Properties of Rigid Polyurethane Foams with Blowing Agents and Catalysts

Choe, Kun Hyung; Lee, Dong Hoon; Seo, Won Ik; Kim, Woo Nyon

doi:10.1295/polymj.36.368

Cited by 85 publications

(49 citation statements)

References 4 publications

(6 reference statements)

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“…The effect of the blowing agent type in apparent density of the foams produced from GCo polyols (Table 1) showed that formulations with physical blowing agents (cyclopentane and n-pentane) produced foams with higher densities than those synthesized with the chemical blowing agent (water). Similar results have been reported in the literature [34][35][36] and this behaviour indicates that smaller cells are formed due to the rapid volatilization of physical blowing agents, which have low boiling point, during the highly exothermic foam growth step in comparison with the CO2, produced by the reaction of water with isocyanate [37]. The effect of blowing agent (water) content in the foams apparent density was also evaluated, as showed in Figure 5a.…”

Section: Resultssupporting

confidence: 84%

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

Carriço¹,

Fraga²,

Carvalho³

et al. 2017

Preprint

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Rigid polyurethane foams were synthesized using a renewable polyol from the simple physical mixture of castor oil and crude glycerol. The effect of the catalyst and blowing agent in the foams properties was evaluated. The use of physical blowing agent (cyclopentane and n-pentane) allowed obtaining foams with smaller cells in comparison with the foams produced with a chemical blowing agent (water). The increase of water content caused a decrease of density, thermal conductivity, compressive strength and Young's modulus, which indicates that the increment of CO2 production contributes to the formation of larger cells. Higher amount of catalyst in the foam formulations caused a slight density decrease and an increase small significance of thermal conductivity, compressive strength and Young's modulus values. These green foams presented properties that indicate a great potential to be used as thermal insulation, as density (23 -41 kg m -3 ), thermal conductivity (0.0128 -0.0207 W m -1 K -1 ), compressive strength (45 -188 kPa) and Young's modulus (3 -28 kPa). These biofoams are also environmental friendly alternatives and can aggregate revenue to biodiesel industry, contributing for reduction of this fuel prices.

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Section: Resultssupporting

confidence: 84%

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

Carriço¹,

Fraga²,

Carvalho³

et al. 2017

Preprint

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“…It is believed that infusion of nanoparticles acts as a catalyst to increase the kinetic rate of this chemical reaction. The increased kinetic rate helps the blowing gas to generate gradually and thus giving larger cell size [20].…”

Section: Chemical and Microstructural Propertiesmentioning

confidence: 99%

High Strain Rate Response of Sandwich Composites with Nanophased Cores

et al. 2005

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Polyurethane foam materials have been used as core materials in a sandwich construction with S2-Glass/SC-15 facings. The foam material has been manufactured from liquid polymer precursors of polyurethane. The precursors are made of two components; part-A (diphenylmethane diisocyanate) and part-B (polyol). In one set of experiments, part-A was mixed with part-B to manufacture the foam. In another set, TiO 2 nanoparticles have been dispersed in part-A through ultrasonic cavitation technique. The loading of nanoparticles was 3% by weight of the total polymer precursor. The TiO 2 nanoparticles were spherical in shape, and were about 29 nm in diameter. Sonic cavitation was carried out with a vibrasound liquid processor at 20 kHz frequency with a power intensity of about 100 kW/m 2 . The two categories of foams manufactured in this manner were termed as neat and nanophased. Sandwich composites were then fabricated using these two categories of core materials using a co-injection resin transfer molding (CIRTM) technique. Test samples extracted from the panel were subjected to quasi-static as well as high strain rate loadings. Rate of loading varied from 0.002 s −1 to around 1300 s −1 . It has been observed that infusion of nanoparticles had a direct correlation with the cell geometry. The cell dimensions increased by about 46% with particle infusion suggesting that nanoparticles might have worked as catalysts during the foaming process. Correspondingly, enhancement in thermal properties was also noticed especially in the TGA experiments. There was also a significant improvement in mechanical properties due to nanoparticle infusion. Average increase in sandwich strength and energy absorption with nanophased cores was between 40-60% over their neat counterparts. Details of manufacturing and analyses of thermal and mechanical tests are presented in this paper.

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“…Addition of surfactants or catalysts may affect the size of the cells and also clay nanocomposite is known to be effective to reduce the cell size. [15][16][17] Moreover, clay is expected to reduce the thermal conductivity of gas diffusion since it can lengthen the pathways of gas diffusion. When synthesizing PUF/clay nanocomposites, uniform dispersion of clay is very important to make sure the cells in PUF are small enough.…”

Section: Introductionmentioning

confidence: 99%

Effects of organoclay on the thermal insulating properties of rigid polyurethane poams blown by environmentally friendly blowing agents

et al. 2007

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A process designed to synthesize rigid polyurethane foam (PUF) with insulative properties via the modulation of PUF cell size via the addition of clay and the application of ultrasound was assessed. The blowing agents utilized in this study include water, cyclopentane, and HFC-365mfc, all of which are known to be environmentallyfriendly blowing agents. The rigid PUFs were prepared from polymeric 4,4'-diphenylmethane diisocyanate (PMDI) and polyether polyol with a density of 50 kg/m 3 . In addition, rigid PUFs/clay nanocomposites were synthesized with clay modified by PMDI with and without the application of ultrasound. The PUF generated using water as a blowing agent evidenced the highest tensile strength. The tensile strength of the PUF/nanocomposites was higher than that of the neat PUF and the strength was even higher with the application of ultrasound. The cell size of the PUF/clay nanocomposites was less than that of the neat PUF, regardless of the type of blowing agent utilized. It appears that the higher tensile strength and lower cell size of the PUF/clay nanocomposites may be attributable to the uniform dispersion of the clay via ultrasonic agitation. The thermal conductivity of the PUF/clay nanocomposites generated with HCFC-141b evidenced the lowest value when PUF/clay nanocomposites were compared with other blowing agents, including HFC-365mfc, cyclopentane, and water. Ultrasound has also proven effective with regard to the reduction of the thermal conductivity of the PUF/clay nanocomposites with any of the blowing agents employed in this study. It has also been suggested that the uniformly dispersed clay particles in the PUF matrix function as diffusion barriers, which prevent the amelioration of the thermal insulation property.

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Properties of Rigid Polyurethane Foams with Blowing Agents and Catalysts

Cited by 85 publications

References 4 publications

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

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

High Strain Rate Response of Sandwich Composites with Nanophased Cores

Effects of organoclay on the thermal insulating properties of rigid polyurethane poams blown by environmentally friendly blowing agents

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