不同铜粉粒径对Cu/LDPE防银变色包装膜性能的影响

Influence of Different Cu Particles Sizes on the Properties of Cu/LDPE Anti-Tarnish Packaging Films for Silver

以不同粒径的铜粉为活性成分,采用挤出流延法制备了铜/低密度聚乙烯(Cu/LDPE)防银变色包装膜,利用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、紫外可见光分光光度计(UV-vis)以及阻隔性能、力学性能、光学性能、银片色差等测试,研究了在8%添加量下,不同铜粉粒径对薄膜各项性能的影响。结果表明,不同粒径铜粉对薄膜的力学性能、光学性能、防银变色性能影响较大。当平均粒径为1.381μm时,薄膜的拉伸性能和防银变色性能最佳,阻光性能较好,与平均粒径为24.08μm的薄膜相比,其拉伸强度和断裂伸长率分别上升了10%和45%;透光率下降了37%,雾度提升了411%;经体积浓度为(11±1)×10^(-6)H_(2)S气体腐蚀试验后,其包装的银片的色差与平均粒径为24.08μm的包装膜相比下降了71%。

The copper/low-density-polyethylene(Cu/LDPE)anti-tarnish packaging films for silver were prepared by extrusion casting method with the copper powder of different particles sizes as the active ingredients.The scanning electron microscope(SEM),differential scanning calorimeter(DSC),ultraviolet visible light spectrophotometer(UV-vis)and the tests of barrier properties,mechanical properties,optical properties,silver flake chromatic aberration were used to investigate the effects of different particles sizes on the properties of the films at the addition of 8%.The results show that different particles sizes have a greater impact on the mechanical properties,optical properties,and anti-tarnish properties of the films.When the average particles size is 1.381μm,the tensile properties and anti-tarnish properties are the best,light blocking performance is rather better.Comparing with the average particles size of 24.08μm,the tensile strength and elongation at break have increased 10%and 45%.The light transmittance decreases 37%,while the haze increases 411%.The chromatic aberration of the silver flakes packaged in a film with the average particles size of 1.381μm decreases 71%,comparing with that of a film with the average particles size of 24.08μm after the volume concentration of(11±1)×10^(-6)H_(2)S gas corrosion test.