Journal of Polymer Science Part A: Polymer Chemistry

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

1 May 2001

Volume 39, Issue 9

Pages 1269–1532

  1. Articles

    1. Top of page
    2. Articles
    1. Radical and cationic polymerizations of 3-ethyl-3-methacryloyloxymethyloxetane (pages 1269–1279)

      Tsuneyuki Sato, Takayuki Oki, Makiko Seno and Tomohiro Hirano

      Article first published online: 6 MAR 2001 | DOI: 10.1002/pola.1104

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      3-Ethyl-3-methacryloyloxymethyloxetane (EMO) was easily polymerized with dimethyl 2,2′-azobisisobutyrate (MAIB) to yield a high vinyl polymer (n = 1–3.3 × 105). The electron spin resonance determined kp and kt values of EMO at 60 °C in benzene are 120 and 2.4 × 105 L/mol s, respectively. EMO was also found to be cationically polymerized through the opening of the oxetane ring to yield a poly(oxetane) of n = 650–3100. Cationic polymerization of the radically formed poly(EMO) gave a crosslinked polymer.

    2. Polymers containing formamidine groups. VI. Structural influences on the formation of cyclic trimers (pages 1280–1287)

      Christoph Kunert, Dieter Voigt, Peter Friedel, Hartmut Komber and Frank Böhme

      Article first published online: 7 MAR 2001 | DOI: 10.1002/pola.1105

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      The condensation reaction of different metasubstituted aromatic diamines with triethyl orthoformate was investigated. Whereas the conversion of 1,3-phenylenediamine resulted in an oligomeric polyformamidine, the formation of cyclic trimers was observed when nitrogen-containing aromatic diamines such as 2,6-diaminopyridine, 2,4-diaminopyrimidine, and 2,4-diamino-6-methyl-1,3,5-triazine were used. The extent of cyclization depended on the number of nitrogen atoms in the aromatic ring and could be attributed to energetically favored conformations of the chain segments. In the case of 2,6-diaminopyridine, the cyclic trimer was obtained quantitatively.

    3. Synthesis and characterization of rigid-chain liquid–crystalline polymers containing laterally attached side rods (pages 1288–1294)

      Lun Zhao, Chaobin He, Zhihua Lu and T. S. Chung

      Article first published online: 7 MAR 2001 | DOI: 10.1002/pola.1106

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      A molecular approach to low dielectric constant polymeric materials is based on a rigid-chain polymer containing laterally attached side rods. The rigidity of the polymer main chain ensures a liquid crystallinity of the polymer (a parallel packing of polymer main chains), whereas the laterally attached side rods push the neighboring chains apart, which results in a less dense packing structure as well as a low dielectric constant of the resulting polymers. Polymer containing 10% of terphenyl side rods exhibits liquid crystallinity and the 20% reduction of dielectric constant compared with the parent polymer.

    4. An efficient route for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages (pages 1295–1304)

      Ashootosh V. Ambade and Anil Kumar

      Article first published online: 7 MAR 2001 | DOI: 10.1002/pola.1107

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      A highly efficient synthetic route, based on the quantitative reaction between amine and isocyanate functionalities, was used successfully for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages.

    5. Cationic ring-opening polymerization of six-membered cyclic carbonates with ester groups (pages 1305–1317)

      Nobukatsu Nemoto, Fumio Sanda and Takeshi Endo

      Article first published online: 8 MAR 2001 | DOI: 10.1002/pola.1108

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      This work deals with the cationic ring-opening polymerization of the ester-substituted cyclic carbonates 5-methyl-5-benzoyloxymethyl-1,3-dioxan-2-one (CC1) and 4-benzoyloxymethyl-1,3-dioxan-2-one (CC4). The polymerization was carried out with trifluoromethanesulfonic acid, methyl trifluoromethanesulfonate, boron trifluoride etherate, or methyl iodide as the initiator. The reactivity of CC1 and CC4 was higher than that of 5,5-dimethyl-1,3-dioxan-2-one (CC7), which had no ester moiety. These results suggest that this ring-opening polymerization was accelerated by the intramolecular ester group. CC1 showed a higher polymerizability than CC4, affording a polymer with a higher molecular weight. Additionally, using methyl iodide as the initiator was effective for increasing the molecular weight of the obtained polycarbonate and decreasing decarboxylation.

    6. Synthesis and specific biodegradation of novel polyesteramides containing amino acid residues (pages 1318–1328)

      Yujiang Fan, Masami Kobayashi and Hideo Kise

      Article first published online: 8 MAR 2001 | DOI: 10.1002/pola.1109

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      Novel polyesteramides containing amino acid residues were synthesized from p-nitrophenyl esters of sebacic or adipic acids and diamines containing α-amino acid ester groups. The biodegradability of the polyesteramides was investigated by in vitro hydrolysis by enzymes. The polymers containing L-phenylalanine were hydrolyzed most effectively by α-chymotrypsin, subtilisin Carlsberg, and subtilisin BPN′. The polyesteramides containing other amino acid residues also underwent hydrolysis to different extents, reflecting the substrate specificity of the proteases. The polymers containing glycine residues were hardly decomposed by any of the enzymes used.

    7. Photochemical reactions of quaternary ammonium dithiocarbamates as photobase generators and their use in the photoinitiated thermal crosslinking of poly(glycidyl methacrylate) (pages 1329–1341)

      Hideki Tachi, Takayuki Yamamoto, Masamitsu Shirai and Masahiro Tsunooka

      Article first published online: 8 MAR 2001 | DOI: 10.1002/pola.1110

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      The photochemical behavior of quaternary ammonium salts (QA salts) with N,N-dimethyldithiocarbamates as photobase generators was investigated. From the results of UV spectral changes with phenol red and 1H NMR analysis, it was proven that the photolysis of QA salts resulted in the quantitative formation of triethylenediamine. QA salts acted as effective photoinitiated thermal crosslinkers for poly(glycidyl methacrylate) films.

    8. Chemical structure of composites derived from poly(silicic acid) and 2-hydroxyethylmethacrylate (pages 1342–1352)

      J. Habsuda, G. P. Simon, Y.-B. Cheng, D. G. Hewitt, H. Toh and D. R. Diggins

      Article first published online: 9 MAR 2001 | DOI: 10.1002/pola.1111

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      Composite materials containing organic and inorganic components were synthesized. The growth and molecular architecture of poly(silicic acid) produced from sodium metasilicate were measured via gel permeation chromatography for molecular weights and via 29Si NMR spectroscopy for the degree of branching. The organic component was derived from 2-hydroxyethylmethacrylate, which showed a good level of compatibility and coexistence with the chemically dissimilar inorganic phase as a result of their mutual hydrophilic hydroxyl groups. This occurred despite a lack of covalent bonding.

    9. Modeling the reversible addition–fragmentation chain transfer process in cumyl dithiobenzoate-mediated styrene homopolymerizations: Assessing rate coefficients for the addition–fragmentation equilibrium (pages 1353–1365)

      Christopher Barner-Kowollik, John F. Quinn, David R. Morsley and Thomas P. Davis

      Article first published online: 14 MAR 2001 | DOI: 10.1002/pola.1112

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      With the cumyl dithiobenzoate-mediated bulk polymerization of styrene at 60 °C as an example, the rate coefficients associated with the addition–fragmentation equilibrium are deduced by the careful modeling of the time-dependent evolution of experimental molecular weight distributions. The rate coefficient for the addition reaction of a free macroradical to a polymeric reversible addition–fragmentation chain transfer (RAFT) species (kβ) is approximately 5 · 105 L mol−1 s−1, whereas the fragmentation rate coefficient of the formed macroradical RAFT species is close to 3 · 10−2 s−1. These values give an equilibrium constant of K = kβ/k−β = 1.6 · 107 L mol−1.

    10. Light harvesting and energy transfer within coumarin-labeled polymers (pages 1366–1373)

      Alex Adronov, Douglas R. Robello and Jean M. J. Fréchet

      Article first published online: 13 MAR 2001 | DOI: 10.1002/pola.1113

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      A series of linear copolymers with pendant coumarin-2 donor and coumarin-343 acceptor chromophores were prepared and studied with respect to light-harvesting and energy-transfer properties. A comparison between previously synthesized dendrimers and these polymer analogues indicates that the polymers have similar energy-transfer properties but reduced solubility as well as quantum yields of flourescence.

    11. Synthesis of poly(lactide-ran-MOHEL) and its biodegradation with proteinase K (pages 1374–1381)

      Hiroyuki Shirahama, Kiyoshi Mizuma, Koichi Umemoto and Hajime Yasuda

      Article first published online: 14 MAR 2001 | DOI: 10.1002/pola.1114

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      Significantly enhanced biodegradability was observed with the introduction of optically active (R)- or (S)-3-methyl-4-oxa-6-hexanolide (MOHEL) into poly(L-lactide) or poly(D,L-lactide) sequences. This resulted in the formation of poly(lactide-ran-MOHEL) (in molar ratios of 86/14 to 43/57), which showed especially high degradability by proteinase K. The biodegradation mechanism is discussed.

    12. Unique dual function of La(C5Me5)[CH(SiMe3)2]2(THF) for polymerizations of both nonpolar and polar monomers (pages 1382–1390)

      Kohji Tanaka, Masahito Furo, Eiji Ihara and Hajime Yasuda

      Article first published online: 16 MAR 2001 | DOI: 10.1002/pola.1115

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      A half-metallocene-type complex, La(C5Me5)[CH(SiMe3)2]2tetrahydrofuran (THF) 1, showed the dual function of performing the controlled polymerizations of nonpolar monomers such as ethylene and styrene as well as polar monomers like methyl methacrylate, hexyl isocyanate, and acrylonitrile in high yields.

    13. Hydrazone initiators for vinyl polymerizations (pages 1391–1402)

      Richard A. Wolf, John M. Warakomski, Thomas L. Staples and Michael J. Fazio

      Article first published online: 14 MAR 2001 | DOI: 10.1002/pola.1116

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      A new class of free-radical initiators, the hydrazones of simple ketones, has been discovered. These hydrazones rapidly initiate the polymerization of acrylate monomers at ambient temperature and more slowly initiate the polymerization of methacrylate monomers. The most active hydrazone initiators are the tertiary butyl hydrazones of aromatic, aliphatic ketones such as the tertiary butyl hydrazone of acetophenone.

    14. Synthesis and hydrophobic association of poly(N,N-dimethylacrylamide) end-functionalized with perfluorocarbon and hydrocarbon groups (pages 1403–1418)

      David Xie, Sandra Tomczak and Thieo E. Hogen-Esch

      Article first published online: 16 MAR 2001 | DOI: 10.1002/pola.1117

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      Polydimethylacrylamides (PDMAs) end-functionalized with perfluorooctanoyl or octadecanoyl hydrophobic groups were synthesized by the reaction of cesium salts of one- or two-ended living PDMA anion with octadecanoyl and perfluorooctanoyl chlorides or with α-phenylacrylate monomers containing an octadecyl group attached via oligooxyethylene spacers to the acrylate functionality. The enclosed figure shows the reduced viscosity plot of the PDMA homopolymer precursor (▴; its matching end-capped, perfluorooctanoyl-end-functionalized polymer (□; and the two-ended, perfluorooctanoyl-end-functionalized polymer in water at 25.0 °C. Similar curves and similar reduced viscosities were obtained for the octadecanoyl groups. The presence of decaoligooxyethylene spacers between the octadecanoyl and acrylamide groups gave rise to dramatically enhanced viscosities.

    15. Study on side-chain second-order nonlinear optical polyimides based on novel chromophore-containing diamines. II. Copolyimides possessing direct photolithographic features (pages 1419–1425)

      Yu Sui, Jiong-Xin Lu, Jie Yin, Yan-Gang Liu, Zi-Kang Zhu and Zong-Guang Wang

      Article first published online: 16 MAR 2001 | DOI: 10.1002/pola.1118

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      Second-order nonlinear optical copolyimides were prepared from novel chromophore-containing diamines, 4,4′-diamino-3,3′-dimethyldiphenylmethane, and benzophenone-3,3′,4,4′-tetracarboxylic dianhydride. Some of the polyimides (PIs) obtained possessed direct photolithographic features, and good photolithographic patterns were easily obtained. All PIs exhibited excellent organosolubility, high transperancy, high glass-transition temperatures, and thermal-decomposition temperatures.

    16. Molecular structure determination of Ni(II) diimine complex and DMA analysis of Ni(II) diimine-based polyethenes (pages 1426–1434)

      J. O. Liimatta, B. Löfgren, M. Miettinen, M. Ahlgren, M. Haukka and T. T. Pakkanen

      Article first published online: 20 MAR 2001 | DOI: 10.1002/pola.1119

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      The solid-state structure of [2,6-C6H3(i-Pr)2N[DOUBLE BOND]C(Nap)[BOND]C(Nap)[DOUBLE BOND] N-2,6-C6H3(i-Pr)2N]NiBr2 (where Nap = 1,8-naphthdiyl) consists of two centrosymmetrically related monomeric moieties, where Ni atoms (five-coordinated with a square pyramidal polyhedron) are bridged by two bromide ligands. The sixth coordination site of the octahedral geometry is blocked by the isopropyl groups of the diimine ligands. However, in solution the complex dissociates into monomeric species of a Brookhart-type catalyst. Under suitable conditions, the catalyst produces with high activity very high molar mass branched polyethene that behaves like an elastomer, as shown by dynamic mechanical thermoanalysis.

    17. Hollow-particle latexes: Preparation and properties (pages 1435–1449)

      V. N. Pavlyuchenko, O. V. Sorochinskaya, S. S. Ivanchev, V. V. Klubin, G. S. Kreichman, V. P. Budtov, M. Skrifvars, E. Halme and J. Koskinen

      Article first published online: 19 MAR 2001 | DOI: 10.1002/pola.1120

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      The preparation of hollow-particle latexes was considered according to the following pathways: (1) core monomers (methyl methacrylate + methacrylic acid + ethylene glycol dimethacrylate) copolymerization, (2) shell monomer (styrene or styrene + acrylonitrile + divinyl benzene) copolymerization, and (3) the neutralization of carboxylated units with ammonia or sodium hydroxide and swelling of the particles followed by the formation of hollows filled with water. The following parameters were shown to be mostly responsible for the hollow-particle geometry (overall diameter and shell thickness): (1) the core polymer/shell polymer ratio, (2) the type and concentration of base used for neutralization, and (3) the neutralization temperature. The opacity of the coatings prepared on the basis of hollow particles was considered.

    18. Block copolymerization of tert-butyl methacrylate with α,ω-difunctionalized polystyrene macroiniferter and hydrolysis to amphiphilic block copolymer (pages 1450–1455)

      Shu-Hui Qin and Kun-Yuan Qiu

      Article first published online: 20 MAR 2001 | DOI: 10.1002/pola.1121

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      The block copolymerization of tert-butyl methacrylate (tBMA) with a difunctionalized polystyrene (PS) macroinitiator was investigated. Kinetic studies indicate the molecular weights of triblock copolymers increased linearly with the conversion. Block copolymers with different lengths of PtBMA segments can be easily prepared by varying the ratio of tBMA and PS macroiniferter or by controlling the monomer conversion. The formations of block copolymers were characterized by gel permeation chromatographic, 1H NMR, and DSC analyses. The PtBMA segments of the triblock copolymer were subsequently hydrolyzed quantitatively to poly(methacrylic acid) segments using concentrated HCl as a catalyst in a refluxing solution of dioxane, and then an amphiphilic ABA triblock copolymer was produced.

    19. Synthesis and polymerization mechanism of bisacetoacetamides (pages 1456–1462)

      Ji Young Chang, Bum Jin Kim, Chong Rae Park, Man Jung Han, Tae Ja Kim and Hoseop Yun

      Article first published online: 20 MAR 2001 | DOI: 10.1002/pola.1122

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      Bisacetoacetamides were prepared, and their polymerization mechanism was investigated. They were polymerized under high pressure (34.5 MPa) at 200 °C for 30 min to give the crosslinked films. The polymerization of bisacetoacetamides proceeded by addition reactions of the isocyanates formed as intermediates and in part by condensation reactions between the acetoacetamido groups. The isocyanates also reacted with the urea groups on the polymer chains to form biurets, which would cause crosslinking.

    20. Stereocontrol during the free-radical polymerization of methacrylates with Lewis acids (pages 1463–1471)

      Yutaka Isobe, Tamaki Nakano and Yoshio Okamoto

      Article first published online: 20 MAR 2001 | DOI: 10.1002/pola.1123

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      The radical polymerizations of methyl, ethyl, isopropyl, and 2-methoxyethyl methacrylates in the presence of Lewis acids, including scandium trifluoromethanesulfonate [Sc(OTf)3], ScCl3, Yb(OTf)3, Er(OTf)3, HfCl4, HfBr4, and In(OTf)3, at 60 °C proceeded with higher isotactic and heterotactic specificities than conventional radical polymerizations. Among the Lewis acids tested, Sc(OTf)3 and Yb(OTf)3 were especially effective in altering the stereochemistry of the polymerization.

    21. Synthesis of poly[(2-oxo-1,3-dioxolane-4-yl) methyl methacrylate-co-ethyl acrylate] by incorporation of carbon dioxide into epoxide polymer and the miscibility behavior of its blends with poly(methyl methacrylate) or poly(vinyl chloride) (pages 1472–1480)

      Sung-Young Park, Hee-Young Park, Hwa-Soo Lee, Sang-Wook Park, Chang-Sik Ha and Dae-Won Park

      Article first published online: 21 MAR 2001 | DOI: 10.1002/pola.1124

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      This study was related to the investigation of the chemical fixation of carbon dioxide to a copolymer bearing epoxide and the application of the cyclic carbonate group containing copolymer-to-polymer blends.

    22. Synthesis and photoinduced deprotection of calixarene derivatives containing certain protective groups (pages 1481–1494)

      Tadatomi Nishikubo, Atsushi Kameyama, Kousuke Tsutsui and Shinichi Kishimoto

      Article first published online: 22 MAR 2001 | DOI: 10.1002/pola.1125

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      Photoreactive calixarene derivatives (1ac) containing tert-butoxycarbonyl (t-BOC) groups were synthesized by the reaction of C-methylcalix[4]resorcinarene (CRA), p-methylcalix[6]arene (MCA), and p-tert-butylcalix[8]arene (BCA) with di-tert-butyl dicarbonate. Photoreactive calixarene derivatives (2ac) containing trimethysilyl ether (TMSE) groups were also prepared by the reaction of CRA, MCA, and BCA with 1,1,1,3,3,3-hexamethyldisilazane. Photoreactive calixarene derivatives (3ac) containing cyclohexenyl ether (CHE) groups were obtained by the reaction of CRA, MCA, and BCA with 3-bromocyclohexene. Each aforemetioned reaction proceeded quantitatively under appropriate reaction conditions. The photochemical reaction of the obtained calixarene derivatives was examined with photoacid generators in the film state.

    23. Polymerizable anthracene derivatives for labeling emulsion copolymers (pages 1495–1504)

      Ronghua Liu, Mitchell A. Winnik, Frank Di Stefano and Jai Vanketessan

      Article first published online: 21 MAR 2001 | DOI: 10.1002/pola.1126

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      Many anthracene derivatives inhibit or retard acrylate polymerization. We describe the synthesis of three anthracene-containing monomers as well as their emulsion copolymerization with 1/1 butylacrylate-methyl methacrylate P(BA-MMA). When copolymers of 5 are heated, particularly in the presence of acid, the chromophore becomes detached from the polymer backbone. Copolymers of 6 are stable under these conditions.

    24. Synthesis of thermosensitive hydrogels from acryloyloxyethyl trialkyl phosphonium chloride–N-isopropylacrylamide–N,N′-methylenebisacrylamide terpolymers and their temperature dependence of water absorption (pages 1505–1514)

      Tsutomu Watanabe, Masayuki Utsunomiya, Seiji Kurihara and Takamasa Nonaka

      Article first published online: 21 MAR 2001 | DOI: 10.1002/pola.1127

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      That the temperature dependence of the acryloyloxyethyl trialkyl phosphonium chloride (AETR)–N-isopropyl acrylamide (NIPAAm)– N,N′-methylenebisacrylamide (MBAAm; X/100/1) terpolymers is different from that of polyNIPAAm can be explained on the basis of the severance of hydrogen bonding between amide groups in NIPAAm and ester groups in AETR in the terpolymers and the deswelling of polyNIPAAm moieties above the lower critical solution temperature of the terpolymers.

    25. Synthesis, characterization, and crosslinking of novel stars comprising eight poly(isobutylene-azeotropic-styrene) copolymer arms with allyl or hydroxyl termini. I. Living azeotropic copolymerization of isobutylene and styrene (pages 1515–1524)

      Diana L. Hull and Joseph P. Kennedy

      Article first published online: 21 MAR 2001 | DOI: 10.1002/pola.1128

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      Conditions were developed for the living azeotropic copolymerization of isobutylene (IB)/styrene charges (St). The azeotropic composition is 21/79 (mol/mol) IB/St. The copolymerization reactivity ratios are rIB = 3.41 ± 0.23 and rSt = 1.40 ± 0.26. The glass-transition temperature of P(IB-aze-St) increases with the copolymer number-average molecular weight and reaches a plateau at about 64 °C with a number-average molecular weight of about 24,0000 g/mol. A subsequent article describes the synthesis, characterization, and crosslinking of octa-telechelic stars containing P(IB-aze-St) arms fitted with crosslinkable termini.

    26. Synthesis, characterization, and crosslinking of novel stars comprising eight poly(isobutylene-azeotropic-styrene) copolymer arms with allyl or hydroxyl termini. II. Stars of eight isobutylene/styrene azeotropic copolymer arms emanating from a calix[8]arene core (pages 1525–1532)

      Diana L. Hull and Joseph P. Kennedy

      Article first published online: 21 MAR 2001 | DOI: 10.1002/pola.1129

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      Novel stars consisting of a calix[8]arene core out of which radiate eight poly(isobutylene-aze-styrene) [P(IB-aze-St)] arms fitted with allyl end groups were synthesized and characterized. The synthesis involve the living azeotropic copolymerization of IB/St charges induced by a calix[8]arene derivative, C[8]OCH3, in conjunction with BCl3 · TiCl4 and end quenching with allyltrimethylsilane. The allyl end groups were quantitatively converted to primary alcohol ([BOND]CH2CH2CH2OH) termini. The architecture of the octa-telechelic stars was established by NMR spectroscopy. Stars with various molecular weight arms were prepared. The glass-transition temperatures increased from 59 to 65 °C as the weight-average molecular weight of the arms increased from about 2500 to 4300 g/mol. Select solution properties (e.g., η, α, and K) of the stars were investigated. The efficient crosslinking of C[8][BOND][P(IB-aze-St)CH2CH2CH2OH]8 with isocyanates was demonstrated.