Preparation of poly(sodium acrylate-acrylamide) superabsorbent nanocomposites incorporating graphene oxide and halloysite nanotubes

Abstract

To investigate the synergistic effect of multi-nanofillers in a superabsorbent nanocomposite, a poly (sodium acrylate–acrylamide) superabsorbent nanocomposite incorporating graphene oxide and halloysite nanotubes (PAA-AAm–HNT–GO) was synthesized via the inverse suspension polymerization method. Graphene oxide (GO) was prepared by an improved method and halloysite nanotubes (HNTs) were modified by grafting carboxyl groups. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were carried out to examine the structure and morphology of the resulting superabsorbent nanocomposite. It was found that HNTs, GO and poly(sodium acrylate-acrylamide) (PAA-AAm) copolymers combine well with each other during the polymerization process. Meanwhile, the particle sizes of the resulting superabsorbent nanocomposite reduced to about one-tenth of the original size after the introduction of HNTs and GO. The PAA-AAm–HNT–GO superabsorbent nanocomposite exhibited a significant improvement in its water absorption and water retention abilities, due to the synergistic effect of the HNTs and GO, compared with controls, which may make it suitable for use in some special applications that demand a higher water absorption and retention capacity.