Rigid polyurethane foams (RPURF) containing a bio-polyol from rapeseed oil and different phosphorus-based flame retardants were obtained. Triethyl phosphate (TEP), dimethyl propane phosphonate (DMPP) and cyclic phosphonates Addforce CT 901 (20 parts per hundred polyol by weight) were used in the synthesis of RPURF. The influence of used flame retardants on foaming process, cell structure, and physical–mechanical properties as well as flammability of RPURF were examined. The addition of flame retardants influenced the parameters of the cellular structure and decreased compressive strength. All obtained foam materials had a low thermal conductivity coefficient, which allows them to be used as thermal insulation. The research results of bio-based RPURF were compared with foams obtained without bio-polyol. All modified materials had an oxygen index above 21 vol%; therefore, they can be classified as self-extinguishing materials. The analysis of parameters obtained after the cone calorimeter test showed that the modified RPURF have a lower tendency to fire development compared to the reference foams, which was particularly noticeable for the materials with the addition of DMPP.
In this article, rigid polyurethane foams obtained with the addition of a bio-polyol from rapeseed oil, were modified with the dimethyl propane phosphonate as additive flame retardant and two reactive flame retardants diethyl (hydroxymethyl)phosphonate and diethyl bis-(2-hydroxyethyl)-aminomethylphosphonate. The influence of used flame retardants on the foaming process and characteristic processing times of tested polyurethane systems were determined. The obtained foams were tested in terms of cell structure, physical and mechanical properties, as well as flammability. Modified foams had worse mechanical and thermal insulation properties, caused by lower cellular density and higher anisotropy coefficient in the cross-section parallel to the foam rise direction, compared to unmodified foam. However, the thermal conductivity of all tested foam materials was lower than 25.82 mW/m∙K. The applied modifiers effectively reduced the flammability of rigid polyurethane foams, among others, increasing the oxygen index above 21.4 vol.%, reducing the total heat released by about 41–51% and the rate of heat release by about 2–52%. A correlation between the limiting oxygen index values and both total heat released parameters from the pyrolysis combustion flow calorimetry and cone calorimetry was observed. The correlation was also visible between the value of the heat release capacity (HRC) parameter obtained from the pyrolysis combustion flow calorimetry and the maximum average rate of heat emission (MARHE) from the cone calorimeter test.
Natural oils from watermelon, cherry, black currant, grape and pomegranate fruit seeds were applied in the synthesis of biopolyols using the transesterification reaction. In this manuscript, the preparation possibility of open-cell foams from a polyurethane system in which petrochemical polyol was fully replaced with biopolyols is analyzed. Firstly, polyurethane foam systems were developed on a laboratory scale, and they were next tested under industrial conditions. It was shown that the foaming method has a significant impact on the foaming process and the cell structure of obtained foams as well as their thermal insulation properties. Based on the conducted research, it was found that the method of processing the polyurethane system has a significant impact on the properties of open-cell spray foams. Foams produced under industrial conditions have a much higher cell density, which has a positive effect on their selected physical–mechanical properties compared to foams produced on a laboratory scale. The open-cell biofoams obtained using a high-pressure machine had apparent densities 12–17 kg/m3, thermal conductivity coefficients 35–37 mW/m·K, closed-cell contents < 10% and were dimensionally stable at low and high temperatures.
In this study, rigid polyurethane foams modified with non-halogenated flame retardant were obtained. The foams were synthesized using two systems containing different blowing agents. In the first one, cyclopentane and water were used as a mixture of blowing agents, and in the second one, only water was used as a chemical blowing agent. The systems were modified with the additive phosphorus flame retardant Roflam F5. The obtained modified foams were tested for their flammability and basic properties, such as apparent density, closed-cell contents and analyses of the cell structures, thermal conductivity, mechanical properties, and water absorption. Increasing the content of Roflam F5 caused a decrease in temperature during the combustion of the material and extended the burning time. The addition of 1.0 wt.% phosphorus derived from Roflam F5 caused the modified rigid polyurethane foam to become a self-extinguishing material. The increase in the content of Roflam F5 caused a decrease in the total heat release and the maximum heat release rate during the pyrolysis combustion flow calorimetry. The foams with the highest content of flame retardant and foamed with a chemical-physical and chemical blowing agent had a lower total heat release by 19% and 11%, respectively, compared to reference foams.
This paper presents new thermo-reflective coatings with different properties. Basic, anti-corrosion and self-extinguishing coatings were analyzed. The coatings were obtained with a thickness varying from 1 to 3 mm. The coatings were subjected to detailed tests assessing their physical-mechanical properties, i.e., tensile strength, abrasion, pull-off test, water absorption, vapor permeability and thermal properties, i.e., the thermal performance of the reflective coatings, thermal transmittance, thermogravimetric analysis, differential scanning calorimetry, as well as thermomechanical analysis and thermal conductivity. In addition, the possibility of using such coatings in a wide range of temperatures and during application to various materials used as a substrate, i.e., concrete, metal and rigid polyurethane foam, was tested. The thermal analysis of coatings revealed that materials are stable to temperatures above 200 °C, there are no thermal transitions in the negative temperature region and shrinking in low temperatures is minimal (less than 0.5%). From the data obtained within the framework of this study, it can be concluded that anticorrosive, basic and self-extinguishing coatings are eligible for thermo-insulation applications in temperatures up to 200 °C.