[2PS-274]
Catalyst Selection and Reaction Condition Optimization for the Depolymerization of Nylon 6,6 for the Chemical Recycling
발표자박현재 (서울대학교)
연구책임자안철희 (서울대학교)
Abstract
Chemical recycling of Nylon 6,6 via ammonia depolymerization was studied with catalyst selection and condition optimization. Ammonia provides stable reaction conditions but lower reactivity than HCl-based systems, requiring activation of the amide bond. Lewis acids were used to reduce carbonyl electron density, and hydrogen-bonding solvents (ethylene glycol, glycerol, PEG 600) were evaluated to weaken amide linkages. With La(OTf)3 at 200 °C under 3 bar NH3 for 24 h, higher hydrogen-bonding functionality decreased the residual polymer fraction to 27.4 wt%, but high-boiling solvents limited separation. Ethylene glycol was selected for processability, and catalyst strength was tuned using La(OTf)3(bpy), La(OTf)3, and In(OTf)3. Stronger Lewis acidity improved depolymerization; In(OTf)3 was optimal. At 0.1 mol% In(OTf)3 and 72 h, residual polymer decreased to 5.2 wt%. DSC and Flory–Fox analysis confirmed reduced molecular weight of precipitated polymer.