Crystallization behaviors and optical properties of isotactic polypropylene: comparative study of a trisamide and a rosin-type nucleating agent

The effects of concentrations of N, N’, N”-tris- tert. butyl- 1,3,5- benzene- tricarboxamide (NA) and a hemiacid of dehydroabietic acid (1:1 K) on the optical properties of iPP were compared with each other. It revealed that the NA was an effective transparent nucleating agent for iPP. The NA had advantage at very concentration (0.02 wt%), while the 1:1 K had some advantage at high concentrations (0.3 wt%∼0.5 wt%), The optimal concentration range of the NA was 0.1 wt% to 0.4 wt%, while the value for 1:1 K was 0.3 wt% to 0.5 wt%. The absence of detectable spherulites in nucleated iPP was confirmed by SEM and POM. This was an important reason why the nucleated iPPP showed improved optical properties. The results of WAXD showed that preferential growth along the b-axis during crystallization and more disordered structures were formed in the nucleated samples. The results of DSC disclosed increased crystallization peak temperature and melting temperature in the nucleated samples.