Synthesis and Characterization of Polyacrylic Acid/Xanthan Gum/Bentonite Superabsorbent Polymer

Abstract

A novel polyacrylic acid /xanthan gum/bentonite superabsorbent polymer (SAP) was prepared through chemical crosslinking by a polymerization technique in a complete aqueous environment. This SAP was fabricated effectively by dispersing xanthan gum (XG) and bentonite in a monomeric solution, using N,N’-methylenebisacrylamide as crosslinker and ammonium persulfate as initiator. Fourier transform infrared (FTIR) spectral analysis showed that graft copolymerization reaction took place between acrylic acid (AA), XG and bentonite. The optimal process conditions of preparing SAP were investigated. Results showed that the relevant SAP had maximal salt-water absorption (98g/g) when mass ratio of m (bentonite):m (AA) was 5:1, m (ammonium persulfate):m (AA) was 1.75×10-4, m (N,N’-methylenebisacrylamide):m (AA) was 3×10-4, m (XG) :m (AA) was 1:5, the neutralization degree of AA was 75%. Bentonite can not only effectively increase water absorbency, but also improve water retention ability.

Superabsorbent Hydrogels in the Agriculture and Reclamation of Degraded Areas

“…Superabsorbents, depending on their chemical composition, can be divided into two groups. The raw materials for production of acrylic SAP are mostly petroleum-based, relatively cheap synthetic copolymers produced from vinyl monomers and chemically modified natural polymers [25,26] based on starch [27][28][29], cellulose [30][31][32][33][34], chitosan [13,[35][36][37], humic acid [38], proteins [39][40][41], alginate [42][43][44][45] agar [46], curdlan [47][48][49], gellan [50], xanthan [51,52] or arabic gum [46,53,54]. It is also possible to produce SAPs as a result of alkaline hydrolysis of polyacrylonitrile waste used for the production of fibres and fabrics [55] or a combination of several processes [56].…”

“…Many materials have also been created consisting of acrylic and/or natural polymers, both chemically modified and grafted polymers additionally containing other functional ingredients (Figure 1). Additions of mineral substances such as silica [57,58], attapulgite [59], bentonite [51][52][53][54][55][56][57][58][59][60][61] or kaolin [62] are often used.…”