Mechanical behaviour in shear and compression of polyurethane foam at elevated temperature

The aim of this work is to evaluate the changes in compression properties of a bio-based polyurethane foam after exposure to 90 °C for different periods of time, and to propose a method to extrapolate these results and use a numerical approach to predict the compression behaviour after degradation for untested conditions at different degradation times and temperatures. Bio-based polymers are an important sustainable alternative to oil-based materials. This is explained by the foaming process and the density along the material as it was possible to see in a digital image correlation analysis. After 60 days, stiffness was approximately decreased by half in both directions. The decrease in yield stress due to thermo-oxidative degradation had a minor effect in the foaming directions, changing from 352 kPa to 220 kPa after 60 days, and the transverse property was harshly impacted changing from 530 kPa to 265 kPa. The energy absorption efficiency was slightly affected by degradation. The simulation of the compression stress-strain curves were in accordance to the experimental data and made it possible to predict the changes in mechanical properties for intermediate periods of degradation time. The plateau stress for the unaged foam transverse to the foaming direction presented experimental and numerical values of 450 kPa and 470 kPa, respectively. In addition, the plateau stresses in specimens degraded for 40 days present very similar experimental and numerical results in the same direction, at 310 kPa and 300 kPa, respectively. Therefore, this paper presents important information regarding the life-span and degradation of a green PUF. It provides insights into how compression properties vary along degradation time as function of material operation temperature, according to the Arrhenius degradation equation.

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“…Additionally, Linul et al (2017) [ 26 ] reported that the best density regarding energy absorption is 100 kg/m

. A density around this value was also studied in the works of Liu et al (2019) [ 27 ], Mazzuca et al (2021) [ 28 ], and Iqbal et al (2022) [ 29 ].…”

Section: Methodsmentioning

confidence: 92%

Accelerated Aging on the Compression Properties of a Green Polyurethane Foam: Experimental and Numerical Analysis

Silva

Barros²,

Vieira

et al. 2023

Polymers

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“…An alternative explanation is that the increase in temperature reduces the modulus of elasticity of the polyurethane material, leading to more rapid collapse of the cells within the foam, and thereby increasing the voltage for the same reason that higher frequencies increase voltage. While we cannot report accurate values of temperature dependence for the foam being tested in this study, various studies of rigid polyurethane foams have demonstrated reductions in the modulus of 25% or more for temperature increases from 20 °C to 70 °C (the temperature increase observed for compression at a steady frequency of 45 Hz in Figure 8 ) [ 31 , 32 ].…”

Section: Discussionmentioning

confidence: 99%

Dual-Sensing Piezoresponsive Foam for Dynamic and Static Loading

Hanson

Newton

Merrell

et al. 2023

Sensors

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Polymeric foams, embedded with nano-scale conductive particles, have previously been shown to display quasi-piezoelectric (QPE) properties; i.e., they produce a voltage in response to rapid deformation. This behavior has been utilized to sense impact and vibration in foam components, such as in sports padding and vibration-isolating pads. However, a detailed characterization of the sensing behavior has not been undertaken. Furthermore, the potential for sensing quasi-static deformation in the same material has not been explored. This paper provides new insights into these self-sensing foams by characterizing voltage response vs frequency of deformation. The correlation between temperature and voltage response is also quantified. Furthermore, a new sensing functionality is observed, in the form of a piezoresistive response to quasi-static deformation. The piezoresistive characteristics are quantified for both in-plane and through-thickness resistance configurations. The new functionality greatly enhances the potential applications for the foam, for example, as insoles that can characterize ground reaction force and pressure during dynamic and/or quasi-static circumstances, or as seat cushioning that can sense pressure and impact.

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“…The mechanical performance of these foams was serious damaged when they were subjected to elevated temperatures or fire. All these drawbacks mentioned above greatly limited the application of syntactic foams ( McKenna and Hull, 2016 ; Mazzuca et al, 2022 ). Considerable attempts have been made by researchers to develop high-performance syntactic foams.…”

Section: Introductionmentioning

confidence: 99%

Hollow glass microspheres/phenolic syntactic foams with excellent mechanical and thermal insulate performance

et al. 2023

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Syntactic foams with low density as well as low thermal conduction and proper mechanical performance are vitally important for aerospace, marine, and automotive industries. Here, phenolic-based syntactic foams were fabricated by combining the hollow glass microsphere (GMs) with phenolic resin of in situ synthesis. Benefited from the stirring and hot-pressing treatment, microspheres dispersed homogeneously in the resin matrix and it greatly reduced the density of the composites. Stretching and compression tests were performed to investigate the mechanical behavior of the foams. It is found that both the compressive and tensile strength decreased as the filler loadings increasing. While the elasticity modulus was improved. On the other hand, thermal properties tests revealed superior thermal stability and thermal insulate performance of the composites. The final residue content of the synthetic foam with 40 wt% filler was improved by ∼31.5% than that of the neat one at 700°C. And samples with 20 wt% microspheres reached a minimum thermal conductivity value of approximately 0.129 W (m·K)−1 which is ∼46.7% lower than that of neat resin [0.298 W (m·K)−1]. This work provides a feasible strategy to construct syntactic foams with low density and ideal thermal properties.

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Mechanical behaviour in shear and compression of polyurethane foam at elevated temperature

Cited by 19 publications

References 14 publications

Accelerated Aging on the Compression Properties of a Green Polyurethane Foam: Experimental and Numerical Analysis

Accelerated Aging on the Compression Properties of a Green Polyurethane Foam: Experimental and Numerical Analysis

Dual-Sensing Piezoresponsive Foam for Dynamic and Static Loading

Hollow glass microspheres/phenolic syntactic foams with excellent mechanical and thermal insulate performance

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