Journal of Polymer Science Part A: Polymer Chemistry

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

1 October 2002

Volume 40, Issue 19

Pages 3191–3326

  1. Articles

    1. Top of page
    2. Articles
    1. Spectroscopic study of the penetration depth of grafted polystyrene onto poly(tetrafluoroethylene-co-perfluoropropylvinylether) substrates. 1. Effect of grafting conditions (pages 3191–3199)

      F. Cardona, G. A. George, D. J. T. Hill and Seneka Perera

      Version of Record online: 13 AUG 2002 | DOI: 10.1002/pola.10409

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      This study concerns the radiation grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropylvinylether) (PFA) substrates and the penetration depth of the graft. Effects of grafting conditions such as the type of solvent, dose rate, and irradiation dose on the grafting yield were investigated. A mixture of methanol and dichloromethane used as a solvent for styrene achieved a higher degree of grafting and concentration of grafted polystyrene onto the surface of PFA substrates than solutions of the monomer in the separate solvents. The increase in the overall grafting yield was accompanied by a proportional increase in the penetration depth of the grafts into the substrate.

    2. Emulsion and miniemulsion polymerizations with an oil-soluble initiator in the presence and absence of an aqueous-phase radical scavenger (pages 3200–3211)

      Yingwu Luo and F. Joseph Schork

      Version of Record online: 13 AUG 2002 | DOI: 10.1002/pola.10408

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      Butyl acrylate emulsion and miniemulsion polymerizations were carried out with an oil-soluble initiator in the presence or absence of an aqueous-phase radical scavenger to investigate the source of radials initiating the polymerizations. It is concluded that (1) for macroemulsion polymerization, the contribution from free radicals originating in the aqueous phase is predominant in the micellar nucleation; (2) free radicals originating in the particle phase contribute to the rate of polymerization; and (3) for polymer particles, polymerization is initiated from free radicals originating in the aqueous phase.

    3. Dramatic decrease of the cis content and molecular weight of cis-transoidal polyphenylacetylene at 23 °C in solutions prepared in air (pages 3212–3220)

      Virgil Percec, Jonathan G. Rudick, Paul Nombel and Wlodzimierz Buchowicz

      Version of Record online: 13 AUG 2002 | DOI: 10.1002/pola.10421

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      cis-Transoidal polyphenylacetylene synthesized with Noyori's catalyst, both in solution and in bulk, in air or under an inert atmosphere, decreases in its cis content and molecular weight. Both in air and under an inert atmosphere, an intramolecular cyclization, followed by chain cleavage accompanied by the release of 1,3,5-triphenylbenzene, is responsible for this process.

    4. Synthesis and polymerization of phosphorus-containing acrylates (pages 3221–3231)

      Duygu Avci and Lon J. Mathias

      Version of Record online: 13 AUG 2002 | DOI: 10.1002/pola.10413

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      Novel phosphorus-containing acrylate monomers were synthesized by two different routes. The first involved the reaction of ethyl α-chloromethyl acrylate and t-butyl α-bromomethyl acrylate with diethylphosphonoacetic acid. The selective hydrolysis of the ethyl ester phosphonic ester compound with trimethylsilyl bromide gave a phosphonic acid monomer. In the second route, ethyl α-hydroxymethyl acrylate and t-butyl α-hydroxymethyl acrylate were reacted with diethylchlorophosphate. The monomers were bulk- and solution-polymerized with 2,2′-azobisisobutyronitrile. The relative reactivities of the monomers in the photopolymerizations were compared.

    5. Synthesis and characterization of functional aliphatic copolyesters (pages 3232–3239)

      Ramaswamy Mani, Mrinal Bhattacharya, Christian Leriche, Li Nie and Sukh Bassi

      Version of Record online: 14 AUG 2002 | DOI: 10.1002/pola.10417

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      Functional aliphatic copolyesters of succinic acid (SA) and citric acid (CA) were synthesized via direct copolycondensation in the presence of 1,4-butanediol, with titanium(IV) butoxide as a catalyst. The effects of the comonomer and comonomer ratio on the polycondensation and the melting and glass-transition temperatures were investigated. The melting temperature was very sensitive to the molar ratio of the SA–CA comonomer units. The chain extension of this poly(butylene succinate citrate) was carried out with hexamethylene diisocyanate. The intrinsic viscosity, crystallinity percentage, and rheological properties of these copolyesters were also studied.

    6. Methylaluminoxane-free ethylene polymerization with in situ activated zirconocene triisobutylaluminum catalysts and silica-supported stabilized borate cocatalysts (pages 3240–3248)

      Sumate Charoenchaidet, Sumaeth Chavadej and Erdogan Gulari

      Version of Record online: 15 AUG 2002 | DOI: 10.1002/pola.10410

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      Heterogenization of tris(pentafluorophenyl)borane [B(C6F5)3] on a silica support stabilized with chlorotriphenylmethane (CICPh3) and N,N-dimethylaniline (HNMe2Ph) creates the following supported borane cocatalysts: [HNMe2Ph]+[B(C6F5)3-SiO2] and [CPh3]+[B(C6F5)3-SiO2]. These supported catalysts were reacted with Cp2ZrCl2 TIBA in situ to generate active metallocene species in the reactor. Triisobutylaluminum (TIBA) was a good coactivator for dichloro-zirconocene, acting as the prealkylating agent to generate cationic zirconocene (Cp2ZrC4H9+). The catalytic performances were determined from the kinetics of ethylene-consumption profiles that were independent of the time dedicated to the activation of the catalysts. The scanning electron microscopy-energy dispersive X-ray measurements showed that B(C6F5)3 dispersed uniformly on the silica support. Under our reaction conditions, the [CPh3]+[B(C6F5)3-SiO2] system had higher productivity and weight-average molecular weight than the [HNMe2Ph]+[B(C6F5)3-SiO2] system. For the [CPh3]+[B(C6F5)3-SiO2] system, the productivity increased with the amount catalyst; however, the polydispersity index of polyethylene synthesized did not change. The final shape of polymer particles was a larger-diameter version of the original support particle. The polymer particles synthesized with supported [CPh3]+[B(C6F5)3-SiO2] catalysts had larger diameters.

    7. Copolymerization of ethene and propene in the presence of Cs symmetric group 4 metallocenes and methylaluminoxane (pages 3249–3255)

      Pasquale Longo, Ermelinda Siani, Stefania Pragliola and Guglielmo Monaco

      Version of Record online: 20 AUG 2002 | DOI: 10.1002/pola.10422

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      Ethene–propene copolymerizations were performed in the presence of Cs symmetric group 4 metallocenes. Substantially alternate, almost random, and blocky copolymers were obtained with titanocene, zirconocene, and hafnocene, respectively, with the bis(dimethylsilyl)-1,1′-2,2′-diyl-(3′,5′-diisopropyl)(4-isopropyl)-(cyclopentadienyl) ligand, and a blocky copolymer was obtained with (diphenyl methylidene)(cyclopentadienyl)(9-fluorenyl)TiCl2.

    8. Diels–Alder modification of poly(ethylene terephthalate-co-anthracene-2,6-carboxylate) with N-substituted maleimides (pages 3256–3263)

      Marian Vargas, Robert M. Kriegel, David M. Collard and David A. Schiraldi

      Version of Record online: 20 AUG 2002 | DOI: 10.1002/pola.10414

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      Poly(ethylene terephthalate-co-anthracene-2,6-dicarboxylate) undergoes Diels–Alder reactions with N-substituted maleimides. The grafting of N-alkyl maleimides affords soluble, hydrophobic polymers, whereas grafting with maleimide-terminated poly(ethylene glycol) affords hydrophilic polymers. The procedure can be applied to thin films, whereby the surface properties are modified.

    9. Decomposition of model alkoxyamines in simple and polymerizing systems. II. Diastereomeric N-(2-methylpropyl)-N-(1-diethyl-phosphono-2,2-dimethyl-propyl)-aminoxyl-based compounds (pages 3264–3283)

      Gennady S. Ananchenko, Marc Souaille, Hanns Fischer, Christophe Le Mercier and Paul Tordo

      Version of Record online: 20 AUG 2002 | DOI: 10.1002/pola.10412

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      A kinetic NMR study of the decomposition of two sets of diastereomeric N-(2-methylpropyl)-N-(1-diethyl-phosphono-2,2-dimethyl-propyl)-aminoxyl (DEPN)-based alkoxyamines at 100 °C in the absence and presence of styrene and methyl methacrylate yielded rate constants for the individual reactions. They are compatible with the applicability of DEPN in living and controlled radical polymerizations of styrene and n-butylacrylate and are used in comparison to DEPN and 2,2,6,6-tetramethylpiperidinyl-1-oxyl as mediators of such processes.

    10. Photoinitiated polymerization of styrene from self-assembled monolayers on gold. II. Grafting rates and extraction (pages 3284–3291)

      Rituparna Paul, Rolf Schmidt, Jianxin Feng and Daniel J. Dyer

      Version of Record online: 20 AUG 2002 | DOI: 10.1002/pola.10418

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      Ultrathin films of polystyrene (PS) were grown from self-assembled monolayers by the “grafting-from” technique. The initiating system consisted of a dithiol azobisisobutyronitrile-type free-radical initiator (1) that was activated by irradiation at 300 nm. The thickness of the PS films ranged from 7 to 190 nm and could be controlled by varying the reaction time or the monomer concentration.

    11. Structural analysis of polyethene prepared with rac-dimethylsilylbis(indenyl)zirconium dichloride/methylaluminoxane in a high-temperature, continuously stirred tank reactor (pages 3292–3301)

      Esa Kokko, Wen-Jun Wang, Jukka V. Seppälä and Shiping Zhu

      Version of Record online: 20 AUG 2002 | DOI: 10.1002/pola.10423

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      The polymerization of structurally simple monomers to produce structurally rich polymers provides a fascinating research field because mechanical and rheological properties of the polymers strongly depend on chain structures. In this work, polyethylenes containing small amounts of methyl, ethyl, and long-chain branching were produced, and branching and chain termination mechanisms were elucidated. Ethene polymerization was carried out in solution (140 °C) with a continuously stirred tank reactor system, and 13C NMR, gel permeation chromatography, Fourier transform infrared, and rheological measurements were used for polymer analyses.

    12. Isobutene polymerization initiated by [CP*TiMe2]+ in the presence of a series of novel, weakly coordinating counteranions (pages 3302–3311)

      K. Rajesh Kumar, Chernoff Hall, Anca Penciu, Mark J. Drewitt, Paula J. McInenly and Michael C. Baird

      Version of Record online: 21 AUG 2002 | DOI: 10.1002/pola.10416

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      The complexes Cp*TiMe2(μ-Me)B(C6F5)3 and [Cp*TiMe2][(n-C18H37E)B(C6F5)3] (E = O, S) are excellent initiators in toluene for the controlled polymerization of isobutene in the studied temperature range.

    13. Chemiluminescence of polyethylene: The comparative antioxidant effectiveness of phenolic stabilizers in low-density polyethylene (pages 3312–3326)

      Fernando Catalina, Carmen Peinado, Norman S. Allen and Teresa Corrales

      Version of Record online: 21 AUG 2002 | DOI: 10.1002/pola.10419

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      The thermal stabilizing efficiency of a range of phenolic antioxidants (Lowinox CA22, Lowinox WPS, Lowinox TBP6, Irganox 3114, Irganox 1330, and Cyanox 1790) was determined in polyethylene films with chemiluminescence and hydroperoxide analysis. Under both nitrogen and oxygen conditions, good correlations were obtained between the two methods, confirming the importance and role of the hydroperoxide functionality and its stability in the oxidative process in polymers. Some of the antioxidants themselves under nitrogen exhibited strong chemiluminescence, which appeared to be a legacy associated with their manufacturing history and the partial oxidation of their structures, which gave oxygenated peroxide functionalities. Under normal practical conditions, such levels of chemiluminescence do not contribute significantly to measurements of stabilized polymer materials.