Morphology and properties of polypropylene nanocomposites based on a silanized organoclay

Abstract

A silanized organoclay (s-M 2(HT) 2) was prepared by reaction of trimethoxyphenyl silane with an organoclay with a M 2(HT) 2 surfactant structure. Nanocomposites were formed from polypropylene (PP) and a blend of PP and maleic anhydride-grafted polypropylene (PP- g-MA) and the M 2(HT) 2 and s-M 2(HT) 2 organoclays by melt processing to explore the extent of exfoliation and the mechanical properties. Wide angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) coupled with detailed particle analysis were used to determine the effect of the organoclay used and the PP- g-MA compatibilizer on exfoliation and mechanical, rheological, and thermal expansion properties. The PP/s-M 2(HT) 2 nanocomposites have higher particle densities than the PP/M 2(HT) 2 nanocomposites though the aspect ratio remains the same. Platelet dispersion is significantly improved by using PP- g-MA compatibilizer for both organoclays. The rheological properties and the relative modulus improve for the PP/s-M 2(HT) 2 nanocomposites but not to the same degree as either organoclay in a PP- g-MA compatibilized matrix. The thermal expansion properties, however, are not improved by using the s-M 2(HT) 2 organoclay. The s-M 2(HT) 2 organoclay is less prone to agglomeration during extrusion than the M 2(HT) 2 organoclay.