Benedikt Fleckenstein - Academia.edu (original) (raw)
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Papers by Benedikt Fleckenstein
In dieser Arbeit wurde der Einfluss von thermischen beziehungsweise hochdruckinduzierten Pasteuri... more In dieser Arbeit wurde der Einfluss von thermischen beziehungsweise hochdruckinduzierten Pasteurisationsprozessen auf die Oberflache von polymeren thermoplastischen Verpackungsfolien und auf eine, in eine thermoplastische Folie eingepresste, regelmasige Oberflachenstruktur untersucht. Die Untersuchung der Auswirkungen erfolgte dabei systematisch in 3 Stufen. Zunachst wurde ein Screening an verschiedenen Einschichtfolien durchgefuhrt. Als Kenngrosen wurden dabei die mittlere Oberflachenrauheit (gemessen mit AFM), die mittlere Rauigkeit (Tastschnittmessung) und die Oberflachenenergie verwendet. Bei Betrachtung der Einwirkung einer Pasteurisation auf die mittlere Rauigkeit konnte sowohl mit dem Rasterkraftmikroskop als auch mit Tastschnittmessungen ein signifikanter Einfluss auf biaxial orientierte Einschichtfolien festgestellt werden. Die Zunahme der Rauigkeit bei den biaxial orientierten Folien kann auf einen Schrumpf der Folie zuruckgefuhrt werden. Die notwendige Energie fur diesen ...
Food Engineering Reviews, 2017
The occurrence of blistering and the formation of bubbles in matrices after a sudden pressure dro... more The occurrence of blistering and the formation of bubbles in matrices after a sudden pressure drop is a wellknown phenomenon in many fields, including in the petroleum industry (Bexplosive decompression failure^), in diving (decompression sickness), in the infrastructure of hydrogen fuel cells, in the foaming of polymers, and in the highpressure processing of food. This usually undesirable effect is caused by the increased absorption of gas in the polymer under high-pressure conditions and the subsequent supersaturation and increase in free energy on rapid pressure release. The exact mechanisms of the resulting expansion of gas, and hence the formation of bubbles, are not fully understood. Regarding the high-pressure processing of food where pressures of up to 6000 bar are reached at moderate temperatures, little information is available about the key factors involved in decompression failure. This review summarizes results and findings from relevant research areas to understand polymer decompression failure. The first part of this review describes the transport properties of gases in polymers under high pressure (sorption and desorption, diffusion coefficient, and permeability coefficient). The second part focuses on damage mechanisms and discusses parameters such as material properties, the nature of the gas, and process conditions (e.g., temperature, decompression rate). Knowledge gaps and proposed research are highlighted.
Packaging Technology and Science, 2016
BO/PEpeel and PET-BO/PE) films were treated by either high pressure (600 MPa) or temperature (80°... more BO/PEpeel and PET-BO/PE) films were treated by either high pressure (600 MPa) or temperature (80°C/90°C) to simulate a high pressure or thermal pasteurization process. The samples were tested by atomic force microscopy (AFM), profile method and surface energy measurements to obtain information about the influence of the treatments on the surface topography and surface energy of the samples and by differential scanning calorimetry and by tensile testing concerning material properties. As key figures arithmetic surface roughness (by AFM at Pulsed Force Mode and profile method), surface energy by surface energy measurement and adhesion between tip and surface by AFM were extracted. Results indicate an influence of both high-pressure processing and thermal-processing on the surface roughness of biaxial oriented polymer films as single layer films. Laminated biaxially oriented polymer films showed no changes regardless of which processing was performed. The surface energy was hardly affected by both of the treatments for any stretched, non-stretched, single or laminated films.
The Journal of Chemical Physics, 2015
Up until now, gas permeation through polymers under high pressure has not been able to be measure... more Up until now, gas permeation through polymers under high pressure has not been able to be measured continuously. The combination of a special high pressure cell and a commercially available fluorescence-based oxygen measurement system allows in-situ monitoring of oxygen permeation through a polymer sample under pressure in an aqueous environment. The principle of the oxygen sensor is based on dynamic fluorescence quenching and measurement of the fluorescence decay time. It was observed that the decay time increases non-linearly with the applied pressure, and hence, the displayed oxygen concentration has to be corrected. This deviation between the measured and the real concentration depends not only on the pressure but also on the absolute oxygen concentration in the water. To obtain a calibration curve, tests were performed in the pressure range between 1 and 2000 bars and initial oxygen concentrations in the range between 40 and 280 µmol/l. The polynomial calibration curve was of the fourth order, describing the raw data with a coefficient of determination R 2 > 0.99. The effective oxygen permeation through polymeric samples can be calculated with this function. A pressure hysteresis test was undertaken but no hysteresis was found. No temperature dependence of the oxygen sensor signal was observed in the range between 20 • C and 30 • C. This study presents for the first time data showing the oxygen permeation rates through a polyethylene film in the pressure range between 1 and 2000 bars at 23 • C.
The effects of high pressure treatment of packed food both on their properties like visual integr... more The effects of high pressure treatment of packed food both on their properties like visual integrity, gas and water vapor barrier and seal strength and on other properties are well investigated as the reviews from Fleckenstein et al. [1] and Juliano et al. [2] show. In contrast there are no publications about the influence of high pressure treatment on the surface of polymeric films. Hence in this study the influence of High Pressure Processing (600 MPa) on the surface of several monolayer (PE-HD, PE-LD, PP-BO, PA6-BO, PET-BO) and one multilayer (PS/PE) was determined by Atomic Force Microscopy (AFM), interfacial tension measurement and profile method. At this the arithmetic roughness average obtained by AFM and profile method and the surface energy respectively adhesion obtained by AFM and interfacial tension measurement were used as key figures. Results indicate an influence of high pressure processing on the surface roughness of unfixed biaxial oriented polymer films but shows no...
Zeitschrift für Konfliktmanagement, 2014
Food Engineering Reviews, 2014
ABSTRACT High-pressure processing (HPP) is a small, but growing and profitable technique to exten... more ABSTRACT High-pressure processing (HPP) is a small, but growing and profitable technique to extend the shelf life of high-quality food products. As tray packages with modified atmosphere packaging (MAP) provide better product presentation and also improved product protection, it seems logical to combine HPP with MAP. Due to the fact that the used gases such as oxygen, nitrogen and carbon dioxide are in a supercritical state during HPP, it is important to give extra attention to these conditions. Several studies were performed dealing with the influence of high pressure on the mechanical and/or barrier properties of packages and polymers. However, little information is known about the combined effect of MAP gases and high pressure on packaging. This study hence evaluates the influence of headspace gases on the morphology and integrity of packages subjected to HPP. Pressure-related changes of the morphology of polymers as commonly used for packaging will be shown. Density as well as crystalline and amorphous content was analyzed quantitatively with Raman spectroscopy by varying headspace volume (15–50 % of the total package), headspace gas composition (air, CO2, N2 and a mixture of 20 % CO2/80 % N2), multilayer structures, film thickness and flexibility of the lid. Additionally the influence of headspace gases in HPP on the barrier properties of an organic and an inorganic material and on the migration of additives into liquid food simulants has been studied.
Packaging Technology and Science, 2013
As high-pressure processing is used increasingly for the treatment of packed products, different ... more As high-pressure processing is used increasingly for the treatment of packed products, different packaging has been investigated with respect to their structural behaviour and stability under high-pressure processing. Often, failures and changes of the polymeric structure occur. Common damage symptoms of high-pressure-treated packaging materials are defined and classified in this review. These damage symptoms are allocated to the physico-chemical effects that created them. The effects may be separated into direct effects induced by the action of the high-pressure alone and indirect effects that are mediated via compressed contents of the package, i.e. filled product and gaseous headspace. The direct effects split up again in reversible and irreversible structural changes. The indirect effects are generated by compressed headspace gases, other compressed substances and the consequences of increased amounts of gases dissolved in the polymers. If applicable, current theoretical approaches have been allocated to the different categories of damage.
In dieser Arbeit wurde der Einfluss von thermischen beziehungsweise hochdruckinduzierten Pasteuri... more In dieser Arbeit wurde der Einfluss von thermischen beziehungsweise hochdruckinduzierten Pasteurisationsprozessen auf die Oberflache von polymeren thermoplastischen Verpackungsfolien und auf eine, in eine thermoplastische Folie eingepresste, regelmasige Oberflachenstruktur untersucht. Die Untersuchung der Auswirkungen erfolgte dabei systematisch in 3 Stufen. Zunachst wurde ein Screening an verschiedenen Einschichtfolien durchgefuhrt. Als Kenngrosen wurden dabei die mittlere Oberflachenrauheit (gemessen mit AFM), die mittlere Rauigkeit (Tastschnittmessung) und die Oberflachenenergie verwendet. Bei Betrachtung der Einwirkung einer Pasteurisation auf die mittlere Rauigkeit konnte sowohl mit dem Rasterkraftmikroskop als auch mit Tastschnittmessungen ein signifikanter Einfluss auf biaxial orientierte Einschichtfolien festgestellt werden. Die Zunahme der Rauigkeit bei den biaxial orientierten Folien kann auf einen Schrumpf der Folie zuruckgefuhrt werden. Die notwendige Energie fur diesen ...
Food Engineering Reviews, 2017
The occurrence of blistering and the formation of bubbles in matrices after a sudden pressure dro... more The occurrence of blistering and the formation of bubbles in matrices after a sudden pressure drop is a wellknown phenomenon in many fields, including in the petroleum industry (Bexplosive decompression failure^), in diving (decompression sickness), in the infrastructure of hydrogen fuel cells, in the foaming of polymers, and in the highpressure processing of food. This usually undesirable effect is caused by the increased absorption of gas in the polymer under high-pressure conditions and the subsequent supersaturation and increase in free energy on rapid pressure release. The exact mechanisms of the resulting expansion of gas, and hence the formation of bubbles, are not fully understood. Regarding the high-pressure processing of food where pressures of up to 6000 bar are reached at moderate temperatures, little information is available about the key factors involved in decompression failure. This review summarizes results and findings from relevant research areas to understand polymer decompression failure. The first part of this review describes the transport properties of gases in polymers under high pressure (sorption and desorption, diffusion coefficient, and permeability coefficient). The second part focuses on damage mechanisms and discusses parameters such as material properties, the nature of the gas, and process conditions (e.g., temperature, decompression rate). Knowledge gaps and proposed research are highlighted.
Packaging Technology and Science, 2016
BO/PEpeel and PET-BO/PE) films were treated by either high pressure (600 MPa) or temperature (80°... more BO/PEpeel and PET-BO/PE) films were treated by either high pressure (600 MPa) or temperature (80°C/90°C) to simulate a high pressure or thermal pasteurization process. The samples were tested by atomic force microscopy (AFM), profile method and surface energy measurements to obtain information about the influence of the treatments on the surface topography and surface energy of the samples and by differential scanning calorimetry and by tensile testing concerning material properties. As key figures arithmetic surface roughness (by AFM at Pulsed Force Mode and profile method), surface energy by surface energy measurement and adhesion between tip and surface by AFM were extracted. Results indicate an influence of both high-pressure processing and thermal-processing on the surface roughness of biaxial oriented polymer films as single layer films. Laminated biaxially oriented polymer films showed no changes regardless of which processing was performed. The surface energy was hardly affected by both of the treatments for any stretched, non-stretched, single or laminated films.
The Journal of Chemical Physics, 2015
Up until now, gas permeation through polymers under high pressure has not been able to be measure... more Up until now, gas permeation through polymers under high pressure has not been able to be measured continuously. The combination of a special high pressure cell and a commercially available fluorescence-based oxygen measurement system allows in-situ monitoring of oxygen permeation through a polymer sample under pressure in an aqueous environment. The principle of the oxygen sensor is based on dynamic fluorescence quenching and measurement of the fluorescence decay time. It was observed that the decay time increases non-linearly with the applied pressure, and hence, the displayed oxygen concentration has to be corrected. This deviation between the measured and the real concentration depends not only on the pressure but also on the absolute oxygen concentration in the water. To obtain a calibration curve, tests were performed in the pressure range between 1 and 2000 bars and initial oxygen concentrations in the range between 40 and 280 µmol/l. The polynomial calibration curve was of the fourth order, describing the raw data with a coefficient of determination R 2 > 0.99. The effective oxygen permeation through polymeric samples can be calculated with this function. A pressure hysteresis test was undertaken but no hysteresis was found. No temperature dependence of the oxygen sensor signal was observed in the range between 20 • C and 30 • C. This study presents for the first time data showing the oxygen permeation rates through a polyethylene film in the pressure range between 1 and 2000 bars at 23 • C.
The effects of high pressure treatment of packed food both on their properties like visual integr... more The effects of high pressure treatment of packed food both on their properties like visual integrity, gas and water vapor barrier and seal strength and on other properties are well investigated as the reviews from Fleckenstein et al. [1] and Juliano et al. [2] show. In contrast there are no publications about the influence of high pressure treatment on the surface of polymeric films. Hence in this study the influence of High Pressure Processing (600 MPa) on the surface of several monolayer (PE-HD, PE-LD, PP-BO, PA6-BO, PET-BO) and one multilayer (PS/PE) was determined by Atomic Force Microscopy (AFM), interfacial tension measurement and profile method. At this the arithmetic roughness average obtained by AFM and profile method and the surface energy respectively adhesion obtained by AFM and interfacial tension measurement were used as key figures. Results indicate an influence of high pressure processing on the surface roughness of unfixed biaxial oriented polymer films but shows no...
Zeitschrift für Konfliktmanagement, 2014
Food Engineering Reviews, 2014
ABSTRACT High-pressure processing (HPP) is a small, but growing and profitable technique to exten... more ABSTRACT High-pressure processing (HPP) is a small, but growing and profitable technique to extend the shelf life of high-quality food products. As tray packages with modified atmosphere packaging (MAP) provide better product presentation and also improved product protection, it seems logical to combine HPP with MAP. Due to the fact that the used gases such as oxygen, nitrogen and carbon dioxide are in a supercritical state during HPP, it is important to give extra attention to these conditions. Several studies were performed dealing with the influence of high pressure on the mechanical and/or barrier properties of packages and polymers. However, little information is known about the combined effect of MAP gases and high pressure on packaging. This study hence evaluates the influence of headspace gases on the morphology and integrity of packages subjected to HPP. Pressure-related changes of the morphology of polymers as commonly used for packaging will be shown. Density as well as crystalline and amorphous content was analyzed quantitatively with Raman spectroscopy by varying headspace volume (15–50 % of the total package), headspace gas composition (air, CO2, N2 and a mixture of 20 % CO2/80 % N2), multilayer structures, film thickness and flexibility of the lid. Additionally the influence of headspace gases in HPP on the barrier properties of an organic and an inorganic material and on the migration of additives into liquid food simulants has been studied.
Packaging Technology and Science, 2013
As high-pressure processing is used increasingly for the treatment of packed products, different ... more As high-pressure processing is used increasingly for the treatment of packed products, different packaging has been investigated with respect to their structural behaviour and stability under high-pressure processing. Often, failures and changes of the polymeric structure occur. Common damage symptoms of high-pressure-treated packaging materials are defined and classified in this review. These damage symptoms are allocated to the physico-chemical effects that created them. The effects may be separated into direct effects induced by the action of the high-pressure alone and indirect effects that are mediated via compressed contents of the package, i.e. filled product and gaseous headspace. The direct effects split up again in reversible and irreversible structural changes. The indirect effects are generated by compressed headspace gases, other compressed substances and the consequences of increased amounts of gases dissolved in the polymers. If applicable, current theoretical approaches have been allocated to the different categories of damage.