Non-isothermal crystallization kinetics and nucleation behavior of isotactic polypropylene composites with micro-talc
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Date
2019
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Abstract
The non-isothermal crystallization (NIC) of isotactic polypropylene (iPP) and its composites with submicronic talc par-
ticles (l-talc) was investigated by differential scanning calorimetry. The modeling of the NIC kinetics of the iPP matrix
was performed using Jeziorny-modified Avrami’s model, Ozawa’s and Mo’s theoretical approaches. The Jeziorny’s and
Ozawa’s theories allowed us to confirm that the l-talc filler particles significantly promote the NIC kinetics of the iPP
matrix which noticeably manifests itself via a change in the nucleation mechanism. However, Mo’s model proved to be the
more relevant model to account for the NIC of the present materials. In parallel, the activation energy and nucleation
activity of NIC were calculated by Kissinger’s and Dobreva’s methods, respectively. Both approaches reveal that a
maximum nucleation activity of l-talc takes place for 20% filler content. This finding is discussed in relation to the l-talc
content thresholds of mechanical percolation and crystallinity saturation that were reported in previous studies for these
composites, about 10 and 30% l-talc, respectively. An endeavor of physical explanation for these phenomena is put
forward.