High Performance Biobased Epoxy Nanocomposite Reinforced with a Bacterial Cellulose Nanofiber Network

This work describes the preparation and characterization of biobased fiber reinforced resins using bacterial cellulose (BC) as the matrix reinforcing phase and diglycidyl ether diphenolate ethyl ester (DGEDP-ethyl) as the biobased epoxy resin. BC mats were prepared by static cultivation of strain Gluconacetobacter xylinus ATCC 700178 in Hestrin-Schramm medium augmented with mannitol in sterile containers. After freeze-drying, the surface of the BC matrix fibers was modified to introduce trimethylsilyl moieties (BCTMS). Reinforced by BCTMS nanofiber networks were fabricated by impregnation of BCTMS matrixes with the resin mixture followed by hot-pressing and curing. Resulting DGEDP-ethyl/BCTMS composites with 5, 10, 20, and 30%-by-vol BCTMS network loading were formed. The BC network proved effective in reinforcing the epoxy resin matrix. The composite Young's modulus (E-T) increased from 1.22 +/- 0.41 GPA for the neat DGEDP-ethyl thermoset to 8.8 +/- 0.98 for the composite with 30%-by-vol BCTMS. Furthermore, the storage modulus (E') increased for DGEDP-ethyl/30%BCTMS relative to the neat DGEDP-ethyl resin below T-g (30 degrees C) by 3-fold (2.27 to 7.7 GPA) and above T-g (180 degrees C) by 100-fold. This work highlights the potential to use prefabricated BC matrixes produced by microbial fermentation along with a biobased epoxy resin to provide high-performance biobased composites.