Effect of foam density on the properties of water blown rigid polyurethane foam

Abstract

Density is an important parameter that influences the properties and performances of rigid polyurethane foam (PUF). Rigid PUF with different densities were prepared by varying the amount of distilled water as blowing agent. This investigation reports the mechanical, morphological, water absorption, thermal conductivity, and thermal behavior of rigid PUF varying with the density, which controls the foam architecture. The density of the PUF decreased from 116 to 42 kg/m 3 with an increase in the amount of water from 0.1 to 3.0 parts per hundred polyol by weight (phr), respectively. It was found that the mechanical properties of the PUFs changed with the foam density. The results of water absorption of the PUFs showed that water absorption increased with decrease in density, due to increase in the cell size and decrease in the cell-wall thickness. The thermal conductivity measurements showed that the thermal conductivity decreased with increase in density. It was due to the decrease in cell size. The thermal analysis of the PUFs shows that the glass transition temperature increases with the decrease in foam density, but the thermal stability decreases with the decrease in foam density.

Polyurethane Foams for Thermal Insulation Uses Produced from Castor Oil and Crude Glycerol Biopolyols

“…The effect of blowing agent (water) content in the foams apparent density was also evaluated, as showed in Figure 5a. Increasing the water amount is observed an decrease of density, which suggests that higher cells are formed with the increasing of CO2 production from the water and isocyanate reaction [38]. Figure 5a also shows the influence of the catalyst content in the foams density.…”

“…A significant decrease in the compressive strength and Young modulus of the foams were observed with the addition of the higher blowing agent amounts, which can be related with the density decreases and the cell size increase. As the cell structure becomes higher, less force is necessary to cause deformation in this foams [38]. The results of compressive strength and Young modulus of foams with different amounts of catalyst in the formulations (Figure 8a and 8b) showed that there are no significantly changes of the values increasing the catalysts amount, especially for the formulations with 4 and 6% of water.…”

Cellulose Nano Whiskers as a Reinforcing Filler in Polyurethanes

“…Afterward, isocyanate was added to reach a select isocyanate/hydroxyl ratio and mixed throughly. As isocyanate is a very reactive chemical and can easily react with a trace of water present in the starting materials and/or react with it self forming trimers, a molar ratio of isocyanate groups to hydroxyl groups higher than 1.0 is often used (Yao et al, 1995;Xu et al, 2007;Thirumal et al, 2008). The mixture was then cast into an open mold and cured under varying conditions (Marcovich et al, 2006;Auad et al, 2008;Auad et al, 2010).…”

Modified Gurson Model to Describe Non-linear Compressive Behaviour of Polyurethane Foam with Considering Density Effect

“…영향변수 밀도에 대한 폴리우레탄 폼 기계적 성질의 문헌조 사는 LNG CCS의 insulation board에 작용하는 주된 하중 인 압축하중에 대하여 수행되었다 (Siegmann et al, 1983;Thirumal et al, 2008 (Tvergaard and Needleman, 1984). …”