A new approach for the use of cellulose-rich solids from biorefinery in the formulation of gel-like materials

Abstract

The increase in environmental problems and the necessity of substituting fossil fuels in the production of materials is increasing the demand for a new type of raw materials and formulation methods. This study used a cellulose-rich solid (CRS) from a biorefinery process to formulate gel-type materials, ionogels, and hydrogels. A phosphate anion ionic liquid, [Emim][DEP], was used to dissolve the CRS and formulate the ionogels. Hydrogels were formulated by submerging the ionogels in water until the ionic liquid was completely removed. Commercial microcrystalline cellulose (Avicel) was used as a reference. Comparing Avicel and CRS gels, it was discovered that the CRS gives higher rheological properties to the materials. In both cases, due to the utilization of a phosphate anion ionic liquid, cellulose phosphorylation gave these materials important properties such as higher bioactivity, flame retardant, or better absorption capacities. On the other hand, the rheological properties for CRS ionogels and hydrogels are double that of Avicel, with values ranging between 103 and 104 Pa, mainly due to the presence of lignin acting as a reinforcement. It was also observed by SEM that this lignin does not affect the internal structure and morphology of the gels. This work successfully demonstrated that a new raw material, a cellulose-rich solid from biorefinery, could be a good substitute for commercial cellulose in the formulation of ionogels and hydrogels for their use in biomedical and energy fields.