Relations between morphology and micromechanical properties of alpha, beta and gamma phases of iPP

0488784 - ÚMCH 2019 RIV GB eng J - Journal Article
Šlouf, Miroslav - Pavlova, Ewa - Krejčíková, Sabina - Ostafinska, Aleksandra - Zhigunov, Alexander - Krzyžánek, Vladislav - Sowinski, P. - Piorkowska, E.
Relations between morphology and micromechanical properties of alpha, beta and gamma phases of iPP.
Polymer Testing. Roč. 67, May (2018), s. 522-532. ISSN 0142-9418. E-ISSN 1873-2348
R&D Projects: GA MZd(CZ) NV15-31269A; GA TA ČR(CZ) TE01020118; GA MŠMT(CZ) LO1507
Grant - others:AV ČR(CZ) PAN-17-18
Program: Bilaterální spolupráce
Institutional support: RVO:61389013 ; RVO:68081731
Keywords : polypropylene * gamma-phase * micromechanical properties
OECD category: Polymer science; Electrical and electronic engineering (UPT-D)
Impact factor: 2.943, year: 2018

The relations between crystalline structure and micromechanical properties of alpha-, beta- and gamma-phase of isotactic polypropylene (iPP) were investigated. The iPP samples with various crystalline phase compositions were prepared by a controlled high-pressure crystallization that enabled us to obtain not only alpha-iPP and beta-iPP modifications, but also a series of almost pure gamma-iPP samples with gradually changing morphology, crystallinity and lamellar thickness. The micromechanical properties were assessed by instrumented microindentation hardness testing (MHI), from which we determined indentation hardness (HIT), indentation modulus (EIT), indentation creep (CIT) and elastic part of the indentation work (ηIT). It was demonstrated that gamma-iPP does not necessarily exhibit better mechanical performance than alpha- and beta-iPP, as suggested by some previous studies, because the final properties are strongly influenced not only by the phase composition (i.e. by the content of alpha-, beta- and gamma-phase), but also by the overall crystallinity.
Permanent Link: http://hdl.handle.net/11104/0283378