Biobased Heat Resistant Epoxy Resin with Extremely High Biomass Content from 2,5-Furandicarboxylic Acid and Eugenol

Preparing a biobased (biomass-based) high performance epoxy resin with extremely large biomass content is of great importance for sustainable development. Herein, a new epoxy resin with a precise structure, bis(2-methoxy-4-(oxiran-2-ylmethyl)phenyl)furan-2,5-dicarboxylate (EUFU-EP), was synthesized from two biobased green and low toxic compounds (2,5-furandicarboxylic acid and eugenol) and the biomass content of EUFU-EP is as large as 93.3%. In addition, a new biobased epoxy resin, EUFU-EP/MHHPA, was prepared by using methyl hexahydrophthalic anhydride (MHHPA) as the curing agent and 2-ethyl-4-methylimidazole as the curing accelerator. The curing reactivity and integrated performances including thermal and mechanical properties as well as flame retardancy of the cured resin were systematically researched and compared with those of petrochemical resource-based epoxy resin (DGEBA/MHHPA) consisting of commercial diglycidyl ether of bisphenol A (DGEBA), MHHPA and 2-ethyl-4-methylimidazole. Results show that EUFU-EP/MHHPA and DGEBA/MHHPA have similar curing reactivity, but cured EUFU-EP/MHHPA resin shows better thermal properties, rigidity, and flame retardancy than cured DGEBA/MHHPA resin. Specifically, the glass transition temperature (Tg) of EUFU-EP/MHHPA resin is as high as 153.4 °C, the storage modulus at 50 °C increases by 19.8%; meanwhile, both peak heat release rate and total heat release reduce by 19.0%. The nature behind these outstanding integrated performances is attributed to the unique structure of EUFU-EP, which is not only rich in aromatic structure but also has a furan ring. The especially large biomass content and outstanding thermal, mechanical, and flame retarding performances clearly show that EUFU-EP resin has a great potential in actual applications.