Počet záznamů: 1  

Origin of toughness in .beta.-polypropylene: the effect of molecular mobility in the amorphous phase

  1. 1.
    0440934 - ÚMCH 2016 RIV GB eng J - Článek v odborném periodiku
    Policianová, Olivia - Hodan, Jiří - Brus, Jiří - Kotek, Jiří
    Origin of toughness in .beta.-polypropylene: the effect of molecular mobility in the amorphous phase.
    Polymer. Roč. 60, 9 March (2015), s. 107-114. ISSN 0032-3861. E-ISSN 1873-2291
    Grant CEP: GA ČR(CZ) GA13-29009S
    Institucionální podpora: RVO:61389013
    Klíčová slova: isotactic polypropylene * β-modification * toughness
    Kód oboru RIV: JI - Kompozitní materiály
    Impakt faktor: 3.586, rok: 2015

    This study aims to explore the origin of toughness in β-phase isotactic polypropylene (i-PP). Samples of commercial-grade i-PP, both neat and nucleated with a specific β-nucleating agent (N,N′-dicyclohexylnaphthalene-2,6-dicarboxamide), were subjected to a combination of structure-sensitive methods and fracture mechanical testing. In addition to common structural characterisation methods, solid-state NMR data were collected to obtain information about the dynamics of the polymer segments as well as the structure. In particular, temperate-induced transformation between the free and constrained amorphous phase was monitored by variable-temperature 13C MAS NMR, whereas T1ρ(1H) relaxation was used to estimate correlations times of segmental motions. Lower thermodynamic stability of rigid amorphous fraction was found in the β-crystalline systems. In contrast helical chains in crystalline and constrained amorphous phase were found to be more restrained in the α-crystalline system. Overall, the results indicate larger restrictions in chain mobility in the amorphous phase of the α-polymorphic PP system than in that of the β-crystalline ones.
    Trvalý link: http://hdl.handle.net/11104/0246163

     
     
Počet záznamů: 1  

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