PENYEDIAAN NANOPARTIKEL PATI SAGU (Metroxylon sagu) SEBAGAI PENGUAT (REINFORCEMENT) BIOPLASTIK

SUMMARY Indonesia has many types of starch that have the potential to be processed into industrial raw materials such as sago starch. Indonesia has sago potential of around 50% of the world's sago production. The production of sago is much higher than the consumption of starch, which still reaches 5 percent of the total potential for sago that can be produced nationally. Sago can be used as food and raw materials for non-food industries. Therefore, it is necessary to think about the technology for providing sago starch as an industrial raw material. Natural starch has a weakness as an industrial raw material, namely its characteristics are not in accordance with industrial needs. One of the efforts to increase the added value of sago starch is to modify it in the form of starch nanoparticles. Nanoparticle technology will improve the characteristics of starch so that it has a low suspension viscosity at a relatively high concentration, and has a high binding strength due to the large active surface area. Starch nanoparticles have the potential to be used in the paper industry, as surface sizing, coating or biodegradable adhesives. The application of starch nanoparticles is also as a reinforcement or filler for synthetic polymers (plastics) and bioplastics. The bioplastic industry is a solution to the use of conventional plastics based on synthetic polymers that cannot be degraded, causing serious problems for the environment. The development of the bioplastic industry is still very slow. This is because the physical and mechanical properties of starch-based bioplastics are generally lower than conventional plastics. The provision of starch nanoparticles as a reinforcing material is an alternative solution to answer the above challenges. In addition to this, the development of starch nanoparticles as a bioplastic reinforcement is to determine the emerging new properties and their effect on the characteristics of bioplastics. Nanoparticle production technology, both top down and bottom up, still has weaknesses such as low yields, long process stages, long processing times, chemical waste, requires sophisticated equipment and expensive prices and limited equipment availability in Indonesia. This causes the availability of starch nanoparticles is still scarce in the market and the price is quite high. Modifying the method of providing nanoparticles with low production costs is an interesting challenge. The purpose of this research is to obtain a new method that is efficient and applicable in producing starch nanoparticles from sago. The second objective was to obtain optimal process conditions in the manufacture of starch nanoparticles from sago and to determine their characteristics. The third objective was to determine the effect of using starch nanoparticles on the characteristics of bioplastics. This research is expected to contribute to science and technology related to starch nanoparticle technology, to develop the bioplastic industry and to increase the added value of sago starch. The novelty of this research is that it produces an efficient method of providing starch nanoparticles with a high yield. The application of sago starch nanoparticles is used as a reinforcement in the manufacture of bioplastic composites with polyvinyl alcohol (PVA) matrix. An analysis and modification of the existing methods has been carried out in order to obtain a new method. Analysis of the hydrolysis-precipitation method for producing sago starch nanoparticles. The preparation of sago starch nanoparticles was carried out in a 2-step process, namely lintnerization (slow acid hydrolysis) and precipitation. The conditions of the hydrolysis process were at a concentration of 2.2 N HCl, room temperature (35°C) and treatment time (12, 24, 48 hours). Types of organic solvents used in precipitation process are 95% ethanol and n-butanol. The lintnerization process played a role in destroying the amorphous regions contained in the starch granules and reducing the starch size from 57 m to 0.7 m. Heat and mechanical treatment during the precipitation process can lead to the formation of smaller particles when the starch is degraded. The characteristics of the starch nanoparticles produced are particle size 21.98 nm, crystallinity index of 41% with a yield of 25%. The process conditions were hydrolysis of 2.2 M HCl for 12 hours, at a temperature of 35°C and precipitation using ethanol. This research still has a weakness, namely the process is quite long with a small yield. The analysis of the second method is to develop an efficient and applicable method in producing nanoparticles from sago on a mini plant scale, namely the Hydrolysis-High Shear Homogenization method. The high shear homogenizer has been successfully designed. This tool is equipped with a PLC (Programable Logic Controller) system which includes settings for power (on/off), speed (5000 – 21000 RPM), timer and pulse. Its production capacity is 100 grams/hour. Treatment time of hydrolysis for 12, 24 and 48 hours. The reduction in the size of starch particles can be produced through a mechanical treatment process, namely high shear homogenization. Experimental conditions were carried out at a stirring speed of 21,000 RPM for 3 hours at a solution concentration of 10%. The high rotational speed produces many small turbulent flows which break the particles in contact with the flow into smaller ones. The optimal production process was obtained at 24 hours hydrolysis treatment, 3 hours homogenization and 10% solution concentration. The characterization results showed that starch nanoparticles had a size of 118.6 nm, a degree of crystallinity of 56% and a yield of 70%. The problem of the method that has been developed previously is a wide particle size distribution starting from the micrometer range and the instability of the particle size during storage, so it is necessary to combine high speed homogenization and ultrasonication techniques. Next is the development of the production method of sago starch nanoparticles, namely hydrolysis-high shear homogenization with ultrasonication treatment. The method that has been determined needs to be optimized before being applied to the production of sago starch nanoparticles on a production scale. Process optimization is carried out using Response Surface Methodology (RSM). Sago starch was hydrolyzed with hydrochloric acid (HCl) with a concentration of 2.2 N with treatment time (12-48 hours) (variable X1) followed by neutralization with 1N NaOH solution. Subsequently, it was High Shear Homogenization of 21,000 RPM for 3 hours with the treatment of solution concentration (5-10%) (variable X2). Ultrasonication with treatment time (5-20 minutes) (variable X3). The characterization of sago starch nanoparticles included particle size (response Y1), yield (response Y2). Data analysis was assisted by Software Design Expert 13.0. The optimization of the process was obtained under conditions of hydrolysis for 12 hours, the concentration of the solution 5% in the high shear homogenization process for 3 hours and ultrasonication time of 20 minutes. The size of the sago starch nanoparticles obtained was 61.2 nm and yield was 72.24%. The desirability value is 0.93. The resulting sago starch nanoparticles were applied in the manufacture of bioplastic composites using PVA as a matrix and sago starch nanoparticles as reinforcement with the aim of improving the characteristics of bioplastics. The characteristics of the sago starch nanoparticles used have an average particle size of 70.81 nm and a crystallinity value of 68%. The addition of sago starch nanoparticles (0%; 1%; 2%; 3%; 4% and 5%) of the total mass of the bioplastic solution. The manufacture of bioplastics is done by casting method. Testing of bioplastic characteristics includes tensile strength, water vapor transmission rate and biodegradability. From the manufacture of bioplastics using PVA as a matrix and sago starch nanoparticles as reinforcement, improvements in the characteristics of bioplastics have been obtained. The addition of 5% sago starch nanoparticles has produced bioplastics that meet the standards where the tensile strength is 15.08 MPa, the water vapor transmission rate is 4.21 g/m2/day and the biodegradability value is 30 days. A new method that is efficient and applicable in producing starch nanoparticles from sago on an industrial scale has been produced, namely a combination of hydrolysis-high shear homogenization with ultrasonication threatment methods. Optimal process conditions in the manufacture of starch nanoparticles from sago are hydrolysis for 12 hours, high shear homogenization for 3 minutes at a concentration of 5% and ultrasonication for 20 minutes. The addition of 5% sago starch nanoparticles has succeeded in improving the characteristics of bioplastics according to food packaging industry standards. Keywords: Starch nanoparticles, hydrolysis, high shear homogenization, bioplastic