PREPARATION OF NANOCELLULOSE FROM INDUSTRIAL TAPIOCA SOLID WASTE AND ITS APPLICATION AS A COMPONENT OF LITHIUM-ION BATTERY POLYMER ELECTROLYTE MEMBRANE

• Main Author: Widiarto, Sonny
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/46572
• Institution: Institut Teknologi Bandung

Indonesia is the third largest cassava (Manihot esculenta Crantz) producing country in the world after Nigeria and Brazil. The volume of cassava production in Indonesia is around 24 million tons per year. Most of the production is utilized by the tapioca industry by leaving solid waste in the form of bagasse and peels. The high cellulose content of cassava bagasse (26.2% of dry weight base) and cassava peel (40.5% of dry weight base) has great potential as a source of cellulose. The last few decades, research in the field of cellulose has led to the making of nanocellulose as an advanced material. Nanocellulose has various advantages and excellence, one of its uses is as a reinforcing agent (reinforcing nanofiller) on the polymer electrolyte membrane in a lithium ion battery. Lithium ion battery is an alternative energy that attracts attention to be developed. Polymer electrolyte membranes have become an attractive material to be developed because they have the advantage of replacing liquid electrolytes that have been used in lithium ion batteries in general. The main disadvantage of the liquid electrolytes is its volatility and flammability when using batteries at high temperatures. Therefore, the purpose of this research is to obtain nanocellulose from materials that are relatively inexpensive, environmentally friendly and study its properties so that it can be utilized for various purposes, including as a reinforcing component in the electrolyte polymer matrix. Utilization of cassava bagasse and peels as a source of cellulose is expected to be able to overcome the environmental problems and increase added value in the tapioca industry in Indonesia. This research is divided into three stages; the first step is to study cellulose extraction from cassava bagasse and cassava peel using three methods (sulfate, nitrate and alkali). The second stage is to study the preparation of nanocellulose (NS) from cellulose via acid hydrolysis and mechanical methods. In the acid hydrolysis method, the acid concentration is optimized, whereas in the mechanical method using a high-shear homogenizer, the optimization of the rotor speed and stirring time is carried out. The third step is to study the preparation of polymer electrolyte nanocomposite membranes by mixing NS with poly(ethylene oxide) (PEO) using the solution casting method by optimizing the composition of PEO:NS and PEO:NS:LiClO4. At each stage, characterization was carried out using FTIR, XRD, TGA, DSC and SEM. The size of the nanocellulose particles was determined using the DLS and TEM methods. The mechanical properties of nanocomposite membranes were measured using tensile testing instruments while the ionic conductivity of nanocomposite membranes was measured by the Gamry Reference 3000 Potentiostat. In the first step, isolation of cellulose from cassava peel using the alkali method produced the highest cellulose content and the highest yield i.e. 92.21% and 17.8%, respectively. The crystallinity index of cellulose increased from 23.41% to 55.54%. The cellulose was then used for making nanocellulose in the second stage of this study. From the results of FTIR and XRD, the two methods used (acid hydrolysis and mechanics) produce similar spectra and diffractogram. The crystallinity index of nanocellulose from acid hydrolysis and mechanical methods are 63.3% and 62.1%, respectively. The average length and diameter of the nanocellulose produced by acid hydrolysis method were found 121.14 nm and 6.07 nm, respectively; while the mechanical method gave the average length and diameter of particles of 178.24 nm and 6.39 nm, respectively. Considering the time efficiency, the use of chemicals and novelty of the research, the nanocellulose from mechanical methods is used in the preparation of nanocomposites at a later stage. In the third stage, the nanocomposite membrane is obtained by the solvent casting method using water as a solvent. The addition of NS to the PEO matrix increases the tensile strength and decreases the elongation at break and does not have a significant effect on the membrane ion conductivity. Addition of LiClO4 salt to the PEO-NS mixture decreases tensile strength, increases elongation at break of the membranes and increases membrane ion conductivity. The optimum membrane conditions were obtained at a ratio of PEO:NS = 80:20 and 15% LiClO4. Addition of LiClO4 > 15% produces a large exothermic process in the thermal properties of the membrane. The addition of NS into the PEO-LiClO4 membrane can reduce the exothermic process. The best ion conductivity of the PEO-NS-LiClO4 membrane was obtained in the composition of PEO:NS:LiClO4 = 72.25%: 12.75%: 15% with a measured ionic conductivity value of 2.28 x 10-3 S.cm-1, while the best tensile strength was obtained in the composition of PEO:NS:LiClO4 = 63,75%:21,25%: 15% with the value of 6.68 MPa.