Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Journal of Polymer Science Part A: Polymer Chemistry

1 April 2003

Volume 41, Issue 7

Pages 873–1045

  1. Articles

    1. Top of page
    2. Articles
    1. Preparation of macroporous functionalized polymer beads by a multistep polymerization and their application in zirconocene catalysts for ethylene polymerization (pages 873–880)

      Chengbin Liu, Tao Tang and Baotong Huang

      Version of Record online: 3 FEB 2003 | DOI: 10.1002/pola.10633

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      Macroporous functionalized polymer beads of poly(4-vinylpyridine-co-1,4-divinylbenzene) were prepared by a multistep polymerization. The beads size was 10–50 μm, and the pore size was 0.1–1.5 μm. The polymer-supported zirconocene catalyst could be exfoliated during ethylene polymerization.

    2. Isolation and identification of cyclic oligomers of the poly(ethylene terephthalate)–poly(ethylene isophthalate) copolymer (pages 881–889)

      Byung-Ho Lim, Soo-Han Kwon, En-Chang Kang, Heon Park, Hyun-Woo Lee and Whan-Gi Kim

      Version of Record online: 4 FEB 2003 | DOI: 10.1002/pola.10637

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      The cyclic oligomers of poly(ethylene terephthalate) (PET), poly(ethylene isophthalate) (PEI), and the PET–PEI copolymer that formed during the polymerization of isophthalic acid and/or terephthalic acid with ethylene glycol were analyzed, and their properties and contents were determined. A condensation polymerization was carried out at a high temperature, and the solid-state polymerization that followed yielded the high molecular weight polymer. The oligomers were extracted from the high molecular weight PET–PEI copolymer and separated with preparative high performance liquid chromatography techniques. Their chemical structures and properties were analyzed and determined by 1H NMR, differential scanning calorimetry, and mass spectroscopy. The oligomers observed at early retention times were a cyclic dimer and cyclic trimers and consisted of [GT]3, [GI]2, [GI]3, [GT]2[GI]1, and [GT]1[GI]2.

    3. Polymers of carbonic acid 32: Influence of catalysts on propagation and cyclization in the interfacial polycondensation of bisphenol A with diphosgene (pages 890–904)

      Hans R. Kricheldorf, Gert Schwarz, Sigrid Böhme and Claus-Ludolf Schultz

      Version of Record online: 10 FEB 2003 | DOI: 10.1002/pola.10507

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      The interfacial polycondensation of bisphenol A with diphosgene was investigated with six different catalysts. The highest molecular weights (weight-average molecular weight up to 106 Da) were obtained with phase-transfer catalysts, and large fractions of cyclic polycarbonates were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    4. Preparation, characterization, and properties of novolac-type phenolic/SiO2 hybrid organic–inorganic nanocomposite materials by sol–gel method (pages 905–913)

      Chin-Lung Chiang, Chen-Chi M. Ma, Dai-Lin Wu and Hsu-Chiang Kuan

      Version of Record online: 4 FEB 2003 | DOI: 10.1002/pola.10624

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      This article describes the preparation of novolac type phenolic resin/silica hybrid organic-inorganic nanocomposite via sol-gel process. FT-IR and NMR identified the structure of modified hybrid nanocomposites. The silica network was characterized by nuclear magnetic resonance (29Si NMR). Results revealed that Q4 (tetrasubstituted) and T3 (trisubstituted) are the major microstructures. The size of silica in the phenolic resin was characterized by scanning electron microscope (SEM). The particle size of inorganic silica in the modified system is less than 100 nm. Furthermore, the thermal properties and mechanical properties show significant improvement. The materials possess excellent flame-retardant properties.

    5. Syntheses and properties of new aromatic polybenzoxazoles bearing ether and phenylethylidene or 1-phenyl-2,2,2-trifluoroethylidene linkages (pages 914–921)

      Sheng-Huei Hsiao and Wei-Tsun Chen

      Version of Record online: 4 FEB 2003 | DOI: 10.1002/pola.10630

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      Aromatic polybenzoxazoles with both ether and phenylethylidene or 1-phenyl-2,2,2-trifluoroethylidene linkages between phenylene units were obtained by a conventional two-step procedure including the low-temperature solution polycondensation of bis(ether acyl chloride)s 1 and 2 with bis(o-aminophenol)s 35, yielding poly(o-hydroxyamide) precursors, and subsequent thermal cyclodehydration. The basic characterization of the poly(o-hydroxy amide) prepolymers and the polybenzoxazoles was examined.

    6. Effects of diamines and their fluorinated groups on the color lightness and preparation of organosoluble aromatic polyimides from 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-hexafluoropropane (pages 922–938)

      Chin-Ping Yang, Ruei-Shin Chen and Kuei-Hung Chen

      Version of Record online: 12 FEB 2003 | DOI: 10.1002/pola.10629

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      A series of soluble and light-colored fluorinated polyimides (5a5f) were synthesized from 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane (2) and various aromatic dianhydrides. For CF3-containing polyimides, the coloration was affected by the position and amount of the CF3 group. The CF3 group close to the imide group was more effective in lowering the color, so the CF3 of 5, 7, and 8f was more effective than that of 6c. The polyimide 5f, synthesized from diamine 2 and 4,4′-hexafluoroisopropylidenediphthalic anhydride, had six CF3 groups in a repeating segment, so it exhibited the lightest color among the four series.

    7. Copolymerization of styrene and conjugated dienes with half-sandwich titanium(IV) catalysts: The effect of the ligand structure on the monomer reactivity, monomer sequence distribution, and insertion mode of dienes (pages 939–946)

      Naofumi Naga and Yukio Imanishi

      Version of Record online: 4 FEB 2003 | DOI: 10.1002/pola.10631

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      The copolymerization of styrene and 1,3-butadiene (Bd) or isoprene (Ip) was carried out with half-sandwich titanium(IV) Cp′TiCl3 catalysts (where Cp′ is cyclopentadienyl, indenyl, or pentamethylcyclopentadienyl) with methylaluminoxane as a cocatalyst. For styrene/Bd copolymerization, the resulting copolymers were composed of a styrene–Bd multiblock sequence. Random copolymers were obtained with styrene/Ip copolymerization. The ligand nature of the catalysts affected the reactivity and sequence distribution of the monomers and the insertion mode of the conjugated dienes in the copolymerization.

    8. Functionalization of polymeric organolithium compounds with 3,4-epoxy-1-butene: Precursors for diene-functionalized macromonomers (pages 947–957)

      Roderic P. Quirk, Deanna L. Gomochak, Chrys Wesdemiotis and Mark A. Arnould

      Version of Record online: 5 FEB 2003 | DOI: 10.1002/pola.10642

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      The functionalization of polymeric organolithium compounds with 3,4-epoxy-1-butene in benzene at room temperature yielded the corresponding butene-ol-functionalized polymers in a 95 wt % yield with 5 wt % of the unfunctionalized polymer isolated. For poly(styryl)lithium, the functionalized product corresponded to approximately equal amounts of 1,4-, 3,4-, and 4,3-addition, as determined by quantitative 13C NMR and attached-proton-test 13C NMR analysis. The 1,4-addition product was obtained in high yields for poly(butadienyl)lithium and poly(isoprenyl)lithium chain ends, at a low temperature (6 °C), by use of inverse addition or by the addition of triethylamine (20 equiv). Dehydration of the butene-ol-functionalized polymer produced the corresponding diene-functionalized macromonomer. All products were characterized by 1H and 13C NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    9. Molecular and structural analysis of a triepoxide-modified poly(ethylene terephthalate) from rheological data (pages 958–969)

      R. Dhavalikar, M. Yamaguchi and M. Xanthos

      Version of Record online: 12 FEB 2003 | DOI: 10.1002/pola.10641

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      The effects of reactive melt modification of poly(ethylene terephthalate) (PET) with a multifunctional epoxide—triglycidyl isocyanurate—that lead to chain extension/branching and formation of gel-like structures were rheologically characterized. The storage and loss moduli and the complex viscosity of the modified PET were larger than those of the unmodified PET. The elastic or solidlike behavior of PET was enhanced after reactive modification as a result of chain extension/branching. Modified Cole–Cole plots revealed that the modified resins show higher elasticity than the unmodified one. Reactive modification characterized by the presence of long-chain branching resulted in a wider molecular weight distribution. The effect of mixing temperature and the concentration of modifier corresponding to different stoichiometries were investigated. Higher amounts of modifier resulted in a polymeric structure near the sol–gel transition point whose linear viscoelastic properties obey a scaling law. The relaxation spectrum was calculated from the oscillatory shear data by Tschoegl equations. Certain modified resins have rheological properties suitable for process operations such as extrusion foaming, blow molding, and thermoforming.

    10. Modification of polycondensation of isophthalic and terephthalic acids and bisphenols with tosyl chloride/dimethylformamide/pyridine by the presence of additives (pages 970–975)

      Fukuji Higashi and Yuhko Shigeta

      Version of Record online: 5 FEB 2003 | DOI: 10.1002/pola.10632

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      The effect of associative interactions between the resulting oligomers and next monomers upon the polycondensation was examined in a two-stage reaction of an equimolar mixture of isophthalic acid and terephthalic acid first with 2,2-bis(4-hydroxyphenyl)propane (BPP) and then with additional BPP in the presence of various additives. It is discussed in terms of the change of distributions of the resulting oligomers by additives.

    11. Method of determining the absolute molecular weight from gel permeation chromatograms for star-shaped styrenic block copolymers (pages 976–983)

      I-Chun Liu and Raymond Chien-Chao Tsiang

      Version of Record online: 12 FEB 2003 | DOI: 10.1002/pola.10636

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      A gel permeation chromatography (GPC) calculation method has been developed to determine the absolute molecular weight of a star-shaped styrenic block copolymer with GPC–ultraviolet/refractive-index calibrated with linear polystyrene standards. The validity of the calculation method was corroborated by the good agreement between the absolute molecular weight determined with this calculation method and that actually measured with a multi-angle laser light scattering device.

    12. Synthesis of comb-type polycarbosilanes via nucleophilic substitution reactions on the main-chain silicon atoms (pages 984–997)

      Tao Zhang, Soo-Young Park, B. L. Farmer and Leonard V. Interrante

      Version of Record online: 11 FEB 2003 | DOI: 10.1002/pola.10648

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      A series of comb-type polycarbosilanes of the type [Si(CH3)(OR)CH2]n {where R = (CH2)mR′, R′ = [BOND]O-p-biphenyl[BOND]X [X = H (m = 3, 6, 8, or 11) or CN (m = 11)], and R′ = (CF2)7CF3 (m = 4)} were prepared from poly(chloromethylsilylenemethylene) by reactions with the respective hydroxy-terminated side chains in the presence of triethylamine. For R = (CH2)11[BOND]O-biphenyl side chains, an analogous side-chain liquid-crystalline polysiloxane derivative of the type [Si(CH3)(O(CH2)11[BOND]O-biphenyl)O]n was prepared by means of a catalytic dehydrogenation reaction. In contrast to the polycarbosilane bearing the same side chain, this polymer did not exhibit any liquid-crystalline phases but melted directly from a crystalline phase to an isotropic liquid at 94 °C.

    13. Ethyl-iso-butylaluminoxane activated metallocene catalyst for olefin polymerization (pages 998–1003)

      Qi Wang, Jian Hong, Zhiqiang Fan and Ruoyuan Tao

      Version of Record online: 13 FEB 2003 | DOI: 10.1002/pola.10628

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      Ethylene and propylene were polymerized by different combinations of metallocenes and aluminoxanes. Ethyl-iso-butylaluminoxane (EBAO) displayed as good polymerization activity as methylaluminoxane when it was paired with some metallocenes. The UV–visible spectroscopic study on different metallocene/aluminoxane pairs suggests that tightness of the ionic pairs generated from the reaction between metallocene and aluminoxane is different for a fixed metallocenium. The loose ionic pair derived from EBAO prefers the monomer propagation and hinders the interaction between active species, which results in high catalytic activity and molecular weight.

    14. Helicity induction on a poly(phenylacetylene) derivative bearing aza-18-crown-6 ether pendants in water (pages 1004–1013)

      Ryuji Nonokawa and Eiji Yashima

      Version of Record online: 12 FEB 2003 | DOI: 10.1002/pola.10634

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      A stereoregular poly(phenylacetylene) bearing the bulky aza-18-crown-6 ether as the pendant (poly-1) formed a predominant one-handed helical conformation upon complexation with various chiral biomolecules, such as amino acids, peptides, aminosugars, amines, and amino alcohols in water to exhibit an induced circular dichroism in the UV–visible region of the polymer main chain.

    15. Molecular composites prepared by in situ direct synthesis of wholly aromatic rigid-rod polyamides via the phosphorylation reaction in a dissolved nylon-6 matrix (pages 1014–1026)

      Satoshi Idemura and Jack Preston

      Version of Record online: 12 FEB 2003 | DOI: 10.1002/pola.10635

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      To create organic nanocomposites, so-called “molecular composites,” a new approach was used. Rigid-rod polyamides were synthesized in situ in a nylon-6 matrix via the phosphorylation reaction. An interpenetrating network formation accompanied by a block-copolymer formation enabled very uniform incorporation of rigid-rod polyamides in nylon-6. Therefore, the rigid-rod chains showed a striking effect on the optical and mechanical properties of the resultant composites.

    16. Stereocontrol during the free-radical polymerization of methacrylamides in the presence of Lewis acids (pages 1027–1033)

      Yutaka Isobe, Yoshikatsu Suito, Shigeki Habaue and Yoshio Okamoto

      Version of Record online: 13 FEB 2003 | DOI: 10.1002/pola.10647

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      The effects of Lewis acids, that is, rare earth metal trifluoromethanesulfonates, on the free-radical polymerization of N-methylmethacrylamide (MMAM), N-isopropylmethacrylamide (IPMAM), N-tert-butylmethacrylamide (tBMAM), N-phenylmethacrylamide (PMAM), and methacrylamide were examined under various conditions. A catalytic amount of Yb(OSO2CF3)3 significantly affected the stereochemistry during the radical polymerization. Polymerization solvents strongly influenced the effect of the Lewis acids. Methanol was the best solvent for increasing the isotactic specificity during the polymerization of MMAM and IPMAM, whereas tetrahydrofuran was more effective for the tBMAM and PMAM polymerizations.

    17. Convenient synthesis and polymerization of 5,6-disubstituted dithiophthalides toward soluble poly(isothianaphthene): An initial spectroscopic characterization of the resulting low-band-gap polymers (pages 1034–1045)

      I. Polec, A. Henckens, L. Goris, M. Nicolas, M. A. Loi, P. J. Adriaensens, L. Lutsen, J. V. Manca, D. Vanderzande and N. S. Sariciftci

      Version of Record online: 13 FEB 2003 | DOI: 10.1002/pola.10646

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      A new synthetic procedure toward substituted dithiophthalides is presented. The 5,6-dioctyloxy- and 5,6-dithiooctyl-substituted monomers were polymerized by a thermal and nonoxidative polymerization that resulted in soluble poly(isothianaphthene) derivatives. Photoinduced absorption measurements revealed the existence of charged excitations upon illumination.