Identification and Quantification of Cell Gas Evolution in Rigid Polyurethane Foams by Novel GCMS Methodology
2. Materials and Methods
2.2. Foam Characterization
2.3. Measurement of Foam Thermal Conductivity
2.4. Measurement of Foam Cell Gas
2.4.2. Chromatographic Analysis
2.4.3. Determination of Cell Gas Content
2.4.4. Prediction of Thermal Conductivity of the Gas Phase of a PU Foam
3. Results and Discussion
3.1. Morphological Characterization
3.2. RPU Foam Cell Gas Composition, Calculated Thermal Conductivity of the Gas Phase and Measured Foam Thermal Conductivity
3.2.1. Measured Foam Thermal Conductivity
3.2.2. Foam Cell Gas Composition
- Considering that the diffusion of gases is one of the mechanisms for deterioration of foam thermal insulation, the measurement of foam thermal conductivity itself does not show the situation with gas composition in every individual foam. Therefore, the GCMS gas content method has shown its benefit as an excellent instrument for the determination of foam cell gas composition and the diffusion of insulation cell gases out of the foam and diffusion of air into the foam cells.
- The presented study was done on two foam types, a reference and one modified with 1.5% talc that have already been described in previous articles, but the gas content method applied in this work made the research of talc incorporation into the foam structure much more comprehensive.
- The sample with talc presented a decrease in the cell size of around 50%, which reduced the radiative contribution to the total thermal conductivity at the initial time of foam manufacturing and, thus, promoted an enhancement of the thermal conductivity. However, that initial thermal improvement shown by foam with 1.5% talc was lost, which has been explained by a higher gas diffusion and, thus, an increase in the thermal conductivity of the cell gas mixture with time.
- GCMS measurement of reference and 1.5% talc modified RPU foams in 10 × 8 × 2.5 cm geometry showed that CO2 leaves the foam after 2.5 months (from 21% to 0.03% for the reference foam and from 17% to 0.03% for the foam with 1.5% talc). C5H10 deviates during 3.5 months, which could be explained by liquid cyclopentane that was probably not evaporated completely during foam manufacturing (from 28% up to 39% for the reference foam and from 29% up to 35% for the foam with 1.5% talc), then it starts to leave the foam and after 3.5 years its content is 13% for the reference and 10% for the foam with talc. Air diffuses inside the cells faster until the one-year point (from 51% up to 79% for the reference and from 54% up to 81% for the foam with talc) and then more slowly until the 3.5-year point (reaching 86% for the reference and 90% for the foam with talc).
- The study of gas mixture content with time could help in the development of the manufacturing of foam with desirable gas compositions and to control the initial thermal conductivity of the foam and, correspondingly, the long-term value.
Conflicts of Interest
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|Foam Index||Density (Kg/m3)||OC (%)||Φ3D (µm)||AR||Foaming Reaction Temperature (°C)|
|Reference||31.2 ± 1.7||8.1 ± 1.9||608 ± 68||1.11 ± 0.29||105.9|
|1.5%Talc||35.6 ± 1.2||9.5 ± 3.1||307 ± 98||1.27 ± 0.27||121.9|
|Sample, Index/Storage Time||N2, vol%||O2, vol%||CO2, vol%||C5H10, vol%||λgas calcul, mW·m−1·K−1|
|85 days (2.5 months)||37.11||27.02||0.17||35.70||21.39|
|113 days (3.5 months)||39.39||21.89||0.17||38.54||20.95|
|144 days (4.5 months)||47.37||20.28||0.16||32.19||21.81|
|372 days (1 year)||62.16||17.08||0.038||20.72||23.26|
|1250 days (3.5 years)||68.13||18.35||0.032||13.48||24.11|
|85 days (2.5 months)||31.23||26.73||0.16||36.25||21.03|
|113 days (3.5 months)||44.94||20.09||0.14||34.83||21.46|
|144 days (4.5 months)||58.96||18.79||0.13||22.12||23.09|
|372 days (1 year)||63.75||17.73||0.042||18.49||23.53|
|1250 days (3.5 years)||70.78||19.04||0.030||10.15||24.48|
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Galakhova, A.; Santiago-Calvo, M.; Tirado-Mediavilla, J.; Villafañe, F.; Rodríguez-Pérez, M.Á.; Riess, G. Identification and Quantification of Cell Gas Evolution in Rigid Polyurethane Foams by Novel GCMS Methodology. Polymers 2019, 11, 1192. https://doi.org/10.3390/polym11071192
Galakhova A, Santiago-Calvo M, Tirado-Mediavilla J, Villafañe F, Rodríguez-Pérez MÁ, Riess G. Identification and Quantification of Cell Gas Evolution in Rigid Polyurethane Foams by Novel GCMS Methodology. Polymers. 2019; 11(7):1192. https://doi.org/10.3390/polym11071192Chicago/Turabian Style
Galakhova, Anastasiia, Mercedes Santiago-Calvo, Josias Tirado-Mediavilla, Fernando Villafañe, Miguel Ángel Rodríguez-Pérez, and Gisbert Riess. 2019. "Identification and Quantification of Cell Gas Evolution in Rigid Polyurethane Foams by Novel GCMS Methodology" Polymers 11, no. 7: 1192. https://doi.org/10.3390/polym11071192