Development and applicational evaluation of the rigid polyurethane foam composites with egg shell waste

This study was designed towards the development of a series of rigid polyurethane foam (RPUF) composites with egg shells (ES) used as natural filler. Another goal was the determination of the filler content influence on the structure of the materials as well as on their physico-mechanical and biological properties. The synthetic procedure for the production of RPUF composites with high content of the natural filler was successfully established and the properties of obtained materials were tested using a variety of analytical procedures. Infrared spectroscopy was applied in order to analyse the chemical constitution of the materials as well as the degree of phase separation and changes related to the aging process. Scanning electron microscopy was used to determine the changes in cell structure of the materials and thermal degradation processes were investigated using thermogravimetric analysis. Powder x-ray diffraction experiments were performed in order to verify the presence of crystalline phase in the samples. Additionally the apparent density, dimensional stability, water absorption, friability and compressive strength were determined for synthesised materials. The biological properties of the obtained RPUFs were examined using the toxicity test employing human monocyte cell line as well as by bacteria adhesion tests. The selection of the optimal product was based on the optimisation of the renewable substrate content and the application properties in order to develop an environmentally-friendly material with the most valuable characteristics.