G. Romano et al., INFLUENCE OF AGING ON THE MECHANICAL-PROPERTIES OF SMECTIC POLYPROPYLENE, Journal of macromolecular science. Physics, B37(6), 1998, pp. 841-850
Isotactic polypropylene (iPP) was quenched to the smectic state and an
alyzed during aging at room temperature for very long times, up to fiv
e years. Calorimetric differential scanning calorimetry (DSC) curves,
dynamic mechanical behavior, and mechanical properties were used to an
alyze the aged samples and data were compared with the results for the
fresh sample. The obtained results can be explained by a reduction of
free volume of the amorphous phase, as well as a concomitant increase
of the smectic domains' dimensions. A good correlation was found betw
een some calorimetric and mechanical parameters.