In this work, the effect of shear rate on the isothermal crystallization of a poly(lactic acid), PLA, was analyzed. The crystallinity evolution of PLA during continuous shear was assessed by collecting X-ray diffraction data at short time intervals by adopting a synchrotron source. Shear rates in the range from 0.1 s(-1) to 1.5 s(-1) were analyzed. It was found that increasing the shear rate induced a dramatic decrease of the half crystallization times, more than one order of magnitude in the analyzed range of shear rates. A model for the description of crystallinity evolution was applied to describe the experimental results. It was found that the nucleation rate needed to describe the data are much larger than what measured in a previous work in the same range of shear rates but adopting a short step shear protocol.
Crystallization of Poly(lactic acid) under continuous shear conditions: On-line x-ray analysis in isothermal conditions
Volpe, Valentina
;Pantani, Roberto
2023-01-01
Abstract
In this work, the effect of shear rate on the isothermal crystallization of a poly(lactic acid), PLA, was analyzed. The crystallinity evolution of PLA during continuous shear was assessed by collecting X-ray diffraction data at short time intervals by adopting a synchrotron source. Shear rates in the range from 0.1 s(-1) to 1.5 s(-1) were analyzed. It was found that increasing the shear rate induced a dramatic decrease of the half crystallization times, more than one order of magnitude in the analyzed range of shear rates. A model for the description of crystallinity evolution was applied to describe the experimental results. It was found that the nucleation rate needed to describe the data are much larger than what measured in a previous work in the same range of shear rates but adopting a short step shear protocol.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
