Origin of toughness in β-polypropylene: The effect of molecular mobility in the amorphous phase

Policianova, Olivia; Hodan, Jiří; Brus, Jiřı́; Kotek, Jiřı́

doi:10.1016/j.polymer.2015.01.047

Cited by 20 publications

(13 citation statements)

References 34 publications

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“…The amount MAF on the other hand is the largest for β ‐iPP (hence, the logarithmic scale). This observation is confirmed by the work of Policianova et al, where solid‐state NMR was used to investigate the molecular mobility in the amorphous and crystalline domains of α and β ‐iPP. Compared to β ‐crystals, the α ‐crystals exhibit larger restrictions on the chain mobility in the crystals, as well as in the constrained amorphous domains.…”

Section: Resultssupporting

confidence: 66%

Deformation and failure kinetics of iPP polymorphs

Caelers

Parodi

Cavallo

et al. 2017

J. Polym. Sci. Part B: Polym. Phys.

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In this study, the mechanical performance of the different polymorphs of isotactic polypropylene, typically present in iPP crystallized under industrial processing conditions, is assessed. Different preparation strategies were used to obtain samples consisting of almost solely a, b, or c crystals. X-Ray measurements were used to validate that the desired phase was obtained. The intrinsic true stress -true strain response of all individual phases was measured in uniaxial compression at several strain rates (deformation kinetics). Moreover, measurements were performed over a wide temperature range, covering the window in between the glass transition and the melting temperature. The relation between obtained yield stress and the strain rate is described with a modification of the Ree-Eyring model. Differences and similarities in the deformation kinetics of the different phases are presented and discussed. Furthermore, the presence of three deformation processes, acting in parallel, is revealed. The ReeEyring equation enables lifetime prediction for given thermal and mechanical conditions. These predictions were experimentally validated using constant load tests in uniaxial compression.

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Section: Resultssupporting

confidence: 66%

Deformation and failure kinetics of iPP polymorphs

Caelers

Parodi

Cavallo

et al. 2017

J. Polym. Sci. Part B: Polym. Phys.

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“…5°. An additional diffraction peak appears at 16.1°, which corresponds to the PP β polymorph [19,20]. This fact indicates that both α and β crystals are formed in MIM PP micro-gears.…”

Section: Effect Of Mold Temperature On the Micro-structure Of Mim Ippmentioning

confidence: 88%

Effect of mold temperature on the structures and mechanical properties of micro-injection molded polypropylene

et al. 2015

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“…Solid state NMR spectroscopy is a powerful tool for studying the polymer segment, structure and dynamics. Macromolecular motions covering a wide range of time scales have long been considered to affect the physical and mechanical properties 37 38 39 40 . Usually, polymers in amorphous state show high-amplitude motions, especially for the temperature above the T g s. As previously mentioned, there are huge differences in physical properties for the amorphous, enantiopure and stereocomplexed-PCXCs in solid state, such as solubility, melting and crystalline behaviour.…”

Section: Resultsmentioning

confidence: 99%

Crystalline CO2-based polycarbonates prepared from racemic catalyst through intramolecularly interlocked assembly

et al. 2015

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The crystalline stereocomplexed polycarbonates can be prepared by mixing enantiopure polymers with opposite configuration, which derived from the asymmetric copolymerization with CO2 using enantiopure catalyst or/and chiral epoxides. Herein, we develop a powerful strategy for producing crystalline intramolecular stereocomplexed polycarbonates from racemic catalysts, which possess similar thermal stability and crystalline behaviour in comparison with the stereocomplexes by mixing opposite enantiopure polymers. Living polymer chains shuttle between catalyst molecules with different configurations to produce diastereomeric active species which is suggested to be responsible for the formation of isotactic multiblock polycarbonates in racemic bimetallic cobalt catalyst-mediated stereoselective copolymerization of CO2 and meso-epoxides. Solid-state NMR spectroscopy study suggests that the interaction in the carbonyl and methine regions is responsible for the strong crystallization capacity and compact package structure in the crystalline polycarbonates.

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Origin of toughness in β-polypropylene: The effect of molecular mobility in the amorphous phase

Cited by 20 publications

References 34 publications

Deformation and failure kinetics of iPP polymorphs

Deformation and failure kinetics of iPP polymorphs

Effect of mold temperature on the structures and mechanical properties of micro-injection molded polypropylene

Crystalline CO2-based polycarbonates prepared from racemic catalyst through intramolecularly interlocked assembly

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