中文摘要：

目的研究超高压对薄膜结构及性能的影响,以及超高压作用下薄膜与食品模拟物的相互作用。方法选择低密度聚乙烯包装袋为研究对象,以体积分数为10%和95%的乙醇作为低密度聚乙烯包装内的食品模拟物。在超高压装置中,分别进行压力为200,300,400 MPa,保压时间为5,15 min,介质温度为20,60℃的处理,放置7,14,21 d后检测膜的结构和性能变化,以及内容物的不挥发物总量变化。结果压力和温度的提高会使链段运动增强,导致低密度聚乙烯薄膜的结晶度变大,同时拉伸强度也变大,但并不显著;压力与氧气透过率的变化成反比,体积分数为95%的乙醇溶液内容物的低密度聚乙烯,其氧气透过率低于体积分数为10%的;内容物的含量对不挥发物总量也会产生较为显著的影响,含量越大,不挥发物的总量越低,迁移量越小。结论压力、温度和内容物含量的变化都会对低密度聚乙烯和乙醇的相互作用产生影响。

英文摘要：

The aim of this work was to study the effects of ultra high pressure on the structure and properties of the film, as well as the interaction between the film and the food simulant under high pressure processing. LDPE packaging bags were selected as the study object, and the 10% and 95% ethanol were chosen as food simulants in the LDPE packages. In a ultra high pressure device, pressure of 200, 300, 400 MPa was applied respectively for 5 and 15 min, and the medium temperature was 20 and 60℃, the changes in the structure and properties of the film as well as the total amount of nonvolatile food simulant after storing under these conditions for 7, 14 and 21 days were determined. The increase of pressure and temperature could enhance the segment motion, leading to increased degree of crystallinity of LDPE film. Meanwhile, the tensile strength was also enhanced, but the change was not significant. With the increasing pressure, the oxygen transmission rate decreased. For LDPE package containing 95% ethanol solution, the oxygen transmission rate was lower than that containing 95% ethanol solution. The concentration of food simulant also significantly affected the total amount of nonvolatile matter. The higher the concentration, the lower the total amount of nonvolatile matter and the smaller the migration. Pressure, temperature and content of food simulant all influenced the interaction between LDPE and ethanol.