Fabrication and characterization of microalgae-based additive ethylene vinyl acetate composites as sustainable bioplastics

Yun-Shiuan Yeh; Yi-Ting Wei; Jo-Shu Chang; I-Son Ng

doi:10.1016/j.ijbiomac.2025.145323

Fabrication and characterization of microalgae-based additive ethylene vinyl acetate composites as sustainable bioplastics

Int J Biol Macromol. 2025 Jun 17:145323. doi: 10.1016/j.ijbiomac.2025.145323. Online ahead of print.

Authors

Yun-Shiuan Yeh¹, Yi-Ting Wei², Jo-Shu Chang³, I-Son Ng⁴

Affiliations

¹ Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
² Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan.
³ Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; Department of Chemical and Materials Engineering, Tunghai University, Taichung 407, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, Taiwan. Electronic address: changjs@mail.ncku.edu.tw.
⁴ Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan. Electronic address: yswu@mail.ncku.edu.tw.

PMID: 40553860
DOI: 10.1016/j.ijbiomac.2025.145323

Abstract

A microalgae-based ethylene vinyl acetate (EVA) composite was developed to enhance recyclability and reduce environmental impact, offering a sustainable alternative for bioplastic applications. Comprehensive bioplastic analysis starts from rheometric, heat press molding, mechanical, morphology, and particle size distribution, and follows by thermal property characterization, such as thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), hardness, crosslinking density and melt flow index in this study. At first, Chlorella sorokiniana PY, processed via spray or freeze drying, significantly improved the melt flow index of recycled EVA foam by 2-5 times. Thermal analysis confirmed that the incorporation of microalgae can maintain EVA stability during processing at 180 °C. Rheological studies revealed that the addition of 10-50 phr microalgae altered the crosslinking behavior, extending foam expansion by 8.8-16.7 times compared to pure EVA. Spray-dried composites exhibited 1.4-1.5 times higher tensile strength than freeze-dried counterparts while preserving acceptable hardness. Furthermore, composites derived from microalgae that cultured in wastewater reduce carbon emissions by 63 % at the optimal loading. This study demonstrated the potential of microalgae-EVA composites as sustainable, high-performance bioplastics for applications in footwear, packaging, and consumer products.

Keywords: Bio-based polymer; Circular economy; Ethylene-vinyl acetate copolymer; Microalgae; Recycling.