DS play the important role in CMC

CMC has wide applications in different fields depending on their DS values. For example, C. Arthur (1989)synthesized CMC with a DS value of 0.5–1.2. Between this range, CMC is widely used in food additives, paper size, paints, coatings, detergents, and oil-well drilling muds. In contrast, Coffey et al. (2006) and Baiqiao et al. (2009) published an article on the synthesis of CMC with a DS value of 0.6–0.95, which has the greatest use in the food industry.

However, in 2011, based on the “Joint FAO/WHO Expert Committee on Food Additives, 2011” principle, Casaburi et al. (2018)also proposed CMCs with a DS interval of 0.2–1.5 for food applications. Among the various uses of CMC in food applications, CMC is widely used to increase the durability of acidic milk drinks. CMC has been used as a stabilizer and improves the stability of milk; this property is ameliorated with increasing DS because increasing DS values improve the electrostatic repulsion in casein particles, reducing the milk sedimentation or phase splitting].

Moreover, Parikh et al. developed cotton burn dressings by partially exchanging sodium cations with silver cations from sodium carboxymethyl cotton for wound dressing or drug delivery purposes. The resulting carboxymethyl gauze/nonwovens with DS of 0.3–0.4 retained a greater amount of silver nitrate solution for better antimicrobial treatment. CMC is used as a hydrogel form with a proper DS value. For example, P. Komorowska et al. (2017) synthesized CMCs with DS values of 0.62–0.79 to make a strong synergism-based Na-CMC/propylene glycol/H2O hydrogel.

Furthermore, in developing the protein–CMC complex, the DS of CMC is an essential factor. During complexation, on the one hand, higher DS inhibits the complex formation. On the other hand, a lower DS provides a better complexation environment between protein and CMC. Y. Wang et al. (2019) reported the highest optical density (higher LPI-CMC complex form) with low DS (0.7) during the interaction between lentil protein isolate (LPI) and CMC.

On the other hand, depending on the suitable DS value, CMC is used in lithium-ion batteries as a suitable binder in the anode. BR Lee and ES Oh (2013) demonstrated CMC as a binder for a Li4Ti5O12 (LTO) anode with an optimum DS vale (1.2). High DS (1.2) improves the strong binding capacity between LTOs, has high ion conductivity, good lithium-ion mobility in the cell, and provides the best cell performance. After all, the DS value of CMC provides an overall performance of the property of CMC. This section has critically reviewed the importance of DS and how the values of DS vary depending on the starting material, reaction conditions, physical factors, for example, particle size, etc.