Improving the interfacial and mechanical properties of short glass fiber/epoxy composites by coating the glass fibers with cellulose nanocrystals

In this study, the interfacial and mechanical properties of cellulose nanocrystals (CNC) coated glass fiber/epoxy composites were investigated as a function of the CNC content on the surface of glass fibers (GF). Chopped GF rovings were coated with CNC by immersing the GF in CNC (0-5 wt%) aqueous suspensions. Single fiber fragmentation (SFF) tests showed that the interfacial shear strength (IFSS) increased by ~69% in composites produced with CNC coated GF as compared to uncoated GF, suggesting an enhancement of stress transfer across the GF/matrix interface. The role of CNC coatings on the tensile, flexural, and thermo-mechanical properties of the CNC-coated GF/epoxy composites was investigated. Incorporation of 0.17 wt% CNC in the composite resulted in increases of ~10% in both elastic modulus and tensile strength, and 40 and 43 % in flexural modulus and strength respectively. In conclusion CNC coatings on GF alter the GF/matrix interface resulting in improvement of the mechanical performance of the corresponding composites.