Effect of functional groups of modified polyolefins on the structure and properties of their composites with lamellar silicates

Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, 56126 Pisa, Italy
Polymer International (Impact Factor: 2.25). 11/2005; 54(11):1549 - 1556. DOI: 10.1002/pi.1881

ABSTRACT The melt mixing of functionalized polyolefins with a surface-modified layered silicate (montmorillonite) was investigated as an approach to prepare the corresponding micro/nanocomposites. The effect of the diethyl succinate groups, derived from the grafting of diethyl maleate (DEM) onto the polyolefins, on compatibility with an inorganic filler and the dispersion in a hydrophobic matrix was extensively investigated. In order to avoid possible interference by polymer multiphase morphology, the amorphous poly(propylene-ran-ethylene) (EPM) (70/30, wt/wt), functionalized with DEM (EPM-graft-DEM), was used in melt mixing with alkyl-ammonium-salt-modified montmorillonite at different weight ratios by using a Brabender mixer. Materials with a nanoscale dispersion of the inorganic phase, as revealed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, were obtained. Specific interactions, involving the carbonyl groups of the polyolefin functional groups and the polar sites on the filler surface, appeared to assist intercalation and/or exfoliation of the layered system. Similar results were obtained by starting with an unfunctionalized EPM and by performing the grafting reaction with DEM during melt mixing according to a one-step simplified procedure. Copyright © 2005 Society of Chemical Industry

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