Algae‐Filled Polypropylene: How Particle Size of <i>Nannochloropsis oculata</i> Biomass Affects Composite Properties

ABSTRACT This study investigates the use of Nannochloropsis oculata biomass, focusing on evaluating the influence of its biomass particle size on the mechanical and thermal properties of polypropylene (PP). Three biomass particle sizes were used: ≤ 0.177, ≤ 0.5, and ≥ 0.5 μm. The morphology and dispersion of the particles were analyzed by scanning electron microscopy (SEM) and optical microscopy. The mechanical properties were evaluated by flexural testing (ASTM D790), while thermal characterization was performed through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The mechanical properties results suggest this material is suitable as a filler, as no significant differences in PP properties occur when biomass is added. To optimize the composite's properties, 6% by weight of compatibilizer, PP‐graft‐maleic anhydride (PP‐g‐MA), was incorporated. This addition resulted in an approximately 285% reduction in Young's modulus, indicating an increase in the system's ductility. Additionally, thermal properties revealed that algae influence the crystallization process and improve the thermal stability of PP, especially with larger particle size.