Chemical modification of rubber with in situ degradation of PET and the production of its biodegradable films with starch

Abstract

Chemical degradation of PET with natural rubber was carried out. The product obtained was characterized by FTIR, and it was found that the intensity of the vibration signal of the carbonyl group (1719 cm−1) depends on the mass of rubber used in the reaction and not on the PET degradation products, reaching an adequate mass ratio of Rubber/PET = 4. The chemical structure of the product obtained was rubber chains with end groups of ethylene terephthalate oligomers. The pasting properties of the banana starch were modified with the resulting product, affecting its gelatinization process and the maximum viscosity value of 5.78 Pa.s to 1.50 Pa.s at a temperature of 25 °C. Starch degraded PET-rubber films have better mechanical properties than starch-only films. Additionally, these films degrade at lower temperatures (491 to 469 °C) than starch-only films. The ability of these films to conduct electrical current increases up to 25.52% with respect to that of the native starch film. SEM morphology of the starch degraded PET-rubber films shows the formation of clusters, which causes the films to present adhesive characteristics, indicating that these films have a high potential for application in the adhesive and paint industry as biodegradable materials.