Nucleation effect of montmorillonite with [beta]-nucleating surface on polymorphous of melt-crystallized isotactic polypropylene nanocomposites

Neat montmorillonite (MMT) causes strong heterogeneous nucleation of [alpha]-phase crystallites in isotactic polypropylene (iPP). By surface modification of MMT with pimelic acid (PA) MMT with tailored ss-nudeation capacity (ss-MMT) has been prepared and nanocomposites with ss-iPP have been made. The polymorphism of the iPP in the nanocomposites, the effect of ss-MMT on the morphology and its crystallization and melting behavior of iPP has been investigated by POM, DSC and XRD. ss-MMT raises the crystallization temperature to a higher value than neat MMT. The ss-nudeation ability of ss-MMT depends both on the MMT/PA ratio and on the ss-MMT content in the composite. The fraction of ss-crystals with respect to the total amount of crystals increases with increasing ss-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 ss-iPP nanocomposites.