Rigid Polyurethane Foams Modified with Soybean-Husk-Derived Ash as Potential Insulating Materials

Abstract

One of the most popular polymeric materials in the building and construction industry is rigid polyurethane foam (RPUF). In order to reduce the number of expensive chemical components, various fillers are used in the RPUF industry. The aim of this work was to investigate the influence of the biomass originated filler soybean-husk-derived ash on the structure and properties of composite RPUF. Firstly, polyurethane foams were obtained using hand mixing and casting techniques. Composite foams contained 5, 10, 15, and 20 wt. % of the filler. Secondly, the obtained composite materials were analyzed considering their cellular structure using optical microscopy and image processing software. All samples were composed of mostly pentagonal, regular-in-shape cells. Their diameters ranged between 100 and 70 µm. The chemical structure of the foams was investigated using infrared spectroscopy. No chemical interactions between matrix and filler were detected. Mechanical testing was performed in order to evaluate the mechanical performance of the materials. Both compressive strength and Young’s modulus were comparable and equaled approx. 130 kPa and 2.5 MPa, respectively. Wettability analysis indicated a hydrophobic nature of the materials. The obtained results suggested that the cellular and chemical structure of the polyurethane matrix was not affected by the filler incorporation.