Microvascular carbon fiber reinforced polymer composites: Enhanced polylactic acid removal via catalytic solvent-swelling modification

Microvascular composites enable the development of multifunctional materials with capabilities such as self-healing, active cooling, and structural health monitoring. The Vaporization of Sacrificial Component (VaSC) technique is a prominent strategy for fabricating such structures, typically utilizing poly(lactic acid) (PLA) microfibers as sacrificial templates. In this study, a novel and robust solvent-swelling manufacturing route was employed to produce PLA microfibers with a reduced depolymerization temperature. Unlike previous approaches, this method utilizes a dichloromethane/methanol mixture supported by hydrochloric acid to fully dissolve the tin(II) oxalate catalyst, ensuring its homogeneous dispersion and effective penetration into the polymer matrix. Thermogravimetric analysis revealed a significant reduction in the PLA depolymerization rate leading to mass removal after 3 hours at for modified samples as opposed to for neat PLA, making the process compatible with standard epoxy prepreg curing cycles. Furthermore, the process efficiency and sustainability were evaluated by reusing the infusion mixture four times with only minor changes in thermal behavior. Finally, the optimized PLA microfibers were utilized to fabricate meandering microchannels ( diameter) within carbon fiber reinforced polymer laminates using a vacuum bagging prepreg process, confirming the viability of this method for advanced composite manufacturing with off-the-shelf components. • Fluorine-free solvent lowers polylactic acid depolymerization to 200 C. • 99% of sacrificial polylactic acid is removed within 3 hours. • 0,25 mm microchannels are formed in carbon fiber reinforced polymers. • Catalyst solution maintains efficiency across 4 reuse cycles.