bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical ageing phenomena in poly(tert‐butylacetylene): influence of the microstructure
Authors: Costa Giovanna , Chikhaoui Saida , Turturro Antonio , Carpaneto Luca
Published: April 2003

Ageing phenomena in cast films of poly(tert‐butylacetylene) (PTBA) of different tacticity were studied by dilatometric and calorimetric techniques and by morphological observations. Films of different density (p) obtained by varying solvent evaporation times, both from cis/trans or 100% cis PTBA, show during the first dilatometric run the presence of a temperature Tp at which a packing effect occurs. Therefore, first dilatometric curves show two linear tracts, the latter representing the sum of thermal dilation and simultaneous packing induced by molecular motions leading to a better packing. Following measurements show a linear increase of the specific volume. The packing process is also revealed by differential scanning calorimetry as a broad endotherm. Δρ is the more pronounced the lower the initial density of the sample for mixed cis/trans PTBA, but, quite surprisingly, in 100% cis PTBA the trend is opposite and, in this case, denser samples undergo a more relevant packing. A tentative explanation is inferred on the basis of a conformational model recently proposed. An improvement of the chain packing is responsible of the fast ageing process of this polymer, as suggested by a preliminary X‐ray diffraction analysis.
ω‐Chloro‐α‐olefins as co‐ and termonomers for the synthesis of functional polyolefins
Authors: Bruzaud Stéphane , Cramail Henri , Duvignac Laurent , Deffieux Alain
Published: April 2003

This paper deals with the use of ω‐chloro‐α‐olefins as monomers for the synthesis of chloro‐functional homo‐, co‐ and terpolyolefins in the presence of (IVb) metallocene/MAO catalytic systems. Two ω‐chloro‐α‐olefins, 11‐chloroundec‐1‐ene and 5‐chloropent‐1‐ene, were tested. It was found that only the functional olefin containing the longer aliphatic spacer between the alkene function and the halide polymerizes readily in the presence of the rac‐Et(Ind)2ZrCl2/MAO catalyst. The drastic influence of the reaction solvent on the chloro‐olefin reactivity and (co)polymerization behavior is examined and discussed. Finally, the terpolymerization of 11‐chloroundec‐1‐ene with ethylene and propene is investigated. In a second part, the quantitative preparation, by derivatization of 11‐chloroundec‐1‐ene units, of functional polyolefins bearing benzoate, hydroxy or azido functions as side groups is described. The corresponding functional polymers are characterized by IR and 1H NMR spectroscopy.
Ni‐catalyzed dehalogenation polycondensation of dihaloaromatic compounds with NaH
Authors: Yamamoto Takakazu , Hayashida Naoki , Maruyama Tsukasa
Published: April 2003

Ni‐catalyzed dehalogenation polycondensation of p‐dichlorobenzene, 2,5‐dichloropyridine, and 1,4‐dialkoxy‐2,5‐dichlorobenzene in the presence of NaH affords corresponding π‐conjugated poly(arylene)s in high yields. In this polymerization system, Ni(II)‐compounds used as the catalyst are considered to be reduced to Ni(0)‐complexes by NaH, and the Ni(0)‐complexes are regarded to be responsible for the polycondensation. The π‐conjugated poly(arylene)s obtained have well‐defined linkages between the monomer units as revealed by NMR spectroscopy. Poly(2,5‐diethoxybenzene‐1,4‐diyl) (PEOP) and poly(2,5‐dibutoxybenzene‐1,4‐diyl) (PBOP) have number‐average molecular weights (Mn) of 4300 and 11 000 as determined by GPC (vs. polystyrene), respectively. The chemical and electrochemical properties of resulting polymers are discussed in comparison with those of corresponding poly(arylene)s reported previously.
Influence of branching on melting behavior and isothermal crystallization of poly(butylene terephthalate)
Authors: Righetti Maria Cristina , Munari Andrea
Published: April 2003

The melting behavior and the isothermal crystallization kinetics of linear and randomly branched poly(butylene terephthalate)

System. name: poly(tetramethylene terephthalate).

(PBT) samples were investigated by differential scanning calorimetry. The multiple endotherms typical of linear PBT were observed also in branched samples and were found to be influenced both by temperature and degree of branching. The isothermal crystallization kinetic constants, obtained applying Avrami's treatment, were analysed on the basis of Hoffman's secondary nucleation theory. A decrease in the crystallization rate was observed as the content of branching units increased. This result was correlated to surface effects: the product of the surface free energies σσe was found to increase with the ramification content. As far as the nucleation process is concerned, the induction time was determined for all the samples at different crystallization temperatures, and the results suggested that in the presence of branching points the nucleation process is favoured.
Synthesis and characterization of poly[(2,6‐dimethyl‐1,4‐phenylene oxide)‐block‐isoprene] diblock copolymers
Authors: Servens Emmanuelle , Löwik Dennis , Bosman Anton , Nelissen Laurent , Lemstra Piet J.
Published: April 2003

As a first stage in the synthesis of a new class of thermoplastic elastomers, a suitable synthetic route for elastomeric tailor‐made diblock copolymers based on poly(2,6‐dimethyl‐1,4‐phenylene oxide), PPE, as the thermoplastic block and on 1,4‐polyisoprene, PIP, as the elastomeric block, is outlined. The 2,6‐dimethyl‐1,4‐phenylene oxide‐block‐isoprene diblock copolymers were synthesized via an amidation coupling route between the ammonium salt of PPE and the monocarboxylic acid of PIP in the presence of dicyclohexylcarbodiimide, DCC. Preliminary studies were focused on the synthesis of a welldefined low molar mass diblock copolymer (Mn = 10000) in order to facilitate the quantitative characterization by proton NMR spectroscopy. The developed amidation coupling route was successively applied to the synthesis of a similar diblock copolymer with a number‐average molar mass of 40000 in order to obtain optimum overall properties.
Partially fluorinated maleimide copolymers for Langmuir films of improved stability, 1. Synthesis, copolymerisation behaviour and bulk properties
Authors: El‐Guweri Moheddin , Hendlinger Peter , Laschewsky André
Published: April 2003

Various new partially fluorinated polymers on the basis of substituted N‐phenylmaleimides are prepared by radical copolymerisation. Nearly alternating copolymers are produced with vinyl ethers and styrene derivatives. The copolymers show high stability against thermal degradation in comparison to conventional vinyl and vinylidene polymers, and high glass transition temperatures. Highest thermal stability is found for copolymers in which the classical hydrophilic and hydrophobic fragments are reduced to a minimum.
Cationic coating polymerization of cyclopentadiene onto silica particles
Authors: Spange Stefan , Langhammer Elke
Published: April 2003

The cationic polymerization of cyclopentadiene (CPD) initiated by different initiators (triphenylmethyl chloride, triphenylmethyl bromide, methyl triflate, and trifluoroacetic acid) onto silica particles yields polycyclopentadiene (PCPD)‐silica composites in high yield beside small amounts of soluble polymers. The novel PCPD‐silica particles are characterized by UV/VIS reflectance spectra and IR spectra. The percentage of coating (PG) is determined by combustion analysis and depends on the reaction temperature and the technical procedure of the polymerization. The influence of the initiator used and initiator/monomer ratio on the PG of the silica particles are investigated, too. It can be shown that the total amount of coating strongly depends on the initiator used. In case of trifluoroacetic acid initiation, particle aggregation takes place if the carbon content of the PCPD particles exceeds 15% carbon weight due to crosslinking between the PCPD layers of the coated silica particles, as evidenced by electron scanning microscopy.
Influence of polymer/solvent acid‐base interactions on the aggregation of stereoregular PMMA
Authors: Bistac Sophie , Schultz Jacques
Published: April 2003

Stereoregular poly(methyl methacrylate) (PMMA) is able to form aggregates in solution. This aggregates formation depends strongly on the nature of the solvent, and occurs only with complexing solvents. The influence of the solvent type on the aggregate formation is not yet clarified. Apparently, there is no obvious relationship between the solvent polarity and the ability to induce aggregation of PMMA chains. In the present work, based on bibliographic studies, we tend to prove that the formation of aggregates depends, among other parameters, on the development of acid‐base interactions between PMMA chains and the solvent molecules. As a matter of fact, the PMMA is considered as a basic polymer, and exchanges strong acid‐base interactions with acidic solvents, like chloroform, which is a non‐complexing solvent. Such acid‐base links prevent PMMA macromolecular chains to aggregate. On the contrary, complexing solvents exhibit a basic character, like PMMA. Therefore, the probability to develop PMMA/solvent acid‐base interactions is strongly reduced. As a consequence, aggregation of PMMA chains is then favoured.
Crosslinked polyimide foams derived from poly(imidepropylene oxide) copolymers
Authors: Hedrick J. L. , Carter K. , Sanchez M. , Di Pietro R. , Swanson S. , Jayaraman S. , McGrath J. G.
Published: April 2003

A new route for the synthesis of high glass transition temperature, thermally stable polymer foams has been developed, using compositionally asymmetric microphase‐separated block copolymers where the minor component (poly(propylene oxide)) is thermally labile and the major component (polyimide) is thermally stable. The minor component decomposes to low molecular weight species upon heating, and the decomposition products diffuse out of the film, leaving behind pores embedded in a matrix of the thermally stable component. In this study, the polyimide block was crosslinked with ethynyl functionalities to obtain a stable porous structure. The decomposition of the propylene oxide in the block copolymer was studied by thermogravimetric, dynamic mechanical and thermomechanical analyses. Mild conditions were required to avoid rapid depolymerization of the propylene oxide and plasticization of the polyimide matrix. The foams showed pore sizes with diameters up to a micrometer in size as well as the expected reduction in the mass density.
Structure and properties of high‐speed spun fibers of nylon 6
Authors: Murase Shigemitsu , Kashima Masaru , Kudo Kazushige , Hirami Matsuo
Published: April 2003

Structure and properties of high‐speed spun fibers of nylon 6 were studied in the range of take‐up speeds from 5 to 12 km/min. With increasing take‐up speed, Young's modulus increased uniformly, while tenacity passed through a maximum at 8 km/min. WAXD data demonstrated the increase in the perfectness of the crystalline state with increasing take‐up speed. First, the γ‐form crystal structure predominated up to 9 km/min along with increase in its crystal size; second, in the range of 9 to 12 km/min, the a‐form crystal structure appeared and developed as reflected by the increase in its crystal perfection. The structure‐properties relationships are discussed, and it is indicated that the increasing tendency of Young's modulus over 9 km/min can be attributed to the development of the a‐form crystals.
Crosslinkable epichlorohydrin terpolymers with aromatic pendent groups
Authors: Reina José Antonio , Cádiz Virginia , Serra Angels
Published: April 2003

Poly(epichlorohydrin) (PECH) and poly[epichlorohydrin‐co‐(ethylene oxide)] (PECH‐PEO) were modified with several aromatic carboxylates (benzoate, 4‐(allyloxy)benzoate, 4‐(5‐hexenyloxy)benzoate, 3‐(allyloxy)‐2‐naphthoate, 3‐(5‐hexenyloxy)‐2‐naphthoate and 2‐(allylthio)nicotinate) under solid‐liquid phase transfer conditions to obtain crosslinkable terpolymers with well‐separated double bonds and a low chlorine content. Simultaneously to the substitution reaction, cleavage and crosslinking reactions take place. Most of these polymers were crosslinked by treating a mixture of them with 10 wt.‐% dicumyl peroxide (bis(‐1‐methyl‐1‐phenylethyl) peroxide). In some cases it was more suitable to use 10 wt.‐% 2,2′‐azoisobutyronitrile as initiator, although it always gave low degrees of crosslinking. Arrhenius kinetic parameters could only be determined for crosslinking processes promoted by dicumyl peroxide.
Preparation and characterization of fluorine‐containing aromatic condensation polymers, 5. Aromatic polybenzimidazoles from 4,4′‐(hexafluoroisopropylidene)dibenzoic acid and aromatic tetramine tetrahydrochlorides
Authors: Saegusa Yasuo , Horikiri Masahiro , Nakamura Shigeo
Published: April 2003

Two novel fluorine‐containing aromatic polybenzimidazoles were synthesized by direct polycondensation of 4,4′‐(hexafluoroisopropylidene)dibenzoic acid with 3,3′‐diaminobenzidine tetrahydrochloride and 1,2,4,5‐benzenetetramine tetrahydrochloride. The effect of introduction of fluorine on the synthesis and properties of these polymers is discussed. The new polybenzimidazoles show good solubility in organic solvents, excellent mechanical properties and high thermal stability.
Synthesis and ion‐coupling reactions of telechelic polystyrene having cyclic onium salt groups
Authors: Tezuka Yasuyuki , Imai Hiroshi , Shiomi Tomoo
Published: April 2003

A series of mono‐ and bifunctional polystyrenes (1 c and 1′c) having 1‐methylpyrrolidinium salt end groups were prepared through sequential derivatization, i.e., tosylation and quaternization reactions, of prepolymers having 3‐hydroxypropyl groups (1 a and 1′a) produced by end‐capping reactions of the relevant living polymers. The 1‐methylpyrrolidinium salt end group was found to undergo a selective ring‐opening reaction at 100°C by nucleophilic attack of a benzoate counter anion introduced by ion‐exchange reaction. The ion‐coupling reaction of 1 c and 1′c with poly(styrene‐co‐acrylate salt) was found to take place upon coprecipitation of an equimolar mixture into methanol to afford ionically linked pseudo‐graft and network products, respectively. The subsequent heat treatment, converting the ionic bond into a covalent one, results in branched and crosslinked polystyrene with predetermined structural parameters.
Synthesis and characterization of new polyquinolines having terdendate N‐N‐N or N‐C‐N binding sites in the main backbone
Authors: Mamo Antonino , Stefio Ivan
Published: April 2003

By reacting the monomer 4,4′‐diamino‐3,3′‐bis(p‐methoxybenzoyl)diphenyl sulfide with 4,4′‐diacetyldiphenyl sulfide and alternatively, with 2,6‐diacetylpyridine or 1,3‐diacetylbenzene in a m‐cresol/di‐m‐cresyl phosphate medium, six new polyquinolines having terdendate N‐N‐N or N‐C‐N binding sites in the main backbone were obtained. The lower is the number of binding sites present in the main backbone the higher is the degree of rigidity of the resulting polymers. 1H nuclear magnetic resonance (NMR) and infrared (IR) spectral data support the structure of the synthesized polymers. Thermal analysis data confirm the good thermal stability of this class of polymers. Two examples of macromolecular complexes with Os++ are also reported.
Synthesis and characterization of polyphosphazene homopolymers and copolymers
Authors: White Michael L. , Matyjaszewski Krzysztof
Published: April 2003

The preparation of polyphosphazene random and block copolymers bearing trifluoroethoxy and alkoxyalkoxy groups by the anionically initiated polymerization of phosphoranimines and poly(diarylphosphazene)s from phosphine azide intermediates is discussed. The properties of these materials were studied by differential scanning calorimetry, wide‐ and small‐angle X‐ray scattering, thermogravimetric analysis, dynamic mechanical analysis, dielectric relaxation spectroscopy, single crystal X‐ray and electron diffraction, density measurements and optical microscopy, and were correlated with molecular architecture, molecular weight, composition and side groups structure.
Synthesis of C60‐capped vinyl ether oligomers by living cationic polymerization technique
Authors: Okamura Haruyuki , Minoda Masahiko , Komatsu Koichi , Miyamoto Takeaki
Published: April 2003

This study concerns the synthesis of C60‐capped vinyl ether (VE) oligomers with well‐defined structure by living cationic polymerization technique. The VE oligomers bearing C60 at the chain end were prepared by addition reaction between monoocynylfulleride anions and living cationic VE oligomers. Living oligo(isobutyl vinyl ether) (IBVE) and oligo(methyl vinyl ether) (MVE) were synthesized using CH3CH(OiBu)Cl/ZnI2 as initiating system. The C60‐capped VE oligomers were obtained as dark brown gummy solid in 28% for IBVE and 34% for MVE. The UV/VIS and 13C NMR spectra indicated the formation of C60‐capped oligomers via 1,2‐addition reaction. It was also found that the films of blends of C60‐capped oligomers with poly(IBVE) and polystyrene (5 wt.‐% C60) are homogeneous on a micron scale and transparent, resulting from a good dispersion of C60 in the polymer matrix.
Water sorption in butyl acrylate zwitterionomers of the ammoniopropanesulfonate and ammonioethoxydicyanoethenolate type
Authors: Galin Monique , Galin Jean Claude
Published: April 2003

Water sorption by amorphous statistical butyl acrylate (A unit) zwitterionomers bearing ammoniopropanesulfonate (B unit, N+(CH2)3SO, μ = 24.0 D) or ammonioethoxydicyanoethenolate (B′ unit, N+(CH2)2OCOC−(CN)2, μ = 25.9 D) dipolar functional groups was studied at 23°C over a broad range of water activity (0.22 < a < 0.93). For a < 0.65, the sorption isotherms may be analyzed according to the BET equation for a multilayer process characterized by a number of site‐bound water molecules per dipolar unit, independent of copolymer composition and close to that measured on the corresponding zwitterionic homopolymers: nm ≈ 2.0 and 0.7 for AB and AB′, respectively. The initial kinetics of the diffusion process may be described according to a Fickian model up to the saturation of the first solvation layer capacity, with a typical increase of the diffusion coefficient for the AB′ copolymers of strongly reduced waterzwitterion interactions. In spite of the complex heterogeneous morphology of these zwitterionomers, of its continuous evolution and of the change of physical state of the hard domains from glassy to viscoelastic upon hydration, the water sorption process appears rather simple: it is essentially monitored by the overall content and the chemical structure of the dipolar units in the copolymer chains.
Copolymerization of γ‐butyrolactone and β‐butyrolactone
Authors: Lee Chan Woo , Urakawa Ryuichi , Kimura Yoshiharu
Published: April 2003

The copolymerization of a 4‐membered β‐butyrolactone (βBL) and a thermodynamically stable 5‐membered γ‐butyrolactone (γBL) proceeds in the bulk state with BF3 · OEt2 as a catalyst at room temperature to give poly[(3‐hydroxybutyrate)‐co‐(4‐hydroxybutyrate)] (P(3HB‐co‐4HB)) whose structure is identical with that of a polyester formed by microorganisms. The copolymer structure was confirmed by 1H and 13C NMR spectroscopy. The monomer reactivity ratios were r(γBL) = 0.48 and r(βBL) = 0.58, respectively, and the unit composition of 4HB increases to 56% at high γBL to βBL ratio in the feed. End group analysis of the copolymer suggests the presence of a hydroxyl group and a carboxyl group at the ends of each polymer molecule. It was postulated that the monomers activated by BF3 react with the hydroxy group derived from the water contaminant in the monomers.
Aromatic polymers obtained by precipitation polycondensation, 2. Synthesis of poly(ether ketone ether ketone ketone) (PEKEKK)
Authors: Zolotukhin Mikhail G. , Rueda Daniel R. , Calleja Francisco J. Baltá , Bruix Marta , Cagiao Maria E. , Bulai Anna , Gileva Natalia G.
Published: April 2003

A high molecular weight, linear aromatic poly(ether ketone ether ketone ketone) (PEKEKK) has been synthesized by electrophilic Friedel‐Crafts acylation condensation of 1,4‐diphenoxybenzophenone with terephthaloyl chloride. The syntheses were performed as precipitation polycondensations, and the polyketones were obtained in particle form. The viscosity (molecular weight), shape and size of these particles were found to be strongly dependent on the reaction conditions. For low monomer concentration, highly ordered needle‐like particles were also obtained. The chemical structure of the polymers obtained was confirmed by 1H and 13C NMR spectroscopy, and para‐substitution in aryl fragments of the main chain was identified. Analysis of the expanded 1H NMR spectra for the ring proton resonances reveals defect meta‐ and ortho‐structures. The amount and isomer ratio of these defect structures depend on the monomer concentration used.
Polymerization of lactams, 88. Copolymers poly(ϵ‐caprolactam)‐block‐polybutadiene prepared by anionic polymerization, part III. Model polymerizations initiated with potassium salt of ϵ‐caprolactam and accelerated with isocyanates and their derivatives
Authors: Sobotík Roman , Šrubař Radim , Roda Jan
Published: April 2003

Anionic polymerization of ϵ‐caprolactam was initiated with the potassium salt of ϵ‐caprolactam and accelerated with phenyl isocyanate, toluylene diisocyanate, 4,4′‐diphenylmethane diisocyanate, some derivatives of these isocyanates (urethanes, ureas, and allophanates), or combinations of phenyl isocyanate with its derivatives at 150°C. The effect of individual structures on the polymerization kinetics and their contribution to the preparation of block copolymers of ϵ‐caprolactam with hydroxy‐terminated prepolymers, in‐situ functionalized with diisocyanates, are discussed on the basis of a detailed analysis of time functions of polymer yield and degree of polymerization.
Biorecognition of sugar containing N‐(2‐hydroxypropyl)methacrylamide copolymers by immobilized lectin
Authors: Rathi Ramesh C. , Kopečková Pavla , Kopeček Jindřich
Published: April 2003

The interactions of sugar containing N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymers with Tetragonolobus purpureas (Lotus tetragonolobus) lectin immobilized on 4% beaded agarose have been studied. HPMA copolymers containing side‐chains terminating in N‐acylated amino sugars, namely, fucosylamine, galactosamine, glucosamine and mannosamine were synthesized and their biorecognition evaluated. As expected, only fucosylamine containing HPMA copolymers showed specific binding to the lectin. The dissociation constants (Kd) for HPMA copolymers were determined by frontal affinity chromatography. The binding constant was dependent on the amount of fucosylamine residues per macromolecule. An increase in fucosylamine content from 9,9 to 33,2 mol‐% resulted in a decrease of Kd by one order of magnitude. Incorporation of hydrophobic side‐chains such as glycylglycyl‐5‐[4‐(2‐aminoethylcarbamoyl)phenylazo]salicylic acid, 1′‐(β‐hydroxyethyl)‐3′,3′‐dimethyl‐6‐nitrospiro(2H‐1‐benzopyran‐2,2′‐indoline) (SP), or 1′‐(β‐glycylglycyloxyethyl)‐3′,3′‐dimethyl‐6‐nitrospiro(2H‐1‐benzopyran‐2,2′‐indoline) (GG‐SP) into the copolymers increased the non‐specific binding to the lectin. Photoinduced isomerization of bound spiropyrans to merocyanines was accompanied by changes in the conformation and biorecognition of HPMA copolymers. The results obtained demonstrated the impact of the structure and solution conformation of sugar containing HPMA copolymers on their biorecognition.
Propene polymerization with MgCl2‐supported catalysts: effects of using a diether as external donor
Authors: Chadwick John C. , Morini Giampiero , Balbontin Giulio , Mingozzi Ines , Albizzati Enrico , Sudmeijer Olof
Published: April 2003

13C NMR analysis of poly(propylene) fractions of different tacticity, obtained using a catalyst system of type MgCl2/TiCl4/diisobutyl phthalate – AlEt3 – diether, has provided further evidence that the active species in this system are similar to those in which the ether is used as “internal” rather than “external” donor. Chain‐end analysis of relatively low molecular weight polymer fractions indicated, for polymers of similar molecular weight, similar proportions of butyl‐terminated chain‐ends, indicative of chain transfer with hydrogen following regioirregular (2,1‐) insertion. The relatively high hydrogen response of diether‐containing catalyst systems can therefore be largely ascribed to this phenomenon, irrespective of whether the diether is used as internal or external donor. At relatively low hydrogen concentrations, chain transfer to hydrogen takes place predominantly after the occasional secondary insertion, while the additional presence of vinylidene chain‐ends in certain xylene‐soluble fractions indicates that chain transfer via β‐H transfer takes place mainly after primary insertion.
Kinetic study of isospecific active sites formed by various alkylaluminiums on MgCl2‐supported Ziegler catalyst at the initial stage of propene polymerization
Authors: Mori Hideharu , Iguchi Hiromitsu , Hasebe Kouichi , Terano Minoru
Published: April 2003

The effect of various kinds of alkylaluminium on the kinetic parameters of the initial stage of propene polymerization with MgCl2‐supported Ziegler catalyst was studied by the stopped‐flow polymerization method. The active sites concentration ([C*]) decreased drastically with the increase of bulkiness of the alkyl group of the aluminium compound, while the change of the propagation rate constant (kp) was rather small and proportional to the meso pentad fraction of the resulting polypropene. The kinetic parameters, kp(insol) and [C*(insol)], were calculated from the yield and number‐average molecular weight of the boiling heptane insoluble fraction. The values of kp (insol) were almost constant, while those of kp depended on the ratio [C*(insol)]/[C*(total)]. The results obtained in this study suggest that isospecific active sites produced by various alkylaluminiums are essentially the same, but the amounts of the active sites formed with a variety of alkylaluminiums are different.
Single crystals of syndiotactic poly[propene‐co‐(1‐octene)] and syndiotactic polypropene crystallized in bulk
Authors: Thomann Ralf , Kressler Jörg , Mülhaupt Rolf
Published: April 2003

Single crystals grown in bulk samples of a syndiotactic random copolymer of propene and 1‐octene with 4 wt.‐% 1‐octene are compared with single crystals of syndiotactic polypropene homopolymer. The random copolymer during isothermal crystallization at low supercoolings forms rectangular single crystals similar to syndiotactic polypropene. The single crystals of the random copolymer do not exhibit transverse cracks in contrast to neat syndiotactic polypropene. Both polymers have nearly the same linear thermal expansion coefficients along their crystallographic a‐ and b‐axis, calculated from temperature‐dependent wide‐angle X‐ray scattering (WAXS) measurements. Therefore, the absence of transverse cracks in single crystals of the random copolymer can only be explained by the relatively high disorder of the crystallite surface caused by the exclusion of 1‐octene segments which leads to a more isotropic thermal expansion coefficient in this region.
Polymers from multifunctional isocyanates, 13. Functional polymers from N‐substituted poly(maleimide‐alt‐isopropenyl isocyanate)s
Authors: Mormann Werner , Grimm Axel
Published: April 2003

Alternating copolymers from isopropenyl isocyanate and N‐substituted maleimides (N‐phenyl, N‐tetradecyl‐ and N‐octadecylmaleimide) were synthesized for the first time. The reactive copolymers with regular structure have an isocyanate group in the constitutional repeating unit which allows modification and functionalization in a polymer analogous reaction. Functionalization has been demonstrated with examples of amphiphilic copolymers having the hydrophobic and the hydrophilic chain attached to the polymer backbone in a regular alternating fashion. A second example is an alternating copolymer with an NLO‐chromophore attached to the polymer.
Synthesis of 3‐amino‐ribofuranans having 1,5‐α and ‐β structures by selective ring‐opening polymerization of a 1,4‐anhydro‐3‐azido‐3‐deoxy‐α‐D‐ribopyranose derivative
Authors: Kang Byoung Won , Hattori Kazuyuki , Yoshida Takashi , Hirai Makoto , Chio Yoon Soung , Uryu Toshiyuki
Published: April 2003

Ring‐opening polymerization of a new anhydro ribose‐type monomer, 1,4‐anhydro‐3‐azido‐3‐deoxy‐2‐O‐tert‐butyldimethylsilyl‐α‐D‐ribopyranose (A3ASR), was investigated. The monomer was synthesized from 1,4‐anhyro‐α‐D‐xylopyranose by three steps comprising Walden inversion at the C3 position into ribose configuration. Ring‐opening polymerization of A3ASR by Lewis acid catalysts such as boron trifluoride etherate and stannic chloride gave a stereoregular 3‐azido‐3‐deoxy‐2‐O‐tert‐butyldimethylsilyl‐(1→5)‐α‐D‐ribofuranan having specific rotations of +246 ∼ +271 deg · dm−1 · g−1 · cm3 and number‐average molecular weights of 18,7 × 103 ∼ 25,1 × 103. When the polymerization was carried out by antimony pentachloride at 0°C, the resulting polymer exhibited a negative specific rotation of −6 deg · dm−1 · g−1 · cm3 and the C1 absorption in the 13C NMR spectrum shifted downfield to 107,5 ppm, suggesting that the polymer might consist of 1,5‐β furanosidic unit. The reduction of the azido group of the 1,5‐α and 1,5‐β furanosidic polymers into amino group and subsequent desilylation gave 3‐amino‐3‐deoxy‐(1→5)‐α‐ and ‐β‐D‐ribofuranans, respectively. In addition, copolymerization of A3ASR with 1,4‐anhydro‐2,3‐di‐O‐tert‐butyldimethylsilyl‐α‐D‐ribopyranose (ADSR) in various feeds was performed by boron trifluoride etherate as catalyst to give copolymers with different monomeric components. The structural analysis of the homopolymers and copolymers was examined by means of 1H and 13C NMR spectroscopies, IR spectroscopy, and optical rotation.
Synthesis and characterization of random and regular L‐lysine‐based polyamides
Authors: Gachard Isabelle , Coutin Bernard , Sekiguchi Hikaru
Published: April 2003

This paper deals with the synthesis of polyamides based on the natural diamine, L‐lysine, on the one hand, and diacids, adipic or glutaric, on the other hand. They were obtained by polycondensation of active diesters, pentachlorophenyl and pentafluorophenyl esters. L‐Lysine being non‐symmetrical, aregic (random) and syndioregic (“head‐to‐head, tail‐to‐tail”) poly(adipoyl‐L‐lysine)s and poly(glutaroyl‐L‐lysine)s were obtained with molecular weights higher than 15000; isoregic (“head‐to‐tail”) poly(adipoyl‐L‐lysine)s and poly(glutaroyl‐L‐lysine)s were prepared with lower molecular weights.
A novel side‐chain liquid crystal polymer of 5‐substituted cis‐cyclooctene via ring‐opening metathesis polymerization
Authors: Winkler Berthold , Rehab Ahmed , Ungerank Markus , Stelzer Franz
Published: April 2003

In this communication, we report the synthesis and ring‐opening metathesis polymerisation (ROMP) of a 5‐substituted cyclooctene‐derivative, (±)‐cis‐[11‐(4′‐cyanobiphenyl‐4‐yloxy)undecyl]cyclooct‐4‐enecarboxylate. A highly active molybdenum‐carbene was used as initiator. The prepared polymer is liquid crystalline and shows a nematic phase between −5 and 53°C.
Crystallization behavior of blends of high‐density polyethylene with novel linear low‐density polyethylene
Authors: Zhao Yong , Liu Shengsheng , Yang Decai
Published: April 2003

Blends of high‐density polyethylene (HDPE) with novel linear low‐density polyethylene (LLDPE) samples in the whole range of compositions were investigated by means of differential scanning calorimetry (DSC), small‐angle X‐ray scattering (SAXS) and wide‐angle X‐ray diffraction (WAXD). The LLDPEs are ethylene/octene‐1 copolymers prepared with a single‐site catalyst, with a narrower distribution of branches compared to Ziegler‐Natta type polymers. It was found that cocrystallization or separate crystallization in the blends profoundly depends on the content of branches in the LLDPE, while the critical branch content of the novel LLDPE for separate crystallization is much lower than that of commercial LLDPE (prepared with Ziegler‐Natta catalysts). This implies that the miscibility of linear and branched polyethylene is also affected by the distribution of branches. The marked expansion of the unit cell in cocrystals, which are formed by HDPE with the novel LLDPE, indicates that the branches are included in the crystal lattice during the cocrystallization process. The result is very helpful to understand the phenomenon that the unit cell dimensions of commercial branched polyethylene are larger than those of linear polyethylene.
A systematic spectroelectrochemical investigation of alkyl‐substituted anilines and their polymers
Authors: Probst Matthias , Holze Rudolf
Published: April 2003

Various aniline derivatives carrying one or two alkyl substituents in various positions (alkylanilines, toluidines and xylidines) were polymerized electrochemically. The obtained conducting polymers were characterized by cyclic voltammetry, in situ infrared spectroscopy and in situ conductivity measurements. Differences in the electrochemical properties of the investigated monomers and polymers are polymers are explained on the basis of steric and electronic effects of the substituents. These conclusions are supported by data of vibrational spectroscopy.
Regioselectivity of the Pd‐catalyzed synthesis of arylenevinylenes and its impact on polymer properties: Model reaction and polyreactions
Authors: Klingelhöfer Stephanie , Schellenberg Carsten , Pommerehne Jörn , Bässler Heinz , Greiner Andreas , Heitz Walter
Published: April 2003

The regioselectivity of Pd‐catalyzed coupling reactions of functionalized benzenes and olefins with respect to the ratio of 1.2‐product/1.1‐product was monitored by model reactions. The coupling of halobenzenes, benzene triflate, and aryldiazonium salts was studied under various reaction conditions. In order to simulate corresponding polyreactions, special focus was on the coupling of ortho‐substituted functionalized benzenes with ethylene or styrene in order to evaluate the input of mono‐ and disubstituted aryl monomers and the choice of the olefin on the regioselectivity of polyreactions. The results of the model reactions were transferred to the polyreactions. The polymers were characterized by NMR, absorption and photoluminescence spectroscopy as well as electroluminescence.
Critically evaluated rate coefficients for free‐radical polymerization, 2.. Propagation rate coefficients for methyl methacrylate
Authors: Beuermann Sabine , Buback Michael , Davis Thomas P. , Gilbert Robert G. , Hutchinson Robin A. , Olaj Oskar Friedrich , Russell Gregory T. , Schweer Johannes , van Herk Alex M.
Published: April 2003

Pulsed‐laser polymerization (PLP) in conjunction with molar mass distribution (MMD) measurement is the method of choice for determining the propagation rate coefficient kp in free‐radical polymerizations. The authors, members of the IUPAC Working Party on Modeling of kinetics and processes of polymerization, collate results from using PLP‐MMD to determine kp as a function of temperature T for bulk free‐radical polymerization of methyl methacrylate at low conversions and ambient pressure. Despite coming from several different laboratories, the values of kp are in excellent agreement and obey consistency checks. These values are therefore recommended as constituting a benchmark data set, one that is best fitted by

The 95% joint confidence interval for these Arrhenius parameters is also given. In so doing, we describe the most appropriate statistical methods for fitting kp(T) data and then obtaining a joint confidence interval for the fitted Arrhenius parameters. As well, we outline factors which impose slight limitations on the accuracy of the PLP‐MMD technique for determining kp, factors which may apply even when this technique is functioning well. At the same time we discuss how such systematic errors in kp can be minimized.
Free radical polymerisation studies of 4‐substituted styrenes, 1. The reactions of 2‐cyano‐2‐propyl radicals with styrene, 4‐methoxystyrene and 4‐methylstyrene
Authors: Berry Robert William Huxley , Ludlow Andrew John , Mazza Robert John
Published: April 2003

Only a limited amount of work has been previously published concerning the free radical polymerisation of 4‐methoxystyrene and 4‐methylstyrene initiated by 2,2′‐azoisobutyronitrile (2,2′‐azobis(2‐methylpropiononitrile)) (AIBN). The present investigation was, therefore, undertaken to establish whether the substituents have a considerable affect on the reaction of 2‐cyano‐2‐propyl radicals at 60°C, relative to styrene. Rates of polymerisation were determined gravimetrically and rates of initiation were calculated from the radioactivity of the polymer, obtained by labelling AIBN with carbon‐14. Number average molecular weights (Mn) were determined by gel permeation chromatography (GPC). The order of reaction with respect to initiator concentration was found to be 0.50 for styrene and 0.48 for both 4‐methoxystyrene and 4‐methylstyrene, which was attributed to their susceptibility to primary radical termination. Polystyryl radicals were also found to undergo primary radical termination and values for the constant {kprt/(ki·kp)} were determined as 1.37 × 104 mol · s · dm−3 for styrene, 1.47 × 104 mol · s · dm−3 for 4‐methoxystyrene and 1.30 × 104 mol · s · dm−3 for 4‐methylstyrene. The rate of initiation for 4‐methoxystyrene is greater than for styrene, which in turn is greater than for 4‐methylstyrene.
Synthesis and characterization of 1,3,4‐oxadiazole‐containing polyethers from 2,5‐bis(4‐fluorophenyl)‐1,3,4‐oxadiazole and various aromatic diols
Authors: Saegusa Yasuo , Iwasaki Takeshi , Nakamura Shigeo
Published: April 2003

Six 1,3,4‐oxadiazole‐containing polyethers with reduced viscosities of 0,65–1,17 dL · g−1 were synthesized by high‐temperature solution polycondensation of an activated difluoride, 2,5‐bis(4‐fluorophenyl)‐1,3,4‐oxadiazole, with aromatic diols possessing a variety of ring structures. The expected chemical structures were confirmed by IR and 1H NMR spectroscopy and elemental analysis. Of all the polymers, two polyethers were highly crystalline and soluble only in limited solvents such as o‐chlorophenol and conc. sulfuric acid. The other polyethers were amorphous and dissolved readily in a variety of organic media including polar aprotic solvents, phenols and chlorinated hydrocarbons. Colorless to slightly yellow‐colored, transparent and tough films could be cast from the N‐methyl‐2‐pyrrolidone or o‐chlorophenol solutions. The mechanical properties were excellent and their tensile strength, elongation at break and tensile moduli were in the ranges of 53–80 MPa, 4–12% and 1,3–2,0 GPa, respectively. The amorphous polyethers had high glass transition temperatures of 195–259°C. All the polyethers were highly thermally and thermooxidatively stable and exhibited no weight loss up to 400°C, with 10% weight loss being recorded at 464–514°C in air.
Syndiotactic polymerization of styrene with cyclopentadienyltribenzyloxytitanium/methylaluminoxane catalyst
Authors: Wu Qing , Ye Zhong , Lin Shangan
Published: April 2003

Syndiotactic polystyrene was efficiently prepared in the presence of a homogeneous catalyst composed of (η5‐cyclopentadienyl)tribenzyloxytitanium and methylaluminoxane (MAO) as a cocatalyst. Influences of various polymerization conditions, e.g., [Ti]. [MAO], [St], temperature and the content of retained trimethylaluminium (TMA) in MAO on the catalytic activity, syndiotacticity and molecular weight of the polymer were studied. It was found that the retained TMA plays an important role in the polymerization. Lowering the retained TMA content in MAO decreases the activity of the catalyst remarkably. Addition of external alkylaluminium (TMA or triisobutylaluminium) into the catalyst system with MAO containing low amounts of retained TMA promotes styrene polymerization.
UV‐curable systems containing perfluoropolyether structures: Synthesis and characterisation
Authors: Priola Aldo , Bongiovanni Roberta , Malucelli Giulio , Pollicino Antonino , Tonelli Claudio , Simeone Giovanni
Published: April 2003

The synthesis of new functionalised macromers containing perfluoropolyether structures (PFPE) is reported. They are obtained by reaction of bis‐CH2OH terminated PFPE with isocyanato‐ethyl methacrylate (EIM), giving rise to the formation of perfluoropolyether bisurethane methacrylate (PFEUMA) oligomers. The products are characterised by NMR and FTIR analyses. The thermal behaviour reveals two amorphous phases, corresponding to the fluorinated and the hydrogenated moieties, while a crystalline phase can be present depending on the macromer structure. The functionalised macromers are UV‐cured in the presence of a photoinitiator and the complete disappearance of the double bonds is obtained. The cured films are characterised by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) confirming the presence of a multiphasic structure. Moreover the optical properties and the surface properties of the cured systems are investigated and discussed.
Amino acid based bioanalogous polymers. Novel regular poly(ester urethane)s and poly(ester urea)s based on bis(L‐phenylalanine) α,ω‐alkylene diesters
Authors: Kartvelishvili Tamara , Tsitlanadze George , Edilashvili Lamara , Japaridze Nona , Katsarava Ramaz
Published: April 2003

Novel biodegradable regular poly(ester urethane)s 2 (ηred ≤ 0,62 dL/g) were synthesized for the first time by polycondensation of di‐p‐toluenesulfonic acid salts of bis(phenylalanine) α,ω‐alkylene diesters 1 with di‐p‐nitrophenyl trimethylenedicarbonate (4) under mild conditions in organic solvents in the presence of triethylamine as acid acceptor. The first synthesis of homopoly(ester urea)s 3 (ηred ≤ 0,33 dL/g) was carried out by polycondensation of 1 with di‐p‐nitrophenyl carbonate (5) under the same conditions. Preliminary in vitro evaluation of specific and nonspecific hydrolysis of the polymers obtained has been brought about using potentiometric titration.
Polymerization behavior of electron‐accepting substituted quinodimethanes
Authors: Itoh Takahito , Iwatsuki Shouji
Published: April 2003

This article describes the polymerization behavior of electron‐accepting substituted quinodimethanes. Chlorine‐substituted quinodimethanes (1a–c) behave differently depending on the number of chlorine substituents. Strong electron‐accepting substituted quinodimethanes like 2a–c and 4 are not homopolymerizable, but copolymerizable with donor monomers like styrene in an alternating fashion. 7,7,8,8‐Tetrakis(alkoxycarbonyl)‐quinodimethanes (3a and 3b) and 7,7,8‐tris(tert‐butoxycarbonyl)‐8‐cyanoquinodimethane (5a) show amphoteric behavior in their alternating copolymerizations and in their charge‐transfer complex formation. Some substituted quinodimethanes with two different substituents on their exocyclic carbons (5b, 6a–c, 7a–e, 8a and 8b, and 9a–e) are homopolymerizable; for instance anionic polymerization of 7,8‐bis(butoxycarbonyl)‐7,8‐dicyanoquinodimethane (6c) takes place in a living way and gives a polymer with a molecular weight above 106. The homopolymerizations are equilibrium polymerization reactions and the thermodynamic parameters were determined. Their copolymerizations with styrene occur in a random fashion. The cross‐propagation step was studied by means of a linear free energy relationship and a new concept of radical alternating copolymerization is proposed.
Preparation and identification of di‐block copolymer composed of crystalline poly(ethylene oxide) and noncrystalline poly(vinyl acetate) with well‐defined structure
Authors: Huang Junlian , Huang Xiaoyu , Hu Wenbin
Published: April 2003

A block copolymer of ethylene oxide (EO) and vinyl acetate (VAc) was prepared by sequential anionic and photo‐induced charge transfer polymerization (CTP) using UV sensible p‐aminophenoxy end groups on PEO (PEOa). The structure and composition of this block copolymer (PEO‐b‐PVAc) were identified in detail. The relationship between polymerization rate (Rp) and the concentrations of benzophenone (BP) and monomer, and the effect of the concentration and molecular weight of PEOa on the polymerization of VAc, are discussed; the relationship Rp ∝ [PEOa‐11000]0.33 [VAc]0.28 [BP]0.47 using benzene as a solvent was derived. The dependence of the thermal properties of PEO‐b‐PVAc on the length of the PVAc block is described. It turned out that the PEO and PVAc blocks are compatible.
Synthesis and properties of poly(ether imide)s derived from 4,4′‐(1,5‐naphthylenedioxy)diphthalic anhydride and various aromatic diamines
Authors: Hsiao Sheng‐Huei , Yang Chin‐Ping , Chu Kuan‐Yu
Published: April 2003

A naphthalene unit‐containing bis(ether anhydride), 4,4′‐(1,5‐naphthylenedioxy)‐diphthalic anhydride, was prepared in three steps starting from the nucleophilic nitro‐displacement reaction of 1,5‐dihydroxynaphthalene and 4‐nitrophthalonitrile in N,N‐dimethylformamide (DMF) solution in the presence of potassium carbonate. High‐molarmass aromatic poly(ether imide)s were synthesized using a two‐stage polymerization process from the bis(ether anhydride) and ten aromatic diamines. The intermediate poly(ether amic acid)s had inherent viscosities of 0,66–1,27 dL/g. The films of poly(ether imide)s derived from some diamines, such as p‐phenylenediamine, benzidine, and bis[4‐(4‐aminophenoxy)phenyl] ether, crystallized and embrittled during the thermal imidization process. The other poly(ether imide)s were amorphous materials and could be fabricated into transparent, flexible, and tough films. These poly(ether imide) films had yield strengths of 111–125 MPa, tensile strengths of 96–150 MPa, elongations to break of 10–38%, and initial moduli of 1,6–2,4 GPa. All of these polymers were insoluble in organic solvents, except for that derived from 2,2‐bis[(4‐aminophenoxy)phenyl]propane. Their Tg's were recorded in the range of 226–265°C by DSC. Thermogravimetric analysis (TG) showed that all the polymers were stable up to 535°C in both air and nitrogen atmosphere.
Semifluorinated diblock copolymers. Synthesis, characterisation and amphiphilic properties
Authors: Krupers Maarten , Möller Martin
Published: April 2003

Semifluorinated diblock copolymers based on methyl methacrylate and 1H,1H,2H,2H‐perfluoroalkyl methacrylates were prepared by nucleophilic catalysed group transfer polymerisation. Characterisation was carried out by 1H NMR spectroscopy, differential scanning calorimetry (DSC) and gel‐permeation chromatography (GPC) in toluene. The latter method revealed the formation of micelles. The surface activity of the materials was demonstrated by tensiometry using a Wilhelmy balance. Measurements on thin polymer films showed low critical surface tensions and low dispersion force contributions to the surface energy indicating the presence of the fluorinated block at the surface.
Polymers of carbonic acid, 23. Photoreactive cholesteric polycarbonates based on isosorbide, 4,4′‐dihydroxychalcone and 4,4′‐dihydroxybiphenyl
Authors: Kricheldorf Hans R. , Sun Shih‐Jieh , Sapich Beate , Stumpe Joachim
Published: April 2003

Numerous copolycarbonates were prepared from 4,4′‐dihydroxychalcone, on the one hand, and methylhydroquinone, 4,4′‐dihydroxybiphenyl or isosorbide (1,4:3,6‐dianhydro‐D‐sorbitol), on the other. Three different polycondensation methods were compared, but polycondensation in an organic solvent using diphosgene as condensing agent proved to be the most satisfactory. The resulting copolycarbonates were characterized by their inherent viscosities, elemental analyses, infrared (IR), 1H nuclear magnetic resonance (NMR) and 13C NMR spectra, by differential scanning calorimetry (DSC) measurements and by optical microscopy. The 13C NMR spectra proved the formation of almost random sequences in all cases. In contrast to the homopolycarbonate of chalcone which is crystalline and insoluble in inert solvents, all copolycarbonates of chalcone are completely or largely amorphous and soluble. Whereas 4,4′‐dihydroxychalcone itself proved to be nonmesogenic, copolycarbonates containing 4,4′‐dihydroxybiphenyl are thermotropic. Ternary copolycarbonates containing isosorbide as a chiral component are cholesteric and form Grandjean textures upon shearing in the molten state. Ultraviolet (UV) irradiation of thin films resulted in crosslinking.