γ-PHASE POLYPROPYLENE CRYSTALLITES INDUCED BY ORGANO-CLAY MODIFIED BY ALKYL PHOSPHONIUM IONS

Abstract

The Organo-Clay was prepared by alkyl phosphonium ions treating of Na-montmorillonite.The X-ray diffraction(XRD) patterns of Na-Clay and Organo-Clay shows that the position of the(001) plane diffraction peak of the Na-Clay appears around 5.94°,corresponding to the interlayer distance(d) of 1.48 nm calculated from the Bragg law,and the position of the(001) plane diffraction peak of the Org-Clay appears around 4.99°,d = 1.78 nm.The result proves that the alkyl phosphonium are intercalated into the galleries of the clay layers.The polypropylene(PP)/Org-Clay nanocomposites were prepared by melt intercalation and XRD and transmission electron microscopy(TEM) both indicated that PP chains could be intercalated into the interlayer of the Org-Clay.The nanocomposites possess exfoliation structure and intercalation structure.The process of melting for PP/Org-Clay nanocomposites were studied with differential scanning calorimetry(DSC),and the result indicted that the addition of the Org-Clay had hardly effect on the degree of crystallization for PP.XRD results shows the position of the γ-PP(130) plane diffraction peak of the PP/Org-Clay nanocomposites appears around 19.8°and DSC heating cuvers of PP /Org-Clay nanocomposites at speed of 5 K/min revealed that the γ-PP melt peak of the PP/Org-Clay nanocomposites appearing around 149℃.It can inferred that the Org-Clay may promote the formation of γ-phase PP crystallites in the PP /Org-clay.When adding 5 wt% Org-Clay,the mass fraction of γ-phase PP is about 12%.