The Structure of Polymer Clusters in Aqueous Solutions of Hydroxypropyl Cellulose

Abstract

The viscosity, turbidity, and heat capacity of dilute aqueous solutions of hydroxypropyl cellulose have been studied in a concentration interval of 0.047-1.5 g/l and a temperature interval of 20-80 ∘ C. The data obtained testify that, if the temperature does not exceed 40 ∘ C, hydroxypropyl cellulose molecules are prolate spheroidal globules with semiaxis lengths of 7 and 490Å. At temperatures above 70 ∘ C, the hydroxypropyl cellulose solution consists of clusters; every cluster is composed of 11 globules and has a prolate spheroidal form with semiaxes of 41 and 490Å. In the temperature interval from 40 to 70 ∘ C, the solution concerned contains both globules and clusters, with the concentration of the latter increasing, as the temperature grows.K e y w o r d s: hydroxypropyl cellulose, globule, rigid-chain polymer.

Structural Transition in Dilute Solutions of Rod-Like Macromolecules

“…The form of molecules in a solution was determined according to the data of the viscometric experiment (the relevant procedure was described in work [4]). Aqueous solutions of metolose manufactured by the Shin-Etsu Chemical Company (Hypromellose USP, Substitution Type 2906, Grade 65SH-50) were studied [3].…”

“…Therefore, the mechanisms of the mentioned structural transition will be studied on an example of the cellulose derivative, hy-droxypropyl methylcellulose (metolose) [3]. To some extent, this article continues our work [4].…”

Кінетика Фазового Переходу В Змінному Температурному Полі

“…Currently, the mechanism of gelation has not been studied enough yet despite the existence of a number of relevant hypotheses (see, e.g., works [10][11][12][13]). Earlier, we studied the thermally induced change in the macromolecular conformation of cellulose derivatives in highly dilute aqueous solutions [14,15]. It was shown that the examined sol-gel transition in those systems has a character typical of the phase transition of the first kind.…”

Phase separation dynamics in aqueous solutions of thermoresponsive polymers

“…Figure 1 illustrates the scheme of the experimental setup, which is an improved version of the device used in [13] for turbidity measuring.…”