Fig. 1a illustrates the DSC heating thermogram of the iPP and
the SBR-based b-NA modified iPP. Single melting peak was observed
in the neat iPP. With the presence of b-NA, the nucleated
iPP exhibited two distinct melting peaks at around 150 C and
168 C. The lower melting peak (the left one) corresponded to
the melting temperature of the b-phase while the higher one represented
that of the a-phase in the nucleated iPP [4,30,31–36]. The
DSC results evidently showed that the b-NA was capable of inducing
two different crystal phases in the iPP, which were subsequently
verified by XRD to be a- and b-crystals.