Synthesis and Properties of Lignin-Based Polyurethane Hydrogels

Abstract

Hydrogels were synthesized from acetic acid lignin by chemical crosslinking with NCO-terminated polyurethane ionomers (IPUI). The swelling ratio of hydrogels increased with pH. The hydrogel prepared at the mass ratio of m_AAL/m_IPUI: 0.35:1 presented maximum swelling ratio in pH 6.8 buffer solutions. The results of thermogravimetric analysis demonstrated that the thermal stability of the hydrogels is improved by the introduction of lignin. The data of release experiments for ammonium sulfate suggests that the hydrogels can be used as coating materials to prepare a slow-release fertilizer.