ordinary fabrication process used for processing the iPP in the
current research hardly induced any b-phase crystals. In the case
of b-NA nucleated iPP, distinct peaks at around 16.0 and 21.0
representing the (30 0) and (3 0 1) reflections were found in the
iPP/b-NA at all b-NA compositions, indicating the existence of
the b-crystal phase in the b-NA nucleated iPP. The XRD result
was in agreement with that found in the DSC melting characteristics.
All the XRD patterns evidently suggested that the b-NA
effectively induced b-crystals in the modified iPP. The higher Tc
in the iPP modified with b-NA upon cooling in Fig. 1b suggested
that the crystallization of the b-crystals started at minutely higher
temperature and the b-NA could accelerate the crystallization
of iPP by starting to nucleate earlier and faster than the unmodified
iPP. Further evaluation was made in order to identify the
changes in the relative fraction of the b-phase, as was reflected
by the Kb, with various b-NA concentrations. Overall, the Kb increased
more rapidly with an addition of the b-NA at only
0.05 wt%. Maximum Kb was found at 0.85 when the b-NA composition
reached 0.10 wt%, beyond which the Kb declined slightly
before approaching the saturation stage. This behavior is in agreement
with the work reported by Yi et al. [4] Zhao et al. [30] and
Zhang et al. [31], signifying that the b-NA modified iPP crystallized
rapidly to form the b-crystals to its maximum capacity at
around 0.10 wt%. Further confirmation was made by continuously
observing microscopically the crystallization process of the neat
iPP and the b-NA nucleated iPP, as discussed in Section 3.3.