The crystallization behavior, the physical properties and the crystal morphology of b-NA nucleated iPP were investigated in the current research. Experimental results indicated that the crys- tallization temperature of iPP was raised to about 120 °C upon the addition of b-NA by only 0.20 wt%. Double DSC melting peaks ver- ified the existence of both b and a phase in the b-NA modified iPP.
XRD patterns confirmed the predominant existence of the b-crystal phase by around 0.85 (or 85%) when 0.10 wt% of b-NA was em- ployed. The transformation of b to a phase, indicated by the low- ered Kb, was observed upon re-heating by re-extrusion. The average crystal size of the b-NA modified iPP was remarkably de- creased compared to that of the iPP. Microscopic observation re- vealed that the iPP crystals grew very slowly with sizes ranging from 100–200 lm. The presence of the nano-scaled b-NA led to higher population of nuclei and a dramatic decrease in the sizes of the spherulites; the crystals grew very rapidly, leading to extre- mely fine morphology. The impact strength of the iPP/b-NA im- proved substantially when 0.10–0.20 wt% b-NA was employed; this was due to the predominant existence of the b-crystals in the crystal morphology. The color measurement implied that the clarity of the iPP/b-NA blends was reduced with greater b-NA con- tent. Injection molding products is a good application of the b- nucleated iPP due to its rapid crystallization rate and requirements of shorter time in the mold. Hence, the cycle time for injection molding can be reduced significantly.