Process-structure-property relationship of ABS, PC, and ABS-PC blends in microscale additive manufacturing

Microscale fused deposition modeling (µ-FDM) requires thermoplastic materials with stable thermal behavior, controlled melt flow, and reliable interlayer mechanical performance. This study investigates the thermal, structural, morphological, and flexural behavior of µ-FDM-printed acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and a 50:50 ABS-PC blend to establish a process-structure-property relationship under microscale deposition conditions. Thermogravimetric analysis (TGA) revealed a progressive increase in degradation temperature from ABS (T max ≈ 416 °C) to the ABS-PC blend (≈ 438 °C) and PC (≈ 520 °C), indicating enhanced thermal stability of the blend. Differential scanning calorimetry indicates partial miscibility between the ABS and PC phases. Fourier-transform infrared and X-ray diffraction analyses confirmed intermolecular interactions and predominantly amorphous structures without new phase formation. Flexural testing demonstrated an increase in ultimate flexural strength from ABS (~38 MPa) to the blend (~44 MPa) and PC (~53 MPa), while the ABS-PC blend exhibited the highest flexural modulus. Fracture and morphological analyses revealed a transition from brittle crack propagation in ABS to ductile deformation in PC, whereas the blend exhibited mixed-mode fracture behavior with improved interlayer load transfer. The results demonstrate that ABS-PC blending provides a balanced combination of thermal stability, stiffness, and mechanical performance, making it a promising material system for µ-FDM-based micromanufacturing applications.