Experimental and numerical analyses of thermal failure of rigid polyurethane foam

He, Yannan; Wu, Jiacheng; Qiu, Dacheng; Yu, Zhiqiang

doi:10.1016/j.matchemphys.2019.05.078

Cited by 14 publications

(14 citation statements)

References 24 publications

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“…Accordingly, it is suggested that the labile part in the RPUF with relatively low heat resistance decomposes at 150 °C, while the main chemical structure with high heat resistance may be difficult to degrade at this temperature. Some urethane groups in RPUF tend to partially decompose at 150 °C, otherwise the decomposition and evaporation of unreacted isocyanate monomers also makes some thermal weight loss in the TGA results . However, the TGA curves after RT vibration failure suggest that there is no significant difference on the thermal weight loss of RPUFs after different vibration failures.…”

Section: Resultsmentioning

confidence: 96%

Failure mechanism of rigid polyurethane foam under high temperature vibration condition by experimental and finite element method

2019

J of Applied Polymer Sci

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The failure mechanism of rigid polyurethane foam (RPUF) under room temperature (RT) and high temperature vibration conditions was investigated by experiment and finite element stimulation. Damaged RPUF specimens were prepared at different vibration amplitudes ranging from 0 to 19.879 mm at RT and 150 °C for different vibration times. The tensile test was utilized to evaluate the vibration damage degree of RPUFs, and the results exhibited that tensile strength decreased gradually with the increase of vibration amplitude and time at both RT and 150 °C. Thermogravimetric analysis and Fourier transform infrared spectroscopy illustrated that thermal degradation of RPUF is attributed to the decomposition of carbonyl urethane groups at 150 °C. The scanning electron microscopy analysis of the tensile fracture surfaces revealed that the vibration failure of RPUF mainly resulted from the existence of microcracks in cell structure. A finite element simulation was established by ABAQUS to study stress distribution of RPUF under different vibration loads, which then demonstrated that the microcracks are most likely to exist on the junction of two microcell units, which is due to convergence of stress in the process of vibration. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48343.

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Section: Resultsmentioning

confidence: 96%

Failure mechanism of rigid polyurethane foam under high temperature vibration condition by experimental and finite element method

2019

J of Applied Polymer Sci

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“…Since the influence of oxygen was not considered in the simulation work, as a comparison, the thermal treatment was performed by a vacuum oven with a pressure lower than 10 −5 torr to ensure the quasi vacuum environment. According to the TGA results in our previous study, 19 the onset temperature of preliminary degradation of RPUF was 383 K and the rate of preliminary degradation reached maximum at 423 K. And when the temperature exceeded 473 K, the macromolecule backbone of RPUF began to degradation and the basic mechanical properties of RPUF cannot be maintained. Hence, the thermal treatment was carried out in the temperature range from room temperature to 473 K. The specific temperatures of thermal treatment which not make the RPUF completely lose its mechanical properties are summarized in Table 1.…”

Section: Methodsmentioning

confidence: 95%

“…The experiments were carried out according to the ISO 1926:2009 20 . The detailed conditions of tensile experiments were shown in the previous study 19 …”

Section: Methodsmentioning

confidence: 99%

Multiscale investigation on molecular structure and mechanical properties of thermal‐treated rigid polyurethane foam under high temperature

Qiu

2021

J of Applied Polymer Sci

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In order to study the relationship between the molecular structure and mechanical properties of rigid polyurethane foam (RPUF) during the mechanical and chemical failure process, the variation of the molecular structure and mechanical properties of RPUF treated in temperature range of 323–473 K were characterized by both theoretical and experimental methods. The molecular structure stability of RPUF varied with thermal treatment temperature was characterized by density functional theory method. The mechanical properties of base material of RPUF were simulated by means of molecular dynamics (MD) simulation. Then the related parameters obtained from the MD simulation were assigned into a representative volume element model of RPUF for the finite element analysis. The results indicated that the vibrational frequencies of isocyanate groups and amino acid ester groups in RPUF molecule increased while the molecular orbital energy gap of RPUF decreased with the increase of treatment temperature. It indicated that the RPUF molecule had high chemical reactivity at high temperature. The results of the multiscale simulation of mechanical properties showed that the defects and voids in RPUF generated under high temperature would grow with the increase of thermal treatment temperature, which intensified the stress concentration in RPUF and decreased the tensile properties of RPUF.

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“…erefore, the antidamage ability of the cell was enhanced and the compression strength finally increased. Wu and He et al [17,18] studied the failure of RPU foam under a high temperature and vibration, and the degree of damage after treatment was evaluated through its tensile properties. e results showed that the tensile strength decreases with the increase in vibration amplitude and time, and the vibration failure of RPU foam was mainly due to the existence of microcracks in the cell structure.…”

Section: Introductionmentioning

confidence: 99%

“…e objective magnification of SEM can be changed from 10 times to more than 300,000 times. It can be used to detect small structural characteristics of foam, such as structural defects that damage the foam of samples [17,18]. Computer image analysis method consists of image processing technology and image analysis technology [26].…”

Section: Introductionmentioning

confidence: 99%

Statistical Characteristics of Polymer Grouting Material Microstructure

Wang

Fang

et al. 2020

Advances in Civil Engineering

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The two-component foaming polyurethane is a kind of grouting material that has recently been widely used in engineering structural repair. Its physical and mechanical properties are closely related to its microstructure. Therefore, the qualitative and quantitative analysis of polymer microstructure has always been a research hotspot. The statistical characteristics of polymer grouting material microstructure are investigated by six groups of specimens with different densities, and the density varies from 0.1 to 0.6 g/cm3. The microstructure morphology of polymer was observed and described by scanning electron microscopy (SEM), and the microstructure feature parameters were extracted and calculated by image processing technology. The quantitative analysis of section cell roundness distribution, cell diameter distribution, and polymer porosity shows that low-density polymer materials have anisotropy. While the density exceeds 0.3 g/cm3, the cell structure tends to be spherical. The section cell diameters obey a normal distribution, and when the density increases, the cell diameter decreases. The porosity of the polymer has a linear negative correlation with the density. The polymer matrix has a density of 1.21 g/cm3. The microstructural information obtained in this study will help establish a cell-based model to explain the mechanical response of rigid polymer foams.

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Experimental and numerical analyses of thermal failure of rigid polyurethane foam

Cited by 14 publications

References 24 publications

Failure mechanism of rigid polyurethane foam under high temperature vibration condition by experimental and finite element method

Failure mechanism of rigid polyurethane foam under high temperature vibration condition by experimental and finite element method

Multiscale investigation on molecular structure and mechanical properties of thermal‐treated rigid polyurethane foam under high temperature

Statistical Characteristics of Polymer Grouting Material Microstructure

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