The influence of a specific nano-scaled styrene butadiene rubber based b-nucleating agent (b-NA) on the
properties of isotactic polypropylene (iPP) was investigated in the current research. b-NA was applied at
the concentration ranged from 0.05 to 0.50 wt%. Microscopic observation revealed that the neat iPP crystals
grew very slowly; they ranged in size from 100 to 200 lm. The addition of b-NA led to higher population
of nuclei and smaller spherulites than those found in neat iPP. The addition of only 0.05 wt% b-NA
significantly decreased the sizes of the spherulites down to 5 lm; the crystal grew very rapidly, leading to
extremely fine morphology. Analysis by X-ray diffraction (XRD) confirmed that iPP/b-NA constituted
mainly of b-crystal structure. The transformation of b to a phase was observed upon re-extrusion, it
was verified by the lowered fraction of the b-crystalline phase (Kb) although the total degree of crystallinity
remained unchanged. A significant improvement in the impact strength of the iPP/b-NA was
observed when the b-NA was employed from 0.10 to 0.20 wt%, leading to the formation of tough b-crystals
in the b-NA nucleated iPP. The color measurement implied that the iPP nucleated with b-NA was superior
in terms of whiteness but it was less transparent, as was evident by the increased haze.