THE EFFECT OF REINFORCING AGAR-BASED BIODEGRADABLE PLASTIC WITH SILICA NANOPARTICLES TO ENHANCE PHYSICAL AND MECHANICAL PROPERTIES AS FOOD PACKAGING

• Main Author: Maulitiva Untoro, Yovilianda
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/64952
• Institution: Institut Teknologi Bandung

Plastics are used as a food packaging material due to their cost-effectiveness and easy to fabricate. The main polymers in the manufacture of plastics are formed from non-renewable environmental sources such as polyethylene and polypropylene. Several studies related to bioplastics for food packaging were carried out to reduce environmental pollution caused by the use of commercial plastics. Bioplastics as food packaging can extend the food shelf life, improve quality and safety, good anti-microbial and anti-oxidant properties. Bioplastics are usually made from starch, lignin, cellulose, and seaweed. Indonesia is one of the largest producers of seaweed in the world. However, the export of seaweed is dominant in form of raw dried material, therefore it is necessary to extract or process seaweed into derivative products such as carrageenan, alginate, and agar to increase its economic value. Agar is produced from the extraction of seaweed Glacillaria sp. which has strong gelling and film-forming strength, good biocompatibility, and a simple extraction process, thus it can be a good candidate as raw material for food packaging bioplastics. Agar is a polymer that has a higher strength than other natural materials commonly used for food packaging applications. However, agar bioplastics still have some drawbacks, such as being brittle, low thermal stability, and less flexibility. Filler is added to the mixture of bioplastics to improve the physical and mechanical properties of bioplastics as food packaging. Silica nanoparticles are non-toxic materials, have a hydroxyl group on the surface, and a large surface area in which it can be a good filler for bioplastic agar as food packaging.The purpose of this study was to find the best method for making bioplastic from agar with the addition of silica nanoparticles (SiO2) as a filler and glycerol as a plasticizer for food packaging applications. This research will also study the effect of adding silica nanoparticle filler on the physical and mechanical properties of the resulting bioplastic. The manufacture of bioplastics is done by mixing agar and glycerol in a ratio of 3:1 (w/w) and the addition of silica nanoparticles with various compositions of 0%, 1%, 2%, 3%, 4%, and 5% (w/w) using the method melt mixing and molding using compression molding method. Optimization of the method using ultrasonication was carried out to improve the homogeneity of the silica nanoparticle’s dispersion in the agar matrix. The characterization carried out included initial tests of silica nanoparticles and bioplastics including functional group analysis, mechanical, morphology, density, moisture content, contact angle, swelling, thermal stability, crystallinity, permeability (WVTR), biodegradation test, and application tests as food packaging. The ultrasonication treatment increased the tensile strength and modulus young of bioplastics significantly in which the optimum bioplastic with a concentration of 5% (w/w) silica nanoparticles through ultrasonication showed a tensile strength of 51.62 MPa with an elongation of 63.16% and an elasticity modulus of 1,014 GPA. The results of the mechanical test were confirmed by SEM cross-sectional micrographs which showed that the ultrasonication increased the homogeneity of the bioplastic mixture. The density, permeability, moisture content, and thermal stability of bioplastics increased with the addition of silica nanoparticle content, while the hydrophobicity (contact angle and swelling value) tended to be stable. The endothermic peak was not observed in the DSC test of bioplastics with the addition of silica nanoparticles. Based on the FT-IR spectrum, shows intermolecular bioplastic bonds that occur through the C-H, C-O, C-O-C functional groups, sulfate esters, and peptides. The functional groups of bioplastics tend to be the same as their constituents. The addition of silica nanoparticles reduced the biodegradation rate and crystallinity of bioplastics.