Hard and flexible coatings based on nanoparticle-filled hyperbranched polymers

POLY 94

Linda Fogelström, linda@polymer.kth.se, Eva Malmström, mave@polymer.kth.se, Mats Johansson, matskg@polymer.kth.se, and Anders Hult, andult@polymer.kth.se. School of Chemical Science and Engineering, Fibre and Polymer Technology, Royal Institute of Technology, KTH, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
The combination of hardness, scratch resistance and flexibility is a highly desired feature in many coating applications. The aim of this study is to achieve this through the introduction of a nano-clay filler in a polymer resin based on the hyperbranched polyester Boltorn H30. Smooth and uniform films could be prepared from both the neat and the nanoparticle-filled hyperbranched resin, and results from DMA rendered indications of a nano-scale dispersion. Furthermore, DMA measurements showed a 10 ºC increase in Tg, a slightly higher storage modulus – both above and below the Tg – and indications of a more crosslinked network, for the clay-containing film. Conventional coating characterization methods demonstrated, in accordance with the DMA results, an increase in the surface hardness with the introduction of clay, and all coatings exhibited excellent chemical resistance and adhesion; however, further characterization is necessary, especially regarding flexibility and scratch resistance.