Synthesis of Cellulose Fiber from Coconut Coir as Potential Application of Dental Flowable Composite Filler

Natural fibers should be further developed for natural fiber technology as a composite reinforcement in the field of dental. But natural fibers have relatively poor interaction with the matrix and low durability. The adhesion becomes weaker between the highly hydrophilic natural fibers and the hydrophobic matrix. This study aims to explore the potential of coconut coir to substitute the existing synthetic fiber as a dental flowable composite filler. A low modulus elasticity and crosslinking ability material required for the basis material would be fulfilled by coconut coir. Cellulose fiber from coconut coir was synthesized through delignification using an organic solvent, bleaching by peroxide in alkali, dissolve using alkali and crosslinking agent, and nucleating process through freeze-drying. The variation observed in this study was the concentration of ethanol as an antisolvent agent and the rate of nucleation. Among the concentration studied, ethanol 96% showed the best nucleation ability of the cellulose, followed by 70% and 50%. Observing the SEM images, it was also found that the increase in nucleation rate caused the fiber became thinner and stronger. In contrast, the low nucleation rate caused the cellulose fibers tended to have a flake-like shape. XRD patterns of the samples showed the change in the crystalline phase of cellulose from amorphous (1b-cellulose) to crystalline (1a-cellulose) during chemical treatment.