The main goal of this work is to analyze the relationships
between the extensional rheological behavior of solid
nanocomposites based on high melt strength polypropylene
(HMS PP) and montmorillonites (MMT) and the cellular structure
and mechanical properties of foams produced from these
materials. For this purpose two systems have been analyzed.
The first one incorporates organomodified MMT and a
compatibilizer and the second system contains natural clays
and is produced without the compatibilizer. Results indicate
that the extensional rheological behavior of both materials is
completely different. The strain hardening of the polymer containing
organomodified clays decreases as the clay content
increases. As a consequence, the open cell content of this material
increaseswith the clay content and hence, themechanical
properties get worse. However, in the materials produced with
natural clays this relationship is not so clear. While no changes
are detected in the extensional rheological behavior by adding
these particles, the nano-filled materials show an open cell
structure, opposite to the closed cell structure of the pure polymer,
which is caused by the fact of having particle agglomerates
with a size larger than the thickness of the cell walls and a
poor compatibility between the clays and the polymer.
