Summary: One strategy to solve the problem of unwanted PET oligomer deposits in textile production is their enzymatic cleavage. In this work a selection of different enzymes (esterases, lipases) were tested for this purpose. The capacity to hydrolyse PET oligomers of some of the tested enzymes has been previously described in the literature. In order to imitate practical conditions both dry and precipitated PET oligomers were used. The decrease in the amount of cyclic trimer, the main component of the PET oligomers, was monitored by HPLC. After treatment with the lipase from Triticum aestivum a decrease of 80 wt.‐% was found. However, the effect of this lipase seems to have less to do with catalysing hydrolytic cleavages of ester groups than with the absorption of the oligomer on the enzyme protein.Cyclic PET trimer (cyclo‐tris[ethyleneglycolterephthalate]).magnified imageCyclic PET trimer (cyclo‐tris[ethyleneglycolterephthalate]).

Summary: Cellulose/N‐methylmorpholine‐N‐oxide monohydrate (NMMO) spinning solutions were modified with surface‐active additives to yield Lyocell fibers with functional properties. Based on cellulose fibers, a new class of materials with tailored adsorption characteristics are produced. Activated charcoal and carbon black used as additives significantly affect the thermostability of the spinning solutions. Considering the degree of filling three general tendencies become evident. It is most obvious that the onset temperature of dope decomposition is shifted towards lower values accompanied by viscosity reduction after annealing at elevated temperatures and an enhanced formation of degradations products. Morpholine, N‐methylmorpholine and formaldehyde as the main degradation products were detected in aqueous distillates by means of HPLC. To study the rate of by‐product formation during preparation of the solution kinetic measurements were carried out. Thermal instabilities are not only initiated by heavy metal ions, especially Fe(II), but also by the particle size and porosity of the charcoal. The nano‐scaled carbon black used causes autocatalytic reactions as revealed by calorimetric measurements.

Cover:The picture on the cover shows a 3-dimensional chromatogram (retention time, absorption, wave length) of amines by HPLC as well as the correlation of measured and predicted onset temperature (T on ). As the beginning of an exothermicity T on can be modeled by the combination of detection of amines and subsequent PLS regression.

A population of 167 samples were monitored using by rheological, calorimetric, chromatographic and spectroscopic methods, which allows a precise description of the thermal behavior. Hierarchical cluster analysis was used to find similarities between groups of samples. Principal components analysis revealed isoperibolic pressure slope, morpholine and N‐methylmorpholine as variables providing most information concerning the thermostability. The onset temperature as the beginning of an exothermicity can be modeled by the combination of detection of amines and aldehydes and subsequent PLS regression.magnified image

A technique has been developed that allows the production of cellulosic micro composites by immobilizing super-ground functionalised materials in the cellulose matrix. For this purpose, the well-established ALCERU 1 process has been a subject of technological modification. Depending on the degree of filling, several types of composites are accessible. At lower concentrations, the fibres maintain their textile-physical parameters and may be used in applications, where a textile appearance is required. The increasing concentration of the functional additives influences increasingly the overall properties of the composite and leads to composites with special functions such as water retention, electric conductivity, and specific absorption ability for organics or heat storage functions. In addition, loads exceeding the cellulose portion are useful as green shapes for ceramics.