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

Abstract

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.

Phosphorus and nitrogen-containing soybean oil polyols: Effect on the mechanical properties and flame retardancy of polyurethane foam

“…For example, using 15% ESBO-DYM by weight in the foam formulation showed a compression value of 158 kPa under identical conditions. Hydrogen bonds between segments in urethane groups and the formation of crosslinks between molecular chains are factors affecting the mechanical properties [ 42 , 43 ]. Typically, the low molecular weight commercial polyether polyol ( M w = 630 g/mol), with higher primary hydroxyl value, induces more reactions between isocyanates, thus forming more urethane and urea linkages between the polymer chains.…”

Aging properties of a vegetable‐based polyurethane foam under high relative humidity and different temperatures

“…24,39,42 The maximum temperature of 90 C was selected for comparison with previous studies involving the same material. 43 The minimum temperature of 60 C was chosen to ensure the observation of a sufficient range of degradation for constructing an Arrhenius curve. Additionally, to prevent prolonged exposure of the material and maintain a substantial difference from the maximum temperature, 60 C was deemed ideal.…”

“…The high RH condition was applied in order to see how the foam would behave in comparison with a non-RH-controlled condition 43 where the effects of erosion, diffusion, and hydrolysis can take place along with the thermo-oxidation. To regulate the aging process, each batch was placed in a computer-controlled climate chamber (CC) manufactured by Climats.…”

Development of BioPolyurethane Coatings from Biomass-Derived Alkylphenol Polyols—A Green Alternative

“…Despite the recent focus on developing BioPU from biomass feedstocks, and on the potential of thermochemical liquefaction to turn biomass subproducts and residues into polyols, relevant studies on the use of these thermochemical liquefaction polyols in BioPU coatings are relatively scarce. Most of these studies apply the liquified biomass-derived polyols to the production of PU foams [42][43][44][45][46][47][48] and adhesives [49][50][51], and are not focused on coatings, as the present paper is. Recently, Gosz et al [52,53] developed BioPU from biopolyols derived from the thermochemical liquefaction of liquified oak and alder wood sawdust, reporting an optimum liquefaction temperature of 150 • C for a period of 6 h. It was stated that the obtained PUs possess a high Young's module, up to 839 MPa, and beneficial properties for coating wood decks.…”