Authors Chen, J. ; Schneider, K. ; Gao, S.-L. ; Vogel, R. ; Heinrich, G.
Title In-situ synchrotron X-ray studies of crystallization of b-nucleated iPP subjected to a wide range of shera rates and shear temperatures
Date 12.10.2015
Abstract Previous study focused on the shear-induced crystallization of ß-nucleated iPP under fixed shear rate and temperature [1]. In this work, in-situ synchrotron X-ray was used to investigate the crystallization behavior of well-selected ß-nucleated iPP under thermo-mechanical conditions in a wide range of shear rates from 2 to 50 s-1 and shear temperatures from 133 to 150 °C. At lower shear rates, we found that the overall crystallization rate of the ß-nucleated iPP was reduced compared with that under quiescent condition. This is mainly ascribed to variation of nucleation-dependent process after application of shear pulse, causing strong reduction of ß-nucleating efficiency. As the shear rate increases from 2 to 50 s-1, the dimensionality of crystal growth basically decreased while the long period of lamellar structure tended to slightly increase. During the shear-induced crystallization, a decreasing temperature was significantly associated with decreased overall dimensionality of crystal growth but increased crystallization rate. Finally, we observed an abnormal increase of long period with time for ß-nucleated iPP sheared at 133 °C.
Journal Polymer 76 (2015) 182-190

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