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  • Articles  (8,715)
  • Springer  (8,131)
  • American Chemical Society  (584)
  • 2010-2014
  • 1995-1999  (8,715)
  • 1998  (8,715)
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (8,715)
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  • Articles  (8,715)
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  • 2010-2014
  • 1995-1999  (8,715)
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  • 1
    Electronic Resource
    Electronic Resource
    Copolymerization of styrene and methyl methacrylate with nickel acetylacetonate/methylaluminoxane catalyst system (1998)
    Springer
    Polymer bulletin 40 (1998), S. 423-429 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The present work deals with copolymerization of styrene (STY) and methyl methacrylate (MMA) catalysed by nickel acetylacetonate - Ni(acac) 2 , employing methylaluminoxane (MAO) as cocatalyst. This catalyst system presented low catalyst activities for STY homopolymerization and very high activities for MMA. It seems that the catalyst system based on Ni(acac) 2 /MAO is effective for the copolymerization of MMA and STY to give block copolymer but it also produced polystyrene and poly(methyl methacrylate) homopolymers. The polymers were characterized by 13 C NMR, GPC and FTIR. The polystyrene homopolymer was identified by IR and NMR analyses of the cyclohexane soluble fraction. The presence of absorption bands correspondent to carbonyl group and aromatic ring was observed in the IR spectrum of the acetic acid soluble part. This result is a clue that STY-MMA copolymer with low molecular weight was produced. The high molecular weight copolymer (acetic acid insoluble fraction) was also characterized by IR analysis which indicated the presence of characteristic absorption bands of carbonyl group and aromatic ring. These results were confirmed by 13 C NMR analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050272
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  • 2
    Electronic Resource
    Electronic Resource
    Small-angle X-ray scattering from sodium hyaluronate in aqueous sodium chloride (1998)
    Springer
    Polymer bulletin 40 (1998), S. 555-562 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Four narrow-distribution samples of sodium hyaluronate with weight-average molecular weights M w of 3.8 × 103 to 1.1 × 104 in 0.02 and 0.1 M aqueous NaCl at 25°C have been studied by small-angle X-ray scattering. Data for their z-average radii of gyration 〈S2〉z 1/2 and particle scattering functions P(θ), together with previous 〈S2〉z data from light scattering for high molecular weights, are compared with relevant theories for the wormlike chain with or without excluded volume, using the parameters estimated previously from intrinsic viscosity ([η]) data. It is shown that for M w lower than 1.1 × 104, 〈S2〉z, P(θ), and [η] of the polysaccharide in the aqueous salts are all consistently explained by this model without excluded volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050290
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  • 3
    Electronic Resource
    Electronic Resource
    Functional polythiiranes 8. Influence of the terminal group on the thermotropic behaviour of side chain liquid crystalline polythiiranes and identification of a crystalline phase (1998)
    Springer
    Polymer bulletin 40 (1998), S. 569-574 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Three new side chain liquid crystalline polythiiranes were prepared with new substituants on the mesogenic groups. Their thermotropic liquid crystalline behaviour was studied by the usual techniques (DSC, X-ray diffraction and polarized optical microscopy). Unlike the polyoxiranes described in the literature, the size of the terminal group has no influence on the nature of the mesophases of polythiiranes ; only slight changes of the transition temperatures were observed. In this series of polymers, a phase, denoted X, appeared at temperatures below the smectic E phase, and could not be identified by usual characterization techniques. An isothermal kinetic study for the smectic E / X phase transition resulted in an Avrami exponent close to 1, suggesting a one-dimensional ordering occurred during the transformation from the smectic phase. This result, combined with other observations, helped us to assign the X phase to the crystalline phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050292
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  • 4
    Electronic Resource
    Electronic Resource
    Properties of PVC-titania hybrid materials prepared by the sol-gel process (1998)
    Springer
    Polymer bulletin 40 (1998), S. 583-590 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Hybrid materials from Polyvinyl chloride (PVC) and titania were prepared using sol-gel technique. In-situ generation of titania network in the PVC matrix was carried out by introducing required amounts of tetrapropylorthotitanate (TPOT) followed by hydrolysis/condensation of TPOT in the matrix. Homogeneous and semi-transparent films were obtained by casting and solvent evaporation. Mechanical properties of these films up to 15 wt. % titania contents were studied. The results showed an increase in the Young's modulus, length at rupture and toughness of the unplasticised PVC. However, the tensile strength and stress at break point decreased with the addition of titania contents. Thermal stability of the material was studied using dehydrochlorination (DHCl) technique and thermogravimetric analysis. The PVC samples with small amount of titania were found to be more stable as compared with the pure PVC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050294
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  • 5
    Electronic Resource
    Electronic Resource
    An improvement of the Mc Bain's microbalance to study transport of solvent vapours into polymeric films (1998)
    Springer
    Polymer bulletin 40 (1998), S. 591-598 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY The sorption characteristics of benzene and cyclohexane vapours in the poly(urethane-urea) (PUU) with well defined structure were measured using an improved version of the Mc Bain's microbalance. The diffusion coefficients were calculated for the different vapour activities from the kinetics of solvent uptake, i.e. the sorption isotherms over time. Sorption and diffusion coefficients measured, showed a strong dependence of the applied vapour activity. The obtained transport parameters were discussed with regard to the polymer structure. Based on the sorption and diffusion data, the pervaporation performance of the PUU-based membrane in separation of the benzene/cyclohexane mixtures was predicted and compared with the experimental pervaporation characteristic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050295
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  • 6
    Electronic Resource
    Electronic Resource
    Isospecific polymerization of styrene with supported nickel acetylacetonate/methylaluminoxane catalysts (1998)
    Springer
    Polymer bulletin 40 (1998), S. 689-694 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The polymerization of styrene with catalysts based on Ni(acac)2 supported on SiO2 and Al2O3 was investigated. Using catalysts based on MAO supported on silica, a highly isotactic polystyrene was obtained. Nevertheless, the Al2O3-supported catalyst can promote isospecific polymerization activated by common. alkyl aluminum compounds even by any prior support treatment with MAO.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050309
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of polymer having β,β-triketone unit in the main chain and its copper (II) complex (1998)
    Springer
    Polymer bulletin 40 (1998), S. 701-706 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A novel polymer having β,β-triketone unit in the main chain was prepared by polycondensation of triethylene glycol bis(p-butoxycarbonylphenyl) ether (1) with triethylene glycol bis(p-acetylacetophenyl) ether (4). The obtained polymer was soluble in CHCl3, DMF, and DMSO. The structure of the polymer was confirmed by 1H-NMR. Insoluble brownish yellow copper (II) chelate was obtained by adding a methanol solution of copper (II) acetate to a chloroform solution of the polymer. The IR analysis and the measurement of copper content by iodometric titration showed the quantitative formation of binuclear copper (II) complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050311
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis and polymerization of 1-trimethylsiloxy- or 1-triphenylsiloxysilacyclobutanes (1998)
    Springer
    Polymer bulletin 40 (1998), S. 715-720 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Synthesis and polymerization behavior of 1-trimethylsiloxy- or 1-triphenylsiloxy-silacyclobutane derivatives were studied. These monomers gave polymers with reasonably high molecular weight by platinum catalyst like platinum 1,3-divinyl-1,1,3,3-tetramethyldisfloxane complex. Side-chain smectic, liquid crystalline polymer was obtained from 1-methyl-1-[3-{(4-cyanobiphenyl-4'-yl)oxy}propyl]dimethylsiloxysilacyclobutane. In the polymerization by butyllithium or phenyllithium, monomers corresponding to the amounts of the initiator were consumed, but no polymers were formed. Apparently, elimination of the trimethylsiloxy or triphenylsiloxy group occurred in the nucleophilic attack of the initiator or propagating species on the silicon atom of the monomer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050313
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  • 9
    Electronic Resource
    Electronic Resource
    Preliminary investigations on polymerization catalysts composed of lanthanocene and methylaluminoxane (1998)
    Springer
    Polymer bulletin 40 (1998), S. 729-734 
    Details
    ISSN: 1436-2449
    Keywords: (Keywords: lanthanocene; methylaluminoxane; polymerization; butadiene; isoprene; styrene.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The polymerization of butadiene(Bd), isoprene(Ip) and styrene(St) has been examined using the six catalyst systems composed of lanthanocene, (C5H9Cp)2NdCl(I), (C5H9Cp)2SmCl(II), (MeCp)2Sm OAr'(III), (Ind)2NdCl(IV), Me2Si(Ind)2NdCl(V) and (Flu)2NdCl(VI), and methylaluminoxane(MAO) respectively. All of them can be used to form the polyisoprene with molecular weights of 1 to 10 thousand and cis-1,4-unit contents of 41 to 47%. (I), (II) and (III) of them can be also used to form the polybutadiene with molecular weights of 10 to 20 thousand and cis-1,4-unit contents of 62 to 78%. In addition, the catalysts from (II) to (V) are still active for St polymerization and (II) of them gives a syndio -rich random polystyrene. It is noteworthy that (II) and (III) are active for homopolymerization of Bd, Ip and St in the same polymerization condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050315
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  • 10
    Electronic Resource
    Electronic Resource
    Phase transition of 2,3-O-methylcellulose (1998)
    Springer
    Polymer bulletin 40 (1998), S. 741-747 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In this work, a series of 2,3-O-methylcellulose (MC) with different DS value were prepared. Its phase transition behavior in aqueous solution was studied in terms of DS value, concentration and molecular weight. The the following conclusions were obtained. (1) All the 2,3-O-MC samples show no sol-gel transition in aqueous solution despite the molecular weight. (2) No phase separation was observed for the 2,3-O-MCs with a DS value lower than 1.0, even when the temperature was raised to 95°C. (3) The precipitation temperature is surprisingly different between 2,3-O-MCs. and other MCs possessing comparable total DS value. (4) The precipitation temperature of 2,3-O-MCs depends on the molecular weight rather than on the concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050317
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  • 11
    Electronic Resource
    Electronic Resource
    Polyacrylamide obtained by plasma-induced polymerization for a possible application in enhanced oil recovery (1998)
    Springer
    Polymer bulletin 40 (1998), S. 757-764 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Ultrahigh molecular weight polyacrylamides (PAAM) were obtained by plasma-induced polymerization in water solutions. The influenceof monomer concentration, sealing pressure, initiation time and post polymerization period on polymer yield and molecular weight were investigated. The viscosity and “screen factor” measurements, as well as the thermally stimulated depolarization currents spectroscopic data of the synthesized polymers, indicate good properties as efficient viscosity modifiers in displacement of fluids for enhance oil recovery (EOR).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050319
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  • 12
    Electronic Resource
    Electronic Resource
    The relaxation behavior of amorphous PET in global chain orientation but nearly random segmental orientation (GOLR) state (1998)
    Springer
    Polymer bulletin 40 (1998), S. 773-778 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In this report, the relaxation behavior of amorphous poly(ethylene terephthalate) (PET) in global chain orientation but nearly random segmental orientation (GOLR) state is studied by infrared dichroism, optical birefringence and hot shrinkage measurements at temperatures below or up PET's glass transition temperature, Tg. The results indicate that the difference in the relaxing rate between global chains and segments is at least in ∼ 102 times order above PET's Tg (∼ 84°C), with a rough approximation; while the sudden decrease of small Δn of the sample (∼ 10−4) upon being treated at about 85 ∼ 90°C, implies us that the small Δn is closely related with the orientation of global chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050321
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  • 13
    Electronic Resource
    Electronic Resource
    In memoriam: Reimund Stadler, Editor of Polymer Bulletin (1998)
    Springer
    Polymer bulletin 41 (1998), S. 129-130 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050342
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  • 14
    Electronic Resource
    Electronic Resource
    High molecular weight polyurethanes and a polyurethane urea based on 1,4-butanediisocyanate (1998)
    Springer
    Polymer bulletin 41 (1998), S. 131-138 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary New biomedical polyurethanes and a polyurethane urea based on Ε-caprolactone and 1,4-butanediisocyanate have been developed. On degradation, only non-toxic products are produced. The polyurethane urea with poly(Ε-caprolactone) soft segments and butanediisocyanate/butanediamine hard segments shows a high tensile strength, a high modulus and a high resistance to tearing but as a result of the strong interactions between the solvent and the polymer processing is difficult. When butanediamine is replaced by butanediol in the chain extension step, a processible polyurethane is obtained but the polymer lacks the desired mechanical properties for biomedical applications. By chain extending with a longer urethane diol block, a processible polymer was obtained with mechanical properties comparable to the polyurethane urea. This polyurethane has been made porous and can be used as a meniscal prosthesis.
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    URL: http://dx.doi.org/10.1007/s002890050343
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  • 15
    Electronic Resource
    Electronic Resource
    Inversion of stereoselectivity in 1,3-butadiene polymerization with a niobium catalyst induced by a change in the solvent system (1998)
    Springer
    Polymer bulletin 41 (1998), S. 175-182 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Catalytic 1,3-butadiene polymerization systems can be obtained with the new complex [NbO(C16H11O6 −)(C2O4 2−)] as a catalyst. When the catalysis occurs in a homogeneous medium (toluene as a solvent) in conjunction with AlEt2Cl, cis-1,4-polybutadiene is obtained. A remarkable inversion of stereoselectivity has been observed when the catalysis is carried out in a two phase system with the molten salt AlCl3.1-methyl-3-n-butyl-imidazolium chloride (MBIC) as a solvent and AlEt2Cl as a cocatalyst, giving the trans 1,4-polybutadiene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050349
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  • 16
    Electronic Resource
    Electronic Resource
    Use of branched aliphatic linkers for the preparation of selective chiral media for the HPLC separation of enantiomers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 183-189 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Highly branched aliphatic molecules have been used for the first time as tethers in the preparation of polymeric chiral stationary phases. Attachment of a specifically designed chiral selector to organic porous polymer beads through a branched linker substantially increases the enantioselectivity compared to that of the equivalent separation medium with a traditional linear tether.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050350
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  • 17
    Electronic Resource
    Electronic Resource
    An EPR study of polysaccharide copper(II) complexes in composite dextran/epichlorohydrin gels (1998)
    Springer
    Polymer bulletin 41 (1998), S. 199-206 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The EPR spectra of composite dextran and carboxymethyldextran gels were studied in order to identify the functional groups involved in copper(II) complexation depending on pH. The porous structure resulting from crosslinking of polymer chains of dextran, via epichlorohydrin, forces the immobilization of Cu2+ ions surrounded by different oxygen groups of the polymer gel matrix. The different polynuclear structures are postulated to be formed depending on the type of polysaccharide derivatives. The results indicate that carboxyl and deprotonated hydroxyl groups participate in the complex formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050352
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  • 18
    Electronic Resource
    Electronic Resource
    Electronic absorption spectroscopy of liquid systems containing polystyrene and polyacrylonitrile 1. Individual polymer solutions (1998)
    Springer
    Polymer bulletin 41 (1998), S. 207-213 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Individual polystyrene (PS) and polyacrylonitrile (PAN) solutions in N,N-dimethylformamide (DMF) were studied by electronic absorption spectroscopy. Upon increasing the polymer concentration in the PS-DMF binary system a bathochromic shift of the band at about 260 nm was found. This spectral effect could be explained by an association of PS phenyl groups and/or by a complex formation between DMF and PS. The UV spectrum of PAN in DMF solution was interpreted in terms of the variety of possible donor-acceptor complex formations. The specific intermolecular interactions in the investigated binary liquid systems were discussed on the basis of the spectral data.
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    URL: http://dx.doi.org/10.1007/s002890050353
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  • 19
    Electronic Resource
    Electronic Resource
    Swelling behavior of emulsion polymer particles: comparison between fully cross-linked and partially cross-linked poly(acrylate) latexes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 231-237 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Measurement of swelling is used to estimate the extent of cross-linking of latex particles prepared by emulsion polymerization. In this paper we report swelling data as a function of solvent activity for two latexes: (1) a poly(butylacrylate) (PBA) latex, and (2) a poly(isodecylacrylate) latex. In the latter case comparison is made between the swelling behavior of fully cross-linked, i.e., networks without free polymer chains, and partially cross-linked latexes. It is demonstrated that the equilibrium swelling properties are only slightly affected by the presence of uncross-linked chains. Swelling gives reliable results for the cross-link density only if the latex does not contain free chains.
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    URL: http://dx.doi.org/10.1007/s002890050356
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  • 20
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    The strength of the tailored polymer/inclusion interface in polymer composites evaluated in situ by acoustic emission (1998)
    Springer
    Polymer bulletin 41 (1998), S. 247-252 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A correlation between interface strength and data of acoustic emission measurements in particle filled polymer composites was found. The method allows the evaluation of the interface strength in situ in polymer composite specimens at uniaxial loading. The measurements have shown that the tailored interface with the monomolecular tethered polymer layers of various grafting density change the mechanism of microdefect formation.
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    URL: http://dx.doi.org/10.1007/s002890050358
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  • 21
    Electronic Resource
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    The synthesis and thermal phase transition behavior of poly(N-isopropylacrylamide)-b-poly(ethylene oxide) (1998)
    Springer
    Polymer bulletin 40 (1998), S. 455-460 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary By using the redox reaction between Ce(IV) and terminal -CH2OH groups of polyethylene oxide(PEO), block copolymers composed of poly(N-isopropylacrylamide)(PNiPAAm) and poly(ethylene oxide) was prepared. The aqueous solution of the block copolymers exhibited thermal phase transition and the phase transition temperature of these block copolymers became higher than the PNiPAAm homopolymer.
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    URL: http://dx.doi.org/10.1007/s002890050276
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  • 22
    Electronic Resource
    Electronic Resource
    Side-chain liquid crystalline polyurethanes on the basis of biphenyl mesogenic units (1998)
    Springer
    Polymer bulletin 40 (1998), S. 469-476 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Liquid crystalline diols containing a biphenyl mesogenic core, methoxy or cyano terminal groups and spacers of various lengths were synthesized and used for the preparation of side-chain thermotropic polyurethanes. The structure of the synthesized diols and polymers was confirmed by elemental analysis, FTIR and NMR spectroscopy. Phase transition temperatures were studied by DSC, while optical textures were characterized by polarizing microscopy. A smectic type arrangement was found for the mesophases of all products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050278
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  • 23
    Electronic Resource
    Electronic Resource
    Polyurethane toughened polylactide (1998)
    Springer
    Polymer bulletin 40 (1998), S. 485-490 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Brittle polylactide (PLA) was toughened by introducing 5 wt % of a poly(ɛ-caprolactone)(PCL) diol- and triol-based polyurethane (PU) network. The extent of cross-linking of the PU was varied by changing the ratio between diol and triol. The effects of the PU content and its crosslink density on the mechanical properties and the toughness of PU/PLA blends were investigated. Maximum toughness of PU/PLA blends, an order of magnitute higher than that of pure PLA, could be achieved by the use of a proper amount of PU and a proper extent of cross-linking.
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    URL: http://dx.doi.org/10.1007/s002890050280
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  • 24
    Electronic Resource
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    Effects of cyclization and electrostatic interactions on the termination rate of macroradicals in free-radical crosslinking copolymerization (1998)
    Springer
    Polymer bulletin 40 (1998), S. 491-498 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Effects of cyclization and ionic group contents on the termination rate of macroradicals formed at zero monomer conversion were investigated. For this purpose, the pregel regime of free-radical methyl methacrylate / ethylene glycol dimethacrylate (MMA/EGDM) and acrylamide / N,N'-methylenebisacrylamide (AAm/BAAm) copolymerization systems was studied by means of the dilatometric technique. To eliminate the chain-length dependent variation of the termination rates, different sets of experiments were carried out each at a fixed monomer and initiator concentration. At low crosslinker contents, the termination rate of zero-conversion macroradicals was enhanced in crosslinking copolymerizations compared to linear polymerization. This is due to the cyclization reactions which reduce the size of the macroradical coils and thus, enhance the termination rates due to the lowering of the thermodynamic excluded volume effect. As the amount of the crosslinker increases, an enhancement in the initial rate of polymerization is observed in all series of experiments, indicating that steric effects on segmental diffusion dominate at high crosslinker contents. The results also indicate a slower rate of termination of ionic macroradicals compared to the non-ionic radicals of the same molecular weight and points the significance of the thermodynamic excluded volume effect on rising the ionic group content.
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    URL: http://dx.doi.org/10.1007/s002890050281
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    Thermal stabilities of end groups in hydroxyalkyl terminated polydimethylsiloxane oligomers (1998)
    Springer
    Polymer bulletin 40 (1998), S. 525-532 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Thermal stabilities of α,ω-hydroxypropyl, α,ω-hydroxybutyl, α,ω-2-hydroxypentyl and α,ω-hydroxyhexyl terminated polydimethylsiloxane (PDMS) oligomers were studied. Hydroxypropyl and hydroxybutyl terminated polydimethylsiloxane oligomers showed degradation upon heating, through the loss of functional end groups as determined by FT-IR spectroscopy and gel permeation chromatography. α,ω-Hydroxyhexyl and α,ω-2-hydroxypentyl terminated polydimethylsiloxane oligomers were stable under similar conditions. Instability of the end groups is due to the back biting of the terminal silicon in the PDMS by the primary hydroxyl oxygen, leading to the formation of 5 and 6 membered, stable, heterocylic compounds. Loss of end groups also resulted in a dramatic increase in the molecular weights of the oligomers produced, as determined by gel permeation chromatography.
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    URL: http://dx.doi.org/10.1007/s002890050286
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    Use of mass spectrometry for the analysis of molecular weight distribution and macrocycles in fuctionalized oligo-ɛ-caprolactones synthesized by heterogeneous AROP in protic conditions (1998)
    Springer
    Polymer bulletin 40 (1998), S. 541-548 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. Functionalized oligo-ɛ-caprolactones synthesized by heterogeneous coordinated anionic ring opening polymerization (AROP) in protic conditions have been analyzed by mass spectrometry in order to investigate the molecular weight distribution as well as the possible occurrence of macrocycles. Mass spectra obtained from LSIMS revealed the presence of fragmentation products and some of them have been identified. Macrocycles were also detected. Nevertheless, ESI and MALDI-TOF spectrometries do not confirm the presence of macrocycles in the samples. The same results have been obtained by analysis of commercially available polycaprolactones.
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    URL: http://dx.doi.org/10.1007/s002890050288
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    Apparent contrast reversal in tapping mode atomic force microscope images on films of polystyrene-b-polyisoprene-b-polystyrene (1998)
    Springer
    Polymer bulletin 40 (1998), S. 549-554 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Thin films of phase separated polystyrene-b-polyisoprene-b-polystyrene block copolymers were studied by tapping mode atomic force microscopy. The relative contrast in height and phase mode images of the phase separated regions was found to be very sensitive to changes in the operating conditions of the microscope. Contrast variations and reversals were observed for height and phase mode images as a function of the set-point amplitude ratio and drive frequency. No unique height or phase contrast was observed for the the tri-block copolymer system examined in this study.
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    URL: http://dx.doi.org/10.1007/s002890050289
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  • 28
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    Dielectric studies on allyl methacrylate-methyl methacrylate copolymers in a slightly polar medium (1998)
    Springer
    Polymer bulletin 40 (1998), S. 563-568 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Dielectric constants of allyl methacrylate-methyl methacrylate copolymers are measured in toluene solution at a constant frequency of 2 MHz, within a wide temperature range (20–70°C). Soluble copolymers have been prepared by group transfer copolymerization. Dipole moments are calculated from Guggenheim-Smith equation. The effects of allyl group on the dipole moments of copolymers in a slightly polar medium are discussed.
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    URL: http://dx.doi.org/10.1007/s002890050291
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  • 29
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    Influence of some aromatic amino acids on the swelling behavior of acrylamide/maleic acid hydrogel (1998)
    Springer
    Polymer bulletin 40 (1998), S. 575-581 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Influence of some aromatic amino acids (histidine, phenylalanine and tryptophan) on the swelling behavior of acrylamide/maleic acid hydrogel (AAm/MA) prepared by γ-radiation was investigated. Swelling tests of AAm/MA hydrogel were made in buffer solutions and amino acid solutions at various pH at 37°C. The pH values are ionization of α-carboxyl groups (pK'1), α-amino groups (pK'2) and, isoelectric points (pI) of amino acids. The swelling of AAm/MA hydrogel increased when pH values of solutions were increased. The value of equilibrium swelling of AAm/MA hydrogel was 1035% at pH 10 buffer, while it was 880% at pH 2 buffer. The values of equilibrium swelling of AAm/MA hydrogel in phenylalanine, tryptophan and histidine solutions varied among 1130–1245% at pH 10, while they were among 790–975% at pH 2. The rate constant of swelling, diffusional exponent, network parameter and, diffusion and intrinsic diffusion coefficient were calculated by swelling kinetics. Diffusion of the penetrants into the hydrogel was found to be non-Fickian character. The diffusion coefficients of the hydrogel varied between 3.33×10−6– 7.71×10−6 cm 2s−1, while the intrinsic diffusion coefficients waried between 4.03×10−6– 8.48×10−6 cm 2s−1.
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    URL: http://dx.doi.org/10.1007/s002890050293
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    Study of rubber-modified epoxy resin using thermally stimulated current (1998)
    Springer
    Polymer bulletin 40 (1998), S. 599-605 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In order to characterize the low temperature relaxation of epoxy resin modified with amine-terminated butadiene acrylonitrile copolymers (ATBN), thermally stimulated current (TSC) and relaxation map analysis (RMA) were investigated. Four relaxation peaks at around −140, −100, −60 and 0°C were observed as the indication of γ-, β-relaxation of epoxy resin, Tg, new unknown peak of ATBN, respectively. The unknown peak at around 0°C was observed due to dipole orientation. The RMA data was showed that compensation temperature (Tc) and degree-of-disorder (DOD) were increased with increasing the content of acrylonitrile and ATBN, whereas the compensation time (τc) was decreased. It can be concluded that the cooperative molecular motion in cured epoxy resin was more active as the concentration of acrylonitrile and ATBN content increases.
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    URL: http://dx.doi.org/10.1007/s002890050296
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  • 31
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    Conducting copolymers of polypyrrole/polytetrahydrofuran (1998)
    Springer
    Polymer bulletin 40 (1998), S. 639-645 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Bifunctional living polytetrahydrofuran (PTHF) was terminated with potassium salt of pyrrole to yield polymers with electrochemically active end groups. These polymers were employed in the second stage to obtain conducting polypyrrole/polytetrahydrofuran block copolymers with short and long polytetrahydrofuran segments by potentiostatic anodic polymerization of pyrrole in different electrolytic media. Syntheses of block copolymers were achieved in media where tetrabutylammonium fluoroborate, sodium perchlorate and sodium p-toluenesulfonate were used as the supporting electrolytes. Characterizations were based on DSC, TGA, SEM, FTIR, and CV analyses. No significant effect of the chain length of polytetrahydrofuran segments on the properties of the copolymers was observed; however, thermal, electrochemical behaviors, and surface morphologies of the films were greatly affected by the supporting electrolytes.
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  • 32
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    Effect of the molecular structure of graft copolymer on the interfacial behavior between two immiscible homopolymers: A Monte Carlo simulation (1998)
    Springer
    Polymer bulletin 40 (1998), S. 607-612 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effects of molecular structure of graft copolymer on the interfacial properties are investigated using a Monte Carlo simulation. The interfacial activity is analyzed by calculating the surface coverage and the concentration profile of graft copolymer at the interface. At low interaction energy between two segments, the graft copolymer having fewer grafting sites and longer grafting chains locates better at the interface than the graft copolymer having more grafting sites and shorter grafting chain. At high interaction energy, this situation is reversed: the graft copolymer with more grafting sites locates better than the copolymer with fewer grafting sites.
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    URL: http://dx.doi.org/10.1007/s002890050297
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  • 33
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    Vinyltrimethylsilane-co-N-vinyl-2-pyrrolidone and vinyltrimethoxysilane-co-N-vinyl-2-pyrrolidone copolymers Synthesis and reactivity ratios (1998)
    Springer
    Polymer bulletin 40 (1998), S. 707-713 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers containing vinyltrimethylsilane and vinyltrimethoxysilane with N-vinyl-2-pyrrolidone at different compositions were synthesized and characterized. The reactivity ratios was estimated by using the classical Fineman-Ross and Kelen Tüdos linear fitting procedures. These parameters were also estimated through a computer program based on nonlinear minimization algorithm, starting from the r1 and r2 values obtained by the former procedures. The analysis of the results allow us to interpret the reactivity behaviour of these polymers in terms of the relative reactivity of the substiuents. The effect of the chemical structure of the polymer side group is discussed in terms of the different contributions to the stabilization of the radical intermediates.
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    URL: http://dx.doi.org/10.1007/s002890050312
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  • 34
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    Highly Pb(II)-selective resin based on crosslinked poly(acrylamido glycolic acid) copolymer (1998)
    Springer
    Polymer bulletin 40 (1998), S. 721-728 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY The crosslinked poly(acrylamido glycolic acid) (180-250 µm) was used in the adsorption/desorption studies. Adsorption rate, capacity of the resin for the selected metal ions, i.e. Cd(III), Zn(II), Hg(II), Pb(II), and Cr(III) were investigated in aqueous media. At different pH values (1.0–5.0) very high adsorption was observed for Pb(II) at pH 3 and 5. The adsorption equilibrium was rapidly achieved in about 5–10 min. However, when the Pb(II) ions competed with Cd(II) (in the case of the adsorption from their binary mixture) the amount of adsorption for Pb(II) decreased. Desorption of Pb(II) was studied by using 1-4M HNO3 and 1-4M HClO4. High desorption ratios (more than 90%) were achieved in all cases. Adsorption/desorption cycles showed the possibility of repeated use of this resin.
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    URL: http://dx.doi.org/10.1007/s002890050314
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  • 35
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    Synthesis of nanosize poly(methyl methacrylate) microlatexes with high polymer content by a modified microemulsion polymerization (1998)
    Springer
    Polymer bulletin 40 (1998), S. 749-756 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Nanosize poly(methyl methacrylate) (PMMA) microlatexes with high PMMA/surfactant ratio have been successfully prepared by a modified microemulsion polymerization, i.e., continuous and slow addition of monomer (MMA) to the polymerizing MMA microemulsion with mild stirring. Number-average diameters of 33–46 nm with narrow polydispersity (Dv/Dn= 1.1) and polymer content of 6–24 wt% were achieved using low levels of surfactant (dodecyltrimethylammonium bromide, DTAB) — less than 1 wt% of the reaction mixture. Particle diameter depended on polymerization temperature, MMA content, and concentrations of initiator and surfactant. Larger particles wereformed when temperature was too high, initiator concentration was too high, or surfactant concentration was too low.
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    URL: http://dx.doi.org/10.1007/s002890050318
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    Rheological characteristics of aqueous solutions of mixtures of chitosan and polyoxyethylene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 115-121 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The rheological characteristics of aqueous solutions of chitosan and polyoxyethylene (POE) with molecular weight in the range of 105–106, as well as of their mixtures are described. It is found that the solutions of each polymer as well as of their mixtures exhibit pseudoplastic non-Newtonian behaviour which is described by the Ostwald-de-Waele model. It is proposed that the chitosan macromolecules determine the rheological behavior of the chitosan/POE mixtures.
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    URL: http://dx.doi.org/10.1007/s002890050340
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    Estimation of the effective conjugation length of oligo-p-phenylenes from specific refractive index increments of solutions (1998)
    Springer
    Polymer bulletin 41 (1998), S. 123-128 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary An unusually strong molecular weight dependence of the specific refractive index increment which has been reported for solutions of oligomers (M 〈 103) of p-2-methyl phenylene is attributed to the exaltation of polarizability of phenylene units. The saturation length is estimated to be l s≅ 6 phenylene units.
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  • 38
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    New imide-copolymers with coronand structure (1998)
    Springer
    Polymer bulletin 41 (1998), S. 153-160 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY The Diels-Alder reaction of bis-(2-pyrone) 2 with various aliphatic and aromatic bismaleimides 1 in dilute solution was carried out to produce linear soluble copolymers with a coronand structure. NMR spectra and model reactions confirm the structure 4 (3). The polymers show weight losses at about 440°C determined by thermogravimetric analysis (Tab. 1).
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  • 39
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    A novel side chain liquid crystalline polyurethane (1998)
    Springer
    Polymer bulletin 41 (1998), S. 139-144 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Side chain liquid crystalline polyurethanes (SCLP) without flexible spacer were synthesized by a two step block copolymerization reaction. The polyurethanes were based on azobenzene-type mesogenic diol chain extender (DR-19), a poly(tetramethylene oxide) (PTMO) soft segment, and different diisocyanates, including 4,4-diphenylmethane diisocyanate (MDI) and hexamethylene diisocyanate (HDI). The polyurethane samples obtained from DR-19 or DR-19 and PTMO with HDI had mesomorphic phases as determined by DSC and polarizing microscopy.
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    URL: http://dx.doi.org/10.1007/s002890050344
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  • 40
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    Grafting phosphonated thiol on hydroxy telechelic polybutadiene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 145-151 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary An hydroxytelechelic polybutadiene (PBHT) of 1200 molecular weight has been modified by the phosphonated thiol HS-(CH2)3-PO(OC2H5)2 (I). The thiol (I) was prepared in three steps: phosphonation of allyl bromide, addition of thioacetic acid and hydrolysis. The grafting rate of (I) on PBHT has been calculated by sulfur analysis and by 1H NMR. The results confirmed that the 1,2 double bonds are 10 times more reactive than the 1,4. The method led to new macromolecular polyols containing between 3 and 5 % in weight of phosphorous. These new long polyols should be very interesting in order to prepare fire retardant polyurethane networks.
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  • 41
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    Preparation and properties of poly(methyl methacrylate) crosslinked with multimonomers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 161-166 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Multimonomers, such as poly(2-acryloyloxyethyl methacrylate) and poly(2-methacryloyloxyethyl methacrylate) were used as new macrocrosslinkers to crosslink poly(methyl methacrylate). The influence of the kind of macrocrosslinker, its molecular weight and amount on the crosslink density and some properties of the crosslinked polymers networks, such as swelling and mechanical properties (tensile strength and elongation at break) have been examined. The results obtained were compared with those for poly(methyl methacrylate) crosslinked with conventional crosslinker 1,4-butanediol dimethacrylate.
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    Synthesis and characterization of novel octa-arm star-block thermoplastic elastomers consisting of poly (p-chlorostyrene-b-isobutylene) arms radiating from a calix[8]arene core (1998)
    Springer
    Polymer bulletin 41 (1998), S. 167-174 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis and characterization of novel octa-arm star-blocks consisting of poly(p-chlorostyrene-b-isobutylene) (PpClSt-b-PIB) arms radiating from a calix[8]arene (C8) core are described. The synthesis was accomplished by living isobutylene (IB) polymerization induced by a novel octafunctional calix[8]arene derived initiator 1, followed by addition and living polymerization of p-chlorostyrene (pClSt). This sequential block copolymerization method allowed for precise molecular weight control of both polymeric blocks and thus gave rise to star-block thermoplastic elastomers (TPE) with an outstanding combination of mechanical and thermal properties, i.e., high tensile strengths (22 – 27 MPa) and elongations (∼500 %). Differential scanning calorimetry (DSC) indicated microphase separation into glassy PpClSt (Tg= 129°C) and rubbery PIB (Tg=−66°C) domains, and transmission electron microscopy (TEM) indicated that the PpClSt domains are dispersed in the PIB matrix.
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    Characterization of PET/LLDPE blends compatibilized with DEM-grafted-polyethylene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 191-198 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Polyethylene terephtalate (PET)/linear low density polyethylene (LLDPE) blend compatibilized with diethylmaleate grafted polyethylene (DEM-g-LLDPE) were characterized by FTIR spectroscopy, thermogravimetrical analysis (TGA) and scanning electron microscopy (SEM). FTIR and TGA results indicate that there are interactions between the components of the blends, which produced variations in the infrared bands associated with the conformational changes (from gauche to trans) within the glycolic sequences of the polyester and a sinergistic effect on the thermal-oxidative stability of the compatibilized blends. Morphological analysis showed a dispersed particle size reduction and a better adhesion between the matrix and the disperse phase.
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    Viscometric detection of polymer inclusion complexes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 215-221 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The reduced viscosity of poly(ethylene glycol) (PEG) is increased in solutions of (2-hydroxypropyl)-α-cyclodextrin (HPACD) significantly more than in the solution of (2-hydroxypropyl)-β-cyclodextrin (HPBCD) in agreement with the fact that a crystalline complex of PEG is formed in solutions of natural α-cyclodextrin but not in solutions of natural β-cyclodextrin. In analogy with that, the viscometry indicates formation of a complex between HPBCD with poly(vinyl alcohol) because the reduced viscosity is markedly increased in solutions of HPBCD but only slightly in solutions of HPACD. On the other hand, the increase in the viscosity of poly(N-vinylpyrrolidone) (PVP) was identical in HPACD and HPBCD solutions; therefore, the viscometry did not provide support for the suggested side-chain complexation between PVP and cyclodextrins.
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  • 45
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    Unperturbed molecular dimensions and the theta temperature of dextran in dimethylsulfoxide (DMSO) solutions (1998)
    Springer
    Polymer bulletin 41 (1998), S. 223-230 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The unperturbed molecular dimensions of dextran samples have been determined in dimethylsulfoxide (DMSO) solutions from intrinsic viscosity measurements at different temperatures. The unperturbed dimension parameter, Ko, has been calculated from extrapolation methods.The unperturbed root-mean-square end-to-end distance, 〈r2〉o 1/2, found for the polymer samples in DMSO solutions, indicate that the polymer coils are contracted. This distance varies from 3.25 × 10−7 cm to 2.94 × 10−7 cm for the sample T 40 and from 8.28 × 10−7 cm to 7.48 × 10−7 cm for the sample T 500, in the chosen solvent as the temperature is raised from 25°C to 45°C. In the system of dextran/DMSO, the long-range interaction parameter, B, was also determined and a significant decrease is observed between 25°–45°C. The theta temperatures, Θ, were obtained as Θ= 327.25 K, Θ= 327.41 K and Θ= 323.38 K from the temperature dependence of the interaction parameter in Kurata-Stockmayer-Fixman, Berry and Inagaki-Suzuki-Kurata equations, respectively.
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    Transcrystallization in syndiotactic polypropylene induced by high-modulus carbon fibers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 239-245 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY It was first shown that transcrystallization can be induced in syndiotactic polypropylene (sPP) when a carbon fiber (CF) of high-modulus (HM) is embedded in the melt of sPP crystallizing under quiescent conditions. High-tenacity carbon fiber (HTCF), on the other hand, did not cause transcrystalline growth. Coating of HMCF by silicon carbide (SiC) stopped the transcrystallization of sPP. The difference in the morphology of the transcrystalline layer between isotactic PP (iPP) and sPP was revealed by phase contrast light (PCLM), scanning electron (SEM) and atomic force microscopy (AFM) taken from the etched surface of single fiber microcomposite specimens.
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    Silica concentration dependence of the kinetics of polydimethylsiloxane adsorption on aggregates (1998)
    Springer
    Polymer bulletin 41 (1998), S. 253-260 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The kinetics of adsorption of pure polydimethylsiloxane or of bimodal mixtures, onto silica aggregates, was observed from the melt as a function both of polymer weight fraction (2.5 to 20 g/g) and of the specific area (50, 150 and 300 m2/g). Attention was focused on filled polymers wherein silica aggregates are connected to one another by adsorbed chains to form a network. Results were analysed according to a molecular approach. All observed kinetics curves were found to obey a property of superposition by using a suitable reduced time variable defined as : ; is the number average molecular weight and Qi is the initial amount of polymer per unit mass of silica. The rate of adsorption is proportional to 1/Qi.
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    Synthesis of deuterobutadiene-butadiene AB2 and AB3 miktoarm star copolymers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 283-289 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis of well-defined, monodisperse AB2 and AB3 miktoarm star copolymers, in which A is polydeuterobutadiene and B is polybutadiene, is described. The synthetic procedure involved reacting living polydeuterobutadiene with a large excess of either methyltrichlorosilane or tetrachlorosilane to yield a ‘one-arm star’. SEC traces of this ‘one-arm star’ are indistinguishable from that of the uncoupled polydeuterobutadiene indicating no further coupling to form multi-arm stars occurs. Unreacted chlorosilane was removed by distillation and the introduction of an excess of living polybutadiene generates the star. The star polymer was isolated from the precursor polybutadiene by fractionation.
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    Synthesis and properties of thermotropic compounds with two terminal mesogenic units and a central spacer Homologous series of polymethylene -α, ω-bis[4-(4'-n-hexyloxybenzoyloxy)benzoate] (1998)
    Springer
    Polymer bulletin 41 (1998), S. 267-274 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY A new series of aromatic esters with two terminal mesogenic units and a central spacer 1 together with the free rodlike mesogenic ester unit 2,was synthesized and studied. The mesogenic properties of these compounds were investigated by differential scanning calorimetry, polarizing microscopy and X-ray diffraction.
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    Polymerization of propynes bearing diphenylamino or indolyl groups (1998)
    Springer
    Polymer bulletin 41 (1998), S. 395-399 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Nitrogen-containing acetylenic monomers including 3-(N,N-diphenylamino)-1-propyne (DPAP), N-(2-propynyl)indole (PI), 2-methyl-N-(2-propynyl)indole (2-MePI) and 3-methyl-N-(2-propynyl)indole (3-MePI) polymerized in the presence of various transition metal catalysts. Poly(DPAP) was obtained with WCl6, MoCl5, Rh and Fe catalysts, and its weight-average molecular weights (M w) reached 140x103. Polymerization of PI and 2-MePI by Rh and Fe catalysts gave good yields of high molecular weight polymers with M w of 340x103 and 640x103, respectively. Polymerization of 3-MePI by WCl6- and MoCl5-based catalysts resulted in a soluble polymer (Mw= 52x103), whereas the use of Rh and Fe catalysts led to the formation of an insoluble polymer. All the polymers exhibited cutoff wavelengths around 450–500 nm, meaning the moderate to fair conjugation along the polymer backbones.
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    Synthesis and characterization of addition-type polyimides functionalized with diamine chromophore (1998)
    Springer
    Polymer bulletin 41 (1998), S. 401-408 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The Bismaleimide-Diamine Chromophore (2) prepolymers were prepared in acetone. The structure of the prepolymer was characterized. The prepolymer exhibited excellent film-forming quality and good solubility in low boiling point solvent. Thermal and NLO properties of the cured polyimides were evaluated. The chromophore content strongly influenced the thermal properties and order parameter Φ.
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    Effect of polymer blending on the electrical conductivity of polypyrrole/copolyester composite films (1998)
    Springer
    Polymer bulletin 41 (1998), S. 713-719 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effect of polymer blending on the electrical conductivity of polypyrrole/copolyester composite film was investigated. Copolyesters containing sodium sulfonate group with various main chain structures were synthesized and blended with PET. The average anionic group contents in the blend samples were controlled to be 3.5 and 6.1 mol%. The polypyrrole composite films were prepared by polymerization of pyrrole through vapor phase absorption onto the copolyester-PET blend films which contained FeCl3. The conductivity of the blend samples containing 3.5 mol% of DMS was greater than that of the copolyester of the same DMS content when the pyrrole vapor exposure time was longer than 30 min. The blends of 6.1 mol% of DMS showed higher conductivity than the copolyesters of the same DMS amount even when the exposure time was short. The high electrical conductivity of the blend samples was thought to be due to the phase separation between PET and copolyesters in amorphous region.
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    Polycarbonate/acrylonitrile-butadiene-styrene blends: miscibility and interfacial adhesion (1998)
    Springer
    Polymer bulletin 41 (1998), S. 721-728 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary By DSC measurements it has been determined that blends of Polycarbonate (PC) and a ABS “core-shell” terpolymer with 24 %-wt of Acrylonitrile and 6 %-wt of Butadiene seems to show limited miscibility due to the partitioning of the oligomers contained on each raw material. Like in other PC blends systems, the composition of the conjugated interphase is not constant but depends on the ratio of components in the blend. In all the compositions studied the apparent solubility of ABS (actually the SAN phase) in the PC-rich phase increase with decreasing volume fraction of PC in blends reaching a maximum at 10 %-wt of ABS. Yield Stress of the blends follows the rule of mixture almost until 10 %-wt of ABS, indicating that interfacial adhesion is strong enough to ensure stress transfer between phases in the course of yielding and drawing. Applying the Puckánszky et al. model, it was observed that over 15 % wt of ABS, the effectiveness in stress transfer depends on the morphologic gradient generated during the mixing and specimens' moulding.
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    (CH3)3SiBr/AlCl3 induced cationic polymerization of 1,3-pentadiene (1998)
    Springer
    Polymer bulletin 40 (1998), S. 21-26 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Cationic polymerizations of 1,3-pentadiene (PD) with AlCl3 in n-hexane were carried out in the absence and presence of trimethylsilyl bromide (Me3SiBr or TMSBr). Structural evidence and proton trap experiment demonstrate that in the TMSBr/AlCl3 induced polymerization the real initiating system is the combination of AlCl3 with HBr resulting from hydrolysis of TMSBr by adventitious water existing in the system. The conversion of the polymerization is greatly increased by adding TMSBr, but the introduction of TMSBr does not exert an effect on the formation of gel (crosslinked product). The molecular weight of the polymer prepared by TMSBr/AlCl3 system shows a maximum in the range of [TMSBr]/[AlCl3] = 1, and excessive TMSBr gives rise to a drop of the polymer molecular weight. Kinetic data show that AlCl3 and TMSBr/AlCl3 induced polymerizations have the comparable polymerization rates.
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    Photolytic generation of an o-quinodimethane derivative and its reactions with unsaturated polymers (1998)
    Springer
    Polymer bulletin 40 (1998), S. 9-13 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Polybutadiene was treated with o-tolualdehyde under UV irradiation to produce random copolymers through Diels-Alder reactions on the backbone double bonds. The physical properties of the polymer products change as more of the aldehyde attaches to it. The copolymers were characterized by NMR spectroscopy. A bifunctional o-tolualdehyde was synthesized and used as a crosslinking agent.
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    Preparation and properties of hyperbranched poly[1-β-(4′-acetylphenyl)vinyl-3-vinyl-1,1,3,3-tetramethyldisiloxane] (1998)
    Springer
    Polymer bulletin 40 (1998), S. 15-20 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Treatment of 1-β-(4′-acetylphenyl)vinyl-3-vinyl-1,1,3,3-tetramethyldisiloxane (I) (an AB2 monomer) with dihydridocarbonyltris(triphenylphosphine)ruthenium (Ru) leads to a hyperbranched material, poly[1-β-(4′-acetylphenyl)vinyl-3-vinyl-1,1,3,3-tetramethyldisiloxane] (II). I has been prepared by a Pd catalyzed Heck reaction between 4-bromo-acetophenone and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane. The structure of the soluble hyperbranched material (II) has been determined by 1H, 13C and 29Si NMR, as well as by IR and UV spectroscopy. It has also been characterized by GPC, TGA, DSC and elemental analysis. Polymerization occurs by Ru catalyzed addition of the aromatic C−H bonds which are ortho to the activating acetyl group of I across the C−C double bond of the terminal Si-vinyl group in an anti-Markovnikov manner.
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    Preparation and crystallization behavior of UHMWPE/LLDPE composites (1998)
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    Polymer bulletin 40 (1998), S. 95-102 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. UHMWPE fiber reinforced LLDPE composites were prepared to develop the impact resistant materials. The crystallization kinetics of LLDPE with UHMWPE fiber was investigated to understand the interfacial adhesion and composite performance. The crystallization behavior of LLDPE depends on the crystallization temperature and existence of UHMWPE fiber. LLDPE matrix crystallization was affected by the inclusion of UHMWPE fiber via preceded transcrystallization on the fiber surface. The interfacial adhesion of composites was changed by cooling rate control with different crystallization behavior.
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    Mid-IR real-time monitoring of the carbocationic polymerization of isobutylene and styrene (1998)
    Springer
    Polymer bulletin 40 (1998), S. 55-61 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The in-situ monitoring of the living carbocationic polymerization of isobutylene (IB) and styrene (St) with a fiber optic Attenuated Total Reflection (ATR) probe in the mid-IR "fingerprint" range is reported here for the first time. Monomer consumption was followed by the disappearance of the C=C stretching for both IB and St, and the C−H bending of the CH3-group in IB. The formation of polyisobutylene (PIB) was also monitored by tracing the asymmetrical doublet characteristic of C−H bending of the t-butyl groups of the PIB. Conversion measurements by conventional off-line gravimetry correlated well with the new technique.
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    Alternating copolymers based on 1-methylpyrrole and thiophene – synthesis and electrochemical studies (1998)
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    Polymer bulletin 40 (1998), S. 167-172 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The synthesis and electrochemical polymerisation behaviour of a series of monomers containing 1-methylpyrrole and thiophene is reported. These monomers provide copolymers of well defined monomer sequence in the backbone.
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    Synthesis and characterization of ABA-triblock copolymers with poly(ethylene glycol) segments and LC-segments (1998)
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    Polymer bulletin 40 (1998), S. 159-166 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. This paper describes the synthesis of ABA-triblock copolymers with poly(ethylene glycol) A-blocks and a liquid crystalline polyester B-block. Three block copolymer series are presented with different block length of A- and B-blocks. The block copolymers show thermotropic liquid crystalline behavior up to a content of poly(ethylene glycol) segments of 50 wt%. Depending on their composition and chain length, the block copolymers are microphase separated or non-microphase separated. In the microphase separated block copolymers the poly(ethylene glycol) segments are able to crystallize. The degree of crystallinity and the spherulite diameter is strongly influenced by the length of the poly(ethylene glycol) segment itself as well as by the length of the incorporated polyester segment.
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    Synthesis and characterization of amphiphilic networks obtained by copolymerization of poly(ethylene oxide) macromonomers with methylmethacrylate (1998)
    Springer
    Polymer bulletin 40 (1998), S. 181-188 
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    ISSN: 1436-2449
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hydrogels whose elastic chains are constituted of hydrophilic Poly(ethylene oxide) (PEO) segments were obtained through free radical homopolymerization with methylmethacrylate (MMA) of α,ω-methacryloyloxy PEO macromonomers. This reaction can be conducted in water solution or in organic solvent. These networks were investigated as gels swollen to equilibrium in THF or in water. The influence of the preparation solvent on the properties of these networks was studied. The mechanical properties of the networks obtained in water are better than those of networks obtained under exactly the same conditions in organic solvents. This result can be explained by the preferential formation in water of micellar structures containing a higher concentration of polymerizable units. The influence of the concentration of the hydrophobic comonomer on the properties of these PEO networks was also examined.
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    Polystyrene–poly(ethylene oxide) diblock copolymers micelles in water (1998)
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    Polymer bulletin 40 (1998), S. 203-210 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Micellization in water of polystyrene–poly(ethylene oxide) diblock copolymers is achieved by the stepwise dialysis technique in order to prepare micellar solutions for copolymers with a wide range of molecular parameters. Hydrodynamic radii, determined by quasielastic light scattering, are correlated with the molecular parameters, e.g. molecular weight and composition, and compared with the theory. Two couples of phenanthrene and anthracene labelled copolymers are used to prepare micellar solutions by mixing them before and after dialysis. The non radiative energy transfer is determined on these solutions to prove that polystyrene-poly(ethylene oxide) diblock copolymers micelles in water are "frozen" micelles even when heated near the Tg of polystyrene.
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    Micellar morphology of a semifluorinated diblock copolymer (1998)
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    Polymer bulletin 40 (1998), S. 211-217 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The diblock copolymer of methyl methacrylate and 1H,1H,2H,2H-perfluorooctyl methacrylate was shown to form micelles which could be deposited and imaged on a flat substrate upon casting from a solvent which is selective for the PMMA block, e.g. toluene and THF. The micelle formation was significantly affected by a small content of PMMA homopolymer. While the pure blockcopolymer formed cylindrical micelles, the presence of the PMMA shifted the associated equilibrium to the side of spherical aggregates.
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    Relaxation patterns of endlinking polydimethylsiloxane near the gel point (1998)
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    Polymer bulletin 40 (1998), S. 267-274 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. While the rheological behavior at the gel point (GP) itself is well known, many questions remain about the approach to the gel point (from either side). For studying this phenomenon, rheological experiments were performed on crosslinked polydimethylsiloxanes (PDMS) and characteristic patterns in the relaxation behavior were abstracted into a phenomenological model for the relaxation time spectrum. The well known power law with slope-n and cutoff at the longest relaxation time λ max governs the relaxation near the gel point. Beyond the gel point, an additional box-like contribution appears in the spectrum. The relaxation exponent n decreases with increasing extent of crosslinking. The longest relaxation time λ max and equilibrium modulus Ge show power-law scaling with the distance from the gel point, |p − pc|. For samples with imbalanced stoichiometric ratios r ≥ 1, the function n (p − pc) is independent of r. Samples with strong crosslinker deficiency (r = 0.5) exhibit a different functional form for n (p − pc) from those with r ≥ 1. The power law relaxation with decreasing n in the terminal zone was found previously for a different crosslinking system. It seems to be a common pattern for partially crosslinked materials from polymeric precursors.
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    Mechanical behavior at low strain of microgel containing elastomers (1998)
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    Polymer bulletin 40 (1998), S. 283-290 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Synthetic routes for the preparation of microgels with defined particle size, crosslinking density and surface chemistry are described. The mechanical effects caused by incorporating such systems in crosslinked rubber (NR and SBR) are described. The mechanical effects are qualitatively related to the state of clustering which is governed by the particle size and the interfacial tension (δ-parameter difference). The reinforcing effects on Young's modulus and the dynamic shear modulus are explained against a comprehensive theoretical background which assumes kinetically controlled cluster-cluster aggregation (CCA) of colloidal filler particles dispersed in entangled polymers. This leads to a control of rubber material properties by chemical means.
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    Solid state carbon-13 NMR studies of silica-filled TBBS-accelerated, sulfur vulcanized, cis-1,4 polyisoprene (1998)
    Springer
    Polymer bulletin 40 (1998), S. 275-282 
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    Notes: Abstract. The network formation of silica-filled, TBBS accelerated sulfur vulcanization of cis-1,4 polyisoprene (Natsyn 2200) was studied by solid state 13C NMR spectroscopy, and equilibrium swelling measurements. Samples with varying silica levels at different stages of cure were analyzed. It was observed that silica retards the cure reaction, and results in an overall lower cure state. Silica also has an influence on the vulcanization chemistry causing an enhancement of the cis-trans isomerization, chain scission, and the formation of monosulfidic linkages. It was also determined that the polysulfidic linkages decreased as silica level was increased. Intermolecular crosslinks decreased, while intramolecular structures (including pendant side groups and cyclic sulfur structures) increased. Cross link density, as determined by swelling measurements, decreased as the silica level was increased.
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    Capillary waves on a poly(vinylacetate) surface studied by off-specular diffuse X-ray scattering (1998)
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    Polymer bulletin 40 (1998), S. 291-296 
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    Notes: Abstract. The waves excited in thermal equilibrium on the surface of a liquid show up in X-ray scattering experiments in a diffuse component with center at the specular beam. They can be studied with the aid of a Kratky-camera carrying out rocking-scans. Results obtained for poly(vinylacetate) agree with the theoretical prediction. Evaluation of the data yields the surface tension.
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    Analysis of the reorganization of poly(ethylen terephthalate) in the melting range by temperature-modulated calorimetry (1998)
    Springer
    Polymer bulletin 40 (1998), S. 297-303 
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    Notes: Abstract. Although melting of flexible macromolecules in an irreversible process, it was demonstrated recently with temperature-modulated calorimetry (TMC) that some of the overall melting may be reversible within a fraction of a kelvin. This was taken as evidence for incompletely melted molecules with a remaining molecular nucleus. The reversing heat capacity that characterizes this effect was observed to decrease with time. It is shown by new TMC experiments that this time effect is not induced by the temperature modulation, but is due to an inherent annealing process. It is also proven that it is not dependent on the type of calorimeter.
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    Temperature-dependent fracture mechanisms in gel-spun hot-drawn ultra-high molecular weight polyethylene fibres (1998)
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    Polymer bulletin 40 (1998), S. 305-311 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Tensile testing of gel-spun hot-drawn ultra-high molecular weight polyethylene (UHMWPE) fibres reveal a ductile-brittle transition temperature. Ductile fracture above the transition temperature is believed to be initiated by a stress-induced orthorhombic-hexagonal phase transition, whereas at lower temperatures brittle fracture occurs in the orthorhombic phase. SEM micrographs of the fracture surfaces of UHMWPE fibres fractured below the transition temperature show fibrillar fracture and cannot be distinguished from fibres fractured in a ductile way above the transition temperature.
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    Considerations concerning the glass temperature of blends of miscible polymers (1998)
    Springer
    Polymer bulletin 40 (1998), S. 321-328 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. It is shown that experimental Tg vs. composition data of miscible polymer blends can be adapted by a third order Tg vs. composition equation characterized by two parameters, K1 and K2, which result in the supposition that besides the thermodynamically claimed favourable energetic hetero-interaction, contributions of conformational mixing entropy are responsible for miscibility. K1 comprises mainly energetic interaction effects, whereas K2 is due to effects of the conformational mixing entropy. It further results surprisingly that K1 is roughly correlated with the difference of the solubility parameters of the blend components. At the moment no explanation can be offered for this observation.
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    URL: http://dx.doi.org/10.1007/s002890050258
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    Vapor induced crystallization of syndiotactic random copolymers of styrene with p-n-butylstyrene (1998)
    Springer
    Polymer bulletin 40 (1998), S. 313-319 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. The vapor induced modification of bulk samples of syndiotactic random copolymers of styrene and p-n-butylstyrene is studied by wide-angle X-ray scattering and light microscopy. Two samples with p-n-butylstyrene contents of 4 and 11 mol% are compared. It is shown that treatment with CHCl3 leads to the formation of a clathrate modification similar to that of neat syndiotactic polystyrene. The change of the surface topography of the copolymers as a result of CHCl3 vapor exposition is studied by tapping-mode/height-mode atomic force microscopy.
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    URL: http://dx.doi.org/10.1007/s002890050257
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    Applying lattice-hole theory to gas solubility in polymers (1998)
    Springer
    Polymer bulletin 40 (1998), S. 329-335 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A recent theory based on the Simha-Somcynsky theory is applied to the solubility of the 1,1,1,2-tetrafluoroethane vapor in polystyrene. The requisite chemical potentials of the vapor and of its condensate in contact with the polymer involve the equations of state (eos) of the 3 species and are evaluated by means of literature information. Good agreement with experiment ensues at 120 °C and pressures up to 35 bar. At 90 °C systematic differences, increasing with pressure, result above 10 bar. These may be caused by the use of melt theory in the glass transition region and/or an inadequacy of the eos of the vapor at lower temperatures and elevated pressures. Extensions to further pairs, gaseous mixtures and the glassy state are indicated.
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    URL: http://dx.doi.org/10.1007/s002890050259
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    Solubility parameters of ethene/1-octene random copolymers (1998)
    Springer
    Polymer bulletin 40 (1998), S. 337-344 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Random copolymers of ethene with 1-octene were investigated by means of pressure-volume-temperature (PVT) measurements. Solubility parameters were calculated from the thermal expansion coefficients and isothermal compressibilities. While expansion coefficients are virtually independent of 1-octene content, compressibilities decrease with increasing 1-octene incorporation. The solubility parameters varied between 17.3 and 15.2 MPa1/2 when 1-octene incorporation was varied between 2 and 100 wt%. In the framework of the solubility parameter concept copolymers containing less than 95 wt% 1-octene were shown to be immiscible with isotactic poly(propene).
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    URL: http://dx.doi.org/10.1007/s002890050260
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    Multifunctional naphthalene containing epoxy resins and their modification by hydrosilation for electronic application (1998)
    Springer
    Polymer bulletin 40 (1998), S. 623-630 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effect of various functionality (di-, tetra-, pentafunctionality) on mechanical, thermal and moisture absorption properties of naphthalene containing epoxy resins cured with diaminodiphenylmethane (DDS) is investigated. It was found that the glass transition temperature, retention of elastic modulus, thermal stability and moisture absorption increased as the epoxy functionality increased, however, an inverse effect on thermal expansion was observed. In order to toughen the naphthalene containing epoxy network, the epoxy resin was partially vinylized with 2-allylphenol, followed by hydrosilation using hydride terminated siloxane oligomer. SEM photographs of the modified epoxy networks exhibited a phase separation and the introduction of siloxane into the epoxy backbone has effectively reduced internal stress of the cured products.
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    URL: http://dx.doi.org/10.1007/s002890050300
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    Synthesis of poly(norbornene-g-ɛ-caprolactone) copolymers by sequential controlled ring opening polymerization (1998)
    Springer
    Polymer bulletin 40 (1998), S. 631-638 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Poly(norbornene-g-ɛ-caprolactone) copolymers have been prepared by the “grafting from” technique. Well controlled polynorbornene containing 5% acetate pendant groups has been firstly synthesized by ruthenium complex-mediated ring opening metathesis polymerization. The acetate groups have been derivatized into aluminum alkoxides by hydrolysis into alcohol followed by reaction of the alcohol with triethylaluminum. The two polymerization steps are under complete control, so that graft copolymers have been synthesized with a narrow molecular weight distribution and are free from any detectable traces of the parent homopolymers as stated by selective fractionation experiments. These original copolymers have been characterized by SEC, FTIR, 1H NMR, DSC, TGA.
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    URL: http://dx.doi.org/10.1007/s002890050301
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    Radical polymerization of (phenylethynyl)styrenes and characterization of poly(phenylethynyl)styrenes as a thermally curable material (1998)
    Springer
    Polymer bulletin 40 (1998), S. 651-658 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The radical polymerizations of 2-, 3-, and 4-(phenylethynyl)styrenes (1a–c) and the copolymerizations of 1a–c (M1) with styrene (M2) were carried out using AIBN as the initiator in toluene at 60°C. The number-average molecular weights (M ns) were extremely low for poly(2-phenylethynylstyrene) (2a) and poly[(phenylethynyl)styrene-co-styrene] (3a), and increased in the order of 2a, 3a 〈〈 2b, 3b 〈 2c, 3c. Monomer reactivity ratios were determined as r 1= 1.80 and r 2= 0.51 for 1a, r 1= 1.72 and r 2= 0.53 for 1b, and r 1= 3.17 and r 2= 0.24 for 1c. Polymers 2a–c and 3a–c underwent an exothermic reaction at elevated temperature to form organic solvent-insoluble polymers. Although the decomposition of 2a was observed from 200°C, 2b and 2c exhibited a high heat-resistance property in both nitrogen and air atmospheres, in particular, 2b showed no significant weight loss below 450°C.
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    URL: http://dx.doi.org/10.1007/s002890050304
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    Crosslinking reaction of glycidyl methacrylate copolymers containing oxime-urethane groups using photogenerated pendant amines (1998)
    Springer
    Polymer bulletin 40 (1998), S. 667-674 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers containing epoxy and oxime-urethane groups were prepared by copolymerization of glycidyl methacrylate (GMA) and benzophenone oxime allylurethane (BAU). The physical properties of these copolymers were characterized by GPC, NMR and DSC analyses. Photo-crosslinking reaction of the copolymers were studied by measuring the insoluble fraction of copolymer films under various reaction conditions. The degree of cross-linking reaction increased with irradiation time, heating temperature and the amount of BAU units in the copolymer. UV and IR absorption spectral studies indicate that thermal cross-linking reaction of the copolymer was catalyzed by the pendant photogenerated amines.
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    URL: http://dx.doi.org/10.1007/s002890050306
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    Complexation of cobalt ion with copolypeptide containing tryptophan treated with nitric acid (1998)
    Springer
    Polymer bulletin 40 (1998), S. 683-688 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Tryptophan within copoly(N-hydroxyethyl L-glutamine-co-L-tryptophan) treated with nitric acid (EGT-N) dissociates negatively above pH 10.5 by the electron-attractive effect of nitro groups introduced into the indole ring. The interaction between EGT-N and various metal ions was investigated using UV/VIS, ESCA, and ICP measurement. EGT-N was found to selectively form a complex with cobalt ions above pH 10.5. The formation of the cobalt ion complex of EGT-N was confirmed to be caused by the cooperative coordination of the tryptophan-introduced nitro groups and the OH groups of hydroxyethyl L-glutamine.
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    URL: http://dx.doi.org/10.1007/s002890050308
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    Polymerization of ethylene by chromium acetylacetonate/methylaluminoxane catalyst system (1998)
    Springer
    Polymer bulletin 40 (1998), S. 695-700 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The present paper deals with polymerization of ethylene by chromium acetylacetonate - Cr(acac)3 - activated by alkylaluminium, e.g. Al(C2H5)3 or Al(i-C5H9)3, or methylaluminoxane (MAO). The influence of polymerization parameters on catalyst performance, such as Al/Cr mole ratio, temperature, aging time, type of cocatalyst, was investigated. High activities were obtained only when MAO was the cocatalyst. The polymers were characterized by size exclusion chromatography (SEC) and differential scanning calorimetry (DSC) analyses.
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    URL: http://dx.doi.org/10.1007/s002890050310
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    A new kind of azo polymeric LB film for reversible optical storage (1998)
    Springer
    Polymer bulletin 40 (1998), S. 735-740 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A Reversed Duckweed polymeric LB film was fabricated by a new kind of amphiphilic polymer which was composed of hexanediamine- epichlorohydrin hydrophilic network and hydrophobic chains containing p-nitroazobenzene groups. Reversible optical birefringence and dichroism have been demonstrated in this polymeric LB film, and this reversible birefringence and dichroism can be cycled many times without appearance of any fatigue and show very good stability.
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    URL: http://dx.doi.org/10.1007/s002890050316
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    Glass transition behavior of polypropylene/polystyrene/styrene-ethylene-propylene block copolymer blends (1998)
    Springer
    Polymer bulletin 40 (1998), S. 765-771 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The glass transition behavior of ternary blends of polypropylene (PP), polystyrene (PS) and styrene-ethylene-propylene-styrene block copolymer (SEPS) was investigated. The blends were prepared by an internal mixer, and their dynamic mechanical properties and morphology were measured. The blends showed phase inversion at around 75wt% PS composition. The glass transition temperature (Tg) of the PP phase shifted to lower temperature as the PS contents were increased in PP/PS binary blends, probably due to the mismatch of thermal expansion coefficients between two components. As the SEPS copolymer contents were increased, the Tg's of the PP phase in the blends increased. In particular, the large increase in Tg of the PP phase was observed in the PP/PS (25/75) blends where the phase inversion takes place.
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    URL: http://dx.doi.org/10.1007/s002890050320
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    HDPE/ROSIN blends: I-Morphology, mechanical and rheological properties (1998)
    Springer
    Polymer bulletin 40 (1998), S. 779-786 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY Melting mixtures of high density polyethylene (HDPE) and glycerol ester of hydrogenated rosin (ester gum) were prepared under select conditions using up to 50% of rosin. All blends showed phase separation. The size of rosin domains varied with the content of low molecular weight constituent. The 50/50 blend showed the highest dispersion and the presence of micro and macro rosin domains. Up to 20% rosin a slight decrease of Young's modulus was noticed while above this rosin content a slight increase occurred. The stress and elongation dropped markedly above 10% of rosin. The hardness of blends showed the same behavior as the elastic modulus. The melt flow index increased exponentially with the rosin content while processability has improved.
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    URL: http://dx.doi.org/10.1007/s002890050322
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  • 83
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    HDPE/ROSIN blends: I-Morphology, thermal and dynamic-mechanical behavior (1998)
    Springer
    Polymer bulletin 40 (1998), S. 787-793 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY Morphological and thermal studies on high density polyethylene (HDPE) / glycerol ester of partially hydrogenated rosin (ester gum) blends reveal phase separation. Both thermal and dynamic-mechanical tests showed no shift of the HDPE glass transition temperature while the HDPE αc transition appeared. The presence of an additional transition was also noticed as the second component increased in blends; this was attributed to a rosin component. The peak ascribed to this transition became broader in blends enriched with oligomer; it moved toward lower temperatures due to the dissolution of low molecular weight HDPE. The melting temperature and crystallinity of HDPE varied slightly with the amount of amorphous oligomeric component in the blends.
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    Poly(ether sulfonamide)s with glycidyl pendant units (1998)
    Springer
    Polymer bulletin 41 (1998), S. 7-14 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY High molecular weight poly (ether sulfonamide) has been prepared by condensation of 4,4'-dichlorosulfonyldiphenylether with ethylenediamine. The reaction of potassium salt of poly (ether sulfonamide) with epichlorohydrin gives the corresponding N-glycidiyl derivative in yield as high as 98%. The resulting polymer offers many functionalization possibilities through ring opening of the oxirane units. Also the glycidiyl bearing polymer may act as multifunctional post-crosslinking agent for polymers carrying hydroxy, amino or carboxyl groups.
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    URL: http://dx.doi.org/10.1007/s002890050326
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    The ROMP catalysts Mo(CO)5PPh3/alkylaluminum with unstrained cyclic and linear dienes as initiators of the addition polymerisation (1998)
    Springer
    Polymer bulletin 41 (1998), S. 21-28 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary We study the polymerisation of a series of unstrained cyclic and acyclic dienes with the catalytic system of Mo(CO)5PPh3/alkylaluminum. The Mo(CO)5PPh3/alkylaluminum catalyse the nonmetathesis polymerisation, through a pair of ionic complexes similar to that of Ziegler-Natta mechanism, and not through the ROMP (Ring-Opening-Metathesis-Polymerisation) mechanism followed by strained olefins. Because of the nature of these complexes the reactivity is lower with respect to that of a common Ziegler-Natta catalyst, such as Cp2TiCl2/Et3Al2Cl3, as it is demonstrated, by means of kinetics and ESR measurements, in the case of the polymerisation of of 1,5-cyclooctadiene. Similarly to the Ziegler-Natta catalysts, they give cyclised products in the polymerisation of 1,5-hexadiene and 1,7-octadiene, and the 1,4-cis unit in the case of the polypentadienes. Finally we find that they are active catalysts for the polymerisation of styrene.
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    Effect of the ionic conductivity of a polymer matrix on the electrooptical properties of polymer-dispersed liquid crystal films (1998)
    Springer
    Polymer bulletin 41 (1998), S. 37-43 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The influence of ionic conductivity on the electrooptical response was investigated. A new monomer of 2-(poly(ethylene glycol)oxycarbonyl)-bicyclo[2.2.1] hepta-2,5-diene (PEGOC-BCHD) was synthesized and polymerized. Polymer/liquid crystal composite films are composed of poly(PEGOC-BCHD), E8, and alkali metal salts. The ionic conductivities were measured as a function of the ratio of LiClO4/ethylene oxide for various molecular weights of poly(ethylene glycol). The results indicate that the threshold field and response rise time can be reduced by increasing ionic conductivity of the matrix polymer. Liquid crystal droplets were observed in a continuous matrix phase in the form of ‘Swiss cheese’ morphology.
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    URL: http://dx.doi.org/10.1007/s002890050330
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    Determination of the vinyl mercaptoacetate content in poly(ethylene-co-vinyl acetate-co-vinyl mercaptoacetate) (EVASH) by TGA analysis and FTIR spectroscopy (1998)
    Springer
    Polymer bulletin 41 (1998), S. 61-67 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY A new method has been developed for determining the esterification degree (ED) of EVASH copolymers by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). A plot of absorbance values (A1736– A720) versus ED in EVASH samples determined by TGA analysis revealed a good linear relationship.
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    γ-Ray induced graft copolymerization of methyl methacrylate onto poly(β-hydroxynonanoate) (1998)
    Springer
    Polymer bulletin 41 (1998), S. 53-60 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers of poly(3-hydroxy-nonanoate), PHN, with methyl methacrylate, MMA, were prepared using 60Co-gamma irradiator. The bulk solutions of PHN in MMA were prepared at different PHN feed concentration and they were irradiated to 8.5 kGy at room temperature. Polymer fractions obtained by solvent-nonsolvent fractional precipitation were carefully characterized using gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR), and thermal gravimetric analysis (TGA) techniques. High copolymerization yield was observed and the copolymer compositions obtained from the TGA measurements were consistent with the NMR results. PHN contents of the copolymer samples changed from 5 to 35 wt.-%. The strain at break and tensile strength values of copolymers were between the values of their respective homopolymers. It was observed that pure copolymer samples showed up to 13 % strain at break.
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    Influence of a copolymer on the mechanical properties of a blend of PP and recycled and non-recycled HDPE (1998)
    Springer
    Polymer bulletin 41 (1998), S. 91-98 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The mechanical and morphological behavior of polypropylene (PP) and high-density polyethylene (HDPE), recycled and non-recycled, by the addition of an ethylene-propylene block copolymer, was studied. In the non-recycled samples, the effect of the copolymer on the mechanical and morphological properties is negligible. In the recycled samples, it was shown that with 5% copolymer, both particle size in the dispersed phase and interface thickness decreased, and that 5% copolymer composition is optimal in improving the adhesion and flexibility of the blend.
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    Effect of EPDM on the mechanical properties of blends of high and low density polyethylene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 99-105 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary We studied the effect of adding ethylene-propylene-diene rubber (EPDM) to blends of high (HDPE) and low (LDPE) density polyethylene. The extrusion torque of the blend without EPDM shows a deviation from the linear addition rule, but blends with rubber follow the addition rule. Two composition regions that are compatible with the torque behavior are present in the Young's modulus and extension at break curves. The EPDM content improves the extension at break of LDPE rich blends. This improvement extends to higher compositions of HDPE as the EPDM content is increased.
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    Liquid-crystalline polyacrylate crosslinked with α, ω polyisoprene diacrylate segments (1998)
    Springer
    Polymer bulletin 41 (1998), S. 291-297 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The preparation of functionalized cis-1,4-polyisoprene and its copolymerization with a liquid crystalline monomer are reported in this paper. A sample of natural rubber Hevea Brasiliensis with HO end group was reacted with acryloyl chloride. The copolymerization between telechelic acrylate polyisoprene and [(4'-methylphenyl)benzoyloxy-4-oxytetramethylene] acrylate (LCM) was performed by radicalar reaction using 2,2'- azoisobutyronytrile as the initiator. The LCM incorporation into the copolymer was analysed by 1H NMR and TGA measurements. The product exhibits liquid crystalline properties observed by polarized optical microscopy and DSC. Some particular mechanical properties were also evaluated by oscillatory tests.
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    On the role of aminolysis and transesterification in the synthesis of ɛ-caprolactone and L-lactide based polyurethanes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 299-306 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Polyurethanes based on a 50/50 copoly(L-lactide/ɛ-caprolactone) prepolymer and butanediisocyanate were made. Chain extending a diisocyanate terminated prepolymer with butanediamine was not possible due to the susceptibility of the lactide bond to aminolysis. Chain extension with butanediol resulted in a polymer with poor mechanical properties due to transesterification. When the copolymer prepolymer was chain-extended with an isocyanate terminated block, transesterification with the chain-extender was avoided and the mechanical properties were increased. When the length of the hard segments was increased the mechanical properties increased further. A L-lactide/ɛ-caprolactone based polyurethane with a tensile strength and modulus of respectively 45 MPa and 60 MPa was made. The polymer contained no poly(L-lactide) crystals and was easy to process. Compared to the high molecular weight 50/50 copoly(L-lactide/ɛ-caprolactone) the polyurethane showed better mechanical properties, is expected to have the same adhesive properties and is expected to have a slower degradation rate. These factors makes this polymer excessively useful for in-vivo tissue engineering in for instance meniscal reconstruction material, nerve guide and artificial skin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050366
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  • 93
    Electronic Resource
    Electronic Resource
    Anisotropy of optical and mechanical properties of stretched low density polyethylene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 311-316 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Parallel measurements of IR dichroism, birefringence and microhardness anisotropy of drawn low density polyethylene films have been carried out. The angle α between the dipole moment vector of the IR band at 1367 cm−1 and the chain axis has a value of 50°. The longitudinal and transverse moduli of the drawn samples, measured by microhardness indentations, increase as the draw ratio increases after passing through a minimum for a draw ratio of around 1.5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050368
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  • 94
    Electronic Resource
    Electronic Resource
    Thermal properties of poly(N-maleyl glycine), poly(N-maleyl glycine-co-acrylic acid), and their metal complexes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 317-324 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The thermal properties of two water-soluble polymers; poly(N-maleyl glycine) and poly(N-maleyl glycine-co-acrylic acid) as well as their metal complexes with Co(II), Zn(II), Ni(II), Cu(II), Fe(III), Cd(II), Pb(II), and Hg(II) ions were investigated. The copolymer-metal ion complexes were obtained in aqueous phase by using the Liquid Phase Polymer-Based Retention (LPR) technique in conjunction with membrane filtration. The water-soluble P(MG) and P(MG-co-AA) are shown to be useful for the retention of different metal ions and their separation from elements not bound to the polymeric reagent. The thermal stability of the copolymer-metal ion complexes under nitrogen atmosphere at 20–500°C was also investigated. The complexes with different transition were characterized with FT-IR and thermogravimetry (TGA). From the TGA data the thermal decomposition temperature (TDT) and kinetic parameters such as activation energy (Ea) and reaction order (n) were determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050369
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  • 95
    Electronic Resource
    Electronic Resource
    Synthesis and TEM studies of metal clusters dispersed in polymers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 333-339 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Solvated metal atoms were obtained by cocondensation of metals and monomers at 77 K. Stable colloids were formed upon warming. Several colloids using iron and nickel have been prepared with the following monomers: styrene, methyl methacrylate, ethyl methacrylate and butyl methacrylate. The colloids were polymerized with two different initiators, benzoyl peroxide (BPO) and 2,2'-bis-azoisobutyronitrile (AIBN). The metal clusters should be stabilized by styrene between the aromatic ring and the vinyl group, and in the acrylate series between the vinyl and the carbonyl group. The yields of the polymers of Ni-styrene and Fe-styrene range from 10–70% and the molecular weights range from 10.000 to 250.000, even higher than the homopolymer. Electron micrographs were obtained by a Jeol JEM 1200 EX II with 4 Å resolution, for the colloids and the polymers. The colloids exhibited a smaller particle size than the metal clusters in the polymers. The styrene with either Fe or Ni clusters should be around 100 Å colloidal sizes. A dramatic increase in the polymer was observed. Very big clusters in the dope polyacrylate were found. During polymerization particle size growing and size increase were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050371
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  • 96
    Electronic Resource
    Electronic Resource
    Study of the solution properties of tactic polystyrenes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 349-354 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Viscosity measurements are reported for syndiotactic polystyrenes in a molar mass range from 35,000 to 400,000 g/mol and standard fractions of narrowly distributed atactic polystyrenes in a molar mass range from 50,000 to 600,000 g/mol in trichlorobenzene at 135 °C. The correlation between molar mass and intrinsic viscosity of different polystyrene samples was investigated as well as their solution properties. The results demonstrate that the intrinsic viscosity of polystyrene in thermodynamically good solvents is independent of the type of tacticity of the polystyrenes investigated here. The dilute solution properties were compared with those for isotactic and atactic polystyrenes. The small differences in their solution viscosities may occur due to the different molar mass distributions of differently synthesized samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050373
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  • 97
    Electronic Resource
    Electronic Resource
    Atomic force microscopic (AFM) study on a self-organizing polymer film (1998)
    Springer
    Polymer bulletin 41 (1998), S. 695-699 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The structure of a self-organized polymer film prepared by slow evaporation of organic solvents is studied by atomic force microscopy, and compared with that of polymer film prepared by natural evaporation of organic solvents. AFM studies clearly indicates that there exists a self-organizing process of alkyl chains resulting in the partial interdigitated layer structure under the condition of slow evaporation of organic solvents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050420
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  • 98
    Electronic Resource
    Electronic Resource
    Polymer-dispersed liquid crystal films using poly(2-methyloxycarbonyl-bicyclo[2.2.1] hepta-2,5-diene-co-poly(ethylene glycol) methacrylate) as a matrix resin (1998)
    Springer
    Polymer bulletin 41 (1998), S. 701-705 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Dependence of the electrooptical response time of a polymer/liquid crystal (LC) composite film on the ionic conductivity and dielectric property of the matrix polymer has been investigated. Poly(2-methyloxycarbonyl-bicyclo[2.2.1]hepta-2,5-diene-co poly(ethylene glycol) methacrylate) was synthesized by photo-polymerization. Ionic conductivity and relative dielectric constant were found to be greatly dependent on the content of poly(ethylene glycol) methacrylate in the copolymer. The results indicate that the matrix polymer with high conductivity and dielectric constant has led to the short response time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050421
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  • 99
    Electronic Resource
    Electronic Resource
    Compatibilizing capability of poly(β-hydroxybutyrate-,co-ε-caprolactone) in the blend of poly(β-hydroxybutyrate) and poly(ε-caprolactone) (1998)
    Springer
    Polymer bulletin 41 (1998), S. 707-712 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In order to increase the miscibility in the blend of poly(β-hydroxybutyrate) [PHB] and poly(ε-caprolactone) [PCL], PHB/PCL copolyesters were used as compatibilizers. These PHB/PCL copolyesters were synthesized by transesterification in solution phase. The melting point [Tm] depression, which was not observed in PHB/PCL blend without compatibilizer, was observed when PHB/PCL copolyesters as compatibilizers were added to the PHB/PCL blend system. As the amount of compatibilizer added to the blend increased, the crystallization temperature [Tc] of PCL in the blend increased and Tc of PHB in the blend decreased. The difference in Tc between PHB and PCL was gradually reduced. When the sequence length of PHB block and PCL block in the PHB/PCL copolyester increased, the miscibility of the blend increased. This is evidenced by the depression in the Tm of PHB and PCL in the blend and by the decrease in the difference of Tc between PHB and PCL. From the polarizing optical micrographs, the phase separation in PHB/PCL blend was observed. However, in the presence of PHB/PCL copolyester, the spherulite of PHB grows in equilibrium with one phase melt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050422
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  • 100
    Electronic Resource
    Electronic Resource
    Poly(N-1-alkylitaconamic acids)/poly(N-vinyl-2-pyrrolidone) blends (1998)
    Springer
    Polymer bulletin 40 (1998), S. 63-67 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Blends containing poly(N-1-alkylitaconamic acids) (PNAIA) and poly(N-vinyl-2-pyrrolidone) (PVP) of two different weight average molecular weights, were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and infrared spectroscopy (FTIR). The phase behaviour of the blends is analyzed in terms of the side chain structure and the specific interactions involved, mainly due to the free carboxylic group and the amide groups in PNAIA and the carbonyl group of PVP. The strength of the interaction was analyzed in terms of the Gordon-Taylor parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050224
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