Production of cellulose carbamate using urea-based deep eutectic solvents

Cellulose carbamate is a bio-based, biodegradable, and environmentally friendly material and thus an interesting alternative to petroleum-based polymers or fibers from cellulose produced using the viscose process for producing fibers from cellulose. In this study we described an efficient and green method to prepare cellulose carbamates by using deep eutectic solvents. Three different urea-based deep eutectic solvents were used with different molar ratios and cellulose consistency. Nitrogen content of cellulose carbamates increases when cellulose consistency increases from 5 to 20%. Also, the reaction temperature affects the nitrogen content. In addition, the cellulose crystallinity decreases during the carbamation reaction with 20% cellulose consistency using any of the three deep eutectic solvents studied, when the sample is processed in a high-consistency reactor. By selecting suitable parameters, the nitrogen content of cellulose carbamates can be easily adjusted to a desired level.