"Aero-Fib" - Investigation of synthesis, characterization and spinning of highly porous aero-cellulosic fibers for applications in technical textiles

• Applicants: Professor Dr.-Ing. Thomas Gries; Professor Dr. Lorenz Ratke
• Subject Area: Polymeric and Biogenic Materials and Derived Composites
• Term: from 2011 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 179080540

Spinning non-porous fibers from cellulose dissolved in ionic liquids has recently aroused the interest of fundamental and industrial research. It has been demonstrated that the production of highly porous and mechanically strong bulk materials from cellulosic aerogels using the salt-hydrate melt route is feasible. Yet, neither have ionic liquids been used for the production of highly porous fibers, nor has the salt-hydrate melt route been investigated systematically for fiber production.The two procedures for dissolution of cellulose – using salt-hydrate melts or ionic liquids – will be investigated with respect to the production and the properties of aero-cellulosic fibers. The developed porous fibers are then processed into adequate textiles, which will be analyzed subsequently. Hence a new fibrous material for filtration, superabsorbers in hygiene products and/or composites has been highlighted. A high level of porosity and mechanical strength is a combination that enhances liquid and particle absorption, thermal insulation and lightweight performance. Preliminary experiments of ITA and DLR have already demonstrated the feasibility of this approach.The investigation will start with the production of cellulosic aerogels by preparing solutions of salt-hydrate melts or ionic liquids with varying cellulose concentrations which subsequently will be dried as bulk materials. The properties of the aerogels (e.g. viscosity, concentration) and the dried aero-cellulosic monoliths (e.g. mechanical strength, porosity) will result in a selection of recipes for fiber spinning trials. Subsequently, an application-specific spinning equipment for processing the recipes will be developed and implemented. The selected recipes will be tested on spinnability. Spinnable recipes will be processed into fibers under varying process parameters (e.g. drawing speed, spin bath temperature) and dried into aero-cellulosic fibers. The properties of fibers (e.g. mechanical strength, morphology) will be analyzed to generate possibilities for textile applications, mainly for filtration or hygiene products.The second stage of this proposal investigates the capability of producing different textile structures (e.g. nonwoven, knitting or woven) with aero-cellulosic fibers. Additionally, the possibility to improve the aero-cellulosic fibers mechanically (e.g. using crosslinking agents) can expand the application of these fibers into the area of composites.The project is expected to provide insights on how to control cellulose arrangement in aerogels and to exhibit the potential of this material for fibers and textiles.

• DFG Programme: Research Grants
• Participating Person: Professor Dr.-Ing. Crisan Popescu