Preparation and characterization of cellulose-based foams via microwave curing

In this work, a mixture of a sodium salt of carboxymethylcellulose (CMCNa) and polyethylene glycol diacrylate (PEGDA700) was used for the prepara- tion of a microporous structure by using the combination of two different procedures. First, physical foaming was induced using Pluronic as a blowing agent, followed by a chemical stabilization. This second step was carried out by means of an azobis(2-methylpropionamidine)dihydrochloride as the thermoinitiator (TI). This reaction was activated by heating the sample homo- geneously using a microwave generator. Finally, the influence of different CMCNa and PEGDA700 ratios on the final properties of the foams was inves- tigated. The viscosity, water absorption capacity, elastic modulus and porous structure were evaluated for each sample. In addition, preliminary biological characterization was carried out with the aim to prove the biocompatibility of the resulting material. The foam, including 20% of PEGDA700 in the mixture, demonstrated higher viscosity and stability before thermo-polymerization. In addition, increased water absorption capacity, mechanical resistance and a more uniform microporous structure were obtained for this sample. In particu- lar, foam with 3% of CMCNa shows a hierarchical structure with open pores of different sizes. This morphology increased the properties of the foams. The full set of samples demonstrated an excellent biocompatibility profile with a good cell proliferation rate of more than 7 days.