A mixture of CMCNa and HEC was first dissolved in distilled water by stirring at room temperature until a clear solutionwasobtained.First,HECwaseasilydispersed,after which CMCNa was added. CMCNa dissolution was slow at the concentration adopted, requiring about 24 hours. Once the cellulose solution was obtained, an aqueous solution of citricacid(1%w/v)wasaddedasacatalyst.Thecarbodiimide was finally added and allowed to dissolve and distribute homogeneously throughout the solution. The crosslinking reactionoccurredinafewhoursatroomtemperature,leading to the formation of a yellowish hydrogel. To remove the unreacted chemicals, the partially swollen hydrogel samples were then soaked in a large amount of distilled water until equilibriumwasattained.Atthisstage,thehydrogelsamples wereperfectlyclearandtransparent.Afterthewashingstage, dry products were obtained by desiccating the hydrogel samples by means of a thermal treatment in a convection oven at 45∘C. Powder-like samples were finally obtained by grinding.Thefinalpowdersizedistributionwasintherange 0.1–1mm.