PBAT/PLA food packaging film containing sodium dehydroacetate-loaded diatomite as an antibacterial agent: Fabrication, water-gas regulation and long-acting antimicrobial mechanism.

Biodegradable food packaging films with good antimicrobial properties are highly sought after for prolonging the shelf-life of fruits and vegetables whilst minimizing waste streams originating from the food sector. In this work, a series of PBAT/PLA food packaging films containing sodium dehydroacetate-loaded diatomite (SD/D) as an antimicrobial agent were fabricated. Structural analyses showed that the sodium dehydroacetate was incorporated into the pores of the diatomite. A uniform dispersion of SD/D in the composite films effectively enhanced water and gas permeability, whilst also giving the films good mechanical properties. The slow release of SD endowed the composite films with long-acting antibacterial ability (>90 % bacteriostasis rate for E. coli and >85 % bacteriostasis rate for S. aureus). The composite films were able to effectively maintain the quality of banana fruits during storage at room temperature, encouraging their use in food applications where non-biodegradable petrochemical-derived packaging films have traditionally been used.

Magnetic-Sensitive Nanoparticle Self-Assembled Superhydrophobic Biopolymer-Coated Slow-Release Fertilizer: Fabrication, Enhanced Performance, and Mechanism.

Although commercialized slow-release fertilizers coated with petrochemical polymers have revolutionarily promoted agricultural production, more research should be devoted to developing superhydrophobic biopolymer coatings with superb slow-release ability from sustainable and ecofriendly biomaterials. To inform the development of the superhydrophobic biopolymer-coated slow-release fertilizers (SBSF), the slow-release mechanism of SBSF needs to be clarified. Here, the SBSF with superior slow-release performance, water tolerance, and good feasibility for large-scale production was self-assembly fabricated using a simple, solvent-free process. The superhydrophobic surfaces of SBSF with uniformly dispersed Fe3O4 superhydrophobic magnetic-sensitive nanoparticles (SMNs) were self-assembly constructed with the spontaneous migration of Fe3O4 SMNs toward the outermost surface of the liquid coating materials ( i.e., pig fat based polyol and polymethylene polyphenylene isocyanate in a mass ratio 1.2:1) in a magnetic field during the reaction-curing process. The results revealed that SBSF showed longer slow-release longevity (more than 100 days) than those of unmodified biopolymer-coated slow-release fertilizers and excellent durable properties under various external environment conditions. The governing slow-release mechanism of SBSF was clarified by directly observing the atmosphere cushion on the superhydrophobic biopolymer coating using the synchrotron radiation-based X-ray phase-contrast imaging technique. Liquid water only contacts the top of the bulges of the solid surface (10.9%), and air pockets are trapped underneath the liquid (89.1%). The atmosphere cushion allows the slow diffusion of water vapor into the internal urea core of SBSF, which can decrease the nutrient release and enhance the slow-release ability. This self-assembly synthesis of SBSF through the magnetic interaction provides a strategy to fabricate not only ecofriendly biobased slow-release fertilizers but also other superhydrophobic materials for various applications.