Among the most effective insulating materials available today are polyurethane foams. Their rigid cell structure minimizes heat transfer between environments. A wide range of applications have been discovered for these products. These include insulating flat surfaces and cylindrical spaces, as well as acoustic insulation. PU foams also offer self-extinguishing capability when used in a fire. However, they can be flammable, particularly in areas with high temperature variations. The use of different flame retardants can help to reduce the flammability of PU foams. Moreover, different production methods can increase the density of the resulting foam.
The first step in this study was to evaluate the mechanical performance of bio-based thermal insulation foam board compared to petroleum-based thermal insulation foam boards. These two types of foams were evaluated with respect to their thermal conductivity, density, compressibility and charring ability. A test specimen was made using the bead foaming technique, which subjected the foam to various temperatures and pressures. In addition, the bulk density of the foam was measured according to ISO 845 standard. The results showed that the bio-based thermal insulation foam board had a density of 0.1 g/cm3 with an 8.16% coefficient of variation.
Similarly, the urethane (roof deck) had a thermal conductivity of 0.021 W/m-K. These findings were comparable to the results of previous studies. The use of fluorocarbon gas in the insulation cells can improve the R-values of the foams. The extruded polystyrene had a thermal conductivity of 0.029 W/m-K. Consequently, the final product was lighter.
The second step was to test the fire behaviour of the PU foam. The foams were reacted to 35 kW/m2 heat flux using a Cone Calorimeter from Fire Testing Technology Ltd. The total smoke release, pHRR, and ignition time were also measured. These tests demonstrated that the bio-based thermal insulation foam board was higher in density than the F150, but lower in mechanical performance. The results also indicated that the combustion behavior of the bio-based thermal insulation foam board was similar to that of the SF.
In the next step, the flammability of the foam was tested with the aid of IM, which was introduced to the foam. During the curing process, the urethane rate equation was applied to predict the temperature profile of the foam. This allowed the researchers to determine the best combination of IM and the urethane rate equation for improving the flammability of the thermal insulation material.
The PU foams were cut on a band saw. They were tested for their thermal conductivity, compression modulus, and total charring ability. The results of the measurements revealed that the bio-based thermal insulation foam board has a thermal conductivity of 5.59 (1.55% CV) and a density of 0.1 g/cm3 while the SF has a density of 0.075 g/cm3. The results indicate that the bio-based thermal insulation foam board is an alternative to the current petroleum-based foam board for thermal insulation. The product has great potential to be used in building systems.
During the past 50 years, the insulation market has been a hotbed of innovation. Many manufacturers have improved the properties of paper, plastic, and other materials to meet the needs of the construction industry. In particular, researchers have focused on the development of flexible polyurethane foams from lignin-like waste residue.