In recent years there has been considerable interest in polymeric surfactants but there is no clear definition of a polymeric surfactant. EO/PO co-polymers (see Section 7.9) and silicone surfactants (Section 10.2) could be looked upon as polymeric surfactants. Polyacrylic acid of low molecular weight (< 15,000), condensates of naphthalene sulphonate with formaldehyde and sulphonated styrene/maleic anhydride co-polymers are often included in descriptions of surfactants. Synthetic resins based on natural fatty acids such as long oil alkyl resins can be made oil soluble or partially water soluble and show some surfactant properties. Natural products such as alginates, pectins, and proteinbased products could all be looked upon as polymeric surfactants. Most of these products show only weak surfactant properties with respect to surface tension reduction in aqueous solution and the formation of micelles. The word polymeric would suggest high molecular weight with a large number of repeating molecular units. Most polymeric surfactants have only a few repeating units and the phrase oligomeric would seem more descriptive. However the word polymeric has now been firmly established and so is used in this book.
KeywordsPhenol Formaldehyde Poly Acrylic Acid Surface Active Property Surface Tension Reduction Polymeric Surfactant
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