Fabrication of composite microbeads consisting of cellulose and covalent organic nanosheets via electrospray process

Microplastics including microbeads that are heavily utilized in our daily necessities such as cleaners, toothpastes, and cosmetic products as well as in industrial applications have become a severe environmental issue because of their non-degradable characteristics. Upon accumulation in aquatic organisms, microplastics eventually enter the human food supply chain, where these are possibly hazardous to humans. Herein, we demonstrate the fabrication of microbeads comprising abundant, sustainable, and biodegradable cellulose through an electrospray-based process of cellulose acetate and subsequent chemical treatment as a sustainable alternative to microplastic particles, which are widely used in a range of consumer products in our daily lives. We further show that inferior mechanical properties, which degrade the potential of cellulose, can be improved dramatically by incorporating triazine-based covalent organic nanosheets (CONs). The compressive strength of composite microbeads at breakage is measured to be 238 ± 18 MPa, which is higher than those of cellulose microbeads without CON (142 ± 22 MPa) and polypropylene microbeads (199 ± 6 MPa). The study proposes a simple albeit effective approach to fabricating cellulose microbeads with enhanced mechanical properties. Thereby, it provides insights into the replacement of petroleum-based microplastics with an environmentally friendly material system.