Kinetics of Catalyzed Thermal Degradation of Polylactide and Its Application as Sacrificial Templates^†

Polylactide (PLA) is an outstanding sacrificial template material for the manufacture of microchannels in a thermosetting matrix. However, the initial thermal degradation temperature of pure PLA is relatively high (about 280°C), which limits its use as a sacrificial template. In this report, we found that TBD, an organic base catalyst, can significantly reduce the thermal degradation temperature of PLA. TBD has higher catalytic activity for the thermal degradation of PLA compared with Tin(II) oxalate (Sn(Oxa)), one catalyst reported in the literature. Moreover, the gaseous products catalyzed by TBD for PLA thermal degradation are mainly lactide, and the formation temperature of the monomer is lower and the yield is higher, which may have potential value for PLA recycling. A combined catalyst, S₈T₂, was composed of 80% low activity catalyst Sn(Oxa) and 20% high activity catalyst TBD, which can catalyze the rapid degradation of PLA without greatly damaging the mechanical properties of PLA. PLA-S₈T₂ sacrificial fibers can form high-precision one-dimensional microchannels in the epoxy resin matrix, and 3D-printed PLA-S₈T₂ sacrificial templates can be used to form three-dimensional microchannels in a thermosetting matrix by vaporization of sacrificial components process (VaSC). These features highlight the great potential of PLA-S₈T₂ as sacrificial template material for the preparation of the complicated microchannels in the thermosetting matrix.