Synthesis and characterization of hyperbranched waterborne polyurethane/Ag nanoparticle composites

The hyperbranched waterborne polyurethane (HWPU)/Ag nanocomposites were prepared by incorporation of silver sol into the HWPU. Formation of Ag nanoparticles in different generation hyperbranched polyesters was confirmed by UV–vis spectra, particle size distribution, and transmission electron microscope. The structures and properties of HWPU and its nanocomposites were measured with X-ray diffraction, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and thermogravimetric analysis, etc. SEM images revealed that the Ag nanoparticles were well dispersed in the HWPU matrix with an increasing of generation number. The DMA analysis results showed that the HWPU/Ag nanocomposites had higher glass transition temperature and dynamic storage modulus than that of pure HWPU, especially incorporation of Ag nanoparticles protected by the third generation polyester. Incorporation of Ag nanoparticles into HWPU not only increased the mechanical properties but also enhanced thermal properties. Furthermore, the Young's modulus, tensile strength, and the initial decomposition temperature of HWPU/Ag nanocomposites are increased with increase in generation number. POLYM. COMPOS., 39:1967–1977, 2018. © 2016 Society of Plastics Engineers