SiO2包覆单硬脂酸甘油酯/聚乙烯基共混膜制备及其长效防雾性能

Preparation of SiO2-coated monostearate/polyvinyl blended membrane and thereof long-lasting anti-fog performance

  • 摘要: 防雾薄膜包装可以降低包装内的水分活度,减少果蔬腐败变质产生的大量浪费,因此具有十分重要的研究意义。本文以SiO2为壁材,采用乳液聚合法对单硬脂酸甘油酯(GMS)芯材进行包覆,并将其与线型低密度聚乙烯(LLDPE)混合,制备出了一种长效防雾薄膜。结果表明:通过FTIR和XRD对制备样品进行了化学成分、晶型结构分析,证明了GMS被成功包覆;通过SEM对样品的微观形貌和防雾膜截面微观结构进行分析,所制备的GMS@SiO2为类球形,在薄膜中分散较好;粒径、DSC测试表明,GMS和正硅酸四乙酯(TEOS)使用量在1∶2条件下制备的GMS@SiO2样品的粒径均一性较好,83.05%集中在20~100 nm,且有着最高的包覆率,为69.9%;N2吸附-脱附结果显示:GMS@SiO2表面存在许多的介孔结构,孔径为17.918 nm,可以有效延缓GMS的释放;通过TG对样品的热性能进行分析,发现SiO2壁材对GMS起到了较好的保护作用,GMS的最大损失温度由298℃提高到了405℃,提升了约107℃;通过热防雾测试发现,所制备的薄膜可有效延长薄膜的防雾时间且防雾性能优越,在1~11 h内,薄膜防雾等级为DE级;11~60 h内,薄膜防雾等级为E级,而直接加入GMS制备的防雾薄膜在1~11 h防雾等级为E级,在11~60 h内防雾等级为D级,所制备的防雾膜在果蔬保鲜等领域将有着广阔的应用前景。

     

    Abstract: Anti-fog film packaging can reduce the water activity in the package and reduce the large amount of waste caused by fruit and vegetable spoilage, so it is of great research significance. In this study, SiO2 was used as the wall material, and the core material of glyceryl monostearate (GMS) was coated by emulsion polymerization and mixed with linear low-density polyethylene (LLDPE) to prepare a long-term anti-fog film. The results show that the chemical composition and crystal structure of the prepared samples are analyzed by FTIR and XRD, which proves that GMS is successfully covered. The micromorphology and cross-sectional microstructure of the samples are analyzed by SEM, and the prepared GMS@SiO2 is spherical, which is well dispersed in the film. The particle size and DSC tests show that the GMS@SiO2 samples prepared under the condition of 1:2 using GMS and tetraethyl orthosilicate (TEOS) have good particle size uniformity, 83.05% are concentrated at 20-100 nm, and have the highest coating rate, 69.9%. The results of N2 adsorption and desorption show that there are many mesoporous structures on the surface of the GMS@SiO2. The pore size is 17.918 nm, which can effectively delay the release of GMS. Through the analysis of the thermal properties of the sample by TG, it is found that SiO2 wall material has a better protective effect on GMS, and the maximum loss temperature of GMS is increased from 298℃ to 405℃, which is increased by about 107℃. Through thermal anti-fog test, it is found that the prepared film can effectively extend the anti-fog time of the film and has superior anti-fog performance, in 1-11 h, the film anti-fog grade is DE grade; Within 11-60 h, the film anti-fog grade is E grade, and the anti-fog film prepared directly added to GMS is E grade in 1-11 h. The anti-fog grade is grade D within 11-60 h, and the prepared anti-fog film will have broad application prospects in the fields of fruit and vegetable preservation.

     

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