Influence of Chemically Treated Palygorskite Over the Rheological Behavior of Polypropylene Nanocomposites

Melt compounding was used to prepare thermoplastic composites reinforced with palygorskite; the chemical modification of the palygorskite surface and the control of extrusion parameters were used to promote good dispersion and a good interface with the matrix, affecting the rheological properties of the mixture, since the melt viscoelastic behavior is sensitive to changes in the molecular structures at nanoscale and mesoscale. The palygorskite nanoclay (diameter 30nm) was extracted from a site in the southeast of the state of Yucatan, Mexico; the palygorskite was subjected to purification and then superficially modified with 3-aminopropyltrimetoxysilane. These processes generated three types of specimens: unpurified, purified and purified-silanized palygorskite; which were subsequently incorporated (0.5 w%) to a polypropylene matrix by twin extrusion. Frequency sweeps were used to evaluate the interaction between the matrix and the nano-reinforcement. The master curves of storage modulus (G’), loss modulus (G”) and complex viscosity (η*) vs angular frequency (ωx) show a change of the interfacial interaction polypropylene/palygorskite when the palygorskite was chemically modified.