Mechanical properties of polypropylene/clay nanocomposites: effect of clay content, polymer/clay compatibility and processing conditions

A.J. TARAPOW, C.BERNAL, V. ALVAREZ

JOURNAL OF APPLIED POLYMER SCIENCE

Wiley Interscience

Año: 2009 vol. 111 p. 758 - 768

0021-8995

In this work polypropylene/clay nanocomposites with 0.5; 1; 3 and 5 wt.% of montmorillonite (unmodified clay) were prepared by intensive mixing at 50 r.p.m. and 10 minutes of mixing. For the highest clay content (5 wt.%), the initial materials or the processing conditions were changed in order to study their independent effect.  On one hand, 10 wt.% of PP-g-MA was incorporated or montmorillonite was replaced by organo- modified clays (C10A and C30B). On the other side, for the initial system, the speed of rotation (100 and 150 r.p.m) and the mixing time (5 and 15 minutes) were altered. In all cases, the state of the clay inside the matrix (DRX), the degree of dispersion in the micro (SEM) and nano (TEM) scales and the rheological and mechanical properties were analyzed. It was found that the stiffness increased with clay content whereas tensile and impact strength did not significantly change. While in the composites with unmodified clay intercalated structures were observed, in the composites with modified clay or PP-g-MA, improved dispersion of clay in PP was found. The mechanical properties increased accordingly. The degree of dispersion of the filler in the matrix appeared to be unaffected by the changes in the processing conditions introduced. Finally, the elastic modulus was modelled by using an effective filler-parameter model based on Halpsin-Tsai equations which also allowed estimating the relative degree of dispersion.