Hydroxypropyl Methyl Cellulose (HPMC) originates from natural cellulose. It is a synthetic polymer produced by chemical modification of natural cellulose. Due to the special structure of natural cellulose, cellulose itself does not have the ability to react with etherifying agents. However, after treatment with swelling agents, the strong hydrogen bonds between and within the molecular chains are destroyed, releasing the activity of hydroxyl groups to form alkali cellulose with reactive ability. Then, after etherification reaction, the -OH group is converted into -OR group, obtaining HPMC.
