Flores-León José Ramón, Rodríguez-Félix Dora Evelia, Quiroz-Castillo Jesús Manuel, Burrola-Núñez Heidy, Castillo-Ortega María Mónica, Encinas-Encinas José Carmelo, Alvarado-Ibarra Juana, Santacruz-Ortega Hisila, Valenzuela-García Jesús Leobardo, Herrera-Franco Pedro Jesús
Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, C.P. 83000 Hermosillo, Sonora, Mexico.
Licenciatura de Ecología, Universidad Estatal de Sonora, C.P. 83100 Hermosillo, Sonora, Mexico.
ACS Omega. 2024 Feb 13;9(8):9526-9535. doi: 10.1021/acsomega.3c09296. eCollection 2024 Feb 27.
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.
本研究探讨了使用聚乳酸（PLA）和壳聚糖制备挤出薄膜的方法，其中有无马来酸酐作为增容剂，用于一次性食品包装的潜在应用。这些薄膜在加速老化试验箱中经历了紫外线照射、水冷凝和温度变化的受控条件。该研究分析了不同暴露时间对薄膜结构、形态、力学和热性能的影响。观察到与含壳聚糖的薄膜相比，PLA薄膜表现出较低的降解敏感性。具体而言，纯PLA薄膜在暴露的最初144小时内弹性模量和强度增加，这与紫外线辐射引起的交联有关。另一方面，由PLA、壳聚糖和马来酸酐组成的薄膜Q2以及不含马来酸酐的薄膜Q1在暴露244小时后拉伸强度损失超过50%。Q2薄膜表现出更高的均匀性，导致其比Q1具有更高的抗降解性。随着降解时间的增加，Q1和Q2薄膜的热稳定性均下降。这些薄膜还表现出由于化学结晶过程导致的结晶度变化，以及玻璃化转变温度和结晶的波动，特别是在288小时时。
