Synthesis and evaluation of novel anionic polymeric surfactants based on polybenzoxazines

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• 作者：Riyad Mahfud ; Tarek Agag ; Hatsuo Ishida ; Sohel Shaikh ; Syed Qutubuddin
• 关键词：Polybenzoxazine ; Polymeric surfactant ; Surface tension ; Critical micelle concentration
• 刊名：Journal of Colloid and Interface Science
• 出版年：2013
• 出版时间：1 October, 2013
• 年：2013
• 卷：407
• 期：Complete
• 页码：339-347
• 全文大小：1669 K

文摘

A novel platform of anionic polymeric surfactants, poly(4HBA-oca^?Na⁺), poly(4HBA-dea^?Na⁺), and poly(4HBA-doa^?Na⁺), has been synthesized by polymerizing benzoxazine monomers that are synthesized by reacting an aliphatic amine of variable chain length (C₈, C₁₀ and C₁₂), with 4-hydroxybenzoic acid and paraformaldehyde. The structures of the monomers and polymeric surfactants are confirmed by NMR and FTIR. The ring-opening polymerization and thermal behavior of the benzoxazine monomers are studied by DSC and TGA. Size exclusion chromatography (SEC) coupled with Viscotek triple detection technique is used to characterize the molecular weight distribution of polybenzoxazine surfactants. The surfactants have low MW, varying from 2200 to 6000, and are fairly polydisperse. The influence of the structure on the surface activity is investigated by measuring the surface tension of aqueous solutions of the polymeric surfactants using the Wilhelmy plate method. The tensiometry results indicate that the adsorption at the air/water interface is similar for the octylamine, decylamine and dodecylamine-based surfactants. Increasing the alkyl chain length from C₈ to C₁₂ does not significantly affect the surface tension at the critical micelle concentration (¦Ã_cmc), while the critical micelle concentration (cmc) gradually increases due to increasing hydrophobic effect. These polymeric surfactants give cmc values ranging from 0.12 g/L to 0.17 g/L, comparable to other polymeric surfactants reported in the literature. The influences of salt addition on the surface tension at the critical micelle concentration (¦Ã_cmc) for these surfactants are studied. Theminimum values of the ¦Ã_cmc are observed around 1 wt % NaCl for the polybenzoxazine surfactant solution.