Nanostructure Evolution in Poly(propylene) During Mechanical Testing

Stribeck, Norbert; Nöchel, Ulrich; Funari, Sérgio S.; Schubert, Tom; Timmann, Andreas

doi:10.1002/macp.200800199

Cited by 32 publications

(32 citation statements)

References 56 publications

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“…Let us call this mechanism domain defragmentation. The PA6-materials, on the other hand, exhibit a more complex response to load-cycling that has also been found in a study [48] of pure polypropylene ( (Figure 14a)). Here low stress suffices to extend and to crystallize pre-ordered HDPE chains that coat the crystalline domains.…”

Section: Response Of the Lateral Nanoscopic Strainsupporting

confidence: 70%

“…Here, during the initial straining branch, ε n,l (t) is first increasing for small t showing domain-growth at low ε. We propose to explain this growth of the crystalline domains by strain-induced crystallization [48] ("epitaxial strain crystallization"). From higher ε and σ , the average ε n,l (t) begins to decrease.…”

Section: Response Of the Lateral Nanoscopic Strainmentioning

confidence: 99%

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Nanostructure Evolution Mechanisms During Slow Load‐Cycling of Oriented HDPE/PA Microfibrillar Blends as a Function of Composition

Zeinolebadi

Stribeck

Sari

et al. 2012

Macro Materials & Eng

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Oriented precursors of MFCs consisting of HDPE and PA6 or PA12 are studied during strain‐controlled slow load‐cycling. In the PA6‐containing blends a strongly retarded nanostrain response is detected. Compatibilization induces nanostrain heterogenization. Stress fatigue is lower in the PA12 blends, but hardly decreased by the compatibilizer. Selective migration of the compatibilizer into a disordered semi‐crystalline fraction of the HDPE matrix can explain the findings. The semi‐crystalline HDPE entities in PA6 blends appear more disordered than in PA12‐blends. An analysis of the HDPE nanostructure evolution during cycling reveals epitaxial strain crystallization. Uncompatibilized PA6 blends cycled about high pre‐strain show plastic flow but nanoscopic shrinkage in the semi‐crystalline stacks. magnified image

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Section: Response Of the Lateral Nanoscopic Strainsupporting

confidence: 70%

Section: Response Of the Lateral Nanoscopic Strainmentioning

confidence: 99%

Nanostructure Evolution Mechanisms During Slow Load‐Cycling of Oriented HDPE/PA Microfibrillar Blends as a Function of Composition

Zeinolebadi

Stribeck

Sari

et al. 2012

Macro Materials & Eng

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“…The determination of relations between mechanical properties and changes in internal morphology by X-ray diffraction is lately easier because the sources of powerful synchrotron radiation are more widely accessible. Results of in-situ SAXS and WAXS measurements were described for many polymers: polypropylene [20,21], poly(vinylidene fluoride) [22], polyamide [23] and polyethylene [24,25]. Usually the studies were focused on the changes in crystalline phase morphology.…”

Section: Introductionmentioning

confidence: 99%

Cavitation during tensile drawing of annealed high density polyethylene

Pawlak

Gałęski

2010

Polymer

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The annealing of semicrystalline polymers usually leads to the crystal refinement and thickening. It appears that also the cavitation during tensile drawing is affected. In the uniaxially drawn high density polyethylene a massive cavitation was detected by X-ray scattering in samples previously annealed at 125 o C. The number of voids depends on the annealing time, while their size and orientation depends on the local strain. The cavitation resulted in 30% increase of volume for annealed samples, strained to 4-5. Cavitation and volume increase were not observed for small and intermediate strains if the polyethylene samples were not annealed. The decrease of drawing rate results in reducing cavitation and also the void stability: at the low strain rate voids were detected during tensile drawing but they disappeared after unloading the sample.

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“…An in-depth discussion of the zones indicated in Fig. 9 is in the original paper [39]. In particular, the combination of SAXS and fatigue test shows the transition from stress-induced crystallization to crystallite rupture σ (t) ≈ 20 MPa.…”

Section: Mapping Of Waxs Patternsmentioning

confidence: 95%

“…Slow continuous mechanical tests of oriented PP are monitored [39] by SAXS and quantitatively evaluated by the CDF [37] method. Fatigue is studied in a load-reversal experiment (between 10% and 35% strain, Fig.…”

Section: Mapping Of Waxs Patternsmentioning

confidence: 99%

Advanced X-Ray scattering methods for the study of structure and its evolution in soft materials with fiber symmetry

Stribeck¹

2010

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Three recently developed evaluation methods for the automated quantitative analysis of Xray scattering data (small-angle (SAXS) and wide-angle (WAXS)) are presented. They are applicable to extensive series of 2D patterns that are recorded in studies of polymer materials with uniaxial symmetry. The experiments comprise time-resolved studies (melting, crystallization, mechanical properties and fatigue) as well as microbeam-scanning for the study of nanostructure gradients. The methods appear suitable to manage the data flood from modern synchrotron radiation setups aiming at the extraction of quantitative information on the structure evolution inside the material.In microbeam-scanning experiments the recorded scattering patterns are smeared. It is proposed to reconstruct desmeared scattering patterns by an X-ray scattering fiber-computer-tomography (XS-FCT). Reconstruction aberrations yield additional structure information. The true structure variation along the fiber radius is established. Compared to general tomography the experiment is faster by a factor of 100, and reconstruction is faster by a factor of 10 4 . In WAXS fiber patterns should first be mapped into reciprocal space before analysis. After having corrected an erroneous tilt-angle equation, automatic tilt-angle tracking and mapping becomes possible. If polymers fail at low strain, the determination of strain and of structural parameters from the scattering patterns require very high accuracy because the observed variations are subtle. Suitable methods are presented both for the high-precision determination of the macroscopic strain, and for the determination of subtle variations of structure parameters.

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Nanostructure Evolution in Poly(propylene) During Mechanical Testing

Cited by 32 publications

References 56 publications

Nanostructure Evolution Mechanisms During Slow Load‐Cycling of Oriented HDPE/PA Microfibrillar Blends as a Function of Composition

Nanostructure Evolution Mechanisms During Slow Load‐Cycling of Oriented HDPE/PA Microfibrillar Blends as a Function of Composition

Cavitation during tensile drawing of annealed high density polyethylene

Advanced X-Ray scattering methods for the study of structure and its evolution in soft materials with fiber symmetry

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