纳米银/低密度聚乙烯复合食品包装薄膜的表征及性能

Characterizations and properties of nano-silver/low density polyethylene composite film for food packaging

将纳米银(Ag)或助剂(光稳定剂783、抗氧剂B900)通过熔融共混的方法添加到低密度聚乙烯(low density polyethylene,LDPE)基材中,再通过挤出机造粒,吹膜机吹塑成薄膜,即制得纳米Ag/LDPE复合食品包装薄膜。借助扫描电子显微镜(Scanning Electron Microscope,SEM)分析了薄膜中纳米银的粒径分布情况;借助原子力显微镜(Atomic Force Microscope,AFM)分析了薄膜的表面微观形貌;对薄膜的力学拉伸性能、透湿性能、透光性、颜色做了相关的测试分析。结果表明,添加纳米银或光稳定剂783、抗氧剂B900会增加LDPE膜的粗糙度,降低LDPE膜的透光性;添加纳米银降低薄膜的断裂伸长率,增加LDPE膜的粗糙度,且使材料颜色偏暗偏黄;所添加的助剂对材料的颜色无影响,但会增加膜的粗糙度。

Nano-Ag/LDPE food packaging films were developed through the following steps：firstly,nano-Ag particles and additives（ Tinuvin 783, Irganox B900） were dispersed into low density polyethylene（ LDPE）, a matrix material,by melting-blending technique;then the particulate polymer composites produced were blown into film by sequential treatment with extruder followed by a plastic film blowing machine;and finally the target product was obtained. Scanning Electron Microscope（SEM） was used to analyze the distribution of Nano-silver particles. Atomic Force Microscope（AFM） was used to analyze the surface micromorphology of films.Tensile mechanical properties,water vapor permeability,light transmittance and color of the films were tested.The results showed that the addition of nano-silver or plastic additives in the materials could increase the roughness of LDPE film,and reduce light transmittance. The addition of nano-silver reduces the elongation at break and the transmittance of the materials,increase the roughness and changes the materials＇ color obviously,more dark and yellow. Plastic additives added in the material had no influence on the the color of materials,but reduced the elongation at break of the materials.