Concentrated O/W Emulsion Stability of Non-Ionic Chitosan Oligomer Surfactants Modified by Epoxidized Fatty Chains at pH7: Influence of Emulsification Conditions

In this study, chitosan-based surfactants were synthesized by epoxy–amine chemistry to stabilize concentrated O/W emulsions at pH7. Chitosan was first depolymerized by nitrous deamination to obtain chitooligosaccharides (COS) with degrees of polymerization of 10 (DP10) and 20 (DP20). Then, three dif...

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Bibliographic Details
Published inPolysaccharides Vol. 5; no. 2; pp. 67 - 84
Main Authors Berthalon, Steve, Frugier, Jérémy, Azema, Nathalie, Negrell, Claire, David, Ghislain
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 11.04.2024
MDPI
Subjects
Adsorption
biobased surfactants
Chemical Sciences
chitooligosaccharides
Chitosan
Cold
concentrated emulsion
Cosmetics
Deamination
Emulsification
Emulsions
epoxy–amine chemistry
Material chemistry
Rheology
Surfactants
Viscosity
biobased surfactants
concentrated emulsion
chitooligosaccharides
epoxy–amine chemistry
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Summary:In this study, chitosan-based surfactants were synthesized by epoxy–amine chemistry to stabilize concentrated O/W emulsions at pH7. Chitosan was first depolymerized by nitrous deamination to obtain chitooligosaccharides (COS) with degrees of polymerization of 10 (DP10) and 20 (DP20). Then, three different epoxidized fatty chains, i.e., octyl/decyl glycidyl ether (C9), hexadecyl glycidyl ether (C16) and epoxidized cardanol (card), were grafted onto the amine groups of chitosan to form six amphiphilic structures. NMR measurements revealed grafting efficiencies ranging from 1 to 30% while HLB values ranged from 13 to 20. The relationships between these surfactant structures and their adsorption properties were investigated by tensiometric measurements, highlighting the need for a short hydrophilic moiety and high grafting efficiency to obtain the best adsorption. Subsequently, concentrated O/W emulsions (66% of oil) at pH7 were produced using COS-based surfactants and the impact of stirring time and speed during the emulsification process was described through rheological, droplet size and microscopy measurements. Finally, emulsions were stored over 2 months in order to study the destabilization phenomenon into the mixture, i.e., coalescence and creaming, by using laser granulometry and Turbiscan. Results demonstrated that stability could be enhanced by increasing emulsion viscosity, reducing droplet size or optimizing the adsorption layer at the O/W interfaces.
ISSN:2673-4176
2673-4176
DOI:10.3390/polysaccharides5020005