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Titolo:
ORDER-DISORDER TRANSITION IN COMB-LIKE BLOCK-COPOLYMERS OBTAINED BY HYDROGEN-BONDING BETWEEN HOMOPOLYMERS AND END-FUNCTIONALIZED OLIGOMERS - POLY(4-VINYLPYRIDINE)-PENTADECYLPHENOL
Autore:
RUOKOLAINEN J; TORKKELI M; SERIMAA R; KOMANSCHEK E; TENBRINKE G; IKKALA O;
Indirizzi:
HELSINKI UNIV TECHNOL,DEPT ENGN MATH & PHYS,RAKENTAJANAUKIO 2 FIN-02150 ESPOO FINLAND HELSINKI UNIV TECHNOL,DEPT ENGN MATH & PHYS FIN-02150 ESPOO FINLAND UNIV HELSINKI,DEPT PHYS FIN-00014 HELSINKI FINLAND SERC,DARESBURY LAB WARRINGTON WA4 4AD CHESHIRE ENGLAND UNIV GRONINGEN,CTR MAT SCI NL-9747 AG GRONINGEN NETHERLANDS UNIV GRONINGEN,DEPT POLYMER SCI NL-9747 AG GRONINGEN NETHERLANDS
Titolo Testata:
Macromolecules
fascicolo: 7, volume: 30, anno: 1997,
pagine: 2002 - 2007
SICI:
0024-9297(1997)30:7<2002:OTICBO>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
MICROPHASE SEPARATION TRANSITION; POLYELECTROLYTE-SURFACTANT COMPLEXES; DYNAMIC MECHANICAL-PROPERTIES; POLYISOPRENE COPOLYMERS; DIBLOCK COPOLYMERS; MESOMORPHIC STATE; MOLECULAR-WEIGHT; TEMPERATURE; SCATTERING; RHEOLOGY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
49
Recensione:
Indirizzi per estratti:
Citazione:
J. Ruokolainen et al., "ORDER-DISORDER TRANSITION IN COMB-LIKE BLOCK-COPOLYMERS OBTAINED BY HYDROGEN-BONDING BETWEEN HOMOPOLYMERS AND END-FUNCTIONALIZED OLIGOMERS - POLY(4-VINYLPYRIDINE)-PENTADECYLPHENOL", Macromolecules, 30(7), 1997, pp. 2002-2007

Abstract

Dynamic mechanical spectroscopy (DMS) is used to further investigate the recently observed order-disorder transition (ODT) in comblike block copolymers obtained by hydrogen bonding between poly(4-vinylpyridine) and pentadecylphenol (P4VP-PDPx). For stoichiometric amounts of pyridine and phenol, i.e., z = 1.0, the ODT to a lamellar structure occursat T similar or equal to 65 degrees C. The dynamic moduli G' and G ''simultaneously show a crossover from a liquidlike behavior (G' similar to omega(1.5) and G '' similar to omega) to a response intermediate between a Newtonian fluid and a solid (G' approximate to G'' similar to omega(1/2)). The behavior above T-ODT differs slightly from a homopolymer melt (G' similar to omega(2.0)) due to composition fluctuations,whereas the behavior below T-ODT is characteristic for quenched blockcopolymer lamellar phases with local uniaxial order and global isotropy. Near room temperature, a transition to solid behavior (G similar to omega(0)) takes place due to crystallization of the alkyl side chains. Larger amounts of PDP lower the T-ODT temperature, and for x = 2.0 the transition to solid response occurs directly from the disordered state. Small and wide angle X-ray scattering (SAXS and WAXS) experiments and differential scanning calorimetry (DSC) corroborate these findings. Furthermore, SAXS and WAXS demonstrate that the low-temperature state of P4VP-PDP2.0 is not stable and indicate that ultimately macrophase separation into a pure crystalline PDP phase and a microphase separated P4VP-PDP phase occurs.

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Documento generato il 02/12/20 alle ore 15:31:10