再生聚乙烯中挥发性气味物质扩散的分子动力学模拟  

Molecular Dynamics Simulation of Volatile Odors Diffusion in Recycled Polyethylene

作　　者：章凯倩 王志伟[1] 曾少甫 胡长鹰[1,3] ZHANG Kaiqian;WANG Zhiwei;ZENG Shaofu;HU Changying(Key Laboratory of Product Packaging and Logistics of Guangdong Higher Education Institutes,College of Packaging Engineering,Jinan University,Zhuhai 519070,Guangdong,China;School of Mechanics and Construction Engineering,Jinan University,Guangzhou 510632,China;Department of Food Science and Engineering,Jinan University,Guangzhou 510632,China)

机构地区：[1]暨南大学包装工程学院,广东省普通高校产品包装与物流重点实验室,广东珠海519070 [2]暨南大学力学与建筑工程学院,广州510632 [3]暨南大学食品科学与工程系,广州510632

出　　处：《材料导报》2023年第22期247-254,共8页Materials Reports

基　　金：国家自然科学基金国际(地区)合作与交流项目(32061160474)。

摘　　要：再生聚乙烯中挥发性气味物质的迁移是其用于食品包装的潜在风险之一。本研究使用分子动力学模拟的方法探讨了再生聚乙烯中甲苯、2,4-二甲基庚烷、α-蒎烯、柠檬烯、二苯醚和α-异甲基紫罗兰酮六种挥发性气味物质在不同温度下的扩散行为。通过气味物质分子的均方位移曲线计算了它们的扩散系数,并与实验值和Limm-Hollifield模型值进行了比较。从气味物质的拓扑结构参数、与聚乙烯的相互作用能、扩散活化能以及运行轨迹等方面分析它们的扩散行为。结果表明,这六种挥发性气味物质的扩散受多种因素综合影响。具有较大分子体积和回旋半径以及结构为球型的分子运动较为困难,因此有较小的扩散系数;当气味物质分子的溶解度参数与聚乙烯相近时,两者的相容性较好,分子也不容易扩散。从能量角度来说,气味物质与聚乙烯的相互作用能及其扩散活化能越大,分子运动所需的能量越大,扩散过程越缓慢。同一种物质在不同温度下的运动轨迹表现为长时间的振动与短时间的跳跃,但是在高温下的运动范围较大,轨迹点呈现明显的团簇。One of the potential risks of recycled polyethylene used in food packaging is the migration of volatile odors in it.In this study,molecular dynamics simulation was used to investigate the diffusion behavior of toluene,2,4-dimethylheptane,α-pinene,limonene,diphenyl ether andα-isomethylionone in recycled polyethylene at different temperatures.The diffusion coefficients of odors in recycled polyethylene were calculated by mean square displacement curve and compared with experimental values and Limm-Hollifield model values.We analyzed the diffusion beha-vior of odors from the aspects of topological structure parameters,interaction energy with PE,diffusion activation energy and movement trajectory.The results showed that the diffusion of the odors is influenced by many factors.Molecules with larger volume,radius of gyration and spherical structure are difficult to move,so they have smaller diffusion coefficient.When the solubility parameters of odors are similar to polyethylene,the compatibility between them is good and the molecules are hard to diffuse.From the perspective of energy,the larger the interaction energy with polyethylene and diffusion activation energy of odors,the greater the energy required for molecular movement,and the slower the diffusion process.The trajectories of the odors at different temperatures are long-term vibrations and instantaneous jump,but the range of motion is larger at high temperature,and the trajectories show obvious clusters.

关 键 词：再生聚乙烯 气味物质 扩散 分子动力学模拟 

分 类 号：TS01[轻工技术与工程]