A preliminary study on the use of microalgae biomass as a polyolefin stabilizer

Abstract

Stabilizers play a crucial role in enhancing the durability of polymers, and recent interest in sustainable materials has accelerated the exploration of natural antioxidants as alternatives to traditional synthetic stabilizers. While antioxidants isolated from natural sources have already been integrated into polymers, the direct introduction of antioxidant-rich biomasses, like microalgae, offers a promising yet less explored approach. This study evaluates the effectiveness of microalgae biomass as a polyethylene (PE) stabilizer, using spirulina (washed and unwashed) and Tetraselmis striata. Antioxidant content was assessed through various extraction agents, revealing that water extracts of spirulina contained the highest polyphenol content (940.35 mg/100 g) and antioxidant activity. These biomasses were then integrated into a PE matrix at different loadings (0–30%) and processed by compression molding, while Tetraselmis was also processed by rotomolding. Washed spirulina significantly enhanced thermo-oxidative stability in PE, with a 30% loading yielding a 197% increase in oxidation induction time (OIT). Tetraselmis also proved to be effective, extending OIT from 0.6 to 44.7 min in compression-molded PE at the highest load. However, Tetraselmis did not yield similar results in rotomolding, where no notable OIT improvement was observed. Comparatively, unwashed spirulina provided moderate stability enhancements, though less effective than the washed biomass. This study suggests that microalgae, particularly washed spirulina, are viable eco-friendly stabilizers for PE, opening pathways for more sustainable polymer development.