Volatile compounds characterization of microalgae biomass (Chlorella sp. HS2) at high processing temperatures for application to an eco-friendly polymer composite

In this study, we investigate the volatile organic compounds release characteristics of microalgae (Chlorella sp. HS2) in relation to temperature in an effort to realize an alternative type of biomass for use in the fabrication of eco-friendly polymer composites. The volatile organic compounds (VOCs) generated during the compounding process of the polymer composite is quantified and the VOC generation pathways are discussed. As the microalgae are heated and their content in the composites increases, the intensity of the VOC release increases. At a high temperature of 180 °C, a typical polymer processing temperature, microalgae release volatile substances. The VOCs are identified as compounds containing ketone functional groups and benzene derivatives through chromatography and spectrometry analyses. VOCs with ketone functional group can originate from small fatty acids by a complex reaction pathway that includes hydrolysis, oxidation, and degradation, while benzene derivatives are from aromatic amino acids, such as Tyrosine, Phenylalanine, and Tryptophan, contained in the microalgae. The findings demonstrate that microalgae biomass particles produce VOCs during polymer processing, which must be considered during the fabrication and eventual commercialization of polymer composites.