Definition, Classification and Properties of Nonionic Surfactants

Ⅰ. Definition of nonionic surfactant

The aqueous solution does not ionize any form of ions. The hydrophilic group is mainly composed of a certain number of oxygen-containing groups (usually ether groups or hydroxyl groups):

(1) High stability, not easily affected by the presence of strong electrolyte inorganic salts

(2) It is not easily affected by Mg2+ and Ca2+ ions, and has good performance in hard water

(3) Not easily affected by acid and alkali

(4) Good compatibility with other types of surfactants

(5) Good solubility in both water and organic solvents

(6) Most of the products of this type of active agent are in liquid and slurry state, easy to use

Ⅱ. Non-ionic surfactants are divided into the following categories according to the hydrophilic group:

1. Polyoxyethylene type

Polyoxyethylene type nonionic surfactant, also known as polyethylene glycol type, is the product of addition reaction between ethylene oxide and compounds containing active hydrogen.

2. Polyol type

Polyol-type nonionic surfactants are esters of organic substances containing multiple hydroxyl groups such as ethylene glycol, pentaerythritol glycerol, sorbitan, and sucrose, and higher fatty acids. The hydrophilic group in its molecule is a hydroxyl group, which is often used as an emulsifier because of its weak hydrophilicity.

3. Alkanolamide type

Alkanolamides are the condensation products of fatty acids, usually coconut oleic acid, fatty acid or lauric acid, and ethanolamines, which are monoethanolamine or diethanolamine. Ethanolamine is the general name of di- and triethanolamine. When ammonia reacts with ethylene oxide, the three active hydrogens in the ammonia molecule will be replaced by hydroxyethyl groups to form monoethanolamine, diethanolamine and triethanolamine.