Dawn D. Rhee, Emma M. Troiano, Grant Floyd, Erdogan Kiran
{"title":"Melting and crystallization temperatures, foaming, and fluid-induced crystallization of poly (ε-caprolactone) in compressed CO2 and N2","authors":"Dawn D. Rhee, Emma M. Troiano, Grant Floyd, Erdogan Kiran","doi":"10.1016/j.supflu.2024.106293","DOIUrl":null,"url":null,"abstract":"<div><p>Melting and crystallization temperatures of poly(ε-caprolactone)(PCL) exposed to CO<sub>2</sub> and N<sub>2</sub> have been evaluated at pressures up to 125 bar using High Pressure Torsional Braid Analysis. It is shown that in contrast to CO<sub>2</sub>, exposure to high pressure N<sub>2</sub> does not lead to a significant depression of T<sub>m</sub> or T<sub>c</sub>. Instead, these transition temperatures tend to increase in nitrogen, reflecting more of a hydrostatic pressure rather than a solvent effect. Another factor that may play a role is the fluid-induced crystallization which tends to increase the melting temperature. By conducting foaming at properly selected temperatures along the rigidity reduction paths which are scaled with respect to the melting temperatures in CO<sub>2</sub> or N<sub>2</sub>, foams with low bulk foam densities of about 0.2 g/cm<sup>3</sup> could be generated in CO<sub>2</sub> at 100 bar and in N<sub>2</sub> at 200 bar.</p></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":null,"pages":null},"PeriodicalIF":3.4000,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Supercritical Fluids","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0896844624001281","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Melting and crystallization temperatures of poly(ε-caprolactone)(PCL) exposed to CO2 and N2 have been evaluated at pressures up to 125 bar using High Pressure Torsional Braid Analysis. It is shown that in contrast to CO2, exposure to high pressure N2 does not lead to a significant depression of Tm or Tc. Instead, these transition temperatures tend to increase in nitrogen, reflecting more of a hydrostatic pressure rather than a solvent effect. Another factor that may play a role is the fluid-induced crystallization which tends to increase the melting temperature. By conducting foaming at properly selected temperatures along the rigidity reduction paths which are scaled with respect to the melting temperatures in CO2 or N2, foams with low bulk foam densities of about 0.2 g/cm3 could be generated in CO2 at 100 bar and in N2 at 200 bar.
期刊介绍:
The Journal of Supercritical Fluids is an international journal devoted to the fundamental and applied aspects of supercritical fluids and processes. Its aim is to provide a focused platform for academic and industrial researchers to report their findings and to have ready access to the advances in this rapidly growing field. Its coverage is multidisciplinary and includes both basic and applied topics.
Thermodynamics and phase equilibria, reaction kinetics and rate processes, thermal and transport properties, and all topics related to processing such as separations (extraction, fractionation, purification, chromatography) nucleation and impregnation are within the scope. Accounts of specific engineering applications such as those encountered in food, fuel, natural products, minerals, pharmaceuticals and polymer industries are included. Topics related to high pressure equipment design, analytical techniques, sensors, and process control methodologies are also within the scope of the journal.