: Shirai Hirofusa , Maruyama Akio , Konishi Mitsugi , Hojo Nobumasa
Published: April 2003

The oxidation of guaiacol by the Fe(III)‐oaPc/H2O2 system is studied by using a stopped flow spectrophotometer. The maximum rate of oxidation reaction by this system amounts to about 1000 times that in the absence of H2O2. The kinetic investigation indicates that the reaction can be regarded as “an ordered two‐substrates reaction” and that the oxidation reaction proceeds according to the peroxidase‐like mechanism. The reaction is inhibited by adding cyanide. The structure of oxidation products is also discussed. The catalytic action of Fe(III)‐oaPc in the presence of various polyelectrolytes such as poly(vinylamine) is also investigated, varying the pH values, and the environmental effect of the polymers in their catalytic behavior is discussed.
The influence of spherulitic size on the environmental stress cracking of low density polyethylene
Authors: Shanahan M. E. R. , Chen‐Fargheon C. , Schultz J.
Published: April 2003

The influence of morphology in a low density, high melt index polyethylene was studied with particular reference to environmental stress cracking (ESC). Test samples of the polyethylene were molded under constant conditions, only the subsequent rate of cooling to room temperature being changed. Several techniques were used to study the resultant polymer including ESC tests, X‐ray diffraction, optical microscopy and constant strain rate stress/strain tests. It was found that the faster the polymer was cooled after molding, the smaller was the typical diameter of the spherulites and the greater the resistance to stress cracking. A hypothesis is proposed to explain the differences in terms of the ease with which a crack can propagate, assuming that propagation is easier in amorphous material than within spherulites.
Mechanism of the methyl methacrylate polymerization photo‐induced by benzoin derivatives
Authors: Merlin André , Fouassier Jean‐Pierre
Published: April 2003

Deoxybenzoin and 2,2‐dimethoxy‐2‐phenylacetophenone (α,α‐dimethoxydeoxybenzoin) were used to initiate the polymerization of MMA in solution. It is shown that hydrogen donating solvents enhance the rate of polymerization. Laser spectroscopy experiments lead to a better insight in the photophysical processes in the excited states. Irradiation of these molecules under various conditions results in the generation of radicals capable of initiating the polymerization. Rate constants of the sensitizer quenching by MMA are determined. Two models are proposed for the initiation of the MMA photopolymerization in solution.
Melting and crystallization behaviour of random copolymers from adipic acid, trans‐3‐hexenedioic acid and 1,16‐hexadecanediol
Authors: Maglio Giovanni , Marchetta Carlo , Palumbo Rosario
Published: April 2003

Copolyesters derived from adipic acid, trans‐3‐hexenedioic acid and 1,16‐hexadecanediol were prepared and investigated by means of X‐ray diffraction and DSC techniques. From the X‐ray results an isomorphous replacement of the saturated and unsaturated diacid units has been suggested. The equilibrium melting temperature T and the heat of fusion ΔHf were slightly dependent on the copolyester composition. The crystallization process was analyzed by means of Hoffman's kinetic crystallization theory for a lamellar type crystal growth. The values of the free energy of formation of a nucleus of critical dimensions ϕ* and the free energy of folding σe were found to decrease regularly with increasing amount of double bonds, varying from 110 to 83 kJ/mol for Δϕ* and from 171 to 127 erg/cm2 for σe. This effect has been interpreted on the basis of an increase of chain flexibility owing to the presence of the trans double bonds.
Melting temperatures and enthalpies of polyethers, 2. Poly(octamethylene oxide)
Authors: Marco Carlos , Fatou José Gómez , Bello Antonio , Blanco Amparo
Published: April 2003

The dependence of the melting temperature on the crystallization temperature for low molecular weight fractions of poly(octamethylene oxide), (poly(oxyoctamethylene)), in the range from Mn = 3400 to Mn = 9 000, is analyzed. It is found that in this molecular weight region, the extrapolated linear relation melting temperature Tm vs. crystallization temperature Tc, for high levels of crystallinity yields an equilibrium temperature, which is in good accord with theoretical expectations; meanwhile the Tm vs. Tc relation for low levels of crystallinity leads to higher equilibrium temperatures. The equilibrium melting temperature corresponds to 356 K for Mn = 9 000 and the enthalpy of fusion was found to be 60,5 cal/g (= 253 J/g).
Darstellung und [η]‐M̄‐Beziehung von Mikrogelen aus polyvinylalkohol
Authors: Arbogast Wolfgang , Horvath Andreas , Vollmert Bruno
Published: April 2003

Microgels were prepared by crosslinking of poly(vinylalcohol)s with different molecular weights (saponification degree: 88 mole‐%) with glutaraldehyde in aqueous solutions. The degree of crosslinking was varied between 0 and 10% (i.e. 10 crosslinks per 100 structural units). Viscosity measurements showed that the viscosity number [η] of the microgels decreases considerably with increasing degree of crosslinking — as to be expected with increasing mean density of the random coils: The mean coil volume in aqueous solution shrinks by introducing 10 crosslinks per 100 structural units to 1/10 of the primary volume. A comparison of the logarithmic [η]‐M̄‐plots of our microgels showed a linear decrease of the exponent a, from a = 0,73 (uncrosslinked) to a = 0,16, with increasing degree of crosslinking. By extrapolation, with a degree of crosslinking of 13% (i.e. 13 cross‐links per 100 structural units of polymer chain), it was found that [η] becomes independent of the molecular weight of the primary PVAl‐samples.
Bildung von Cyclopentenylverbindungen beim Metathese‐Abbau von modifiziertem 1,4‐Polybutadien
Authors: Hummel Klaus , Heiling Peter , Karaoulis Christos , Kathan Wolfgang , Stelzer Franz
Published: April 2003

This investigation deals with metathesis degradation products of modified 1,4‐polybutadiene (poly(1‐butenylene)) which have not been taken into consideration as yet, e.g. substituted cyclopentene and linear isomerization products. Substituents were introduced into 1,4‐poly‐butadiene either by partial bromination with N‐bromosuccinimide followed by a Grignard‐Wurtz reaction or by reaction with the corresponding methyl compound and dicumyl peroxide. Polymers with 2‐methylbenzyl, 4‐methylbenzyl, 4‐chlorobenzyl, 4‐methoxybenzyl, 2‐naphthylmethyl, 2,4,6‐trimethylphenyl, 1‐naphthyl, 9‐anthryl, and 9‐phenanthryl substituents were degraded by metathesis with 4‐octene using WCl6/(CH3)4Sn as a catalyst and were analyzed by gas chromatography/mass spectrometry and by liquid chromatography.
X‐ray and neutron small‐angle scattering of random coil polymer solutions
Authors: Koyama Ryuzo
Published: April 2003

Small‐angle scattering curves of random coil polymer solutions are calculated from the general scattering theory of solutions by making use of a previous calculation of the Yvon‐Born‐Green integral equation for the radial distribution function of the solute polymer molecules. The calculated scattering function is a monotonously decreasing function of the scattering angle at low polymer concentration, and it has a minimum and a maximum at high concentration, where the polymer interaction is repulsive. For large scattering angle, the reciprocal values of the scattering function increase almost linearly with sin2(θ/2), where θ is the scattering angle. This calculated result is in qualitative agreement with recent experimental results of X‐ray and neutron small‐angle scatterings of polymer solutions.
Darstellung von neuen makromolekularen stoffen aus derivaten der 3‐aminocrotonsäure und dimaleinimiden
Authors: Haug Theobald
Published: April 2003

Cross‐linked polymers are formed by a new addition polymerization of dimaleinimides with bis(3‐aminocrotonic acid)‐esters, ‐amides, or ‐nitriles. Model reactions show that the derivatives of 3‐aminocrotonic acid add to the electrophilic double bond of maleinimide. The resulting succinimid derivatives rearrange thermally to the corresponding pyrrolinones. At higher temperatures, especially in the presence of an excess of maleinimide, a second molecule of maleinimide is added to the pyrrolinone. Some properties of moulded and casted polymers are described.
Ternary copolymerization of carbon dioxide with epoxybutanes
Authors: Inoue Shohei , Matsumoto Kunio , Yoshida Yasuhiko
Published: April 2003

The ternary copolymerization of carbon dioxide with 1,2‐epoxybutane and other epoxybutane isomers using the diethylzinc/water system as catalyst was carried out to investigate the relative reactivity between epoxides. cis‐2,3‐Epoxybutane was much more reactive than trans‐2,3‐epoxybutane in the copolymerization with carbon dioxide. The copolymer obtained from the reaction of carbon dioxide and cis‐2,3‐epoxybutane upon hydrolysis gave threo‐2,3‐butanediol, indicating the exclusive inversion of configuration in the ring‐opening of the epoxide. In the formation of cyclic carbonate as a byproduct of the copolymerization, cis‐2,3‐epoxybutane and trans‐2,3‐epoxybutane exhibited a similar reactivity.
Untersuchungen zur kettenspaltung und entstehung von π‐bindungen in der vinylkette von polystyrol in lösung unter sauerstoff‐ und lichteinfluß
Authors: Woliński L.
Published: April 2003

The influence of the solvent on chain degradation of polystyrene (PS) as well as the formation of π‐bonds in the vinyl chain is investigated, the latter caused by irradiation of PS‐solutions with long wave UV light (λ ≥ 270 nm) and reactions of singlet‐oxygen O2 (1Δg). Unambiguous qualitative proof could be given for chain degradation of polystyrene under the given experimental reaction conditions. Quantitative considerations though, based on different oxygen content in the respective solutions, different tension of the macromolecular chain and/or different contraction of the macromolecular coils proved to be not tenable or incomplete. It is shown that under the given experimental conditions formation of π‐bonds in PS results from a reaction of chlorine radicals with PS molecules. The kinetics of π‐bond formation in CCl4 and CHCl3 solutions is investigated by light scattering measurements. The conclusions aim at a quantitative determination of the saturation state in the formation of π‐bonds in both solutions.
The action of tin compounds in condensation‐type RTV silicone rubbers
Authors: van Der Weij Frederik Willem
Published: April 2003

The vulcanization of RTV (=room temperature vulcanizing) silicone rubbers under the action of organotin compounds is investigated. The mechanism for the cure is inferred from the chemical properties of a variety of relevant organotin compounds and is illustrated with the reactions that occur when dialkyltin dicarboxylates (A) are used as catalysts. The resulting organotin hydroxide (B) is shown to be the actual catalyst. With tetraethoxysilane (2) it forms organotin silanolates (D). Silanolysis of this compound results in the formation of a new siloxane linkage and recovery of the actual catalyst. Alkoxysilanes in which part of the alkoxy groups is replaced by siloxy groups, appear to be more reactive than the initial alkoxysilanes. At elevated temperatures side‐reactions like condensation of silanols with alcohols under the action of organotin compounds become increasingly prominent. Heating during cure effects, that part of the silanols becomes blocked by alkoxy groups. The mechanical properties of the resulting rubbers are usually far from optimum. During heating of cured rubber in a confined atmosphere, i.e., in the presence of the alcohol formed during cure, condensation of silanols with alcohol occurs too. Because these are equilibrium reactions, this process finally leads to complete degradation of the rubber.
Redox polymerisation, 5. Kinetics of the polymerisation of acrylonitrile and methyl methacrylate initiated by the system cyanoacetic acid‐Mn(III)(acac)3 in DMF and DMSO
Authors: Haragopal Mahadevan , Mahadevan Venkatanarayana
Published: April 2003

Polymerisation of acrylonitrile and methyl methacrylate initiated by the system cyanoacetic acid‐Mn(III)(acac)3 is investigated in DMF and in DMSO at 25–35°C. Kinetics of reduction of the complex by cyanoacetic acid shows the formation of a mixed ligand complex whose decomposition yields the primary radicals. Efficient initiation of polymerisation by these radicals followed by exclusive mutual termination accounts for the kinetics of polymerisation. Rate and equilibrium parameters are evaluated and their significance discussed.
Graft copolymerization of methyl methacrylate on chlorinated natural rubber, 1. Initiation by various organometallic complexes
Authors: Nogues P. , Dawans F. , Maréchal E.
Published: April 2003

Metallic compounds able to abstract chlorine atoms are investigated for initiating the graft copolymerization of methyl methacrylate on chlorinated natural rubber. An improved method for the separation of the side homopolymer from the graft copolymer is described. The cumulative results demonstrate the greater graft efficiency of the new initiating systems than of the usual free radical initiators.
The γ → α partial transformation in nylon 12 by drawing
Authors: Ishikawa Toshihiko , Nagai Susumu , Kasai Nobutami
Published: April 2003

Partial development of the α form crystals in γ nylon 12 has been found to take place by drawing near the melting point. The confirmation of the α form has been made by X‐ray diffraction, infrared absorption, and differential scanning calorimetry. The amount of the α form varies depending upon the temperature of drawing and draw ratio, whereas it is almost independent of the rate of drawing. The minimum draw ratio necessary to yield the α form increases as the temperature of drawing decreases. The crystallinity, determined from the density, also increases with the increase in the temperature of drawing and draw ratio, while it decreases slightly with the increase in the rate of drawing. The development of the α form is ascribable to the transformation from the γ form rather than the crystallization from the amorphous region. The total figure of the polymorphism in nylon 12 is proposed.
A theoretical study on the 1H NMR chemical shift of alanine oligopeptides
Authors: Asakura Tetsuo
Published: April 2003

All the NH and α‐CH proton chemical shifts of alanine oligopeptides (Ac‐(Ala)n‐NHMe, where n = 1–6) with extended and α‐helical conformations and anti‐parallel β pleated‐sheet structure, were calculated by taking into account the magnetic anistropy effect due to the CO and two kinds of CN bond anisotropies, and the electric‐field effect. The observed spectral behavior of the NH or CH protons in Ac‐Ala‐NHMe and Ac‐(Ala)2‐NHMe could be mostly predicted from the calculation, which indicates that the NH and CH chemical shifts in these oligomers are mainly determined by the intramolecular shielding effect. On the other hand, the appearance of the “doublet α‐CH peak” for oligomers with chain lengths of five or more reported by Goodman et al. could not be interpreted in terms of the intramolecular shielding effect. In this case, therefore, whether the CH protons are shielded from the solvent or not, seems to be a dominant factor for the origin of the “doublet peak”. The magnetic anisotropy effect of a peptide group was also examined.
1H and 13C NMR studies on N‐acetyl‐L‐alanyl‐L‐alanine‐methylamide
Authors: Asakura Tetsuo
Published: April 2003

1H and 13C NMR spectra of N‐acetyl‐L‐alanyl‐L‐alaninemethylamide and N‐acetyl‐L‐alanyl‐L‐alanine methyl ester were measured in [2H]6‐dimethyl sulfoxide and deuteriochloroform/trifluoroacetic acid solutions. The assignments of the N‐terminal and internal NH proton peaks of the amide could be made by means of deuterium exchange experiments in [2H]6‐dimethyl sulfoxide solution. An association model of the amide with an antiparallel β‐sheet structure was proposed by taking into account the presence of an IR absorption at 1 690 cm−1 as amide I band and the results of the measurement of 3JHN‐CαH coupling constants, as well as the deuterium exchange experiment. Moreover, the interaction between the peptide units in these two compounds and trifluoroacetic acid seems to be weaker than the N‐acetyl‐L‐alaninemethylamide‐acid interaction in a deuteriochloroform/trifluoroacetic acid solvent system of the same concentration.
Gas permeability of the racemic form of poly(γ‐benzyl glutamate)
Authors: Vivatpanachart Somsak , Tsujita Yoshiharu , Takizawa Akira
Published: April 2003

Sorption of carbon dioxide gas by a film of the racemic form of poly(γ‐benzyl glutamate) was observed over the temperature range from 10 to 40°C and the permeability coefficient of carbon dioxide gas through the film was measured over the temperature range from 30 to 120°C. Different sorption isotherms were obtained in the ranges above and below the glass‐like transition temperature, respectively. The result indicates that the sorption behavior is influenced by the side chain mobility. The amount of sorption by the racemic form of poly(γ‐benzyl glutamate) does not vary with the intermolecular benzene ring stacking, but is similar to that of the form C of poly(γ‐benzyl‐L‐glutamate) which contains no stacking. The breakdown of the intermolecular benzene ring stacking, which was confirmed by X‐ray diffraction analysis and differential scanning calorimetry, results in an abrupt increase of the permeability and the diffusion coefficients, and conversely the formation of the stacking leads to an abrupt decrease in the permeability and the diffusion coefficients. Below the transition temperature, the permeability coefficient of the racemic form of poly(γ‐benzyl glutamate) is smaller than that of the forms A, B, and C of poly(γ‐benzyl‐L‐glutamate), related to the benzene ring stacking. The diffusion coefficient was estimated from the free volume theory, and the calculated value was compared with the value obtained from the permeability and the solubility coefficients. The fractional free volume was estimated to be about 0,068, when the best fit between the experimental and the calculated diffusion coefficients was obtained by a trial and error method.
Versuche zur umsetzung von methylendiphenolen mit glucosederivaten und zur kondensation von O‐phenylglucosidderivaten
Authors: Kämmerer Hermann , Ritz Jürgen
Published: April 2003

Attempts to apply known methods of glucosidation to oligo[(hydroxyphenylene)methylene]s were not satisfying. The reaction of 4,4'‐dimethyl‐2,2'‐methylenediphenol (1a) with 2,3,4,6‐tetra‐O‐acetyl‐α‐D‐glucopyranosyl bromide gave a monoglucoside in 11% yield. A second attempt, the condensation of suitable O‐phenylglucoside derivatives was unsuccessful. From a series of O‐phenylglucosides (4) only 4‐(2,3,4,6‐tetra‐O‐acetyl‐α‐D‐glucopyranosyloxy)benzylbromide could be condensed with O‐(4‐hydroxymethylphenyl)‐2,3,4,6‐tetra‐O‐acetylglucopyranose to the corresponding diglucoside of 4,4'‐oxydimethylenediphenol (7). Condensation reactions of the O‐phenylglucoside 4k, to obtain an O‐glucosidized poly[(hydroxyphenylene)methylene], were accompanied by decomposition. The results showed that the usual methods of the preparation of glucosidized phenols cannot be transferred to oligomeric or polymeric derivatives.
Interaction of human serum proteins with synthetic polymers in heterogeneous system
Authors: Ohno Hiroyuki , Nii Atsushi , Abe Koji , Tsuchida Eishun
Published: April 2003

The interactions of human serum proteins with synthetic macromolecules were studied in heterogeneous solution systems. An alternating copolymer of styrene with maleic anhydride was crosslinked by diamines with different number of methylene groups varying from 2 to 10, and the degree of crosslinking (mole fraction of amide linked units) was changed from 7 to 43% in order to elucidate the effects of pore size, density of ionic site, and flexibility of the macromolecules. The adsorption of serum proteins on the resins was studied with human serum albumin and γ‐globulin as typical proteins in human serum. The resins were dispersed in phosphate buffer solutions, and these were mixed with the phosphate buffer solutions of albumin and/or γ‐globulin. After a suitable period of incubation at 20°C, the mixed solutions were centrifuged. The degree of protein‐adsorption was determined from the remaining amounts of proteins in the supernatant as measured by U.V. spectrometry. It was observed that the adsorption of albumin was influenced by the subtle balance of hydrophobicity and hydrophilicity of the resin. On the other hand, γ‐globulin was adsorbed not only by the hydrophobic resin but also by the hydrophilic (ionic) resin. The resin which was crosslinked to 16% by hexamethylenediamine showed high affinity towards γ‐globulin at pH 7,4. Selective adsorption was also possible: Almost all of the γ‐globulin and only little of the albumin were adsorbed within half an hour at 20°C by the use of this resin.
Refractive indices and refractive index increments of liquid systems at elevated pressures, 1. Design of an instrument and refractive index of trans‐decalin as function of temperature and pressure
Authors: Hammel G. L. , Schulz G. V. , Lechner M. D.
Published: April 2003

A new interferometer has been designed in order to perform measurements of refractive indices and refractive index increments on liquid systems under elevated pressure at different temperatures. The method of measurement, the calibration of the instrument and the treatment of data are described. With a series of test measurements on trans‐decalin it is shown that with this instrument reliable results are obtained.
Refractive indices and refractive index increments of liquid systems at elevated pressures, 2. Refractive index increment of the system polystyrene/trans‐decalin as function of temperature and pressure
Authors: Hammel G. L. , Schulz G. V. , Lechner M. D.
Published: April 2003

Refractive indices and refractive index increments of the system polystyrene/trans‐decalin were measured under pressures up to 500 bar and at temperatures between 20 and 60°C. The measurements were performed with a new, recently designed interferometer. The results demonstrate a sufficient agreement of the refractive index values measured at different temperatures and pressures with the equations of Eykman and Gladstone‐Dale whereas the Lorenz‐Lorentz equation indicates larger deviations. The experimental data of the refractive index increment follow none of the refractive index mixture rules. It is therefore recommended to determine refractive index increments at different pressures experimentally.
Preparation and homopolymerization of 2‐arylazo‐5‐dimethylaminobenzyl acrylates and methacrylates
Authors: Lokaj J. , Pivcová H. , Hrabák F.
Published: April 2003

2‐Arylazo‐5‐dimethylaminobenzyl alcohols (1) were prepared and used for the preparation of 2‐arylazo‐5‐dimethylaminobenzyl acrylates (2) and methacrylates (3); these compounds were characterized by melting points, IR and 1H NMR spectra. The coloured compounds 2 and 3 were subjected to radical homopolymerization in solution initiated with AIBN at 70°C, and [η], IR and 1H NMR spectra of the polymers were determined. Alternatively, the coloured polymer with 2‐(2‐chlorophenylazo)‐5‐dimethylaminobenzyl methacrylate monomeric units was prepared by coupling of the copolymer of 3‐dimethylaminobenzyl methacrylate and styrene with 1‐chlorobenzenediazonium chloride.
Polymer incompatibility study of a polystyrene network contaminated by linear polyisoprene chains
Authors: Rietsch François , Dambrine Françoise , Morcellet Joëlle
Published: April 2003

The present paper deals with the study of anionic polystyrene (PS) networks containing linear polyisoprene (PI) chains. Special attention was devoted to the problem of the compatibility of such a system, depending on the molecular weight M̄w (weight average) or M̄n (number average) of the chains in the polymeric network and the number average molecular weight M̄n of the linear polyisoprene chains. For that purpose, three different methods were used: diffusion of a concentrated linear polyisoprene solution into the polymeric network, “in situ” polymerization of isoprene inside the polystyrene network, and crosslinking of “living” polystyrene in a linear polyisoprene solution.
Dielectric behaviour of poly(sulfonyl‐1‐butylethylene) in concentrated solutions
Authors: Araki Kazuo , Aoki Harumi , Imamura Yoshio
Published: April 2003

Measurements of the dielectric relaxation of three poly(sulfonyl‐1‐butylethylene)s, (PSB), of different molecular weights were carried out in benzene solutions of polymer contents from 3,0 to 50,0 wt.‐%. It was found that the distribution parameter of the dielectric relaxation time was constant above a critical polymer contents and the activation energy increased with polymer contents. The observed relaxation time was analyzed by Fröhlich's theory assuming limiting relaxation times. The lower limit in the relaxation time, τ1, was independent of polymer contents above the critical polymer contents, in contrast to the upper limit relaxation time, τ2, which depended on polymer contents. The polymer contents dependence of the critical frequency below and above the critical polymer contents was interpreted by the free volume effect. The unperturbed molecular dimension at the critical polymer contents was also discussed.
Flexibilität und hydrodynamische eigenschaften von polymethylmethacrylat in binären mischlösungsmitteln
Authors: Wunderlich Winfried
Published: April 2003

Light scattering and viscosity measurements of poly(methyl methacrylate) have been carried out, in order to investigate the correlation of unperturbed dimensions and intrinsic viscosity of the polymer relative to the thermodynamic properties of solvent mixtures as compared to results obtained in single component solvents. The unperturbed dimensions of the polymer turned out to be unaffected by the mixed solvent, whereas a strong dependence of the hydrodynamic radius on the enthalpy of mixing of the two solvent components was observed. Hence unequivocal conclusions about the chain structure of the dissolved polymer cannot be drawn from hydrodynamic measurements in mixed solvents. If values of the viscosity constant K0 in these systems in the vicinity of the Θ‐point are extrapolated according to the Burchard‐Stockmayer‐Fixman equation, they do not agree with data measured at T = Θ.
Mechanism of radiation‐ and photo‐induced polymerizations of styrene elucidated by the stereoregularity of the polymers
Authors: Matsuzaki Kei , Ichijo Chikara , Kanai Taiichi
Published: April 2003

The stereoregularity of polystyrenes (PS's) obtained by γ‐ray and UV light irradiation was determined by 13C NMR spectroscopy, and the mechanism of polymerization was discussed. PS's obtained by 60Co γ‐ray irradiation in bulk, methylene chloride and carbon tetrachloride at 0°C showed bimodal molecular weight distributions. The stereoregularity expressed by the fraction of racemic dyads in the high molecular weight portions and the low molecular weight ones separated by thin layer chromatography (TLC) was 66 – 67% and 71%, respectively. The results indicate that the former portions are formed by a cationic mechanism and the latter by a radical mechanism. It was also confirmed that the polymerization by UV light irradiation with pyromellitic dianhydride (1,2:4,5‐benzenetetracarboxylic dianhydride) as an electron acceptor propagates by a cationic mechanism in polar solvents and by a radical mechanism in the bulk.
Linear oligopeptides, 70. Study of the relationship between conformation and nature of the side chain: Homologous series derived from α‐amino acid residues with linear hydrocarbon side chains
Authors: Toniolo Claudio , Bonora Gian Maria , Crisma Marco , Bertanzon Francesco , Stevens Eugene S.
Published: April 2003

A series of N‐ and C‐protected L‐α‐aminobutyric acid homo‐oligopeptides from dipeptide through heptapeptide was synthesized by the dicyclohexylcarbodiimide and acyl azide coupling methods. The monodisperse peptides were characterized and found to be chemically and optically pure. By means of infrared absorption and circular dichroism in the vacuum ultraviolet (150 nm) the occurrence of the intermolecular β‐conformation in the higher oligopeptides in the solid state was ascertained. In solvents of low polarity at high dilution the amount of intramolecularly hydrogen‐bonded folded structure formation was established as a function of peptide chain length. Unordered and intermolecular β‐structures were found in alcohols and in water/2,2,2‐trifluoroethanol mixtures. The results obtained are compared with those already published of other homologous peptide series derived from L‐α‐amino acid residues with linear hydrocarbon side chains, namely alanine, norvaline, and norleucine. Analogies and differences with the series from β‐ and γ‐branched residues are also discussed.
The influence of molecular interaction on polymerization, 6. GPC study of polymethacrylates obtained in different solvents
Authors: Boudevska Hrissanta , Brutchkov Christo , Platchkova Svetla , Pascault Jean‐Pierre
Published: April 2003

Poly(2‐naphthyl methacrylate)s (P‐2‐NM), poly(benzyl methacrylate)s (PBzMA) and poly‐(methyl methacrylate)s (PMMA) obtained by radical polymerization initiated with 2,2′‐azo‐isobutyronitrile (AIBN) in benzene, acetone and acetonitrile were investigated by means of gel permeation chromatography (GPC). The GPC curves of the polymethacrylates containing aromatic rings show lower molecular weights and higher polydispersities than those of PMMA. The polymerization in benzene leads to polymers with higher molecular weights and higher polydispersities than that in acetonitrile. Acetonitrile causes a formation of polymethacrylates with lowest molecular weight distribution. In comparison with the other solvents acetone gives PMMA with lowest molecular weight. Inversely, P‐2‐NM and PBzMA prepared in acetone are of highest molecular weights. The molecular weight and molecular weight distribution of PMMA is less sensitive to the change of the solvent than those of aromatic methacrylates.

The GPC curves indicate similar dependence on the change of the polymerization medium for the copolymers of 2‐naphthyl methacrylate (2‐NM) with methyl methacrylate (MMA), and of benzyl methacrylate (BzMA) with maleic anhydride (MA) prepared in benzene, carbon tetrachloride, chloroform and acetonitrile.

The results are explained assuming various termination and transfer reactions in different solvents. Some correlations established between the GPC curves and the association and dissociation of the monomer molecules in dependence of the dielectric constant of the solvent, previously observed by 1H NMR, are also discussed.
Polymorphic behaviour of poly[oxyoctanedioyloxy‐1,4‐phenylene‐(1‐methylvinylene)‐1,4‐phenylene] and poly[oxydecanedioyloxy‐1,4‐phenylene‐(1‐methylvinylene)‐1,4‐phenylene]
Authors: Roviello Antonio , Sirigu Augusto
Published: April 2003

The polymorphic behaviour of polymers

(n = 8, 10) has been investigated. They show thermotropic, mesophasic properties with a nematic structure. Both polymers exhibit a multiple solid state polymorphism which is a function of the temperature and of their thermal history.
Study on polymer solutions in solvent mixtures in the vicinity of the critical point of the solvents, 3. Turbidimetric study of four new ternary systems
Authors: Staikos George , Skondras Panayotis , Dondos Anastasios
Published: April 2003

Turbidimetric results obtained with the ternary systems N,N‐dimethylformamide/cyclohexane/polystyrene, N,N‐dimethylformamide/cyclohexane/polybutadiene, methanol/cyclohexane/polystyrene, methanol/cyclohexane/poly(ethylene glycol) are reported. These results show that a very small quantity of polymer changes drastically the demixing curve of the two partially mixed liquids. The displacement of the heterogeneous region starts from the domain of the critical point of the two liquids and becomes more significant in the domain of compositions of the two liquids rich in the poor solvent of the polymer. A qualitative explanation of this phenomenon is attempted based on the theory of the isorange lines of two partially miscible liquids.
Redox polymerization, 7. Kinetics of the polymerization of acrylic acid derivatives initiated by the systems cyanoacetic acid/Mn(OCOCH3)3 and ethyl acetoacetate/Mn(OCOCH3)3 in glacial acetic acid
Authors: Haragopal Mahadevan , Jayakrishnan Athipettah , Mahadevan Venkatanarayana
Published: April 2003

The kinetics of polymerization of acrylamide, acrylonitrile and methyl methacrylate by the systems cyanoacetic acid/Mn(OCOCH3)3 as well as ethyl acetoacetate/Mn(OCOCH3)3 were investigated in glacial acetic acid medium in the temperature range of 25–45°C. Oxidation proceeds through intermediate complex formation between reactants. Competitive complexation of the substrates by Mn(II) leads to retadation of the rates by added manganous ions. Primary radicals from the substrate account for the initiation when acrylamide is used as the monomer, but with acrylonitrile and methyl methacrylate secondary radicals formed by the interaction of the 1:1 complex with monomers account for initiation. In presence of the monomers the retardation due to added manganous ions is absent. Termination in all cases is of the mutual type. Rate and equilibrium constants were evaluated.
Preparation of living mono‐ and dicationically growing polyacetals and attempts to prepare block copolymers thereof
Authors: Chwiałkowska Wiesława , Kubisa Przemysław , Penczek Stanisław
Published: April 2003

Mono‐ and dicationically living poly(1,3‐dioxolane) (pdxn) and poly (1,3‐dioxepane) (pdxp) were obtained with CF3SO3H (trifilic acid‐tfac) and (CF3SO2)2O (triflic anhydride‐tfan), respectively. Concentration of the active species and living character of polymers were established by applying the ion‐trapping technique. Addition of a second cyclic acetal to the living bifunctional polyacetal (e. g. addition of dxn to pdxp) leads to the formation of a block copolymer (according to 13C NMR), but before the second monomer polymerizes completely, the transacetalization process leads to the conversion of the internal homoblock to a more or less (depending on time) statictical copolymer. Thus, competition of the homopropagation and transacetalization is not in favor of formation of the block copolymers with pure homoblocks, at least when the second block, built on the already existing homoblock, is formed slower than the homoblock is reshuffled by transacetalization.
Étude de la stabilité à la lumière du poly(chlorure de vinyle) chloré
Authors: Decker Christian , Balandier Michel
Published: April 2003

The light‐stability of chlorinated poly(vinyl chloride) (PVCC) is investigated and the quantum yields of the major process involved are determined. By UV exposure, PVCC undergoes a fast dehydrochlorination process which develops ten times more efficiently than with poly(vinyl chloride) (PVC), leading to long chlorinated polyene sequences which are responsible for the rapid coloration of the irradiated polymer. Chain scission and crosslinking occur simultaneously, both in the presence and in the absence of oxygen, indicating that UV radiations are able to cleave the polymer chains. By reaction with polyenyl radicals, oxygen reduces slightly the efficiency of the dehydrochlorination, while promoting at the same time the formation of carbonyl and hydroperoxide groups in the polymer chain. The reasons of the high instability of PVCC against UV light are discussed and an overall reaction scheme is suggested to account for the various processes observed and their relative efficiencies.
Synthesis of polyamides containing cytosine and hypoxanthine
Authors: Muraki Michiro , Miura Yozo , Kinoshita Masayoshi
Published: April 2003

The di(cyanomethyl) methylsuccinate derivative of cytosine and di(p‐nitrophenyl) methyl‐succinate derivative of hypoxanthine were prepared and polycondensed with a variety of diamines to provide powdery polyamides with molecular weights in the range of 1000–3100. The polyamides are soluble in DMSO and formic acid, but insoluble in ordinary organic solvents.
Structure and properties of a polyelectrolyte complex consisting of the three materials. [2‐(diethylamino)ethyl]dextran hydrochloride, sodium dextran sulfate, and poly(styrene sulfonate)
Authors: Kikuchi Yasuo , Sasayama Shizuko
Published: April 2003

[2‐(Diethylamino)ethyl]dextran hydrochloride (EA) was reacted with a mixture of sodium dextran sulfate (DS) and poly(styrene sulfonate) (NaSS) to form a novel water‐water precipitate, a so‐so polyelectrolyte complex (PEC), comprising three biomedical materials. The mole ratios of (DS + NaSS)/EA in PEC's prepared at higher [H+] were greater than at lower [H+] except for those PEC's prepared in 5% NaOH solution. IR, elemental analyses, solubility measurements, and blood clotting tests for PEC's revealed that the molecular structure of the various PEC's differed according to the [H+], order of mixing in solution, though all PEC's were prepared from the same starting materials. It appears that the degree of dissociation and the conformation of DS, NaSS, and EA change with [H+] and that a different neutralization reaction occured in terms of different order of mixing. Blood clotting tests were performed on PEC tablets. It was found that PEC's suppressed the coagulation of blood compared with glass.
Determination of network structure by extraction and random degradation, 2. Experimental results: Functionality, inhomogeneity and efficiency of crosslinking
Authors: Hoffmann Martin
Published: April 2003

Experiments on networks crosslinked by peroxides show that the amount of extracted molecules as well as the time needed for a dissolution of a network during random degradation and the molecular mass

“Relative molecular mass” (systematic IUPAC name) is shortened to “molecular mass” throughout this paper.

of high molecular mass degradation products may be used to determine previously inaccessible structural details, such as molecular mass of the network chains, weight fraction of chains with one free end, functionality of the crosslinks, and inhomogeneity of crosslinking, i.e. the amount, the diameter, and the concentration of crosslinking units of anomalously and strongly crosslinked regions. In crosslinking of polydienes, chain splitting is negligible, but the functionalities of the crosslinks are abnormally high for low peroxide concentrations, because the peroxide radicals may connect more than two chains by polymerization. A relatively high spatial inhomogeneity of the concentration of crosslinking units occurs with polybutadienes, presumably because the radicals of this polymer have especially long life‐times so that they can polymerize sequences of polyfunctional crosslinks via kinetic chains with transfer reactions. In crosslinking of polyisoprene the apparent efficiency of this peroxide is about 1,0 if one takes into account not only the number of crosslinks, but also that of loops, and if one neglects transfer. The efficiency of this peroxide is ≫ 1 in the crosslinking of polybutadiene, because of pronounced transfer reactions.
Polymères thiocarboxyliques, 2. Synthèse par modification de polymères préformés
Authors: Haraoubia Rachid , Gressier Jean‐Claude , Levesque Guy
Published: April 2003

Dithioester groups were introduced into linear or crosslinked polystyrenes by Friedel‐Crafts reaction with ClCH2Si(CH3)3/CS2 or with ethyl chlorodithioformate, as well as thioamide groups by reaction with ethoxycarbonyl isothiocyanate. Treatment of several copolymers of acrylonitrile with ethanethiol and hydrogen chloride and subsequently with H2S led to copolymers with dithioester and thioamide groups in the side chains without cyclization. Most of these reactions occur without crosslinking.
Oxydation photothermique d'élastomères de polyuréthannes thermoplastiques, 2. Influence de la longueur d'onde et des conditions d'irradiation sur le jaunissement des polyuréthannes à structure aromatique
Authors: Gardette Jean‐Luc , Lemaire Jacques
Published: April 2003

The detrimental yellowing of aromatic polyurethanes by irradiation may be accounted for by two mechanisms based on the formation of different photo‐products. The first is observed at short wave lengths and proceeds through a photo‐Fries type reaction; the second mechanism is observed at longer wave lengths and involves quinoidic structures derived from primary hydroperoxides. These two paths may be differentiated by incorporation of well‐known additives into the polymer or by selection of various irradiation wave lengths.