Enhancement of the sacrificial material for synergistic molding of microvascular composites

Abstract Poly(propylene carbonate) (PPC) is a promising material for the synergistic molding of microvascular composites due to its thermal depolymerization characteristics. However, its low mechanical strength makes it susceptible to deformation under the high vacuum pressures required during composite fabrication. To address this limitation, this study investigates the effects of polylactic acid (PLA), poly(vinyl alcohol) (PVA), and nano-sized silicon dioxide (SiO 2 ) as modifying additives, using blending and filling techniques to enhance the mechanical properties of PPC. The results show that all three additives improve the properties of PPC, with the formulation containing 7.5 wt% SiO 2 exhibiting the most significant enhancement. The tensile strength increased from 30.15 MPa to 40.63 MPa (a 34.76 % improvement), and the Young’s modulus increased from 393.05 MPa to 668.23 MPa (a 75.1 % increase). The onset decomposition temperature is 115.5 °C, and the fastest decomposition temperature is 159.3 °C. Microvascular composites were successfully fabricated using the vacuum-assisted resin transfer molding (VARTM) process combined with frontal polymerization. Under a vacuum pressure of −0.95 bar, the aspect ratio (AR) of the microvascular cross section improved from 1.67 ± 0.15 to 1.03 ± 0.01, confirming that the optimized, SiO 2 -reinforced PPC is suitable for use as a sacrificial template in high-pressure composite molding processes.