快速分析食品包装复合膜材质结构的方法研究

Research on the method for rapid analysis of the material structure of food packaging composite film

目的研究快速分析食品包装复合膜材质结构的方法。方法将样品用夹具固定,切片机切片处理后获得材料横截面,并标记样品内外层,利用扫描电子显微镜仪(scanning electron microscope, SEM)对样品层数和由外到内厚度进行表征和测量。利用衰减全反射(attenuated total reflection, ATR)对材料的内外表层进行材质分析,切下的材料薄层采用傅里叶显微红外光谱仪(micro-Fourier transform infrared spectroscopy,Micro-FTIR)对各层树脂进行材质鉴定,结合ATR测试内外表层结果确定复合膜由外到内材质组成。结果该包装复合膜由7层结构组成,由外到内材质依次为聚对苯二甲酸乙二醇酯(polyethylene terephthalate,PET)/聚酰胺(polyamide,PA)/聚乙烯(polyethylen,PE)/PA/乙烯-乙烯醇共聚物(ethylene-vinyl alcohol copolymer,EVOH)/PA/PE,厚度依次为14, 18, 54, 17, 11, 18, 81μm。结论通过切片机切片获取样品横截面和薄层样品,SEM、Micro-FTIR联合进行分析,可以确认食品包装复合膜的整体组成结构及每层材质信息。该方法无需树脂包埋和有毒有机溶剂浸泡剥离,方法前处理简单,可以快速、准确地完成多层未知复合膜材料的结构分析。

Objective To investigate the method of rapid analysis of compound film material structure of food packaging. Methods The sample was fixed and the material cross-section surface with the slicer was got, the inner and outer layers of sample on the clamps were marked, and the layer numbers and thickness of the sample could be characterized and measured by a scanning electron microscope(SEM). The material of the inner and outer surface layers of the sample was analyzed by attenuated total reflectance(ATR), and the material of each layer of sample was identified by micro-Fourier transform infrared spectroscopy(Micro-FTIR). At last, the order of materials combination from the outside to inner was confirmed combining the ATR test results. Results The packaging composite material was composed of seven layers, with polyethylene terephthalate(PET)/polyamide(PA)/PE/PA/ethylene-vinyl alcohol copolymer(EVOH)/PA/PE from outer surface to inner surface. The thicknesses were about 14, 18, 54, 17, 11, 18 and 81 μm, respectively. Conclusion The cross-section of the sample and the thin-layer sample can be obtained by slicer. SEM and Micro-FTIR can be used to analyze the overall composition and structure of the food packaging composite film and the combination order of each layer. It is a simple operation without any resin embedding and solvent-peeled layering, and the structure analysis of the multilayer unknown composite film can be completed quickly and accurately.