Modelling of environmental impacts of printed self-healing products.

Products utilising self-healing materials have the potential to restore some of their function following damage, thereby extending the product lifespan and contributing to waste prevention and increased product safety. Despite the growing interest in these products, there a lack of comprehensive studies on the environmental implications of self-healing products and the parameters that influence impacts. The study presented in this paper combined life cycle assessment combined with a Taguchi experimental design and analysis of variance to investigate the effect of various parameters across the life stages of a self-healing composite product manufactured by 3D printing using poly-lactic acid (PLA) and self-healing polyurethane (PU). The results of this study suggests that impacts are primarily affected by avoided production due to the increased service of the product, followed by electricity requirements and material deposition rate (efficiency) of 3D printing. In the case of water consumption raw material manufacturing of PLA and PU are the highest and hence should be a target for research on reducing their water footprint. When comparing self-healing vs. regular products it is evident that most of the impacts are dominated by the electricity consumption of the manufacturing process. These results suggest that maximising avoided production can play a major role in reducing impacts of 3D printed products. The results are important for maximising the circularity of additive manufacturing products while minimising their life cycle impact.

Characteristics of nano-plastics in bottled drinking water.

Plastic pollution in water is threatening the environment and human health. Previous relevant studies mainly focus on macro and micro plastic pollutions and their characteristics. Little is known about the extent and characteristics of nano-scale plastics in our drinking water systems, mainly due to difficulties in their isolation and analysis. These nano-plastics may pose higher risk to human health than micro-plastics. Here we report the collection and analysis of organic nanoparticles from commercial bottled water of two brands. Novel nano-plastic particle imaging and molecular structure analysis techniques have been applied. The findings show the existence of organic nanoparticles, and a likely source has been identified to be the degradation of plastic water bottles.

COVID-19 PPE plastic material flows and waste management: Quantification and implications for South Africa.

The COVID-19 pandemic has exposed the vulnerability of countries to resource constraints while highlighting the indispensability of plastic. Personal protective equipment (PPE), comprising plastic materials, is experiencing an unusual increase in demand globally due to unprecedented consumption for the protection of healthcare workers and the general population. There is a need to model and better understand the material implications of the pandemic. In this research, material flow analysis was used to model the flow of plastic material pre-COVID-19 in South Africa and the additional contribution of the COVID-19 PPE to the plastic footprint. Sankey diagrams were developed to capture the material flow analysis. The mass flow of PPE through the supply chain during the ongoing pandemic is relatively smaller compared to the total national plastic. However, the number of separate PPE items presents a major and growing problem for waste management systems. This paper puts the COVID-19 resource requirements into perspective in relation to South Africa's total national plastic and provides the first known estimate of COVID-19 plastic material resources and waste legacy.