Hydroxypropylcellulose--the reaction of alkali cellulose with propylene oxide

Several methods for the hydroxypropylation of alkali cellulose have been investigated to obtain a uniformly substituted material soluble in dilute alkali and regenerable in dilute acid. The reaction in which alkali cellulose is reacted with a 60% concentration of liquid propylene oxide based on the cellulose content was found to be reproducible giving a film‐forming derivative of 6% substitution with minimum by‐products in less than 2 hr. During the course of this work, hydroxypropylcellulose solutions and films were prepared and evaluated. A valid comparison of the physical properties with those of hydroxyethylcellulose and viscose solutions and films has been made.