Estudo microrreólogico de PP reciclado com argila montmorilonita e anidrido maleico

Abstract

The objective of this work is to investigate the effect of incorporating organophilic montmorillonite clay (OMMT) and polypropylene grafted with maleic anhydride (PPg-MAH) in the linear viscoelasticity region of recycled polypropylene (rPP) from mineral water bottles. The polymeric nanocomposites containing 1, 3 and 5 wt% of OMMT and using 3 wt% of PP-g-MAH were molded by injection, according to the ASTM D638 standard. The microrheological behavior was carried out using melt flow index (MFI) measurements, parallel plate rheometry and scanning transmission electron microscopy (STEM). The mechanical properties were measured by uniaxial tensile and Shore D hardness tests. The X-ray diffractogram was used to evaluate the physical properties. Using MFI it was found that the addition of OMMT and PP-gMAH promoted significant changes in rPP, making it possible to demonstrate a decrease in the fluidity index proportional to the increase in clay concentration in the mixture, consequently, an increase in viscosity. The rheological data obtained in the linear viscoelasticity region revealed significant changes in the rheological behavior of polymer composites when compared to rPP. XRD showed signs of OMMT exfoliation in the polymer matrix. Using STEM, the interaction of clay and PP-g-MAH in the rPP matrix was observed. The Shore D tensile and hardness test showed improvements in mechanical properties. However, the microrheological results together with the others detected that the incorporation of PP-g-MAH favored the formation of attractive interactions, promoting a better dispersion of the clay in the rPP matrix, and the obtaining of partially intercalated and exfoliated nanocomposites.