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Authors
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Du, M. ; Jariyavidyanont, K. ; Kühnert, I. ; Boldt, R. ; Androsch, R.
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Title
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Effect of molar mass on critical specific work of flow for shear-induced crystal nucleation in poly (l-lactic acid)
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Date
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13.04.2021
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Number
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59981
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Abstract
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The concept of specific work of flow has been applied for the analysis of critical shearing conditions for the formation of crystal nuclei in poly (l-lactic acid) (PLLA). Systematic variation in both time and rate of shearing the melt in a parallel-plate rheometer revealed that these parameters are interconvertible regarding the shear-induced formation of crystal nuclei; that is, low shear rate can be compensated for by increasing the shear time and vice versa. This result supports the view that critical shearing conditions can be expressed by a single quantity, providing additional options for tailoring polymer processing routes when enhanced nuclei formation is desired/unwanted. Analysis of PLLA of different mass-average molar masses of 70, 90, 120, and 576 kDa confirmed improved shear-induced crystal nucleation for materials of higher molar mass, with critical specific works of flow, above which shear-induced nuclei formation occurs, of 550, 60, 25, and 5 kPa, respectively.
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Publisher
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Polymers
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Wikidata
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Citation
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Polymers 13 (2021) 1266
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DOI
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https://doi.org/10.3390/POLYM13081266
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Tags
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