Polymers, Vol. 14, Pages 88: Crystallization of Isotactic Polypropylene Nanocomposites with Fibrillated Poly(tetrafluoroethylene) under Elevated Pressure
Polymers doi: 10.3390/polym14010088
Nanocomposites of isotactic polypropylene with 1&ndash;5 wt.% of fibrillated PTFE (PP/T) were prepared, and their crystallization during cooling under elevated pressure, in a wide pressure range, up to 300 MPa, as well as the resulting structure, were examined. The crystallization peak temperatures of PP/T, especially with 3 and 5 wt.% of PTFE, exceeded by up to 13 &deg;C those of neat PP. Moreover, a fine-grain structure was formed in PP/T in the entire pressure range, which proved the ability of the fibrillated PTFE to nucleate crystallization of PP in the &gamma;-form under elevated pressure. This also resulted in a higher crystallinity level developed in the &gamma;-domain, before the temperature range of the &alpha;-domain was reached during cooling. Hence, the &gamma;-content increased in comparison to that in neat PP, under the pressure up to 200 MPa, especially under 50&ndash;100 MPa.
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