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

Abstract

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<0.0001) alongside a non-significant lack of fit (p = 0.1034). Polymer concentration exerted the strongest control over fiber thickening. Crucially, flow rate coupled with needle size (p = 0.0130), reflecting a coupled electro-hydrodynamic effect specific to the viscoelastic rheology of the r-PET solution. Numerical optimization (D = 1.000) targeted minimal fiber thickness, identifying ideal coordinates at 10.00 wt% concentration, 1.07 mL/h feed rate, and a 22G nozzle tip. This combination predicted an AFD of 209.52 nm. Bench tests performed in triplicate confirmed these predictions, producing uniform, bead-free nanofibers with a mean diameter of 218 ± 42 nm. A minimal 3.89% deviation verifies the practical accuracy of the model, establishing a batch-consistent quantitative baseline for bottle-derived r-PET filtration substrates.

Keywords

• Recycled PET
• Nanofiber
• Needle electrospinning
• Box-Behnken design
• Process optimization
• Desirability function

Ethical Statement

Ethics committee approval was not required for this study because of there was no study on animals or humans.

References

1. Abbas, J. A., Said, I. A., Mohamed, M. A., Yasin, S. A., Ali, Z. A., & Ahmed, I. H. (2018). Electrospinning of polyethylene terephthalate (PET) nanofibers: Optimization study using taguchi design of experiment. IOP Conference Series: Materials Science and Engineering, 454, 012130. https://doi.org/10.1088/1757-899X/454/1/012130
2. Aydemir, H., & Demiryürek, O. (2023). The effect of electrospinning parameters on morphology and diameter of polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) nanofibers. The Journal of The Textile Institute, 114(10), 1443–1454. https://doi.org/10.1080/00405000.2022.2131341
3. Aydemir, H., Demiryürek, O., & Erol, M. (2025). Structural and sound absorption properties of polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) nanofibers. The Journal of The Textile Institute, 116(4), 722–732. https://doi.org/10.1080/00405000.2024.2352181
4. Baselga-Lahoz, M., Yus, C., Arruebo, M., Sebastián, V., Irusta, S., & Jiménez, S. (2022). Submicronic Filtering Media Based on Electrospun Recycled PET Nanofibers: Development, Characterization, and Method to Manufacture Surgical Masks. Nanomaterials, 12(6), 925. https://doi.org/10.3390/nano12060925
5. Bonfim, D. P. F., Cruz, F. G. S., Bretas, R. E. S., Guerra, V. G., & Aguiar, M. L. (2021a). A Sustainable Recycling Alternative: Electrospun PET-Membranes for Air Nanofiltration. Polymers, 13(7), 1166. https://doi.org/10.3390/polym13071166
6. Bonfim, D. P. F., Cruz, F. G. S., Guerra, V. G., & Aguiar, M. L. (2021b). Development of Filter Media by Electrospinning for Air Filtration of Nanoparticles from PET Bottles. Membranes, 11(4), 293. https://doi.org/10.3390/membranes11040293
7. Gazzano, M., Gualandi, C., Zucchelli, A., Sui, T., Korsunsky, A. M., Reinhard, C., & Focarete, M. L. (2015). Structure-morphology correlation in electrospun fibers of semicrystalline polymers by simultaneous synchrotron SAXS-WAXD. Polymer, 63, 154–163. https://doi.org/10.1016/j.polymer.2015.03.002
8. Gergely, A. (2020). The Production of Polyethylene Terephthalate Nanofibers by Electrospinning with Minimum Amount of Trifluoroacetic Acid. Biomedical Journal of Scientific & Technical Research, 29(3). https://doi.org/10.26717/BJSTR.2020.29.004795

9. Gergely, A., Kántor, J., Bitay, E., & Biró, D. (2019). Electrospinning of Polymer Fibres Using Recycled PET. Acta Materialia Transylvanica, 2(1), 19–26. https://doi.org/10.33924/amt-2019-01-04
10. Gulino, E. F., & Scaffaro, R. (2025). Electrospinning with Green Solvents: Overcoming Constraints While Tailoring Nanofibrous Structures. IOCPS 2025, 40. https://doi.org/10.3390/proceedings2026136040
11. Haider, A., Haider, S., & Kang, I.-K. (2018). A comprehensive review summarizing the effect of electrospinning parameters and potential applications of nanofibers in biomedical and biotechnology. Arabian Journal of Chemistry, 11(8), 1165–1188. https://doi.org/10.1016/j.arabjc.2015.11.015
12. Hoque, M. E., Sarker, M. A., Alam, M. R., & Gafur, M. A. (2024). Development of Multi-Walled Carbon Nanotube-Integrated Recycled Polyethylene Terephthalate Electrospun Antibacterial Face Mask. Journal of Science and Technology Research, 5(1), 63–74. https://doi.org/10.3329/jscitr.v5i1.74005
13. Hossain, M. T., Shahid, M. A., & Ali, A. (2022). Development of nanofibrous membrane from recycled polyethene terephthalate bottle by electrospinning. OpenNano, 8, 100089. https://doi.org/10.1016/j.onano.2022.100089
14. Kijeńska-Gawrońska, E., Wiercińska, K., & Bil, M. (2022). The Dependence of the Properties of Recycled PET Electrospun Mats on the Origin of the Material Used for Their Fabrication. Polymers, 14(14), 2881. https://doi.org/10.3390/polym14142881
15. Medeiros, G. B., Chagas, P. A. M., Da Mata, G. C., Bonfim, D. P. F., De Almeida, D. S., & Aguiar, M. L. (2026). rPET Nanofiber Membranes for Air Filtration: High Performance via Electrospinning Optimization. Nanomanufacturing, 6(1), 4. https://doi.org/10.3390/nanomanufacturing6010004
16. Naeim, H., Mahdavian, F., & Rodrigue, D. (2025). Review on electrospinning of recycled polymer-derived fibers: A road towards sustainability, production and applications. Journal of Environmental Chemical Engineering, 13(6), 119283. https://doi.org/10.1016/j.jece.2025.119283
17. Nam, C., Lee, S., Ryu, M., Lee, J., & Lee, H. (2019). Electrospun nanofiber filters for highly efficient PM2.5 capture. Korean Journal of Chemical Engineering, 36(10), 1565–1574. https://doi.org/10.1007/s11814-019-0370-3
18. Ng, W. L., Zhou, L., Sulong, A. B., Ng, E.-P., & Tan, S. H. (2022). Modification of the commercial polyester filter media support with electrospun polyethylene terephthalate fibers and its application for air purification. Science and Technology for the Built Environment, 28(7), 928–943. https://doi.org/10.1080/23744731.2022.2075188
19. Opálková Šišková, A., Frajová, J., & Nosko, M. (2020). Recycling of poly(ethylene terephthalate) by electrospinning to enhanced the filtration efficiency. Materials Letters, 278, 128426. https://doi.org/10.1016/j.matlet.2020.128426
20. Sigonya, S., Mokhena, T. C., Mayer, P., Makhanya, T. R., & Mokhothu, T. H. (2024). Electrospinning and Rheological Characterization of Polyethylene Terephthalate and Polyvinyl Alcohol with Different Degrees of Hydrolysis Incorporating Molecularly Imprinted Polymers. Polymers, 16(23), 3297. https://doi.org/10.3390/polym16233297
21. Strain, I. N., Wu, Q., Pourrahimi, A. M., Hedenqvist, M. S., Olsson, R. T., & Andersson, R. L. (2015). Electrospinning of recycled PET to generate tough mesomorphic fibre membranes for smoke filtration. Journal of Materials Chemistry A, 3(4), 1632–1640. https://doi.org/10.1039/C4TA06191H
22. Veleirinho, B., Rei, M. F., & Lopes‐DA‐Silva, J. A. (2008). Solvent and concentration effects on the properties of electrospun poly(ethylene terephthalate) nanofiber mats. Journal of Polymer Science Part B: Polymer Physics, 46(5), 460–471. https://doi.org/10.1002/polb.21380
23. Wang, C., Lee, M.-F., & Wu, Y.-J. (2012). Solution-Electrospun Poly(ethylene terephthalate) Fibers: Processing and Characterization. Macromolecules, 45(19), 7939–7947. https://doi.org/10.1021/ma300121k