Application of factorial experimental design to optimize radiation‐synthesized and biodegradable super water absorbent based on cassava starch and acrylic acid

Abstract Super water absorbent (SWA) for agricultural applications must be optimized to withstand diminishing consequences in real soil system. A 3 3 × 1 2 full factorial design and soil water retention experiments were explored to optimize agricultural SWA made from acrylic acid (AA) and cassava starch. Four synthesis parameters such as degree of neutralization (DN), AA concentration, cassava starch concentration, and absorbed dose affecting the gel properties of SWA were investigated in the experimental design. The results showed that AA concentration and DN has strong interaction effects toward the degree of swelling (DS), gel fraction (GF), and gel strength (GS) of SWA. The soil water retention of SWA reduces with time due to microbial degradation and multivalent cations present in the soil. The optimum formulation is 20% AA 10% Starch 30% DN 10 kGy has predicted values (176 ± 68 g/g DS, 93 ± 5% GF, and 137 ± 23 kPa GS) close to the experimental values (132 ± 0.2 g/g DS, 91 ± 0.2% GF, and 141 ± 88 kPa GS). The chosen optimized formulation is 20% AA 7.5% starch 30% DN 20 kGy with 46% biodegradability after 218 days and stable soil water retention compared to commercial SWAs.