Density, Microstructure, and Strain-Rate Effects on the Compressive Response of Polyurethane Foams

Bhagavathula, KB; Meredith, Christopher S.; Ouellet, Simon; Satapathy, S.; Romanyk, Dan L.; Hogan, James D.

doi:10.1007/s11340-021-00772-z

Cited by 20 publications

(2 citation statements)

References 59 publications

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“…When the additional amount reached 5 wt% or even more, the gas produced inside the material was too much to cause the foaming reaction to continue; the polyurethane could not dissolve the excess gas, causing excessive pressure in the system, so that the foam was produced by the constant contact and extrusion of small bubbles, and the surrounding bubbles quickly formed large bubbles that overflowed, resulting in the collapse of the bubble holes, reducing the porosity of the material. In addition, the reaction rate was too fast, so the gel time and foaming time were not equal, which is required for foam stability, and so the stability of the material was relatively loose and the density was reduced [ 33 ]. This meant the bubble holes were easily ruptured, and the regular and complete structure of the bubble holes was reduced, resulting in an increase in the density of the material.…”

Section: Resultsmentioning

confidence: 99%

Effect of Secondary Foaming on the Structural Properties of Polyurethane Polishing Pad

Chen,

Jiang,

Zhu

et al. 2024

Materials

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Polyurethane polishing pads are important in chemical mechanical polishing (CMP). Thus, understanding how to decrease the density but increase the porosity is a crucial aspect of improving the efficiency of a polyurethane polishing pad. According to the principle of gas generation by thermal decomposition of sodium bicarbonate and ammonium bicarbonate, polyurethane polishing pad was prepared by a secondary foaming method. The influence of adding such an inorganic foaming agent as an auxiliary foaming agent on the structure, physical properties, and mechanical properties of polyurethane polishing pads was discussed. The results showed that compared with the polyurethane polishing pad without an inorganic foaming agent, the open-pore structure increased, the density decreased, and the porosity and water absorption increased significantly. The highest porosity and material removal rate (MRR) with sodium bicarbonate added was 3.3% higher than those without sodium bicarbonate and 33.8% higher than those without sodium bicarbonate. In addition, the highest porosity and MRR with ammonium bicarbonate were 7.2% higher and 47.8% higher than those without ammonium bicarbonate. Therefore, it was finally concluded that the optimum amount of sodium bicarbonate to be added was 3 wt%, and the optimum amount of ammonium bicarbonate to be added was 1 wt%.

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Section: Resultsmentioning

confidence: 99%

Effect of Secondary Foaming on the Structural Properties of Polyurethane Polishing Pad

Chen,

Jiang,

Zhu

et al. 2024

Materials

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“…The research results of Wang, Z., et al [ 7 ] show that the effect of water will affect the performance of rigid polyurethane foam. Research conducted by Bhagavathula, K.B., et al [ 8 ] found that the cell structure of rigid polyurethane foam will affect the density and material properties of rigid polyurethane foam.…”

Section: Introductionmentioning

confidence: 99%

Study on the Cross-Scale Effects of Microscopic Interactions and Mechanical Properties of Rigid Polyurethane Foam Driven by Negative-Temperature Environments

Wei,

Bi,

2024

Polymers

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In order to investigate the cross-scale effects of the interaction between the hard and soft segments of stiff polyurethane foam on the material’s mesoscopic pore structure and macroscopic compression characteristics in various negative-temperature environments, this paper used molecular dynamics to calculate the interaction differences between hard and soft segments in different negative-temperature environments. The effects of various negative-temperature settings on the cell structure of stiff polyurethane foam were investigated using scanning electron microscopy and Image J software. Finally, macro experiments were used to determine the influence of a negative-temperature environment on the characteristics of stiff polyurethane foam (such as compressibility). The molecular simulation calculation results show that in a negative-temperature environment, decreasing temperature gradually increases the interaction between hard segment molecules and soft segment molecules, resulting in an increase in the molecules’ modulus and cohesive energy density. The scanning electron microscope results reveal that a negative-temperature environment gradually increases the pore diameter of stiff polyurethane foam. The compression experiment findings demonstrate that, for the same service duration, the compressive strength in the −20 °C environment is 27.53% higher than that in the 0 °C environment. The study’s findings reveal a microscopic mechanism for the following receiving alterations and toughness enhancement of rigid polyurethane foam throughout service in negative-temperature conditions.

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Free‐Standing, Multifunctional Thermoelectric and Acoustic Absorbing Nanocomposite Foams

Liu,

Sun,

Liu

et al. 2024

Advanced Sustainable Systems

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Thermoelectric materials are potential energy harvesting technologies that enable direct, clean conversion between thermal and electrical energy. The efficacy of thermoelectric energy conversion is influenced by the electrical conductivity, thermal conductivity, and Seebeck coefficient. Flexibility, manufacturability, and cost‐effectiveness are also important factors. Polymeric nanocomposites offer advantages in these respects. However, the development of conductive‐polymer thermoelectric materials is limited to an in‐plane architecture, which does not resemble common real‐world scenarios. Moreover, existing works have low thermoelectric properties or rely on additives for performance improvement. In this work, a free‐standing thermoelectric nanocomposite foam is fabricated via the integration of thermally activated microspheres. Due to the microstructure, a thermal conductivity as low as 0.03 W m−1 K−1 is achieved, which is lower than reported for aerogels fabricated via freeze‐drying methods. Additionally, the nanocomposite foam can reach a maximum electrical conductivity of 1.13 S cm−1, power factor of 0.12 µW m−1 K−2, and thermoelectric figure of merit of 3.0 × 10−4. The study also evaluated the compressive stiffness and demonstrated the potential for sound absorption. With the unique combination of the thermoelectric, sound absorption, and mechanical behavior, these nanocomposite foams would offer versatile solutions to address the next generation energy harvesting and acoustic absorption applications.

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Density, Microstructure, and Strain-Rate Effects on the Compressive Response of Polyurethane Foams

Cited by 20 publications

References 59 publications

Effect of Secondary Foaming on the Structural Properties of Polyurethane Polishing Pad

Effect of Secondary Foaming on the Structural Properties of Polyurethane Polishing Pad

Study on the Cross-Scale Effects of Microscopic Interactions and Mechanical Properties of Rigid Polyurethane Foam Driven by Negative-Temperature Environments

Free‐Standing, Multifunctional Thermoelectric and Acoustic Absorbing Nanocomposite Foams

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