Refine
Document Type
- Journal article (27)
- Patent / Standard / Guidelines (3)
- Book chapter (2)
- Conference proceeding (1)
Is part of the Bibliography
- yes (33)
Institute
- Life Sciences (33)
Publisher
- Elsevier (8)
- De Gruyter (7)
- MDPI (5)
- Wiley (4)
- American Chemical Society (1)
- Hanser (1)
- Hindawi (1)
- JoVE (1)
- Springer (1)
- University of Technology and Economics, Department of Polymer Engineering (1)
Die Erfindung betrifft eine Vorrichtung und Verfahren zur Analyse eines Materialstroms S mit einem Einlassbereich E, einem Messbereich M und einen Auslassbereich A sowie mit einer ersten Weiche W1 und einer zweiten Weiche W2 und einem Umlenkbereich U, wobei die beiden Weichen W1, W2 in einem ersten Schaltzustand Z1 einen durchgängigen ersten Materialdurchströmungsraum vom Einlassbereich E über die erste Weiche W1 durch den Messbereich M über die zweite Weiche W2 bis zum Auslassbereich A ausbilden und in einem zweiten Schaltzustand einen durchgängigen zweiten Materialdurchströmungsraum vom Einlassbereich E über die erste Weiche W1 durch den Umkenkbereich U über die zweite Weiche W2 bis zum Auslassbereich A ausbilden.
Die Erfindung betrifft eine Vorrichtung und Verfahren zur Analyse eines Materialstroms (S) mit einem Einlassbereich (E), einem Messbereich (M) und einen Auslassbereich (A) sowie mit einer ersten Weiche (W1) und einer zweiten Weiche (W2) und einem Umlenkbereich (U), wobei die beiden Weichen (W1, W2) in einem ersten Schaltzustand (Z1) einen durchgängigen ersten Materialdurchströmungsraum vom Einlassbereich (E) über die erste Weiche (W1) durch den Messbereich (M) über die zweite Weiche (W2) bis zum Auslassbereich (A) ausbilden und in einem zweiten Schaltzustand einen durchgängigen zweiten Materialdurchströmungsraum vom Einlassbereich (E) über die erste Weiche (W1) durch den Umlenkbereich (U) über die zweite Weiche (W2) bis zum Auslassbereich (A) ausbilden.
Block-copolyesters of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) were synthesized via reactive extrusion. The influence of processing parameters on the material properties on a molecular scale like degree of trans-esterification, block length, and degree of randomness were investigated. The varied process factors were extrusion temperature and rotational speed. The effects of process parameter variation were investigated by 1H-NMR-spectroscopy. The experimental results show a clear dependence of the molecular properties on the processing conditions. By using statistical experimental design (DoE), it was possible to prepare defined copolyesters from PET and PEN without addition of further chemicals. With a degree of randomness between 0.05 and 0.5, the presence of an actual copolyester was confirmed when appropriate extrusion conditions were applied. The reactive extrusion process was confirmed to be suitable to produce defined block-copolyesters in a predictable and reproducible way. It was possible to produce designed sequence lengths, which could be adjusted within a range of 11–136 repeating units in the case of PET and, in the case of PEN, of 2.5–26. The produced materials can be used as barrier materials or barrier coatings to protect substrates against molecular oxygen and water vapour, e.g., in organic photovoltaic applications or food packaging. The described method is a one-pot alternative method to the previously described chemical recycling pathway.
It has been widely shown that biomaterial surface topography can modulate host immune response, but a fundamental understanding of how different topographies contribute to pro-inflammatory or anti-inflammatory responses is still lacking. To investigate the impact of surface topography on immune response, we undertook a systematic approach by analyzing immune response to eight grades of medical grade polyurethane of increasing surface roughness in three in vitro models of the human immune system. Polyurethane specimens were produced with defined roughness values by injection molding according to the VDI 3400 industrial standard. Specimens ranged from 0.1 μm to 18 μm in average roughness (Ra), which was confirmed by confocal scanning microscopy. Immunological responses were assessed with THP-1-derived macrophages, human peripheral blood mononuclear cells (PBMCs), and whole blood following culture on polyurethane specimens. As shown by the release of pro-inflammatory and anti-inflammatory cytokines in all three models, a mild immune response to polyurethane was observed, however, this was not associated with the degree of surface roughness. Likewise, the cell morphology (cell spreading, circularity, and elongation) in THP-1-derived macrophages and the expression of CD molecules in the PBMC model on T cells (HLA-DR and CD16), NK cells (HLA-DR), and monocytes (HLA-DR, CD16, CD86, and CD163) showed no influence of surface roughness. In summary, this study shows that modifying surface roughness in the micrometer range on polyurethane has no impact on the pro-inflammatory immune response. Therefore, we propose that such modifications do not affect the immunocompatibility of polyurethane, thereby supporting the notion of polyurethane as a biocompatible material.
Ethylene terephthalate and ethylene naphthalate oligomers of defined degree of polymerization were synthesized via chemical recycling of the parent polymers. The oligomers were used as defined building blocks for the preparation of novel block-co-polyesters having tailored sequence compositions. The sequence lengths were systematically varied using Design of Experiments. The dispersive surface energy and the specific desorption energy of the co-polymers were determined by inverse gas chromatography. The study shows that polyethylene terephthalate-polyethylene naphthalate (PET-PEN) block-co-polyesters of defined sequence lengths can be prepared. Furthermore, the specific and dispersive surface energies of the obtained block-co-polyesters showed a linear dependence on the oligomer molecular weight and it was possible to regulate and control their interfacial properties. In contrast, with the corresponding random-block-co-polyesters no such dependence was found. The synthesized block-co-polyesters could be used as polymeric modifying agents for stabilizing PET-PEN polymer blends.
We present the modification of ethylene-propylene rubber (EPM) with vinyltetra-methydisiloxane (VTMDS) via reactive extrusion to create a new silicone-based material with the potential for high-performance applications in the automotive, industrial and biomedical sectors. The radical-initiated modification is achieved with a peroxide catalyst starting the grafting reaction. The preparation process of the VTMDS-grafted EPM was systematically investigated using process analytical technology (in-line Raman spectroscopy) and the statistical design of experiments (DoE). By applying an orthogonal factorial array based on a face-centered central composite experimental design, the identification, quantification and mathematical modeling of the effects of the process factors on the grafting result were undertaken. Based on response surface models, process windows were defined that yield high grafting degrees and good grafting efficiency in terms of grafting agent utilization. To control the grafting process in terms of grafting degree and grafting efficiency, the chemical changes taking place during the modification procedure in the extruder were observed in real-time using a spectroscopic in-line Raman probe which was directly inserted into the extruder. Successful grafting of the EPM was validated in the final product by 1H-NMR and FTIR spectroscopy.
Thermoplastic polycarbonate urethane elastomers (TPCU) are potential implant materials for treating degenerative joint diseases thanks to their adjustable rubber-like properties, their toughness, and their durability. We developed a water-containing high-molecular-weight sulfated hyaluronic acid-coating to improve the interaction of TPCU with the synovial fluid. It is suggested that trapped synovial fluid can act as a lubricant that reduces the friction forces and thus provides an enhanced abrasion resistance of TPCU implants. Aims of this work were (i) the development of a coating method for novel soft TPCU with high-molecular sulfated hyaluronic acid to increase the biocompatibility and (ii) the in vitro validation of the functionalized TPCUs in cell culture experiments.
Silicones
(2014)
Silicones are found in a variety of applications with requirements that range from long life at elevated temperatures to fluidity at low temperatures. This chapter first considers silicone elastomers and their application in room temperature vulcanizing (RTV) and heat curing systems (HTV). Also, new technologies for UV curing are introduced. Coverage of RTVs includes both one-component and two-component systems and the different cure chemistries of each, and is followed by a separate discussion of silicone laminates. Due to the high importance of silicone fluids, they are also discussed. Fluids include polishes, release agents, surfactants, and dielectric fluids.