(75b) Flax Fiber Interfacial Bonding Improvements

Flax fiber has become increasingly attractive as reinforcement in polymer matrix composites for structural applications. Due to its lighter weight, flax fiber reinforced composites can perform similar to glass fiber reinforced composites on a specific property comparison. However, in order maximize natural fiber reinforced composite performance; fiber surface modification and/or matrix manipulation are required. The interface between fiber and matrix plays an extremely important role in composite properties because it facilitates the load transfer between phases. Therefore, the key to improved performance is in controlling the chemical and mechanical properties of the fiber-matrix interface. Surface treatment is one way to reduce the hydrophilicity of the fiber by reacting the hydroxyl groups in the fibers in order to improve the adherence between flax fiber and polymer matrix. Matrix manipulation is another way to obtain a more congruent interaction between the flax fiber and polymer matrix. In this presentation, a multitude of different unidirectional flax fiber/vinyl ester composites were produced via a modified vacuum assisted resin transfer molding (VARTM) process. Higher specific properties (tensile, flexure, interlaminar shear, fiber bundle pull-out, etc.) of chemically treated flax fiber reinforced composites over those of glass fiber reinforced composites were obtained and will be discussed.