The effect of hybridization on moisture absorption and mechanical degradation of natural fiber composites: An analytical approach

Abstract The method of hybridization by adding synthetic hydrophobic fibers into the natural fiber reinforced composites is used to reduce moisture absorption and mechanical degradation of the composites. A linear constitutive model for this hybrid fiber composite is proposed to study the effect of hybridization on the mechanical properties of the composites. The natural fibers absorb large amounts of water when exposed to the humid environment, which causes remarkable modulus loss and interface damage between natural fiber and matrix. Based on the Rule of Hybrid Mixture (RoHM), the overall mechanical properties of the hybrid short fiber reinforced composites are obtained, in which one internal variable is introduced to reflect both the modulus loss of natural fibers and the interface damage. From the thermodynamics modeling, the evolutions of moisture absorption and mechanical degradation are derived. Compared with the experimental results of hemp and glass fiber reinforced composites, a good agreement is obtained.