The Effects of Gamma Radiation on Bioplastics

Abstract

Bioplastics have been gaining traction in these few years and but still need to achieve the level of physical properties found in petrochemical plastics for wider use in applications involving radiation techniques. This study aimed to investigate the synthesis of starch bioplastic from plant sources such as starch and understand how radiation affects such a material relative to petrochemical plastic. The starch bioplastic samples were synthesised from corn flour and irradiated with a low dose along with PET and PE for comparison. Analysis was done on surface morphology, Vickers hardness test and FTIR for comparison between samples without irradiation and with irradiation. This study found almost no changes in PET, PE and starch bioplastic when exposed to 13.05 mGy of absorbed dose. Comparison between samples of the same material without and with irradiation found no observable changes in the surface morphology. After undergoing irradiation, the Vickers hardness value was found to have changed, for PET a decrease of 1.2 HV from 21.9 HV to 20.7 HV; for PE an increase of 1.57 HV from 5.49 HV to 7.06 HV; for starch bioplastic a slight increase of 0.28 HV from 1.74 HV to 2.02 HV. As for FTIR spectroscopy, the irradiated PET sample displayed slight decreased absorption for overall absorption spectra and significant decreased absorption of peaks at 1700 cm-1, 1250 cm -1, 1000 cm-1 and 720 cm-1 compared to non-irradiated sample. For PE, decreased absorption was found in the overall absorption spectra for sample with irradiation. For starch bioplastic however, no difference was found in the absorption spectra for both samples without and with irradiation. With these findings along with identified issues involved in the synthesis process of the starch bioplastic, this study would help to increase the favourability of bioplastics over conventional petrochemical plastics used in disposable consumer products.