A simple model of flow-induced crystallization memory |
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| Authors: | Andrzej Ziabicki Giovanni Carlo Alfonso |
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| Affiliation: | 1. Polish Academy of Sciences, Institute of Fundamental Technological Research, 21 Swietokrzyska St., Warsaw, Poland;2. Institute of Chemistry and Industrial Chemistry, University of Genoa, via Dodecanese 31, Genoa, Italy |
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| Abstract: | Flow induced crystallization of polymer systems exhibits strong memory effects. Crystalline structures gradually change when the flow is switched off and the polymer is relaxed prior to crystallization. A simple model based on the multidimensional theory of crystal nucleation[1] is proposed. Steady, potential flow applied to a polymer fluid above melting temperature (Tp > Tm) results in molecular orientation of crystallizing units. The flow controls formation of molecular clusters which convert into athermal nuclei when the system is cooled down to crystallization temperature, Tc < Tm. Orientation effects gradually disappear when the melt is relaxed above Tm in the absence of flow or stress. |
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