Effects of process conditions and mixing protocols on structure of extruded polypropylene nanocomposites

Document Type

Article

Publication Date

8-15-2004

Abstract

Polymer melt-direct intercalation or exfoliation is a promising approach for the preparation of nanocomposites. The structure of nanoclay platelets in the nanocomposites depends not only on the properties of polymer matrix and nanoclay, but also on the operating conditions during processing. The objective of the present work is to investigate the effects of clay chemical modifiers, mixing protocols, and operating conditions upon the clay structure in nanocomposites prepared with a corotating twin-screw extruder. Two mixing methods were used for the nanocomposite preparation: two-step mixing and one-step mixing. Experimental results obtained from melt flow index and complex viscosity measurements suggest that nanoclay C15A is more exfoliated than C30B in a polypropylene ho-mopolymer containing a maleic anhydride grafted PP (PB) as compatibilizer. The two-step mixing method results in better exfoliation for the nanofillers than the one-step mixing method. A numerical simulation has been carried out to evaluate the mean residence time and shear rate in different screw configurations under various process conditions. X-ray diffraction experiments indicate that the residence time is a dominant factor in producing satisfactory nanocomposites in extruders. However, high shear rate coupled with long residence time might result in poor exfoliation of clay. © 2004 Wiley Periodicals, Inc.

Identifier

3142607103 (Scopus)

Publication Title

Journal of Applied Polymer Science

External Full Text Location

https://doi.org/10.1002/app.20658

ISSN

00218995

First Page

1891

Last Page

1899

Issue

4

Volume

93

This document is currently not available here.

Share

COinS