Recycling of Poly(L-Lactic acid) based 3D printed objects using Sn, Ti and triazabicyclodecene-based catalysts in film or microfiber form

In this study, 3D printed polylactic acid (PLA) objects were recycled into lactide monomers using various commercially available catalysts, including triazabicyclodecene (TBD), tin (II) ethylhexanoate; Sn(Oct)2 and titanium (IV) isopropoxide; Ti(OiPr)4. The PLA objects were first dissolved in dichloromethane and then processed into catalyst embedded films or electrospun fibers. The degradation of PLA was performed under both static air and nitrogen flow conditions, demonstrating that electrospun fibers with 0.5 % mol catalyst loadings exhibited superior degradation performance compared to films. For instance, the electrospun fibers with Sn(Oct)2 catalyst achieved a turnover frequency (TOF) of 3400 h-1. Thermogravimetric analysis (TGA) and degradation constant (kobs) calculations confirmed that the fibers had a significantly higher degradation rate due to their increased surface area and better catalyst distribution. The isolation of L-lactic acid (L-LA) from the degradation products was achieved with an average yield of 95 %, indicating the effectiveness of the recycling process. This research highlights the potential for efficient PLA recycling using catalyst-embedded electrospun fibers, offering a sustainable approach to polymer waste management.