不同无机填料及其含量对LDPE薄膜性能的影响

Effects of Different Inorganic Filler and Its Amount on LDPE Packaging Film's Properties

目的研究纳米TiO_2、纳米级ZSM-5分子筛、微米级ZSM-5分子筛这3种无机填料对LDPE（低密度聚乙烯）薄膜的力学性能的影响。方法将不同无机填料通过双螺杆挤出机与LDPE造粒后,通过单螺杆挤出机挤出流延成膜,并考察薄膜的性能。结果制备的薄膜厚度为91~174μm,实验结果表明,无机填料的加入使LDPE薄膜的拉伸强度及断裂伸长率有不同程度的降低,氧气透过系数增加了17.3%~60.5%,添加填料的LDPE薄膜的二氧化碳透过系数是空白膜的1.3~3倍,ZSM-5分子筛的添加对薄膜的水蒸气透过系数有所提升,而二氧化钛的添加则导致水蒸气透过系数下降。结论无机填料的加入提升了LDPE薄膜的透气性能,但是还需要更进一步的改性,更大程度地改善其透气性、水蒸气透过性和力学性能。

The work aims to study the effects of inorganic fillers of nano-scale TiO_2, nano-and micro-scale ZSM-5 zeolites for low density polyethylene（LDPE） on the properties of LDPE films. Different inorganic fillers were added into LDPE by twin-screw extruder to make master batch, and then modified casting LDPE film was made by single screw extruder. And then the comprehensive mechanical properties of these films were investigated. The thickness of these films was 91~174 μm. The experimental results showed that the addition of inorganic filler decreased tensile strength and elongation at break of LDPE films to different degrees, but, the oxygen permeability was increased by 17.3%~60.5%, carbon dioxide permeability coefficient of LDPE film was 1.3~3 times of the blank film. ZSM-5 zeolite improved the film water vapor transmission coefficient whereas titanium dioxide decreased its water vapor transmission coefficient. In conclusion, due to the presence of inorganic filler, the gas permeability of modified LDPE films is increased. More efforts are needed to improve the gas and water vapor permeability and mechanical property of LDPE packaging films.