Investigation of covalently colored polyurethane latexes based on novel anthraquinone polyurethane chain extenders

Preparation and Properties of Rosin-based Anthraquinone Fluorescent Waterborne Polyurethane

Fluorescent polyurethane has been widely used as fluorescent probes and switches due to its diverse structure and properties, but most of them are solvent-based and synthesized from petroleum-based products. A new type of rosin-based anthraquinone fluorescent waterborne polyurethane (WPU-DAAQ) with good and stable fluorescence properties was synthesized by reacting rosin modified ester (RAG) as a diol and 2, 6-diaminoanthraquinone (DAAQ) as a fluorescent agent with diisocyanate. The structure of WPU-DAAQ was characterized by Fourier transform infrared spectroscopy, UV-vis absorption spectroscopy, and hydrogen magnetic resonance spectroscopy. The fluorescence properties, water resistance, and solvent resistance of WPU-DAAQ were tested. The results showed that DAAQ was successfully grafted onto the polyurethane molecular chain. The fluorescence intensity of WPU-DAAQ increases and then decreases with increasing excitation wavelengths, and increases with the increase of solvent ether content, and is significantly enhanced compared to DAAQ. The dispersion stability was good with the increase of DAAQ. The introduction of DAAQ into polyurethane improved the thermal stability, hydrophobicity, and solvent resistance of WPU-DAAQ. Therefore, WPU-DAAQ is a new type of fluorescent waterborne polyurethane with stable dispersion properties, good fluorescent properties, heat resistance and water resistance.

Synthesis and Morphological Control of Biocompatible Fluorescent/Magnetic Janus Nanoparticles Based on the Self-Assembly of Fluorescent Polyurethane and Fe₃O₄ Nanoparticles

Functionalized Janus nanoparticles have received increasing interest due to their anisotropic shape and the particular utility in biomedicine areas. In this work, a simple and efficient method was developed to prepare fluorescent/magnetic composite Janus nanoparticles constituted of fluorescent polyurethane and hydrophobic nano Fe₃O₄. Two kinds of fluorescent polyurethane prepolymers were synthesized by the copolymerization of fluorescent dye monomers, and the fluorescent/magnetic nanoparticles were fabricated in one-pot via the process of mini-emulsification and self-assembly. The nanostructures of the resulting composite nanoparticles, including core/shell and Janus structure, could be controlled by the phase separation in assembly process according to the result of transmission electron microscopy, whereas the amount of the nonpolar segments of polyurethane played an important role in the particle morphology. The prominent magnetic and fluorescent properties of the Janus nanoparticles were also confirmed by vibrating magnetometer and confocal laser scanning microscope. Furthermore, the Janus nanoparticles featured excellent dispersity, storage stability, and cytocompatibility, which might benefit their potential application in biomedical areas.

Preparation and Characterization of Controlled-Release Avermectin/Castor Oil-Based Polyurethane Nanoemulsions

Avermectin (AVM) is a low-toxic and high-active biopesticide, but it can be easily degraded by UV light. In this paper, biodegradable castor oil-based polyurethanes (CO-PU) are synthesized and used as carriers to fabricate a new kind of AVM/CO-PU nanoemulsion through an emulsion solvent evaporation method, and the chemical structure, colloidal property, AVM loading capacity, controlled-release behavior, foliar adhesion, and photostability of the AVM/CO-PU drug delivery systems are investigated. Results show that AVM is physically encapsulated in the CO-PU carrier nanospheres, the diameter of the AVM/CO-PU nanoparticles is <50 nm, and the AVM/CO-PU films are flat and smooth without any AVM aggregate. The drug loading capacity is up to 42.3 wt % with a high encapsulation efficiency of >85%. The release profiles indicate that the release rate is relatively high at the early stage and then slows, which can be adjusted by loaded AVM content, temperature, and pH of the release medium. The foliar pesticide retention of the AVM/CO-PU nanoemulsions is improved, and the photolysis rate of AVM in the AVM/CO-PU nanoparticles is significantly slower than that of the free AVM. A release mechanism of the AVM/CO-PU nanoemulsions is proposed, which is controlled by both diffusion and matrix erosion.