The accessibility of cellulose (acessibility), that is, the difficulty of the reaction reagent to reach the cellulose. And the degree of hydroxyl activation on the cellulose molecules are two important factors affecting the chemical reaction of cellulose and its derivatives. And directly affect the degree of cellulose reaction and product performance. Through the systematic study of HEC concentration, activator concentration, dosage, reaction time and temperature of reaction parameters on the product viscosity. Determine the best process parameters, make the cellulose molecule of the hydrophobic monomer to reach the appropriate degree. And the reaction system is in the most appropriate state of swelling and dispersion.
Thus, epohexane-modified hydroxyethyl cellulose (EP10-HAHEC) and epohexadane-modifie hydroxyethyl cellulose (EP18-HAHEC). And 1-brododecane-modified hydroxyethyl cellulose (BD-HAHEC) and epohexadane-modifie hydroxyethyl cellulose (EP16-HAHEC) were obtained. Among them, the apparent viscosity value of BD-HAHEC reaches 450mPa.s at the concentration of 0.45 g/dl. While the apparent viscosity of the similar polymer reporte at the polymer concentration is 2 g/dl only reaches this value. EP16-HAHEC has a lower critical association concentration and better viscation properties than BD-HAHEC.
Reports of hydrophobic action studies were first reported in the late 19th century, Traube! In early studies, Like-to-like attraction) was use to explain the association of hydrocarbon chains in micellar molecules. Suggesting that the intermolecular van der Waals force is responsible: However, the van der Waals force between hydrocarbon molecules and water molecules are fundamental. Therefore, it is not complete to explain the association of hydrocarbon molecules. In aqueous solution solely by the van der Waals force. Inde, this phenomenon is to the structural disruption of water when organic molecules are dissolve in water, i. e., with the hydrophobic lipophilic interactions, and the van der Waals force is only a component of the hydrophobic lipophilic interactions.
- After organic molecules are dissolve in water, water molecules want to maintain the original structure and the tendency to reject organic molecules is calle hydrophobic action;
- The Van der Waals attraction between organic molecules is calle the lipophilic action. It is generally believe that the association of organic molecules in aqueous solution is an entropic favorable process.
When organic molecules are dissolve in water, water molecules are highly around them in order, and this unfavorable entropy change makes organic molecules tend to associate together to minimize the contact surface of water and organic molecules, thus reducing the overall structure and increasing the entropy.