Environmental impact analysis of surface printing and 3D inkjet printing applications using an imine based covalent organic framework: A life cycle assessment study

Abstract

Covalent organic frameworks (COFs) are emerging materials with structural modularity that allows their applications in many fields. The aim of this work is to determine the environmental impact of using an imine based covalent organic framework (RT-COF-1) for both surface printing (Case A) and 3D inkjet printing (Case B) by applying Life Cycle Assessment (LCA) methodology. Experimental data on its synthesis as well as results obtained by simulation of RT-COF-1 precursors synthesis, 1,3,5-tris-(4-aminophenyl) benzene (TAPB) and 1,3,5-benzenetricarbaldehyde (BTCA), are used. LCA results show that monomers synthesis are the most important contributors to environmental impacts in both case studies. On the other hand, the contribution of solvents used as solvent in Case A is also remarkable. The comparison between both case studies indicate that the environmental impacts of Case B is lower than that of Case A (reduction within 5%-65%). Finally, LCA results of Case B are compared to other materials used for 3D-printing, such as polymerizable ionic liquids (PILs). The results show that RT-COF-1 compares favourably with PILs in five of nine impact categories, being especially relevant the reductions achieved in the abiotic depletion and acidification potential (> 90%), in the primary energy consumption (⁓35%) and carbon footprint (⁓50%), suggesting the potential of RT-COF-1 as 3D-printing material from an environmental perspective. This work is a first step for further research to highlight the main environmental burdens of using COF-based materials in this application. Keywords: COF, LCA, additive manufacturing, surface printing, 3D-printing, inkjet printing.