A Superabsorbent Resin with Photo and Biological Double Degradability Containing Organic Montmorillonite and Titanium Oxide

A superabsorbent resin (SAR) with good degradability was prepared with acrylic acid (AA), acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), organic montmorillonite (OMMT) and titanium dioxide (TiO2) through inverse suspension polymerization, using potassium persulfate (KPS) as initiator and N,N-methylenebisacrylamide (MBA) as crosslinker. The structure and micrographs of the SAR were fully characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD). Meanwhile, the effects of major factors such as initiator, crosslinker, OMMT and TiO2 contents and the oil–water ratio on liquid absorbency were investigated, which reached 769.3 g/g in distilled water and 91.1 g/g in 0.9wt% NaCl solution, respectively. The equilibrium degradation performances were evaluated under the optimum conditions by the mass loss of the SAR in the soil and under the ultraviolet light, which reached 32.3wt% after 120 days and 83.9wt% after 40 h, respectively. The introduction of OMMT promoted the photodegradability obviously. The maximum photodgradation of PAA/TiO2 SAR reached 74.3wt% after 60 h, which was lower than the PAA/OMMT/TiO2 SAR. The degradable SAR has an encouraging potential for agricultural and forestry applications.