Deuterium oxide d2o

The commercial carpet was a polyamide‐6 (PA‐6)/polyamide‐66 (PA‐66)/polypropylene (PP) rug from Kilands mattor. PA‐6 granules (crystallinity 21.3%) were from Akulon and PA‐66 granules (crystallinity 15.5%) from Technyl Polyamides. Polypropylene (crystallinity 41.1%) was purchased from Domolen. Hydrochloric acid (HCl, 37%), hexamethylenediamine (98%), 6‐aminocaproic acid (99%), and sulfuric acid (H₂SO₄, 95–98%) were purchased from Sigma–Aldrich. Phosphoric acid (H₃PO₄, 85–90%) and adipic acid (99%) were purchased from Fluka. Deuterium oxide (D₂O, 99.96%) for NMR analysis and methanol (MeOH, 95.8%) were purchased from VWR. 1,1,1,3,3,3‐hexafluropropan‐2‐ol (HFIP) was obtained from Apollo and α‐cyano‐4‐hydroxycinnamic acid (>99%) from Fluka.