DELGADO, N.; YSAMBERTT, F.; CHÁVEZ, G.; BRAVO, B.:
Proceedings, Biocomp 2016: The 13th Pacific Rim Bio-Based Composite Symposium, 136-140 (2016).
After cellulose, lignin is the second most abundant biopolymer in the vegetable world. Lignin is founded in the cell walls of plants and represents 15-40% by dry weight of plant biomass. Since lignin is a natural phenolic polymer, it is used in various elds and there are a variety of potential products obtainable by chemical modi cation, including surfactants. In this regard, the technical or commercial lignins are of great interest because they represent a byproduct in the production of pulp industries for papermaking, which usually is burned to generate power and recover the reagents used in the process; however, this byproduct can be harnessed for obtaining aromatic derivatives of industrial interest.
To enhance surfactant properties of lignin is necessary to change existing functional groups in order to change its hydrophilic-lipophilic balance (HLB). Therefore, the microwave assisted chemical modi cation of lignin was performed by an esteri cation reaction with alkenylsuccinic anhydrides (C9, C12 and C16). The characterization was carried out by Fourier Transform Infrared Spectroscopy (FTIR). In the FTIR spectra of lignin derivatives it was observed decreased band corresponding to the characteristic hydroxyl groups of the biopolymer (where the reaction occurs), and the appearance of the band associated with the carbonyl groups of carboxylic acid and ester incorporated into structure by ring opening of the anhydride. On the other hand, the evaluation of surfactant properties showed that all the derivatives decreased surface tension of water a greater proportion than the starting lignin. The surfactant character of the derivatives obtained increases with the number of carbon atoms in the chain alkenyl anhydride incorporated due to the hydrophobic effect that makes the derivative migrate to the surface instead of remaining within the solution.