SURFACE MODIFICATION OF HALLOYSITE FOR EPOXY NANOCOMPOSITE APPLICATIONS

摘要

Polymer nanocomposites have been extensively investigated over the past two decades, resulting in a wide range of applications because of their excellent performance. Halloysite, a type of naturally occurring aluminosilicate, has attracted increasing interest in polymer nanocomposite applications, especially for the enhancement of mechanical properties owing the tubular structure of halloysite. Herein, we report a facile approach to achieve a high level of dispersion of halloysite nanotubes (HNTs) in epoxy by treating HNTs with a low concentration (0.015mol/L) of sodium hydroxide (NaOH). The NaOH treatment resulted in the formation of hydroxyl groups on the surface of HNTs, leading to a better dispersion of HNTs in polar solvent and epoxy matrix, which was verified by the Zeta potential characterization. Such a higher level of dispersion and strong interface helped enhance the modulus and fracture toughness of epoxy/HNT ( 5 phr HNT) by and 18% and 43%, respectively, in comparison to the neat epoxy. The dynamic mechanical analysis (DMA) revealed a 13% increment in the storage modulus of the composite at 50 °C. The SEM images of the fractured surfaces further confirmed the better dispersion of treated HNTs in the epoxy matrix, as opposed to the large agglomeration of untreated HNTs in the epoxy nanocomposite.