改性二氧化硅对SiO2/PLA复合膜性能的影响

目的研究改性二氧化硅对聚乳酸力学性能、氧气透过性能和水蒸气透过性能的影响。方法选择粒径为50nm的工业级二氧化硅为添加剂,使用KH570硅烷偶联剂对其进行改性,然后通过溶液浇铸法将改性后的二氧化硅与聚乳酸共混制备成膜。测试分析拉伸性能、透氧性能和透水蒸气性能,表征复合膜的力学性和阻隔性能。结果与纯PLA膜相比,改性复合膜的拉伸强度和弹性模量分别提高了18.65%和19.91%;玻璃化转变温度比纯PLA膜高11℃左右,热稳定性得到增强。与纯PLA膜相比,改性复合膜的氧气透过系数和水蒸气透过系数分别降低了29.89%和43.76%,阻隔性明显提高。结论经KH570硅烷偶联剂改性的二氧化硅对聚乳酸材料性能的增强效果更佳,为聚乳酸材料在包装领域的应用提供了依据。

Effect of Modified Silica on Properties of SiO2/PLA Composite Films

The paper aims to study the effect of modified silica on mechanical properties, oxygen permeability and water vapor permeability of polylactic acid. In this study, industrial grade silica with a particle size of 50 nm was selected as an additive to be modified with KH570 silane coupling agent; and then the modified silica was blended with polylactic acid by solution casting to prepare a film. The tensile properties test, oxygen permeability test and water vapor permeability test analysis were used to characterize the mechanical properties and barrier properties of the composite film. The results showed that, compared with the pure PLA film, the tensile strength and elastic modulus of the modified composite film were increased by 18.65% and 19.91%, respectively; the glass transition temperature was about 11 °C higher than that of the pure PLA film; and the thermal stability was enhanced. Compared with the pure PLA film, the oxygen permeability coefficient and the water vapor permeability coefficient of the modified composite film were reduced by 29.89% and 43.76%, respectively, and the barrier property was significantly improved. The silica modified with KH570 silane coupling agent has better effect on improving the performance of polylactic acid materials, providing a theoretical basis for the application of polylactic acid materials in packaging.