Chemical upcycling of polylactide (PLA) and its use in fabricating PLA-based super-hydrophobic and oleophilic electrospun nanofibers for oil absorption and oil/water separation

Biodegradable polylactide (PLA) is a promising alternative to conventional plastics. Although the material is degradable, a process for converting its post-consumer products to other value-added products is of interest. In this work, PLA-based nanofibers with a super-hydrophobic property are developed by using the chemical recycling products of PLA as an additive. An alcoholysis with glycerol was employed to generate glycerolized PLA (gPLA), i.e., hydroxyl-capped lactate oligomers with tunable structures. The materials were then used as OH-templates for reacting with a hydrophobic agent, alkyl ketene dimer (AKD). The PLA/gPLA blends were fabricated by electrospinning, whose surfaces were modified by directly adding AKD or dipping them into an AKD solution to enhance their surface hydrophobicity. The resulting super-hydrophobic and oleophilic nanofibers exhibited a high oil absorption rate and capacity (lubricant, diesel, and cooking oil), with the reusability of more than 10 cycles. The materials also showed high oil/water separation performance for practical use in the oil decontamination process. After application, the materials are designed to be re-utilized by a similar chemical recycling process to achieve the circularity of materials.