Figure 13.

Concentration increase of PU adhesive over time, [PU_L] [mg mL⁻¹]: (a) for each MFPF with 100 vol % formic acid and at 75 °C; (b) for sample D at 50, 65, and 75 °C with 100 vol % formic acid; (c) for sample B at 50, 75, 85, and 100 vol % formic acid at 75 °C; (d) for sample B and D both at 0.005 g mL⁻¹ S/L (straight lines) and also at 0.12 and 0.025 g mL⁻¹ S/L ratio, respectively (dashed lines) with 100 vol % formic acid and at 75 °C. The plateau means 100 % delamination and might lie differently depending on which sample or the amount of sample used in the experiment.