Isothermal Nanocalorimetry of Isotactic Polypropylene

Santis, Felice De; Adamovsky, Sergey; Titomanlio, G.; Schick, Christoph

doi:10.1021/ma071491b

Cited by 152 publications

(130 citation statements)

References 61 publications

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“…From Fig. 3A, it is observed that virgin i-PP shows the characteristic double bell-shaped curve [51]. The observed kink at 40 C is attributed to a change from the a-crystal phase at higher crystallization temperatures to a combination of the a-crystal and mesomorphic structure at lower isothermal crystallization temperatures.…”

Section: Isothermal Fast Cooling Of Nucleated and Non-nucleated I-ppmentioning

confidence: 87%

Fast cooling of (non)-nucleated virgin and recycled poly(propylenes): Effect of processing conditions on structural and mechanical properties

et al. 2015

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. Fast cooling of (non)-nucleated virgin and recycled poly(propylenes) : effect of processing conditions on structural and mechanical properties. Thermochimica Acta, 603, 94-102. DOI: 10.1016/j.tca.2014 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. A B S T R A C TIn this study, the effect of processing parameters, i.e., the cooling rate and pressure, on the structureproperty relationships for nucleated and non-nucleated i-PP from virgin and recycled sources was investigated. Special attention was given to the brittle-to-ductile transition of nucleated i-PP from plastic packaging waste. Differential fast scanning calorimetry and dilatometry were used to mimic industrial process conditions. From the calorimetric experiments, it was observed that under ambient pressure the mesomorphic phase was formed upon fast cooling, which was confirmed by WAXD analysis. The dilatometry results showed that by applying pressure also g-phase crystals are formed. Nucleated samples showed an increased tendency for the g-phase formation and a decreased tendency for mesomorphic phase formation. Up to now, recycled i-PP showed a brittle behavior, but this study showed that by applying a sufficiently high cooling rate, the yield stress can be reduced and a stabilization of the deformation can be obtained leading to a ductile behavior for recycled i-PP.

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Section: Isothermal Fast Cooling Of Nucleated and Non-nucleated I-ppmentioning

confidence: 87%

Fast cooling of (non)-nucleated virgin and recycled poly(propylenes): Effect of processing conditions on structural and mechanical properties

et al. 2015

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“…Recent analysis of the temperature dependence of the crystallization rate by fast scanning chip calorimetry (FSC) of several polymers including isotactic polypropylene (iPP) and its random copolymers with 1-alkenes [20][21][22], or poly (butylene terephthalate) [23], indeed revealed two separate maxima which were discussed of being related to heterogeneous and homogeneous nucleation effective at relatively low and high supercooling, respectively. Similar FSC studies were also performed on PA 6 [24], however did not yet reveal an unambiguous picture regarding the effect of variation of the nucleation mechanism on the crystallization rate.…”

Section: Introductionmentioning

confidence: 99%

Morphology of cold-crystallized polyamide 6

2012

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The structure of cold-crystallized polyamide 6 (PA 6) has been analyzed by wide-angle X-ray scattering, atomic force microscopy, and polarizing optical microscopy. It has been found that ordering of initially fully amorphous and glassy PA 6 on slow heating to temperatures higher than the glass transition temperature results in formation of spatially non-organized short lamellae/nodules with a size depending on the maximum annealing temperature. In contrast, melt crystallization at low supercooling is connected with formation of spherulites and laterally extended lamellae. The observed experimental results demonstrate that crystals of qualitatively different morphology and higherorder organization can be generated by variation of the pathway of crystallization. It is assumed that the different structures obtained in melt-and cold-crystallized samples are related to heterogeneous and homogeneous nucleation, respectively.

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“…The molecular weight distribution was determined by a size exclusion chromatography, with weight-average molar mass Mw of 376 kg mol -1 , polydispersity index M w /M n of 6.7, and a meso-pentads content 87.6%. The glass transition temperature (T g ) and the nominal melting temperature of Moplen T30G i-PP are -15 °C and 166 °C, respectively [1][2][3].…”

Section: Methodsmentioning

confidence: 99%

Spherulitic nucleation and growth rates in a sheared polypropylene melt

Santis¹,

Scermino²,

Pantani³

et al. 2014

AIP Conference Proceedings

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In common polymer processing operations such as injection molding, film blowing, and fiber spinning, the molten polymer is subjected to intense shear and/or elongational flow fields and crystallizes during or after the application of flow. The semicrystalline morphology that develops in the final product is typically very different from what is observed during quiescent crystallization of the same polymer, and the properties change accordingly. The possibility of controlling the final morphology and the resulting mechanical and functional properties of semicrystalline polymers based on the study of polymer melt crystallization stimulated by flow is highly intriguing. This work starts from the experimental evidence that there exists qualitatively three regimes of crystallization under shear: (a) very low shear rates, in which there is no effect on kinetics; (b) higher shear rates, in which orientational effects enhance just the nucleation and growth rates, and spherulitic crystallization is observed; and (c) high shear rates, in which molecular stretching occurs giving rise to a fibrillar morphology development under very fast kinetics. The first two regimes are explored and analyzed by means of experimental protocols developed on purpose. In particular: -spherulitic nucleation and growth rates under continuous shear rates were carefully measured and related to molecular strain -the condition below which crystallization turns out to be essentially quiescent was evidenced.

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Isothermal Nanocalorimetry of Isotactic Polypropylene

Cited by 152 publications

References 61 publications

Fast cooling of (non)-nucleated virgin and recycled poly(propylenes): Effect of processing conditions on structural and mechanical properties

Fast cooling of (non)-nucleated virgin and recycled poly(propylenes): Effect of processing conditions on structural and mechanical properties

Morphology of cold-crystallized polyamide 6

Spherulitic nucleation and growth rates in a sheared polypropylene melt

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