Effect of nGO on Morphology, Mechanical Properties and Thermal Behavior of PLA/nGO Sheets Before and After Thermoforming: An Experimental Study

Today, contrary to the benefits and advantages that the use of polymer materials has had for humans, the use of these materials has caused environmental problems for human life due to their non-degradability in nature. Therefore, the use of biodegradable polymers such as polylactic acid (PLA) is increasing. One of the main applications of plastic materials is the production of disposable containers. In this research, the thermoforming process of PLA sheets reinforced with graphene oxide nanoparticles (nGO) (0.4 and 1 wt.%) was investigated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to study the morphology of the samples before and after thermoforming. The mechanical properties before and after the thermoforming process were investigated by tensile test. The results showed that after the thermoforming process, the tensile strength of the sheets significantly increased, so that for the sample containing 1wt.% of nGO, the tensile strength increased by about 70%. The results of the thickness distribution investigation showed that the lowest amount of thickness reduction, approximately 68%, is related to the sample containing 1 wt. % of nGO. The results of the DSC thermal test showed that the degree of crystallinity of the samples significantly decreased after thermoforming.