Hydrophobically rosin-modified hydroxyethyl cellulose stabilizes oil-in-water emulsion gel with high compliance

Emulsifiers based on amphiphilic cellulose are typically created by adding a hydrophobic group to hydrophilic cellulose. There are few reports on the use of rigid large skeleton structures as hydrophobic groups in the modification of hydrophilic cellulose. This study investigated the hydrophobic rosin (DAGE, containing a large rigid hydrogenated three-phenanthrene ring) modified hydroxyethyl cellulose (HEC), and it was applied to stabilize emulsion gels as an emulsifier (DAGE-g-HEC). DAGE-g-HEC was successfully prepared and DAGE-g-HEC (I-V) were obtained with different grafting degrees ranging from 34.65 % to 46.20 %. In terms of lowering water surface tension, DAGE-g-HEC demonstrated greater activity than HEC, and the γ_CMC was about 36.00 mN/m. DAGE-g-HEC stabilized emulsion gels with 80 % oil phase showed that emulsion stability remained for more than six months at 0.05 wt% or above 0.05 wt% DAGE-g-HEC concentration due to the tight interfacial films established by the rigid group of rosin. The rheological property showed that as the DAGE-g-HEC concentrations rose, so did the emulsions' apparent viscosity. All emulsion gels exhibit strong elastic behavior, according to the loss tangent (tan δ = G″/G') evolutions.