Colored polyurethane foams with enhanced mechanical and thermal properties

Abstract

Very often, colored polyurethane (PU) foams are used in the industry, but until now the influence of the dye on the properties of PU foams has not been evaluated. Because of this, PU foam composites were prepared by the addition of red color pigment (Acid Red 74). This pigment was chosen due to its strong color that can enhance the aesthetic value of the foam. Additionally, the research allowed to determine how the pigment influenced the mechanical and functional properties of the PU foams. In this study, PU foams were prepared with the addition of commercial pigment with different weight ratios (0.1, 0.5 and 2 wt%) as a particulate modifier of PU foams composites. The features of resulting composite foams were evaluated by morphological (Scanning Electron Microscopy, SEM), thermal (Thermogravimetric Analysis, TGA), mechanical (compressive test, three-point bending test, Charpy impact test) and physical properties (apparent density, dimensional stability, contact angle, water uptake, color characteristics). Color analysis reveals that the addition of color pigment in PU foams has greatly improved the color of the PU foams to red. Moreover, it has been found that compared to the reference foam, composition with 0.1 wt% of the filler showed greater compressive strength (increase of 12%, from 0.25 to 0.28 MPa), better flexural strength (increase of 11%, from 0.41 to 0.46 MPa), less water uptake (decrease by 43%, from 9.8 to 6.5% after 24 h) as well as lower thermal conductivity (0.027 Wm−1K−1).