Refine
H-BRS Bibliography
- yes (2)
Departments, institutes and facilities
Document Type
- Article (2)
Year of publication
- 2022 (2) (remove)
Language
- English (2)
Has Fulltext
- yes (2)
Keywords
- Mass transport (1)
- Nafion™ (1)
- PEM electrolysis (1)
- Permeation (1)
- Tap water (1)
- blown film extrusion (1)
- chain-extending cross-linker (1)
- ozone (1)
- poly(butylene adipate terephthalate) (1)
- poly(lactic acid) (1)
Process-induced changes in the morphology of biodegradable polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA) blends modified with various multifunctional chainextending cross-linkers (CECLs) are presented. The morphology of unmodified and modified films produced with blown film extrusion is examined in an extrusion direction (ED) and a transverse direction (TD). While FTIR analysis showed only small peak shifts indicating that the CECLs modify the molecular weight of the PBAT/PLA blend, SEM investigations of the fracture surfaces of blown extrusion films revealed their significant effect on the morphology formed during the processing. Due to the combined shear and elongation deformation during blown film extrusion, rather spherical PLA islands were partly transformed into long fibrils, which tended to decay to chains of elliptical islands if cooled slowly. The CECL introduction into the blend changed the thickness of the PLA fibrils, modified the interface adhesion, and altered the deformation behavior of the PBAT matrix from brittle to ductile. The results proved that CECLs react selectively with PBAT, PLA, and their interface. Furthermore, the reactions of CECLs with PBAT/PLA induced by the processing depended on the deformation directions (ED and TD), thus resulting in further non-uniformities of blown extrusion films.
Operating an ozone-evolving PEM electrolyser in tap water: A case study of water and ion transport
(2022)
While PEM water electrolysis could be a favourable technique for in situ sanitization with ozone, its application is mainly limited to the use of ultrapure water to achieve a sufficient long-time stability. As additional charge carriers influence the occurring transport phenomena, we investigated the impact of different feed water qualities on the performance of a PEM tap water electrolyser for ozone evolution. The permeation of water and the four most abundant cations (Na+, K+, Ca2+, Mg2+) is characterised during stand-by and powered operation at different charge densities to quantify underlying transport mechanisms. Water transport is shown to linearly increase with the applied current (95 ± 2 mmol A−1 h−1) and occurs decoupled from ion permeation. A limitation of ion permeation is given by the transfer of ions in water to the anode/PEM interface. The unstabilized operation of a PEM electrolyser in tap water leads to a pH gradient which promotes the formation of magnesium and calcium carbonates and hydroxides on the cathode surface. The introduction of a novel auxiliary cathode in the anolytic compartment has shown to suppress ion permeation by close to 20%.