In this study, nanocrystalline cellulose was synthesized from banana stem fiber by acid hydrolysis process. Method optimization was carried out in order to get the lowest acid concentration that able to produce a higher percentage yield of nanocrystalline cellulose. Morphological of nanocrystalline cellulose synthesized was observed by FESEM and the chemical composition was analyzed by using FTIR. Crystallinity and thermal degradation were identified by XRD and TGA analysis. Modification reaction on the nanocrystalline cellulose surface was performed by an acetylation reaction in order to convert the hydrophilic to hydrophobic property for the purpose to reduce the tendency of nanocrystalline cellulose to agglomerate. This process resulted in increasing of nanocrystalline cellulose crystallinity that is indicated by the XRD analysis. Meanwhile, the confirmatory test was carried out by FTIR analysis, which shows the presence of an acetyl group absorption peak on nanocrystalline cellulose spectrum. Development of biocomposites of nanocellulose reinforced PLA thin films was carried out by solvent casting method. The reinforcement of unmodified and acetylated nanocrystalline cellulose to the polymer matrix shows that the great distribution occurs at a low percentage of reinforcing materials. A thin film of PLA reinforced by acetylated nanocrystalline cellulose gives higher tensile strength as compared to the use of unmodified nanocrystalline cellulose. This result proved that the reinforcement of nanocrystalline cellulose with hydrophobic properties gives a better distribution in hydrophobic polymer matrix. Finally, soil burial degradability study was carried out in order to investigate the degradability property of neat PLA, PLA reinforced by nanocrystalline cellulose (uNC-PLA) and PLA reinforced by acetylated nanocrystalline cellulose (aNC-PLA). Based on the optical observation, reducing weight and tensile strength of the sample, it can be clearly said that the thin film of uNC-PLA and aNC-PLA shows higher degradation rate as compared to the neat PLA thin film. Overall, it can be concluded that these research findings can widen the scope of biocomposites research area and have significant implications for the commercial application of biomass products especially for biodegradable packaging materials.
