Effects of the molecular structure on the vibration reduction and properties of hyperbranched waterborne polyurethane–acrylate for damping coatings.

A series of hyperbranched waterborne polyurethane–acrylate (HWPUA) hybrid emulsions were prepared with isocyanate‐terminated PU prepolymers, hyperbranched polyol (HP), and acrylate monomers. The HP as crosslinker was synthesized with isophorone diisocyanate, dimethylol propionic acid, and diethanol amine. The influence of the HP content on the chemical structure, particle size, morphology, damping properties, and thermal stability of the HWPUA hybrid emulsions and films were investigated by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, dynamic mechanical analysis (DMA), and thermogravimetric analysis, respectively. The results show that the addition of HP obviously improved the damping and thermal properties of the HWPUA films. However, the addition of excessive HP had a detrimental impact on the performance of films. The DMA curves indicated that when the HP content was 1%, tan δ was 0.3 or greater and spanned the broadest temperature range, with a maximum value of 0.65. The HWPUA hybrid emulsions could be used as damping coatings. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47733. [ABSTRACT FROM AUTHOR]