Yi Ding,Wenwen Yu,Jie Zhang,Wenying Liu,Fengbo Zhu,Yanan Ye,Qiang Zheng
The Ag@MgO nanoparticles (NPs), consisting of silver NPs with a size range of 6–15 nm well-dispersed on the surface of MgO nanoparticles, were synthesized using a simple and efficient in situ synthesis method. These NPs exhibited superior antibacterial activity compared to bare MgO NPs. Subsequently, they were incorporated into poly(butylene succinate- co -terephthalate) (PBST) matrix to prepare antibacterial food packaging films. The effects of Ag@MgO NPs morphology on the compatibility, mechanical, water vapor barrier, UV blocking and antibacterial properties of PBST matrix were evaluated. Unmodified Ag@MgO NPs caused agglomeration and poor mechanical properties. However, when the Ag@MgO NPs were surface modified and interacted with the PBST matrix, the dispersion of nanoparticles and crystallinity improved, resulting in enhanced tensile strength and barrier properties of the composite films. Furthermore, the well-formed of Ag@MgO NPs in the films played a positive role in controlling the growth of microorganisms. Upon incorporation of the modified Ag@MgO NPs, the PBST nanocomposite films exhibited a 23.5% increase in the tensile strength and a 63% decrease in the water vapor permeability compared to PBST films. Moreover, the UV blocking performances were enhanced, and high antibacterial rates of 99.8% and 99.7% were achieved against E. coli and S. aureus , respectively. All the results indicate that the PBST incorporating modified Ag@MgO NPs have excellent potential for use in food packaging applications.
Inspired by the transpiration in the tree stem having a vertical and porous channel structure, high efficiency of formaldehyde removal is realized by the multi-scale micro–nano channel structure in a hybrid P(AAm/DA)-Ag/MgO hydrogel coating cross-linked on microfiber-based polyurethane. The present multi-scale channel structure is formed by a joint effect of directional freezing and redox polymerization as well as nanoparticles-induced porosity. Due to the large number of vertically aligned channels of micrometer size and an embedded porous structure of nanometer size, the specific surface area is significantly increased. Therefore, formaldehyde from solution can be rapidly adsorbed by the amine group in the hydrogels and efficiently degraded by the Ag/MgO nanoparticles. By only immersing in formaldehyde solution (0.2 mg mL–1) for 12 h, 83.8% formaldehyde is removed by the hybrid hydrogels with a multi-scale channel structure, which is 60.8% faster than that observed in hydrogels without any channel structure. After cross-linking the hybrid hydrogels with a multi-scale channel structure to microfiber-based polyurethane and exposing to the formaldehyde vapor atmosphere, 79.2% formaldehyde is removed in 12 h, which is again 11.2% higher than that observed in hydrogels without any channel structure. Unlike the traditional approaches to remove formaldehyde by the light catalyst, no external conditions are required in our present hybrid hydrogel coating, which is very suitable for indoor use. In addition, due to the formation of free radicals by the Ag/MgO nanoparticles, the cross-linked hybrid hydrogel coating on polyurethane synthetic leather also shows good anti-bacterial capability. 99.99% of Staphylococcus aureus can be killed on the surface. Based on the good ability to remove formaldehyde and to kill bacteria, the obtained microfiber-based polyurethane cross-linked with a hybrid hydrogel coating containing a multi-scale channel structure can be used in a broad field of applications, such as furniture and car interior parts, to simultaneously solve the indoor air pollution and hygiene problems.
危险品化学品经营许可证（带存储）