HEC (hydroxyethyl cellulose) is a non-ionic, water-soluble polymer that is widely used in various industries such as personal care, pharmaceuticals, and food as a thickening, binding, and stabilizing agent. The degree of substitution (DS) is a critical parameter that can significantly affect the properties and performance of HEC.
The degree of substitution refers to the average number of hydroxyethyl groups that are attached to each anhydroglucose unit of the cellulose backbone. In other words, it measures the extent to which the cellulose molecule has been modified with hydroxyethyl groups.
The influence of the degree of substitution on HEC quality is significant. Generally, as the degree of substitution increases, the solubility of HEC in water increases, and its viscosity decreases. HEC with a higher degree of substitution has a lower viscosity, and it is more soluble in water. This is because the hydroxyethyl groups disrupt the hydrogen bonding between the cellulose chains, leading to a more open and flexible structure.
Moreover, a higher degree of substitution can improve the thermal stability of HEC and increase its resistance to enzymatic degradation. However, an excessively high degree of substitution can lead to a decrease in the molecular weight and a loss of the original properties of the cellulose backbone, which can affect the overall performance of HEC.
In summary, the degree of substitution is a critical parameter that can significantly affect the properties and performance of HEC. A higher degree of substitution can improve the solubility and thermal stability of HEC, but an excessively high degree of substitution can lead to a loss of the original properties of the cellulose backbone, which can affect the overall performance of HEC.