IR Investigation of Some Degraded Starch Based Biopolymers

Abstract

Bio-polymers for packaging were obtained by extrusion from different mixtures of starch, water and glycerol. These materials were subjected to various methods of degradation such as hydration-drying or heating at high temperatures in order to study the possibilities of destruction or recycling after the end of life-cycle. There were prepared three types of samples with different concentrations of starch and glycerol maintaining their ratio of 4: 1 but with different starch-water ratios. Changes of some physical properties due to these actions were investigated by IR spectroscopy [1]. The samples were comparatively studied before and after degradation. Spectra of degraded samples contain vibration bands of components: starch, glycerol and water, with intensities proportional to their concentration. Degradation by drying leads to the removal of a part of the water without affecting the molecular vibrations of the starch. Heating the samples at high temperature has the effect of removing water without a major change in the bond molecular vibrations. The samples with higher content of starch are less affected by thermal degradation and maintain longer time their ordered structure.