Phase structure and thermal behaviour of polypropylene/hydrogenated poly(cyclopentadiene) blends.

Isothermally crystallized blends of isotactic polypropylene (iPP) with saturated polycyclopentadiene (PCP) were examined by differential scanning calorimetry and wide- and small-angle X-ray scattering. The presence of PCP did not interfere with the apparent crystal size, and a possible correction by paracrystallinity or microstrain did not produce a significant difference. The long period increased as a function of PCP content, which suggests its distribution in the intedamellar regions. The samples were subjected to chloroform extraction. This solvent, able to remove the PCP fraction, produces a rearrangement of the remaining iPP structure. The crystallinity and apparent crystal size did not change, whereas the microstrain correction became more significant. The long period assumed a new value which was the same for all extracted blends. Density measurements showed swelling of the amorphous phase. The specific volumes of the extracted blends depended on the initial PCP content.