A method for preparing epoxy-cellulose nanofiber composites with an oriented structure

A method was developed for processing cellulose nanocomposites using conventional vacuum infusion. Porouscellulose nanofiber networks were prepared via ice-templating and used as preforms for impregnation with a bioepoxyresin. Microscopy studies showed a unidirectionally oriented micrometer-scale pore structure that facilitatedthe infusion process by providing flow channels for the resin. The permeability of the preforms wascomparable to that of natural fiber mats, and the infusion time significantly decreased after optimizing theprocessing temperature. The flexural modulus of the bio-epoxy increased from 2.5 to 4.4 GPa, the strengthincreased from 89 to 107 MPa, and the storage modulus increased from 2.8 to 4.2 GPa with 13 vol% cellulosenanofibers. The mechanical properties also showed anisotropy, as the flexural and storage moduli were approximately25% higher in the longitudinal direction, indicating that the nanofiber network inside the epoxymatrix had an oriented nature.Validerad;2019;Nivå 2;2019-08-13 (johcin)