Utilisation of Potato Leaves and Organophilic Montmorillonite for the Preparation of Superabsorbent Composite under Microwave Irradiation

Abstract

A novel superabsorbent composite from potato leaves (PL, a kind of agricultural waste materials), organophilic montmorillonite (OMMT), acrylic acid (AA) and acrylamide (AM), PL-g-P(AA-AM)/OMMT, was synthesised by microwave irradiation, using potassium persulfate (KPS) as the initiator and N,N′-methylenebisacrylamide (MBA) as the crosslinker. The polymerisation conditions were investigated by orthogonal tests, and the optimal conditions were determined. The superabsorbent composites were characterised by FTIR, XRD, and TGA, the results show that AA and AM successfully grafted onto the PL chain, the layers of OMMT were exfoliated and dispersed in the composite after copolymerisation. The introduction of PL in the composite slightly increased the water absorbency. And the thermal stability, water absorbency, water retention and swelling rate of the superabsorbent composite were also improved by the introduction of 5% OMMM into the PL-g-P (AA-AM) network. The use of a microwave irradiation method not only greatly enhanced the reaction rate, but also increased the water absorbance over the conventional method. All of the results indicated that this new approach showed promise in utilising such waste in the production of useful products, which are economical and environment-friendly.