聚乳酸材料的阻气性能研究进展

Research progress on gas barrier properties of polylactic acid material

中文关键词:  聚乳酸  可生物降解  阻气性能  改性方法

英文关键词:polylactic acid  biodegradation  gas barrier properties  modification method

中文摘要:

      在环境污染、能源紧缺的社会背景下, 发展性能优异的生物可降解包装材料替代传统石油基材料迫在眉睫。聚乳酸(polylactic acid, PLA)强度高、刚性大、加工性能好、高度透明, 且来源广泛、价格较低, 成为最具有竞争力的生物可降解材料, 但是其阻气阻水性能相对较差, 不能满足高性能要求的食品包装, 限制了其在食品包装领域的发展。基于气体分子的渗透理论, 本文分析了PLA材料的气体分子阻隔机制, 从两个方面阐述了PLA材料阻隔性能的改进方法。一是在PLA的基体内设置不渗透性的气体分子扩散障碍物, 可通过填充无机或有机纳米材料设置气体阻隔屏障和调控晶体结构(提高晶体结晶度、定向排列晶体)的方式进行; 二是对PLA表面进行改性, 即减少气体分子与聚合物表面的接触, 可通过对聚合物材料的表面涂覆阻隔涂层来实现。最后本文分析了各种PLA材料阻气性能改性方法的优势和弊端, 并对其研究趋势和应用前景进行了展望, 以期为开发阻气性能优良、绿色环保的食品包装提供参考。

英文摘要:

      In the context of environmental pollution and energy scarcity, it is imperative to develop biodegradable packaging materials with superior performance to replace traditional petroleum-based materials. Polylactic acid (PLA) stands out as the most competitive biodegradable material due to its high strength, rigidity, good processing performance, high transparency, wide range of sources, and low price. However, its relatively poor gas and water barrier properties cannot meet the high gas barrier requirements of food packaging, limiting its development in the field of food packaging. Based on the theory of gas molecule permeability, this paper analyzed the gas molecular barrier mechanism of PLA, and elaborated on the modification methods of polymer barrier performance from 2 directions. Firstly, impermeable gas molecule diffusion barriers could be set up within the PLA matrix by filling with inorganic or organic nanomaterials to set up gas barrier barriers and regulating the crystal structure (increasing crystal crystallinity, aligning crystals in a directional manner). Secondly, the surface of the PLA could be modified by reducing the contact between gas molecules and the polymer surface, which could be achieved by coating the surface of the polymer material with a barrier coating. Finally, this paper analyzed the advantages and disadvantages of various methods for modifying the gas barrier properties of PLA, and prospected their research trends and applications, aiming to provide references for the development of green and environmentally friendly food packaging with excellent gas barrier properties.