New bio-derived superabsorbents from nature

Abstract

Superabsorbent polymers have been around for nearly half a century. Presently, petroleum-based polyacrylic acid-type polymers are used in the majority of superabsorbent applications and markets. However, the rising costs of petroleum and the lack of a sustainable supply of fossil-based chemicals is driving a need for alternative, renewable based chemicals. Herein, we report the synthesis and superabsorbent properties of novel polymers derived from nature. Free-radical, emulsion polymerization methods were used to generate cross-linked polyacrylates containing lactone functionality, which were saponified into the corresponding cross-linked ionomers in a second step. The final cross-linked products displayed >50× absorption of water per weight of polymer and absorption under load of >15× the weight of saline solution per weight of polymer. The technology also offers the opportunity to perform additional chemistry and modification to the polymer backbone in order to improve its properties.