High sulfur content composite materials from renewable fatty acid cellulose esters (FACEs) via inverse vulcanization

Abstract

Herein, we introduce an efficient inverse vulcanization of fully renewable cellulose-based monomers. Therefore, biobased fatty acid cellulose esters (FACEs) with different degrees of substitution (0.38 ≤ DS ≤ 0.62) were inversely vulcanized to obtain high sulfur content composite materials (∼95 wt% sulfur). In-depth structural characterization of the crosslinked sections via differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), energy dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM) revealed an increased amount of covalently incorporated sulfur (5.67 wt% ≤ sulfur wt% ≤ 56.2 wt%) with a higher DS of FACEs. Investigating structure–property relationships further revealed an increase in thermal stability (227 °C ≤ T_d,5% ≤ 247 °C) accompanied by a decreased wettability (87° ≤ θ ≤ 99°) with DS. The obtained materials showed application possibilities for water purification, i.e. for mercury extraction (70% ≤ Hg_removal²⁺ ≤ 95%).