Polyamide 6 recycled fishing nets modified with biochar fillers: An effort toward sustainability and circularity

In a further research effort toward sustainability and circularity, this work demonstrates the possibility of designing and producing novel blends derived from recycled polyamide 6 (PA6) fishing net, incorporating two biochars, i.e., carbonaceous materials obtained from the controlled pyrolysis of vegetable biomasses, at different loadings (namely 5, 10, and 15 wt%). The biochar derived from lignocellulosic biomass enhanced both the mechanical properties and moisture resistance of the recycled polyamide, increasing the elastic modulus from 2.6 to 4.5 GPa and reducing water uptake from 3.6 % to 1.8 %. Interestingly, thanks to its high silica content, the biochar derived from rice husk accounted for an increase in the activation energy for combustion of the polymer matrix (from 43.6 to 70.9 kJ/mol). However, it also showed a detrimental effect on the water uptake and the mechanical behaviour of the blends. Besides, the possibility of replacing up to 15 wt% of petroleum-derived carbon black pigments with the biochars decreased the overall cost of PA6 blends. Also considering the biochar densities that are lower than those of traditional carbon fillers, the proposed blends may pave the way for the design, development, and exploitation of novel sustainable materials suitable for lightweight applications.