RESUMEN
This study addresses the fabrication of extruded films using poly(lactic acid) (PLA) and chitosan, with and without maleic anhydride as a compatibilizing agent, for potential applications in disposable food packaging. These films underwent controlled conditions of UV irradiation, water condensation, and temperature variations in an accelerated weathering chamber. The investigation analyzed the effect of different exposure periods on the structural, morphological, mechanical, and thermal properties of the films. It was observed that PLA films exhibited a lower susceptibility to degradation compared to those containing chitosan. Specifically, the pure PLA film showed an increase in elastic modulus and strength during the initial 144 h of exposure, associated with cross-linking induced by UV radiation. On the other hand, film Q2 composed of PLA, chitosan, and maleic anhydride and Q1 without maleic anhydride experienced a tensile strength loss of over 50% after 244 h of exposure. The Q2 film exhibited greater homogeneity, leading to increased resistance to degradation compared to that of Q1. As the degradation time increased, both the Q1 and Q2 films demonstrated a decline in thermal stability. These films also exhibited alterations in crystallinity attributed to the chemo-crystallization process, along with fluctuations in the glass transition temperature and crystallization, particularly at 288 h.
RESUMEN
The purpose of this paper is to study the effect of polypyrrole (PPy) on cellulose acetate (CA) membranes prepared by the electrospinning technique (controlled variables) in the recovery of gold complexes of aqueous solutions that are environmentally ecofriendly. CA-PPy membranes were characterized by SEM, EDS, FTIR spectroscopy, contact angle measurements, electrical conductivity, and mechanical tests. They were submerged in two aqueous solutions using two gold complexes, AuI2 - and AuBr4 -, at room temperature. The recovery percentage was evaluated for several hours using the atomic adsorption technique for both complexes. The main findings indicate that the percentage of recovery in the first hours of the test was very high (>80%). The adsorption efficiency maxima were similar for both complexes (91%). The Langmuir model suggests the formation of a monolayer on the surface. The electrical conductivity did not change over time, and the mechanical properties indicate reuse in several experiments. Furthermore, the theoretical analysis showed that the system is helpful at acidic pH, funding its minimum energy. It is shown in this study that the used CA-PPy membranes show adsorption, absorption, and reusable properties with the effective recovery of the complexes in the first hours. These membranes could substitute for materials that are not environmentally ecofriendly.