Guest Speaker : Dr Carlos Dominguez, direceur du Polymer Technology Laboratory in Madrid
Summary :
Nowadays, given the challenges faced by our world due to plastic contamination and its environmental impact, recycling has become a key solution to combat this issue. Significant progress has been made regarding recycling of plastics, from better collecting and sorting technologies to development and improvement of both mechanical and chemical recycling processes. However, despite these advances a lot of plastic waste is still not correctly recycled, either due to lack of interest of the recycling stream or loss of properties after its useful life. A clear example is fishing nets waste which have significant degradation and/or contamination that limits its use and recycling, making these plastic goods one of the largest generators of ocean plastic waste. This fact leads not only to harmful effects on marine flora and fauna due to discarded fishing gear, but also cause and striking economic and social damage.
Nevertheless, recycling of fishing goods is a complex process because they are made from different plastics like polyamide (PA), polyethylene (PE), and polypropylene (PP). Among these resins, recycling rates differs depending on their ease of recycling and availability. PA is extensively used, mainly for manufacturing of gill nets due to its toughness and elasticity. Discarded fishing nets from PA are mainly chemically recycled via depolymerization and used again in the manufacture of sport clothing or different products like bags or shoes. Fishing nets made of PE or PP are more difficult to recycle through chemical recycling process as higher conditions are required. Therefore, these products are commonly mechanically recycled but until now the recycled resins obtained have poor properties, mainly because of the presence of impurities and organic matter. Until now, most research has been focused on the use of these recyclates as reinforcements fibers for construction applications and in general in applications where low technical requirements are necessary. In addition, these applications only absorb a very low part of this residue, which is so necessary to address.
In this work, the potential use of recycled fishing nets PE-made in the development of high-demanding applications have been evaluated. The applications studied were blow-molding for goods and pipes made from PE which require good quality PE resins with well-balanced short and long-term properties. To enhance the features of the recycled resin covering those applications, the recycled resin was blended with different virgin PE grades at different rates, where blend preparation, miscibility and compatibility have been evaluated. Finally, short-term and long-term properties were determined and discussed. The solution and results presented in this work are hopeful and represent a good way to channel and value this large amount of plastic waste that until now do not have a clear way out.
