Analysis of the retrograde behavior in PMMA-CO2 systems by measuring the (effective) glass transition temperature using refractive index variations.
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| Title: | Analysis of the retrograde behavior in PMMA-CO2 systems by measuring the (effective) glass transition temperature using refractive index variations. |
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| Authors: | Rodríguez, D. Cuadra1 (AUTHOR) dcuadra@fmc.uva.es, Carrascal, D.1 (AUTHOR), Solórzano, E.2 (AUTHOR), Pérez, M.A. Rodríguez1 (AUTHOR), Pinto, J.1 (AUTHOR) jpinto@fmc.uva.es |
| Source: | Journal of Supercritical Fluids. Apr2021, Vol. 170, pN.PAG-N.PAG. 1p. |
| Subjects: | Refractive index, Behavioral assessment, Glass transition temperature, Manufacturing processes, Low temperatures |
| Abstract: | • A new optical-based method allows determining the effective T g of PMMA-CO 2 systems. • Retrograde behavior was experimentally confirmed at low pressures and temperatures. • The physical properties of the PMMA strongly influence the effective Tg evolution. • The obtained results clarified previous discrepancies found in the literature. • PMMA industrial processing could be performed at mild conditions introducing CO 2. ga1 The physical behavior of polymethyl methacrylate-carbon dioxide (PMMA-CO 2) system was studied in a wide range of temperatures (0–100 °C) and pressures (0.1–10 MPa). The glass transition temperature of the systems was determined by a new optical observation methodology. The developed procedure is based on the refraction index variations between rubbery and glassy states, which allowed to differentiate both PMMA states for each pair of temperature and pressure conditions. Following this procedure, retrograde behavior was confirmed for three different grades of PMMA, finding significant differences in their behavior. In addition, the study of the glass transition temperature of the PMMA-CO 2 systems included the low-pressure and low-temperature region, scarcely studied before. The new results obtained in the low pressure-temperature region are critical to design advanced foaming approaches and manufacturing processes at low temperatures. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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