Nucleation effect of montmorillonite with β-nucleating surface on polymorphous of melt-crystallized isotactic polypropylene nanocomposites

摘要

Neat montmorillonite (MMT) causes strong heterogeneous nucleation of α-phase crystallites in isotactic polypropylene (iPP). By surface modification of MMT with pimelic acid (PA) MMT with tailored β-nucle-ation capacity β-MMT) has been prepared and nanocomposites with β-iPP have been made. The polymorphism of the iPP in the nanocomposites, the effect of β-MMT on the morphology and its crystallization and melting behavior of iPP has been investigated by POM, DSC and XRD. β-MMT raises the crystallization temperature to a higher value than neat MMT. The β-nucleation ability of β-MMT depends both on the MMT/PA ratio and on the β-MMT content in the composite. The fraction of p-crystals with respect to the total amount of crystals increases with increasing β-MMT content and decreasing MMT/PA ratio. It can be adjusted between 0% and 98%. The accomplished surface modification of the MMT provides a simple and efficient way to prepare β-iPP nanocomposites.