Efficient Conversion of Cellulose to Thermoplastics by Mechanochemical Esterification

Despite the melting processibility of cellulose is of great importance to convert this abundant biomass to various products, the efficient and sustainable preparation of a thermoplastic cellulose material remains a challenge. Herein, we report a novel one-step ball-milling mechanochemistry method for efficiently converting cellulose to melt-processable cellulose stearates (SCEs) without sacrificing excess reagents. By adjusting the reaction conditions, a series of SCEs with degrees of substitution (DS) ranging from 1.30 to 2.37 are synthesized. Besides, the relationship between DS and the thermoplasticity of SCEs is well investigated. The obtained SCEs with DS beyond 1.62 show favorable thermoplasticity, which can be processed into homogeneous films with a maximum tensile strength of 12.4 MPa and an elastic modulus of 353.6 MPa by a conventional hot-pressing technique (160 °C, 10 MPa). Moreover, this method is universally used for achieving various thermoplastic fatty acid cellulose esters with different numbers of carbons (10–18) in side chains. Due to its high efficiency and sustainability, this approach holds great potential for the large-scale fabrication of thermoplastic cellulose-based materials.