Synthesis and characterization of CuO nanoparticle reinforced starch based bio-plastic

Abstract

For the last 50 years, plastics are being widely used all over the world starting from drinking cups and disposable silverware to parts for automobiles and motorcycles. These materials have brought a lot of convenience and attraction to the agro, food and packaging industry. However, increased use of plastic has created serious ecological problems to the environment because of their resistance to biodegradation, thus disposal issues along with the non-renewability of these materials. Due to the growing concern over environmental problems of these materials, interest has shifted towards the development and promoting the use of “bio-plastics”. Bio-plastic is a term used for renewable resources i.e. produced from agro/food sources, materials such as starch, cellulose, etc. and which are considered safe to be used in food packaging applications and the field of medical science. The quality of bio-plastics can be expressed in terms of different properties like physical, thermal, mechanical, antibacterial, and water barrier properties. To enhance these properties, it can be blended easily with other polymers as well as with nanoparticles. For the research purpose CuO nanoparticles was have blended in the starch based bio-plastic. Thus this work outlines the synthesis and characterization of a starch-based biodegradable plastic that can meet the demand and can be disposed to the environment. Synthesis of biodegradable plastics was done by mixing distilled water, Glycerol, 10% Acetic Acid with starch powder. Various amount of CuO nanoparticles was used as a percentage of starch in the main composition. The FTIR, XRD, SEM, EDX, DSC, TGA, tensile strength, and UV-Vis of the samples were done to measure viability of the biopolymer.The peaks shift to lower wavenumber and the decrease in area under the peaks give clear indication of CuO interaction with the functional groups (OH, CH, CH2, CO). The amorphous nature of the final products happen with the increment of the content of CuO NPs in the host matrix indicates high miscibility of CuO nanoparticles in the starch matrix leading to the increased barrier properties.According to the SEM the rigidity that replaced the gummy surface, some agglomeration and weakening of cross links indicates that after a certain level of CuO NPs addition, it deteriorates the mechanical properties after initial enhancement.The chemical analysis (EDX) graphs indicate the presence of Cu other than C, O2 and as with the incrementof CuO the Cu peaks go up.Indicates thermal stability of the CuO NPs reinforced bio-plastics with temperature as the glass transition temperatures go up with approximately fixed melting temperature.The weight loss against temperature curves also support the transition temperature shift to a higher temperature and the mass losses temperature ranges have gone up that indicates thermally more stable bio-plastics reinforced CuO NPs into those bio-plastics.The standard tensile strength for food packaging is 4MPa, which is also what the pure starch bio-plastic is showing and the 0.5% and 1% CuO NPs reinforced bio-plastics show promising results. Although the 2% and 4% CuO NPs reinforced samples have fallen below the threshold, they can be used for other purposes.The direct band gap increment, blue shift, is an indication that the final CuO reinforced products will be good contender to be used as semi-conductors in Photo amplifier and modulators for optical fiber communications.