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Number of results: 5
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Abstract

The results of experimental investigations into foaming process of poly(ε-caprolactone) using supercritical CO2 are presented. The objective of the study was to explore the aspects of fabrication of biodegradable and biocompatible scaffolds that can be applied as a temporary three-dimensional extracellular matrix analog for cells to grow into a new tissue. The influence of foaming process parameters, which have been proven previously to affect significantly scaffold bioactivity, such as pressure (8-18 MPa), temperature (323-373 K) and time of saturation (1-6 h) on microstructure and mechanical properties of produced polymer porous structures is presented. The morphology and mechanical properties of considered materials were analyzed using a scanning electron microscope (SEM), x-ray microtomography (μ-CT) and a static compression test. A precise control over porosity and morphology of obtained polymer porous structures by adjusting the foaming process parameters has been proved. The obtained poly(ε-caprolactone) solid foams prepared using scCO2 have demonstrated sufficient mechanical strength to be applied as scaffolds in tissue engineering.

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Authors and Affiliations

Katarzyna Kosowska
Marek Henczka
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Abstract

In this study, the process of membrane cleaning by supercritical fluid extraction was investigated. Polypropylene microfiltration membranes, contaminated with oils, were treated in a batch process with a supercritical fluid (SCF). As extractant, pure supercritical carbon dioxide or supercritical carbon dioxide with admixtures of methanol, ethanol and isopropanol were used. Single-stage and multi-stage extraction was carried out and process efficiency was determined. The obtained results showed that addition of organic solvents significantly enhances the cleaning performance, which increases with increase of organic solvent concentration and decreases with increasing temperature. All three solvents showed a comparable effect of efficiency enhancement. The results confirmed that supercritical fluid extraction can be applied for polypropylene membrane cleaning.

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Authors and Affiliations

Jan Krzysztoforski
Andrzej Krasiński
Marek Henczka
Wojciech Piątkiewicz
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Abstract

Biocomposite foam scaffolds of poly(ε-caprolactone) (PCL) with different porogenes were produced with batch foaming technique using supercritical carbon dioxide (scCO2) as a blowing agent. In performed experiments composites were prepared from graphene-oxide (nGO), nano-hydroxyapatite (nHA) and nano-cellulose (nC), with various concentrations. The objective of the study was to explore the effects of porogen concentration and foaming process parameters on the morphology and mechanical properties of three-dimensional porous structures that can be used as temporary scaffolds in tissue engineering. The structures were manufactured using scCO2 as a blowing agent, at two various foaming pressures (9 MPa and 18 MPa), at three different temperatures (323 K, 343 K and 373 K) for different saturation times (0.5 h, 1 h and 4 h). In order to examine the utility of porogenes, a number of tests, such as static compression tests, thermal analysis and scanning electron microscopy, have been performed. Analysis of experimental results showed that the investigated materials demonstrated high mechanical strength and a wide range of pore sizes. The obtained results suggest that PCL porous structures are useful as biodegradable and biocompatible scaffolds for tissue engineering.

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Authors and Affiliations

Katarzyna Sawicka
Katarzyna Kosowska
Marek Henczka
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Abstract

This perspective paper focuses on the changes in teaching chemical engineering in Europe triggered by new challenges and megatrends observed in the chemical and related industries. Among the new teaching areas to address those challenges and megatrends, process intensification, digitalization and advanced materials are expected to play the most important role and are discussed in more detail. The discussion on incorporation of those new areas in the university curricula is illustrated with a comparison of educational approaches to the chemical engineering teaching at two universities – Delft University of Technology and Warsaw University of Technology. The aim of this paper is to focus the attention of university teachers and potential decision makers on the most important challenges for contemporary teaching of chemical engineering.
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Authors and Affiliations

Andrzej I. Stankiewicz
1
Marek Henczka
2
Eugeniusz Molga
2
ORCID: ORCID

  1. Delft University of Technology, Process and Energy Department, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
  2. Warsaw University of Technology, Faculty of Chemical and Process Engineering, ul. Warynskiego 1, 00-645 Warsaw, Poland
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Abstract

The role of capillary pumping on the course of cleaning porous materials containing liquid contaminants using supercritical fluids was investigated numerically. As a specific process to be modelled, cleaning of porous membranes, contaminated with soybean oil, using supercritical carbon dioxide as the cleaning fluid (solvent) was considered. A 3D pore-network model, developed as an extension of a 2D drying model, was used for performing pore scale simulations. The influence of various process parameters, including the coordination number of the pore network, the computational domain size, and the external flow mass transfer resistance, on the strength of the capillary pumping effect was investigated. The capillary pumping effect increases with increasing domain size and decreasing external flow mass transfer resistance. For low coordination numbers of the pore network, the capillary pumping effect is not noticeable at macro scale, while for high coordination numbers, the opposite trend is observed – capillary pumping may influence the process at macro scale. In the investigated system, the coordination number of the pore network seems to be low, as no capillary pumping effects were observed at macro scale during experimental investigation and macro-scale modelling of the membrane cleaning process.
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Authors and Affiliations

Jan Krzysztoforski
1
ORCID: ORCID
Karim Khayrat
2
Marek Henczka
3
Patrick Jenny
2

  1. Warsaw University of Technology, Faculty of Chemical and Process Engineering, Warynskiego 1, 00-645 Warsaw, Poland
  2. ETH Zurich, Institute of Fluid Dynamics, Sonneggstrasse 3, 8092 Zurich, Switzerland
  3. Warsaw University of Technology, Faculty of Chemical and Process Engineering, ul. Warynskiego 1, 00-645 Warsaw, Poland

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