Determination of Cellulose Degree of Polymerization in Lignocellulosic Biomass

Lu Liu^*, Hou-min Chang, Hasan Jameel, Sunkyu Park

Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, USA

* Presenting author: llui@ncsu.edu

Degree of polymerization (DP) is one of the most important structural properties of cellulose. Cellulose chain length expressed as cellulose DP can affect the mechanical properties of composite materials and paper products, the solubility of cellulose in a given solvent, and the efficiency of enzymatic hydrolysis of lignocellulosic biomass. Hence it is critical to establish an accurate method to determine the cellulose DP. However, current measurement technique has a major limitation that non-cellulosic components such as lignin and hemicellulose can inhibit the accurate measurement of cellulose DP. In order to overcome this limitation, we present a method with lignocellulosic biomass as a starting material using carbanilation reaction and GPC-based molecular weight (MW) distribution measurement. Delignification, alkaline extraction, and NaBH_4­-based reduction were applied as pretreatment in certain cases to ensure full carbanilation reaction without significant reduction in chain length. The study showed that the removal of ~ 90% of lignin by acid chlorite followed by NaBH₄ reduction can reduce the possibility of cellulose chain cleavage in carbanilation reaction. The alkaline extraction can remove most of the hemicellulose and the rest of lignin, which can provide an accurate result of cellulose DP. This method can be applied to both softwood and hardwood samples, which can make it a general methodology in cellulose DP determination for lignocellulosic biomass.