In the present investigation, carbon nanofibers (CNF) were dispersed in epoxy matrix to form CNF/glass fiber/epoxy composites. Before blending, CNF was oxidated to get more functional groups on CNF and improve the interface combination between resin and CNF, the infrared spectrum was used to test the efficiency. After that, tensile modulus tests were carried on for CNF/glass fiber/epoxy composites with different CNF fractions, the results indicated that there were slight improvements of tensile modulus when adding CNF. At 3.0 wt% of CNF, composites have the high improvement of tensile modulus, but the reinforcement of CNF decreased at 5.0 wt% of CNF. And the CNF reinforcement efficiency was analyzed using modified Coxs model and rule of mixture.
