Surface-treated oil palm empty fruit bunch fiber improved tensile strength and water resistance of wheat gluten-based bioplastic

This study evaluated the morphology, chemical composition and color parameters of oil palm empty fruit bunch (OPEFB) fiber after surface treatment with hot water (90 °C) and alkali treatments (1 w/v% and 5 w/v% NaOH). Treatment of the fiber with a 5 w/v% solution of NaOH more effectively eliminated residual surface contaminants than hot water treatment and alkaline treatment with 1 w/v% NaOH. However, color parameters were slightly reduced. The tensile strength and water absorption of composites of wheat gluten and surface-modified fiber were compared with the same properties of composites loaded with unmodified fiber. The highest tensile strength and lowest water absorption were obtained with a composite of wheat gluten and 15 wt% OPEFB fiber treated with 5 w/v% NaOH. The good adhesion between the fiber and the wheat gluten matrix enabled a more effective transfer of stress from the wheat gluten matrix to the fiber and also reduced water absorption into the wheat gluten matrix. Therefore, composites of wheat gluten and oil palm empty fruit bunch fiber have potential to be developed for use as green composite materials.