Fabrication and characterization of polyamide 6,6/organo-montmorillonite nanocomposites with and without a maleated polyolefin elastomer as a toughener

Abstract

In this study, polyamide 6,6 (PA 6,6)-based nanocomposites were prepared using a twin-screw extruder. One commercial organo-montmorillonite (denoted as 30B) and one maleated polyolefin elastomer (denoted as POEMA) served as the reinforcing filler and toughener, respectively. The X-ray diffraction (XRD), scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS), and transmission electron microscopy (TEM) results confirmed the nano-scaled dispersion of 30B in the composites. The presence of POEMA slightly depreciated the dispersibility of 30B. Differential scanning calorimetry (DSC) results indicated that the addition of 30B accelerated the crystallization of PA 6,6, whereas the simultaneous additions of 30B and POEMA led to a reverse effect. Complex melting behaviors, mainly associated with the “recrystallization/reorganization” of PA 6,6 crystals upon heating, were observed for neat PA 6,6 and the nanocomposites. The presence of exfoliated/intercalated 30B hampered the “recrystallization/reorganization” of PA 6,6 crystals. The thermal stability enhancement of PA 6,6 after the addition of 30B and/or POEMA was confirmed using thermogravimetric analysis (TGA). The rigidity, including storage modulus, Young's modulus and flexural modulus, of PA 6,6 increased after adding 30B. However, these properties declined after the further incorporation of POEMA. The PA 6,6/POEMA/30B nanocomposites basically displayed balanced properties between those of the neat PA 6,6 and PA 6,6/POEMA blend.