Formulation of ionogel, hydrogel and films using a cellulose rich solid obtained from Pinus radiata

The purpose of my internship, carried out during my Erasmus period at the Complutense University of Madrid, was focused on the formulation of ionogels and hydrogels for the obtainment of films with high lignin content, and on their characterization measuring their antibacterial properties. For biomass formulation I used lignocellulosic biomass (Pinus Radiata) as raw material and ionic liquid as solvent. The two ionic liquids proposed were: 1-ethyl-3-methylimidazoliumdimethylphosphate [Emim][DMP] and 1-ethyl-3-methylimidazoliumdiethylphosphate [Emim][DEP]. The two-starting cellulose-rich solids were obtained from Pinus radiata wood that had been submitted to an organosolv process, to reduce its lignin content to fifteen (ORG15) and twenty per cent (ORG20). Having two ionic liquids and two solids available, the first phase of the project was devoted to the screening of both solids in both ionic liquids. Through this, it was possible to identify that only the [Emim][DMP] ionic liquid fulfils the purpose. It was also possible to discard the cellulose-rich solid ORG20 because its dissolution in the ionic liquid was not possible (after the time fixed) and, additionally, a Pinus radiata cellulose-rich solid bleached with hydrogen peroxide and containing ten per cent of lignin (ORG10B) was included in the screening. After screening, a total of five ionogels were subsequently formulated: two gels were formulated with the starting raw material ORG15 (with 1% and 1.75% cellulose, respectively) and three with ORG10B (with 1%, 1.75% and 3% cellulose, respectively). Five hydrogels were obtained from the ionogels. Rheological tests were performed on each ionogel and hydrogel. Finally, films were formulated from hydrogels and they were analysed by antibacterial testing to see if they could be applied as food packaging. In addition, antioxidant and properties such as opacity and transparency were also studied.