Abstract
Flexural moduli (FM), and heat distortion temperature (HDT) of polypropylenes (PPs) were high in PPs with high isotacticity or with low molecular weight. These two characteristics of PPs were not affected by the crystallinity estimated with X-ray diffraction patterns. The degrees of the two characteristics seemed to depend on the total amount of the “intermediate phases” which are located between adjacent crystal units; the more the amount of intermediate phase, the higher the degree of FM and HDT. Areas of tanδ-peaks, which correlate to molecular mobility, corresponded inversely to the degrees of FM and HDT. The lengths of the long periods, which were measured by X-ray diffraction, corresponded to the molecular weight, but did not have any correlation to the degree of three dimensional regularity of PP-polymers. The sizes of crystal lattice of PP-1-3 were similar to each other irrespective of their molecular weights. The growth rate of each crystal was high in the PPs with the low molecular weight and with high three dimensional regularity. A new model of PP-polymers was proposed, in which the intermediate phases are indicated in three different PP-polymers.
