Carbon-13 Solid State NMR Study of Polypropylene/Clay Nanocomposite

摘要

As it is known there are at least three ways to prepare a nanocomposite: solution casting, polymerization in situ and melting extrusion. In this work we have chosen to prepare the hybrids nanocomposite of polypropylene with brazilian clay (montmorillonite) using two types of blending mixers: one was a rheometer mix and the other one an extrusion process with the polypropylene/clay (PP/clay) proportion 95/5 w/w. The conditions of blending processing were: temperature 180 ℃ for 10 minutes. The objective of this work is to evaluate the characteristics of both types of nanocomposites obtained, employing solid state nuclear magnetic resonance (NMR). The ~(13)C and ~(27)Al NMR techniques were employed to obtain the nanocomposites homogeneity and dispersion of nanocomposite components. A comparison of the carbon-13 CPMAS NMR spectra of polypropylene and their nanocomposites prepared in Haake and extruder, revealed changes in the chains packing and ordination. Changes in both chemical and line width of ~(27)Al NMR spectra indicates the formation of nanocomposite. To confirm these results, X-ray diffraction pattern was also registered. When the sample was prepared in the Haake only a composite was formed, but when the blend was performed in the extruder an exfoliated and dispersed nanocomposite was obtained.