Poly(methyl methacrylate) (PMMA) and its composites are widely used in industrial applications; therefore, their durability is of great concern. In this study, the photooxidative degradation behavior of nanosilica-filled PMMA composite films and the cooperative effect of mixed solvents containing tetrahydrofuran (THF) and chloroform (TCM), as well as interfacial functional groups, was investigated. The surface functional groups of nanosilica fillers, such as polar, aryl, and alkyl moieties, significantly affect the photodegradation kinetics and pathways for PMMA. The key process lies in the modulation of solvent–solvent reaction selectivity at the polymer–filler interface. Functional groups that selectively promote the chlorination reaction between THF and TCM accelerate PMMA photodepolymerization, while those that suppress this reaction hinder degradation. This interfacial effect is validated by trends in molecular weight loss, volatile product profiles, and MMA yields during aging. Our findings reveal that the photodegradation behavior of PMMA composites is not only governed by environmental conditions but also critically influenced by interfacial chemistry. In this way, this study provides novel insight into the interfacial aging process for polymer nanocomposites, as well as guidance for the rational design of PMMA-based materials with improved durability.
The development of antibiotic-loaded wound dressings is of great importance in wound healing and infection treatment. However, in traditional antibiotic-loaded wound dressings, antibiotics are released uncontrollably from the dressings primarily by passive diffusion. The overuse of antibiotics may lead to drug resistance and side effects, which could hinder the healing process. To overcome these shortcomings, a wound dressing with UV-responsive antibacterial property was developed in this study. Levofloxacin (LF) was first conjugated to amine-terminated poly(ethylene glycol) through a photolabile ortho-nitrobenzyl linker to obtain a photo-cleavable polyprodrug (LHP), which was then loaded into a poly(vinyl alcohol)/sodium alginate (PVA/SA) wound dressing. Compared to the PVA/SA dressing, the LHP-loaded dressing showed larger swelling capacity and retained good cytocompatibility. It was found that LF could be cleaved from LHP under UV irradiation at 365 nm and released gradually from the wound dressing with an increase in UV irradiation time. The antibacterial zone test proved that the LHP-loaded wound dressing possessed UV-responsive antibacterial properties against Staphylococcus aureus.
危险品化学品经营许可证（带存储）