Optimization of Waste-Derived Recycled Polyethylene Terephthalate (r-PET) Nanofiber Production via Box-Behnken Design

Upcycling waste plastics demands strict process control. Here, post-consumer r-PET flakes dissolved in a trifluoroacetic acid/dichloromethane (TFA/DCM) solvent system were processed into sub-micron fibers using needle electrospinning. A three-factor, three-level Box-Behnken design (BBD) coupled with response surface methodology mapped how polymer concentration (10–15 wt%), solution feed rate (0.5–1.9 mL/h), and nozzle geometry (18–22G) govern average fiber diameter (AFD). The resulting quadratic model fit the experimental data remarkably well. It accounted for 99.88% of process variance (R2 = 0.9988, F-value = 473.60, P