Fabrication of cellulose/plant oil based flexible epoxy thermoset with excellent UV-blocking performance

Flexible epoxy thermosets have promising applications in modern industry. However, the development of next-generation flexible epoxy thermosets with high biomass content and multi-functions remains challenging. In this work, a sustainable cellulose/plant oil based flexible epoxy thermoset with excellent mechanical property, reprocessing performance, and UV absorption property was prepared. First, the amino cellulose is synthesized and used as a reinforcement and curing agent, and then the flexible epoxy thermoset is prepared by curing reaction of amino cellulose, citric acid, and flexible epoxy resin using zinc acetylacetonate as the transesterification catalyst. The epoxy thermosets show excellent thermal stability, the temperature at maximum weight loss reached 425 degrees C. Mechanical property tests indicate that these thermosets have high mechanical strength (19.6 MPa) and satisfactory stretchability (36.1%-118%). The dynamic transesterification ester groups endow the epoxy thermoset with reprocessing ability. In addition, these epoxy thermosets show outstanding and stable UV absorption properties even after long-time UV-light irradiation or heating treatment, which makes these flexible epoxy thermosets have promising applications in UV-blocking coating.