Preparation of Extruded Melt-Mixed Polypropylene/ Montmorillonite Nanocomposites with Inline Monitoring

摘要

This article advances the use of an inline optical detector to monitor the disaggregation of the montmorillonite (MMT) clay factoids during the preparation of polypropylene (PP)/MMT nanocomposites via polymer melt compounding. During the exfoliation of the factoids their size are reduced below the minimum particle size to produce light extinction and so, the signal of the inline detector reduces as the nanosize composite is formed. The measurement is done at the transient state with the MMT clay added as a pulse with constant weight into the PP extrusion melt flow and followed by the optical detector. The data comes out as the common residence time distribution curves having its maximum intensity related to the factoids average particle size, keeping all other variables constants. The light extinction was measured for composites with different clays (Cloisite~R 15A, 30B, Na~+, and Sintered 20A) using the same PP grafted with maleic anhydride com-patibilizer. The dissaglomeration/exfoliation efficiency increases as: "Sintered 20A" < "Na+ clay" < "organo-modified clay" < "organo-modified clay + compatibil-izer". The best result is obtained using Cloisite~R 15A and Cloisite~R 20A following the expected reduction of the particle size obtained during a nanocomposite melt processing.