Synthesis Optimization And Characterization Of Hydrophobically Modified Alginate

Due to the properties of biocompatibility,biodegradability,and nontoxicity,sodium alginate?SA?has a broad range of applications,mainly in the food,medical,pharmaceutical.In this paper,dodecyl glycidyl ether?DGE?was chosen as a hydrophobic chain to modify sodium alginate,and amphiphilic alginate derivative was obtained.The objective of this paper was to optimize the HM-alginate synthesis conditions by orthogonal method,and the micellar properties,rheological properties,drug loading performance and emulsifying properties of HM-alginate were also investigated.1.HM-alginate was successfully obtained in basic aqueous solution,based on single-factor tests of the previous studies,the volume of deionized water,reaction temperature,mole ratio of SA to DGE,and SDS content were determined as the key synthesis factors affecting the yield of the product.Using orthogonal optimization methods,the optimum combined parameters were explored as follows:75°C,70 m L H₂O,2×10^-6 mol sodium dodecyl sulfate?SDS?and 2.0 m L DGE?mole ratio of SA to DGE,2.1:1?,the maximum yield was 112.62%.2.HM-alginate has a distinct surface activity in aqueous solution,can be formed a core-shell micelle with alkoxy chain as the hydrophobic core and sodium alginate as hydrophilic shell.The critical micelle concentration of HM-alginate was0.1 mg/m L.The size of the micelles in 0.1 mg/m L HM-alginate solution is about1500 nm,and the?-potential is about-82 mV,which can be stably existed in the solution.3.The hydrophobic end of HM-alginate exists in a more stretched way in ethanol solution resulted in the increase of CMC value,stable performance is reduced,at the same time the effective volume of micelle increases,the flow resistance increases,and the viscosity increases.4.Effect of salt on micelle properties showed that the presence of counter ions weakened the repulsive interaction between surfactant ions,decreased the CMC value of the HM-alginate,reduced stability performance and the effective volume dimensions of HM-alginate and hence viscosity.5.When the pH of solution is in the range of 5⁹,the?-potential of hydrophobically modified alginate does not change much,so it has good stability.6.HM-alginate was used as emulsifier,soy oil as oil phase,and emulsion was obtained after homogenization.Emulsions?oil-water ratio was 1:7?containing 15mg/mL HM-alginate presented better stability during 15 days storage,which stating clearly that HM-alginate is an effective emulsifier to stabilize oil-in-water emulsions.