Properties of rigid polyurethane foams blown by HCFC 141B and distilled water

Jung, Hyung Chul; Ryu, Seung Chan; Kim, W. N.; Lee, Y.-B.; Choe, Kun Hyung; Kim, S.-B.

doi:10.1002/app.1461

Cited by 30 publications

(16 citation statements)

References 27 publications

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“…They reported that the average cell size decreased with the increase of initial water concentration [18] . However, opposite conclusion was obtained in this study and Jung's paper [9] . It may be a result from the effect of mass transfer and more coalescence of bubbles in the practical foaming process.…”

Section: Effect Of Water Level On Cell Size and Morphology Of Rigid Fcontrasting

confidence: 79%

“…It is well known that compressive strength of rigid foam has a significant relationship with density. A power-law expression can be used to show the relationship between compressive strength and density [9,16] .…”

Section: Effect Of Water Level On Density and Mechanical Properties Omentioning

confidence: 99%

“…Nichol et al [8] reported the effects of equivalent weight and functionality of polyol on the properties of foams. Recently, Jung et al [9,10] compared the properties of rigid polyurethane foams blown by HCFC-141b with those by distilled water. In their work, however, the structure characteristics and dimensional stability of foams were not referred to, and all of data were only limited to the system water level ranging from 0.5 pph to 3.0 pph.…”

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confidence: 99%

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Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

Cao

Zhang

2006

SCI CHINA SER B

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Rigid polyurethane foams blown by varying water level were prepared in this study. The structures and physical properties of rigid polyurethane foams blown by water were measured with FT-IR, universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that polyurea and polybiuret were the typical characteristics, and the cream time and gel time were shorter for the fully water blown rigid foams than that for the fully cyclopentane blown foams. The density of foam samples decreased from 45.0 kg/m 3 to 27.4 kg/m 3 with the increase of water level from 3 pph to 7 pph. Compressive strength exhibited the similar behavior with density. The average cell size of foam samples ranged from 241 µm to 356 µm with the increase of water level from 3 pph to 7 pph, respectively. At the same time, poorer dimensional stability was encountered with the increase of average cell size due to fast diffusion rate of CO 2 out of the foam. The results of thermal analysis show that the glass transition temperature (T g ) shifted to a higher temperature with the increase of isocyanate level when more water was used as chemical blowing agent.

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Section: Effect Of Water Level On Cell Size and Morphology Of Rigid Fcontrasting

confidence: 79%

Section: Effect Of Water Level On Density and Mechanical Properties Omentioning

confidence: 99%

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confidence: 99%

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Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

Cao

Zhang

2006

SCI CHINA SER B

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“…Water blown foams also had a higher thermal conductivity. So, besides water, HCFC141b was used as blowing agent due to its lower thermal conductivity and good foam surface quality [11]. A determined amount of part A solution was mixed thoroughly in a plastic cup by mechanical stirrer for 3 min under ambient temperature (Table 2).…”

Section: Preparation Of Polyurethane Foamsmentioning

confidence: 99%

Characterization of polyurethane foams prepared from liquefied sawdust by crude glycerol and polyethylene glycol

2018

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The aim of this study was to investigate polyurethane foams (PUF) properties obtained from crude glycerol (CG) and polyethylene glycol (PEG) based liquefaction of sawdust. The four types of foam were prepared by producing polyols from different weight loadings of PEG to CG as the liquefaction solvent. The produced polyurethane foams showed densities from 0.042 to 0.08 g/cm 3 and compressive strengths from 200 to 311 kPa. The foams obtained from CG/PEG based liquefaction, had more uniform and regular cell structure than foams derived from liquefaction by CG. Also with the increasing percentage of PEG to CG in liquefaction, closed cell content of the synthesized foams increased and the size of cells decreased. The thermal conductivity of the produced foams was between 0.031 and 0.040 W/m K. Foams produced from liquefaction by binary solvent had lower thermal conductivity. However all foams showed approximately similar thermal degradation curves; maximum thermal decomposition temperature was seen for the foam produced from higher weight ratio of PEG to CG in liquefaction. PU foams produced from PEG/CG based liquefaction process had improved properties over from foams derived from sawdust liquefaction by CG.

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“…Jung et al [10] compared the properties of rigid polyurethane foams blown by HCFC-141b with those by distilled water. Nichol et al [11] reported the effects of equivalent weight of polyol on the properties of foams.…”

Section: Introductionmentioning

confidence: 99%

Properties of water blown rigid polyurethane foams with different functionality

Cao

Zhang

2008

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer (NDJ-1), universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that the viscosity of polyether polyol increases exponentially from 62 mPa•s to 6 000 mPa•s with the increase of functionality from 2 to 5.6, respectively. The overall density of foam increases slightly from 31.7 kg/m 3 to 37.4 kg/m 3 with increasing functionality while core density exhibited little difference. Compressive strength of foam shows the similar behavior with density except for 2-functional sample. At the same time, dimensional stability becomes better with increasing functionality except for 5.6-functional foam that has worse stability than 4.8-functional foam. From the SEM results, the functionality is not an important factor in determining distribution of cell size of foam. According to the results of thermal analysis, the glass transition temperature (T g ) shifts to a higher temperature from 128.9 ℃ to 166.3 ℃ for the 2 to 5.6 functional foam, respectively.

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Properties of rigid polyurethane foams blown by HCFC 141B and distilled water

Cited by 30 publications

References 27 publications

Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

Characterization of polyurethane foams prepared from liquefied sawdust by crude glycerol and polyethylene glycol

Properties of water blown rigid polyurethane foams with different functionality

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