Study on the properties of composite superabsorbent resin doped with starch and cellulose

In order to reduce the damage to soil caused by degradation residues in the application of superabsorbent resin (SAR), the primary target of this study was to improve its biodegradability by doping with starch and cellulose. After that, the water absorption performance of composite SAR doped with starch and cellulose was improved as much as possible by changing the formulation when the biodegradability changed in a narrow range. The degradation percentage in soil and compost after 60 days is much higher than that of the SAR without doping which is 8.42 and 14.17%, but the performance for water absorption depends on the type of starch that was used. Experiments showed that the presence of amylopectin in starch contributes significantly to the performance for water absorption of composite SAR. The more amylopectin content, the better performance for water absorption, but the specific relationship between the degradability and the amylopectin content has not to be proven. Finally, the best mass ratio of starch, cellulose, and acrylic was 4.2:1.8:65, which was determined via the experiments. A kind of composite SAR doped with starch and cellulose with excellent performance was obtained.

Kinetic model of a carboxymethylcellulose-agar hydrogel for long-acting and slow-release of chlorine dioxide with a modification of Fick’s diffusion law

A long-acting and slow-release material for chlorine dioxide, based on bagasse pulp (BP) was prepared with a superabsorbent resin as the slow-release substrate and agar as the cross-linking agent. The stable ClO2 solution and the acidic activator were locked into the network structure of the superabsorbent resin, which was prepared with a carboxymethyl cellulose made from bagasse pulp. Because of the network structure of the resin, the diffusion resistance was greatly increased, and the effective release time was up to 2 months. The mechanism for the release process of the ClO2 was explored, and a kinetic model was established based on modified Fick’s diffusion law. The results showed that the release process was a diffusion-controlled process. When compared with a zero-order kinetic model and a Higuchi model, the new established model had better fitting results, and it more fully reflected the release patterns and characteristics of the ClO2.