Hyperbranched Polymers in a Supercritical Fluid: Recent Progress on Phase Behavior and Modeling

Abstract

The advent of new chemistries has led to the creation of well-defined, novel polymer architectures. Due to their unique structures, hyperbranched polymers are receiving more and more attention and widely applied in various fields in the past two decades. In spite of their increasingly mature applications, some fundamental properties of star polymers are still lacking, such as their solubility behavior in different solvents, especially at high pressures. On the other hand, supercritical fluids (SCF) are ideal environmentally preferable solvents for polymer processing. This article intends to review the recent progress on the experimental determination and modeling of phase behavior of hyperbranched polymer systems, especially hyperbranched polymers in SCF. Following a brief description of the definition, properties, and applications of hyperbranched polymers, a detailed overview will be presented on the recent studies on phase behavior of hyperbranched polymer systems. Emphasis will be laid on the high-pressure phase behavior of polymers in SCF. Different models proposed by previous researchers will be then compared for the purpose of accurately predicting the phase equilibrium data. Finally current challenges will be discussed for future work.

Pressure-Volume-Temperature Property Determination for Fluids at Extreme Pressures

“…Same with the floating-piston apparatus, the Cailletet tube is able to simultaneously determine highpressure density and phase transition data in a single experiment. However, the operation of this system needs to handle hazardous mercury and the glass tube limits the use of the apparatus at ultra-high pressures [63]. Tanaka et al [64,65] used a high-pressure burette apparatus made of Pyrex glass for the determination of densities of hydrocarbon mixtures and ethanol-water mixtures at temperatures to 75°C and pressures to 150 MPa.…”

The phase behavior in supercritical carbon dioxide of hyperbranched copolymers with architectural variations

“…Identification of highly CO 2 -soluble polymers has been a subject of intense research for the last twenty years. [5][6][7][8][9][10] In our previous paper [11] a more detailed description of results on phase behavior of polymers in CO 2 solutions published in the open literature up to 2009 was presented. We refer a reader to this publication for more information on the subject.…”

Synthesis, Characterization, and Solubility in Supercritical Carbon Dioxide of Hyperbranched Copolyesters

“…Design and synthesis of CO 2 -soluble surfactants, ligands and phase transfer agents demand a broad knowledge on solubility of polymers in dense carbon dioxide. Identification of highly CO 2 -soluble polymers has been a subject of intense research for the past 20 years. − In our previous paper, a more detailed description of results on phase behavior of polymers in CO 2 solutions published in the open literature up to 2009 was presented. We refer a reader to this publication for more information on the subject.…”