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Thermodynamic Studies on the Preparation of Pourous Structure by Supercritical Fluid

Author: GuiQiuZuo
Tutor: LiuZhiJun
School: Dalian University of Technology
Course: Chemical Process Equipment
Keywords: Supercritical Fluid Phase inversion Porous structure Thermodynamics Ternary phase diagrams
CLC: TK123
Type: Master's thesis
Year: 2011
Downloads: 42
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Abstract


In recent years, with the rapid development of cell biology, molecular biology and bio-materials research, tissue engineering as an emerging interdisciplinary research and application has made great progress. The ideal cell selection and preparation of the scaffold is a major element in the study of tissue engineering. Supercritical induced phase transformation of the porous structure of prepared traditional phase inversion process on the basis of the development of a new preparation process. To study the thermodynamic behavior involved in the process, in-depth analysis and calculate the induced phase transformation of supercritical fluid process parameters, in order to better optimize the preparation process of the porous structure. Flory-Huggins polymer solution theory, to establish a \ternary phase diagrams, including further study of supercritical fluid-induced phase transformation process in the preparation of porous structure phase separation behavior. By analysis of the ternary phase diagram, divided into \Optimized to provide a theoretical basis. Thermodynamic model of supercritical carbon dioxide (ScCO2) - acetone (AC) - poly caprolactone (PCL) ternary system and \The system for thermodynamic calculation, the results are as follows: 1. ternary system critical point calculation results show that the position of the critical point in the phase diagram the closer solvent - non-solvent axis, the system is more prone to polymer depleted phase separation of the nucleation, more conducive prepared good performance of the porous structure. 2.ScCO2-AC-PCL ternary system Thermodynamic calculations show that, as the pressure increases or temperature decreases, the interaction parameter χ12 non-solvent / solvent and non-solvent / polymer interaction parameter χ13 decreases, ie, non- a solvent with a solvent or non-solvent-polymer interactions are enhanced. Further analysis of the influence on the phase diagram of χ12 with χ13 found, χ13 more significant impact on the position of the double line in the phase diagram, in the χ13 under the influence of the average pore diameter of the porous structure with the pressure increase or decrease of temperature is increased. Ternary system. ScCO2-AC-PCL, the interaction of the relevant parameters of the double line away from the polymer - solvent axis, homogeneous area increases, the two-phase zone decreases, the average pore size of the porous structure prepared increases; when the system reaches thermodynamic equilibrium, with the polymer-rich phase and a lean phase links the slope of the line increases, the phase separation time will be shortened, so that the average pore size of the prepared porous structure. 4.ScCO2-DCM-PLLA ternary system thermodynamics calculation results show that the variation in the ternary system of the influence of pressure and temperature on the non-solvent / solvent and non-solvent / polymer interaction parameters between ScCO2-AC-PCL ; variation of the slope of the double line and the location of the spinodal link line in the phase diagram of the ternary system with ScCO2-AC-PCL calculation results are basically similar. More significant due to the different nature of the polymer itself, compared with the PCL system parameters such as pressure and temperature of PLLA ternary system. Thermodynamic calculations using the ternary system were prepared as a porous structure of the various systems for analysis, each parameter change in the phase diagram can be well explained different experimental parameters of the law of the influence of the conditions on the pore size and morphology of the porous structure, \

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CLC: > Industrial Technology > Energy and Power Engineering > Thermal engineering, heat > Thermal Engineering Theory > Engineering Thermodynamics
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