The film casting process of an isotactic polypropylene was adopted as the source of data to evaluate the behavior of a crystallizing polymer. The increase in viscosity due to the crystallization was quantified, and a model was proposed to estimate the normalized rheological function (NRF) during the process. The estimation was based also on the availability of rich sets of data, i.e., the polymer temperature and crystallinity, the film velocity and width distribution along the draw direction, gathered during the process. The quasi-experimental NRF evolutions were compared with just two of the very numerous hardening models proposed in literature, and the main result is that the process is coherent with the choice of an NRF model which predicts the increase in viscosity only for substantial crystallinity amount.
Process validation of the normalized rheological function behavior during polymer crystallization
LAMBERTI, Gaetano
2012-01-01
Abstract
The film casting process of an isotactic polypropylene was adopted as the source of data to evaluate the behavior of a crystallizing polymer. The increase in viscosity due to the crystallization was quantified, and a model was proposed to estimate the normalized rheological function (NRF) during the process. The estimation was based also on the availability of rich sets of data, i.e., the polymer temperature and crystallinity, the film velocity and width distribution along the draw direction, gathered during the process. The quasi-experimental NRF evolutions were compared with just two of the very numerous hardening models proposed in literature, and the main result is that the process is coherent with the choice of an NRF model which predicts the increase in viscosity only for substantial crystallinity amount.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
