Details

Autor(en) / Beteiligte

• Shenoy, Suresh L
• Fujiwara, Tomoko
• Wynne, Kenneth J

Titel

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO2 Utilizing a Linear Variable Differential Transformer

Ist Teil von

• Macromolecules, 2003-05, Vol.36 (9), p.3380-3385

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2003

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Supercritical CO2 plasticization of semicrystalline poly(vinylidene fluoride) (PVDF) was investigated by measuring linear dilation as a function of temperature (75−130 °C) and pressure (138−670 bar) using a linear variable differential transformer (LVDT). The robustness of the LVDT technique allows the study of CO2 plasticization at high temperatures (to T m) and pressures. Experiments at constant temperature (varying pressure) and constant pressure (varying temperature) were performed. With constant temperature experiments below 100 °C, dilation increased up to 414 bar, while at higher pressures, the change of dilation with pressure attenuated. At higher temperatures (≥117 °C), dilation increased almost linearly with pressure through the experimental range. Constant pressure experiments were carried out to assess the effect of CO2 pressure on T m. With increasing pressure, T m decreased to a minimum of 135 °C at 483 bar (ΔT m = 23 °C). Above 483 bar, hydrostatic effects override plasticization and T m increases. By comparing T m under N2, a gas with minimal interaction with the polymer, competition between plasticization and hydrostatic pressure on T m is clarified.