The dissolution of cellulose in different ionic liquids will be described as a very recent subject for a direct dissolving process, which was used to prepare regenerated cellulose fibres. The preparation of the dopes was arranged starting from slurry of cellulose in the aqueous ionic liquid by removing the water at elevated temperature, vacuum and high shearing rates. As ionic liquids, the 1-N-Butyl-3-methylimidazolium chloride, the 1-Ethyl-3-methylimidazolium chloride, the 1-N-Butyl-2,3-dimethylimidazolium chloride, the 1-N-Butyl-3-methylimidazolium acetate and the 1-Ethyl-3-methylimidazolium acetate were investigated. The cellulose solutions in ionic liquids were characterised by means of light microscopy, coneplate rheometry and particle analysis. In addition these results were compared with cellulose solutions in N-methyl-morpholine-N-oxide monohydrate. Finally the cellulose dopes were shaped by a dry-wet spinning process to manufacture cellulose fibres. The properties of the resulted fibre had been determined and will be discussed.

Ionic liquids (IL) are new direct dissolving systems for cellulose characterized by unique dissolving properties and simple technical handling. Selected IL‐systems are non toxic and chemically as well as physically neutral which represents an advantage as compared to the commonly used direct solvent N‐methyl‐ morpholine‐N‐oxide (NMMO). Fibres can easily be prepared by coagulation in water. The BASF company as a leading producer of ionic liquids investigates the technical conversion of the preparation of cellulosic fibres using ionic liquids in cooperation with the Institut für Textilchemie und Chemiefasern (ITCF), Denkendorf and the Thüringisches Institut für Textil‐ und Kunststoff‐Forschung (TITK), Rudolstadt. The major targets of this project are the selection of appropriate IL‐systems, the IL recycling, rheology of spinning dopes and the charcterization of resulting fibre profiles. Essential results of this work and the potential for establishing a technical‐ scale process are summarized.

The interactions of ionic liquids (IL) with solvents usually used in liquid‐state nuclear magnetic resonance (NMR) spectroscopy are studied. The 1H‐ and 13C‐NMR chemical shift values of 1‐n‐butyl‐3‐methyl (BM)‐ and 1‐ethyl‐3‐methyl (EM)‐substituted imidazolium (IM) ‐chlorides (Cl) and ‐acetates (Ac) are determined before and after diluting with deuterated solvents (DMSO‐d6, D2O, CD3OD, and CDCl3). The dilution offers structural modifications of the IL due to the solvents capacity to ionization. For further investigation of highly viscous cellulose dopes made of imidazolium‐based IL, solid‐state NMR spectroscopy enables the reproducibility of liquid‐state NMR data of pure IL. The correlation of liquid‐ and solid‐state NMR is shown on EMIM‐Ac and cellulose/EMIM‐Ac dope (10 wt %).

Summary: Functional cellulose shapes offer valuable properties for innovative application potentials in textile and medical products. Thereby excellent textile physiological properties of cellulose are allowed to be connected with novel application characteristics like bioactivity, electrical conductivity, heat storage or ability to adsorb liquids or gases. A very advantageous way to modify the properties of fibres, films or textile structures is to introduce particular additives via the Lyocell process. Regard to technical applications, functional additives will be able to incorporate themselves in the shape matrix and, in the case of using N‐methylmorpholine‐N‐oxide monohydrate (NMMO) as solvent, implicate massive technological difficulties and deterioration of properties of the spinning dope. Beside a couple of limiting moments, ionic liquids (ILs) offer as direct solvents an excellent chance for physical modification of cellulose shapes. In contrast to NMMO, they exhibit a significantly higher thermal stability as well as a higher chemical resistance. ILs exhibit most widely a better dissolving capability for a number of different polymers. First results of the development of adsorber materials as well as novel bioactive fibres will be discussed and fibre characteristics will be given.

Properties of cellulose solutions in different direct dissolving liquids such as N-methylmorpholine-N-oxide and ionic liquids with varied cations and anions were investigated. The effects of different cations and anions of the used ionic liquids on the solution state were studied on the basis of the rheological characteristics of the resulting polymer solutions. The influence of these components is discussed in terms of zero shear viscosities, master curves with storage and loss moduli as well as complex viscosities using comparable molar ratios between cellulose and solvent and comparable polymer concentrations. Furthermore anisotropic properties of highly concentrated cellulose solutions were determined by means of polarised light microscopy and rheological methods subjected to the used solvent and variation of the polymer concentration as well as the temperature.

The acetylation of cellulose in ionic liquids (ILs) and the subsequent dry/wet spinning of these processing solutions were investigated. The homogeneous acetylation in ILs was carried out using different molar ratios of acetic anhydride to the anhydroglucose unit (AGU). The obtained solutions of cellulose acetates were characterised analytically by means of rheological methods. DS and $\overline {DP}$ of the prepared cellulose acetates were determined. Furthermore the processing solutions of the acetylation were shaped by means of a dry/wet spinning process to fibres with varied properties. The resulting fibre properties were discussed in consideration of the DS and in comparison with unsubstituted cellulose fibres.

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