Microwave-Assisted Hydrothermal Decomposition of Super Absorbent Polymers

Abstract

Absorbent hygiene products contain a super absorbent polymer (SAP) as one of the main constituents that is not easily biodegraded or recycled. Currently, the vast majority of the material is landfilled after a single use. Therefore, it is highly desirable to develop technology to recycle and reuse these polymers. In this paper, the depolymerization of SAP under hydrothermal conditions via microwave heating was investigated. High molecular weight, cross-linked SAP was converted to oligomers with Mw < 5000 Da by treatment with 0.5 wt % H2O2 followed by microwave heating at 200 °C for 3 min. A design of experiments approach was deployed to systematically determine that reaction temperature had the most significant influence on SAP product Mw, polydispersity index (PDI), and yield, followed by reaction time and initial SAP concentration.