Development of Non Sodium Silicate Flyash-based Geopolymer Film for Preliminary Urea Diffusion Study

Geopolymer is a material that involves natural occurring silico-aluminates and is based on the chemistry of alkali-activated inorganic binders. In this works, geopolymer is produced from flyash as raw material and low concentration of KOH as alkali activator without sodium silicate. The highest concentration of 5.5 M KOH resulted in 3 hours setting time. The highest compressive strength obtained was 21.91 MPa at 4.5 M KOH at curing temperature of 60 oC which reflects good mechanical property and can be developed for coatings. Subsequently, geopolymers synthesized were characterized for possible application as coating for urea. By determining the capability of transportation of urea through geopolymer film showed that the diffusion coefficient of 3.6E-08 m2/s was obtained and reach equilibrium after 20 days