聚乙烯膜的卵磷脂改性及表面性能研究

Modification of polyethylene film by lecithin and analysis of surface properties

以聚乙烯(PE)膜为基材,以两亲分子卵磷脂(PC)为改性剂,采用紫外光交联法制备改性PE膜,大幅度提升改性PE膜的亲水性能,使其获得良好的抗蛋白粘附性能。用单因素实验考察PC浓度、光引发剂种类、真空干燥时间、紫外光照时间对制备改性PE膜亲水性能的影响,然后用正交实验优化改性PE膜制备条件。结果表明,PC浓度对亲水性影响最大,真空干燥时间次之,光照时间和光引发剂对其影响较小,得到的最佳工艺条件为PC浓度5%(质量分数),真空干燥60min,紫外光照45min,选用光引发剂为ITX浓度3%(质量分数)。此条件制备的改性PE膜水接触角由88°降低至低于4°,亲水性能优于其他学者所做实验。用红外光谱分析PE膜改性前后基团变化,证明了PC在PE膜上形成了修饰层。采用一种简单有效的新方法——通过实验室自制的80°斜面装置进行抗蛋白粘附性能测试,发现改性PE膜对大豆蛋白溶液、牛血清白蛋白溶液、纯牛奶的粘附量分别减少51%和75%以及87%,表明改性PE膜的抗蛋白粘附性能得到明显改善。改性PE膜经过10d暴露于空气中,接触角增加7°,持久性实验表明改性PE膜的表面性能具有良好的稳定性。

A method to modify polyethylene film with lecithin by UV cross-linking was devised in this paper.The property of hydrophilicity and anti-protein adhesion are improved for the modified PE film.First,single factor experiments for the hydrophilicity of modified PE films were used to investigate the influence of PC concentration,photoinitiator type,vacuum drying time and UV irradiation time.Then orthogonal experiment is used to optimize the process.The results show that PC concentration has the greatest effect on hydrophilicity,followed by vacuum drying time,light time and photoinitiator type.The optimum conditions are as follows:PC concentration5wt%,vacuum drying60min,UV light45min,photoinitiator ITX3wt%.The contact angle of the modified PE film was reduced from88°to less than4°.Surface morphology and surface chemical composition were analyzed by infrared spectroscopy(FT-IR/ATR)and scanning electron microscopy(TEM).It proves that there is a layer of lecithin on the surface of modified PE film.An effective new device called80°slanting device was used to test the property of anti-protein adhesion.It was found that the adhesion of modified PE film to soybean protein solution,bovine serum albumin solution and pure milk got reduced by51%,75%and87%,respectively,which indicated the property of anti-protein adhesion was significantly improved.In the persistence test,the modified PE film was exposed to air for10days and the contact angle increased by only7°.It shows that the surface property of modified PE film gets good stability.