abstract
Polyamides (PAs) are extensively utilized across various applications, yet the accumulation of PA residues presents significant ecological and environmental challenges. Given that a substantial portion of fishing nets are composed of nylon, a type of PA, this material's disposal raises environmental concerns impacting marine life and the global ecosystem. Therefore, to enhance sustainability, they could be collected and recycled. This study introduces a method for the chemical recycling of PA waste using hydrochloric acid (HCl). Through solvolysis, a PA was depolymerized, and the effect of various reaction conditions on the depolymerization yield was analyzed, being the best conditions established in this work (100 degrees C, 4 h, and an HCl/PA ratio of 11:1, wt.wt-1). Next, a novel separation methodology was employed to isolate recycled products from salts formed during neutralization. Subsequently, these recycled products were incorporated as a partial substitute (up to 10% wt.wt-1) for a conventional PA in a new material production. The results indicate that the presence of recycled products enhances material stiffness due to crystallinity differences compared to the virgin matrix. In turn, the introduction of lower-molecular-weight species increases the materials' glass transition temperature (Tg) and their melt flow index (MFI). This research underscores a sustainable pathway for PA recycling aligned with circular economy principles, contributing positively to environmental conservation efforts.
subject category
Science & Technology - Other Topics; Environmental Sciences & Ecology
authors
Gama, N; Araújo, J; Godinho, B; Ferreira, A; Barros-Timmons, A
our authors
Ana Margarida Madeira Viegas de Barros Timmons
Associate Professor
Artur Jorge Faria Ferreira
Professor Coordinator
Bruno Miguel Marques Godinho
Researcher
Nuno Vasco da Costa Gama Batista de Melo
Junior ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This study was funded within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, financed by National funds through the FCT/MCTES (PIDDAC). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No. 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC).