GREEN COMPOSITE: SODIUM-BASED GEOPOLYMER REINFORCED WITH CHEMICALLY EXTRACTED CORN HUSK FIBERS

摘要

Geopolymers are an inorganic polymeric material composed of alumina, silica, and alkali metal oxides. Geopolymers have shown promise as a low cost, environmentally friendly structural material. The addition of a reinforcing phase vastly improves the strength and toughness of the composite. For this study, sodium-based geopolymer is reinforced with chemically extracted corn husk fibers via a paste and weave approach followed by cold press and 50°C curing. Corn husk fibers (CHF) are a low cost, abundant and sustainable resource. They show moderate strength and high elongation to failure equating to high work of rupture for a natural fiber which acts as a toughening mechanism for this biocomposite. CHF are chemically extracted from com husks using a room temperature alkali bath (10:1 molar ratio of H_2O:NaOH) with manual agitation for 30 minutes and are rinsed with water to neutralize the pH. Composite tensile and flexural strength are determined for both quasi-aligned and randomly oriented fibers. Composite microstructure is also evaluated with the SEM focusing on fiber continuity and fiber/matrix interface.