A preliminary assessment on the preparation of Spirulina/PE blends by compression molding

Abstract

Substituting petrochemical plastics with biobased plastics from natural feedstock offers an environmentally friendlyalternative to reduce the carbon footprint. Proteins are promising biopolymers that can be transformed into plastics andsourced from various types of biomass, such as microalgae. Microalgae, particularly spirulina, is considered an excellentrenewable resource for bioplastic production due to its high protein content. This study focuses on the characterizationof spirulina-polyethylene (PE) composites molded by compression molding technology. Both washed (for salt removal), andunwashed biomass were used in order to explore a potentially more sustainable and cost-effective option. Various loadings ofboth biomass types (5 % - 30 % by weight) were investigated, and the mechanical (tensile, flexural, and impact resistance) aswell as thermal properties (thermogravimetric analysis and differential scanning calorimetry) of the resulting compositeswere determined. The mechanical properties remained nearly unchanged compared to neat PE when the biomass content waskept under 10 wt.% for both the washed and unwashed biomass. At higher biomass loadings, a reduction in mechanical performance was observed; however, the molded parts maintained good aesthetics and acceptable properties. Despite the predictable adverse changes in thermal behavior, the processability of the materials was not affected. Differential scanningcalorimetry indicated that total plasticization of the biomass protein was not achieved during the molding process. Additionally, no significant differences were found between the washed and unwashed biomass, suggesting that using unwashed biomasscould be more economically and environmentally beneficial