3D-Printed Pinewood Biochar-Reinforced Polylactic Acid/Polybutylene Adipate-co-Terephthalate (PLA/PBAT) Composites: A Green Solution for High-Performance Antistatic Applications

Abstract

The growing demand for sustainable antistatic materials in electronics and packaging has prompted research into biodegradable polymer composites with conductive biofillers. However, achieving optimal electrical conductivity while maintaining mechanical integrity remains challenging in conventional processing methods. This study investigated 3D-printed PLA/PBAT composites reinforced with sustainable pinewood (Pinus radiata.) biochar (BC) at loadings from 0 to 15 wt%. Filaments were prepared via melt mixing followed by single-screw extrusion, then fused filament fabricated (FFF) at optimized parameters. The biochar was synthesized by pyrolysis method. Scanning electron microscopy (SEM) and confocal Raman imaging confirmed uniform biochar dispersion and enhanced PLA-PBAT compatibility, with reduced phase separation compared to unfilled blends. Fourier transform infrared spectroscopy (FTIR) revealed specific polymer-filler interactions through selective peak shifts. Mechanical testing showed that the 1 wt% biochar composite (BC1) achieved optimal properties with significant improvements in mechanical properties over the pure blend. Higher biochar loadings caused agglomeration and reduced mechanical performance. Thermogravimetric analysis indicated consistent thermal stability at low biochar concentrations. Electrical measurements demonstrated that all biochar-containing composites met antistatic requirements, with BC1 exhibiting surface resistivity of 6.59 × 10¹¹ ± 2.08 × 10⁹ Ω/sq and volume resistivity of 7.84 × 10¹⁰ ± 3.5 × 10⁹ Ω cm at room temperature. The BC1 composite emerged as the optimal formulation, offering a balanced combination of mechanical robustness, thermal stability, and antistatic performance suitable for electronics packaging and electrostatic discharge protection applications.