Shakoor Shar Abdul, Wang Ningning, Chen Tianyu, Zhao Xiaoying, Weng Yunxuan
College of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China.
Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China.
Polymers (Basel). 2023 Oct 11;15(20):4049. doi: 10.3390/polym15204049.
Poly (lactic acid) (PLA) is a promising green substitute for conventional petroleum-based plastics in a variety of applications. However, the wide application of PLA is still limited by its disadvantages, such as slow crystallization rate, inadequate gas barrier, thermal degradation, etc. In this study, lignin (1, 3, 5 PHR) was incorporated into PLA to improve the thermal, mechanical, and barrier properties of PLA. Two low-viscosity epoxy resins, ethylene glycol diglycidyl ether (EGDE) and poly (ethylene glycol) diglycidyl ether (PEGDE), were used as compatibilizers to enhance the performance of the composites. The addition of lignin improved the onset degradation temperature of PLA by up to 15 °C, increased PLA crystallinity, improved PLA tensile strength by approximately 15%, and improved PLA oxygen barrier by up to 58.3%. The addition of EGDE and PEGDE both decreased the glass transition, crystallization, and melting temperatures of the PLA/lignin composites, suggesting their compatabilizing and plasticizing effects, which contributed to improved oxygen barrier properties of the PLA/lignin composites. The developed PLA/lignin composites with improved thermal, mechanical, and gas barrier properties can potentially be used for green packaging applications.
聚乳酸（PLA）在各种应用中是一种很有前景的绿色替代传统石油基塑料的材料。然而，PLA的广泛应用仍然受到其缺点的限制，如结晶速率慢、气体阻隔性不足、热降解等。在本研究中，将木质素（1、3、5质量份）加入到PLA中以改善PLA的热性能、机械性能和阻隔性能。使用两种低粘度环氧树脂，乙二醇二缩水甘油醚（EGDE）和聚乙二醇二缩水甘油醚（PEGDE）作为增容剂来提高复合材料的性能。木质素的添加使PLA的起始降解温度提高了15℃，增加了PLA的结晶度，使PLA的拉伸强度提高了约15%，并使PLA的氧气阻隔性提高了58.3%。EGDE和PEGDE的添加均降低了PLA/木质素复合材料的玻璃化转变温度、结晶温度和熔融温度，表明它们的增容和增塑作用，这有助于提高PLA/木质素复合材料的氧气阻隔性能。所开发的具有改善的热性能、机械性能和气体阻隔性能的PLA/木质素复合材料有可能用于绿色包装应用。
