Yan Jing, Cheng Wencai, Ding Congcong, Qiu Ze, Li Xiaoan, Lu Xirui
State Key Laboratory of Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, P. R. China.
National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010, P. R. China.
ACS Omega. 2024 Sep 8;9(37):38668-38677. doi: 10.1021/acsomega.4c04407. eCollection 2024 Sep 17.
Radiation stability of food packaging materials is the key to ensuring food quality. In this study, Co γ-ray was selected to investigate the radiation resistance of food packaging polystyrene (PS) resin material, although the FTIR analysis showed that the intensity of several peaks decreased slightly. The gel permeation chromatography (GPC) results displayed that the value of peak molecular weight (Mp) of PS went from 2.68 × 10 g/mol down to 2.22 × 10 g/mol. Moreover, the residual mass (Res) of PS increased from 7.208 to 30.23%, indicating that the tendency of coking of PS was stronger after irradiation. In addition, the peak intensities of the three main pyrolysis products -CH-, CH, and CH=CH increased by more than 30% compared to unirradiated PS, and a large number of them were detected in the whole pyrolysis process. Moreover, mechanical property analysis finds that both breaking strength and elongation data increased before irradiation dose of 50 kGy, then, decreased sharply with further increase of irradiation dose. The theoretical bond order analysis confirmed that the tertiary carbon bond attaching the benzene ring had the lowest bond energy. This study can give helpful guidance when using PS for food packing materials.
食品包装材料的辐射稳定性是确保食品质量的关键。在本研究中，选择钴γ射线来研究食品包装聚苯乙烯（PS）树脂材料的抗辐射性，尽管傅里叶变换红外光谱（FTIR）分析表明几个峰的强度略有下降。凝胶渗透色谱（GPC）结果显示，PS的峰值分子量（Mp）从2.68×10 g/mol降至2.22×10 g/mol。此外，PS的残余质量（Res）从7.208%增加到30.23%，表明PS在辐照后焦化的趋势更强。另外，与未辐照的PS相比，三种主要热解产物—CH-、CH和CH=CH的峰强度增加了30%以上，并且在整个热解过程中检测到大量此类产物。此外，力学性能分析发现，在辐照剂量达到50 kGy之前，断裂强度和伸长率数据均增加，然后随着辐照剂量的进一步增加而急剧下降。理论键级分析证实，连接苯环的叔碳键具有最低的键能。本研究可为将PS用作食品包装材料时提供有益的指导。
