Melting and Crystallization Temperatures of Ethylene‐Octene Block Copolymers in Compressed Carbon Dioxide and Nitrogen
Year: 2025
Type: article
Abstract: ABSTRACT Melting and crystallization temperatures of poly(ethylene‐co‐octene) and a lightly crosslinked form of the polymer have been measured in both carbon dioxide and nitrogen over a pressure range up to 200 bar. The measurements have been made by high‐pressure torsional braid analysis. Swelling with and sorption of CO2 and N2 in these polymers were also determined at 200 bar as a function of temperature using a magnetic suspension balance. The results show that both polymers display a depression of both the melting and crystallization temperatures in carbon dioxide. However, at pressures above 100 bar, a tendency for these transition temperatures to increase is observed. In compressed nitrogen, uncrosslinked polymer shows a small decrease in T m and T c again with the trend showing an increase at pressures above 100 bar. In contrast, the crosslinked polymer displays an increase in T m and T c at all nitrogen pressures. The differences in the T m and T c of these polymers in CO2 and N2 are discussed in terms of changes in the relative rigidity, damping, and relative importance of the diluent versus hydrostatic effects on the thermal transitions of polymers in these compressed fluids.
DOI: 10.1002/app.57143
Institution: Virginia Tech
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,140
OpenAlex ID: W4409405287