Abstract
Agriculture modernization and biomass processing generate millions of tons of waste per year containing different amounts and quality of polymeric components such as starch, sugar, lignin, cellulose and hemicellulose. The raw material for extraction was the green plantain peel (Musa paradisiaca), obtained from a local company that produces fried plantain snacks. This work presents the comparisons between the synthesis by wet extraction method and the modification of natural biopolymer with polyhydric alcohol (glycerin). Four blends were prepared at different concentrations of starch, glycerin and water to create a modified biopolymer. Later they were characterized with Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Amylose-Amylopectin ratio. In the unmodified starch samples, the observed bandwidth at 3373 cm-1 can be attributed to amylopectin O-H stretching (55%) and its width was attributed to the formation of inter- and intramolecular hydrogen bonds, also in the region known as the fingerprint (close IR), ranging from 400 to 1250 cm-1, four characteristic peaks are observed in the spectra between 520 and 1020.16 cm -1, which are attributed to the stretching of the C-O bond. For both unmodified starch and modified starch, the TGA tests showed that the weight loss started at a temperature of about 310 °C, but in modified starch the total degradation temperature increases to about 610 °C. Starch extraction from plantain peel wastes has demonstrated its potential for waste use and the production of value-added products, like degradable polymers. The mixtures of starch, glycerin and water (labeled 1, 2, 3, and 4) have different characteristics, shown in the FTIR spectra. Mixture number 4, with 35% glycerin, has a significant peak at 3425 cm-1, corresponding to the OH group stretching. The bending peak at 1641 cm-1, has less transmittance, since the percentage of water in the mixture is zero. The transmittance band between 1060 and 990 cm-1, is characteristic of the polysaccharides, of amorphous structure.
