The commonly used surfactants are low molecular weight compounds with molecular weight of several hundred. With many hot areas, such as enhanced enhancedoil recovery, drug carrier and controlled release, biological simulation, polymer LB membrane, medical polymer materials (anticoagulant), emulsion polymerization and so on, the requirements for surfactant have been increasingly diversified and highly performance-based. Polymer compounds with surface activity have become the focus of attention.
Generally, the substances with molecular weight over several thousand and surface activity are called polymer surfactants. Similar to common surfactants, there is no standard classification for polymeric surfactants. Generally, according to the classification of low molecular surfactants and their ionic properties in water, they can be divided into anionic, cationic, zwitterionic and nonionic types. According to the formation of micelles in solution, it can be divided into polysoap and water-soluble polymer surfactant.
The polymer surfactants that do not form micelles in solution are mainly water-soluble ones. It can be divided into three categories according to the sources of synthetic and semi natural surfactants.
Natural polymers, such as gum, starch, microbial fermentation polysaccharides, etc;
Semi synthetic polymers are all kinds of polymers obtained by chemical modification of starch, cellulose and protein, such as cationic starch, methylcellulose, etc;
Synthetic polymers, such as polyacrylamide derivatives, polyacrylic acid and so on, are obtained from the polymerization of petrochemical derived monomers.
Application in pharmaceutical industry
They are widely used in pharmaceutical industry because of their excellent wettability and block surfactant. In addition, polymer surfactants are widely used in pharmaceutical analysis as phase transfer catalysts in pharmaceutical synthesis.
Application in petroleum industry
Because the crude oil contains solid paraffin, the fluidity of crude oil is poor, which brings some difficulties to the production, storage, transportation, processing and other processes of this kind of oil. This problem can be solved by adding pour point depressant or fluidity improver. The dispersibility of oil soluble polymer surfactant can further improve the fluidity improver and prevent the paraffin in fuel oil from forming precipitation during transportation and storage.
Application in textile printing and dyeing industry
Polyether polymer surfactants are often used as low foaming detergents, emulsifiers, dispersants, defoamer, antistatic agents, wetting agents, printing and dyeing agents, etc. polyvinyl alcohol and other high molecular compounds are widely used in the preparation of emulsion dyeing auxiliaries as thickeners and protective colloids. Carboxymethyl cellulose and other cellulose derivatives are used as detergents for detergents and lignin. Sulfonate and phenolic condensate sulfonate are used as dispersants for insoluble dyes.
Application in paper industry
Polymer surfactants play an important role in improving the performance of paper and improving the efficiency of paper machine, so more and more attention has been paid to them in recent years. Some studies have shown that the effect of deinking is remarkable when maleic acid monoester is prepared from different molecular weight polyethylene glycol and maleic anhydride, and then polymerized with acrylic acid to form maleic acid monoester and acrylic acid copolymer.