Novel types of polyester hydrochlorides and polyesters were synthesized from N-octyl- or N methyldiethanolamine and organic acid chlorides. Montmorillonite (MMT) was modified by cation exchange with the polyester hydrochlorides. The basal spacing, determined by X-ray diffraction, was not significantly influenced by the length of organic acid chain but increased with the length of the alkyl group attached to nitrogen atom. Cation ratio of MMT and hydrochloride must have been at least 1:3 for quantitative cation exchange, indicating that only a part of polycation chain adheres to MMT surface.
COBISS.SI-ID: 4096538
The liquefaction of different wood pulp cellulose was studied in ethylene glycol in the presence of p-toluene sulfonic acid or sulphuric acid being the catalysts. The study was performed by gravimetric analysis, by X-ray diffraction of the residual cellulose and by monitoring of the molar mass decrease over different time intervals. The disordered regions degraded in the initial minute of liquefaction, while the crystalline cellulose regions remained relatively stable for a longer time. None the less, partial degradation of the highly ordered regions of the cellulose was achieved.
COBISS.SI-ID: 4104218
Wood liquefaction with glycols using p-toluenesulfonic acid as the catalyst was carried out under microwave heating. With temperatures in the 190–210 °C range complete liquefaction was achieved in 7 min. Efficiency was dependent on the choice of glycol and was higher for symple glycols. The use of glycerol in mixtures showed a synergistic effect. Size exclusion chromatography followed the gradual emergence of liquefaction products and the recondensation of products that start forming early in the reaction and precipitate from solution when molar masses of approx. 1 × 104 g/mol are reached.
COBISS.SI-ID: 4128026
We studied the elution behavior of poly(lactide-co-succinimide) copolymers in SEC column to assure the separation of macromolecules according to their size. Copolymers behave like ionomers which exhibit polyelectrolyte effect that can be supressed by the addition of simple salts and/or acids (LiBr and/or H3PO4). The amount of additives has to be adjusted for each copolymer according to its composition. In the case of too high ionic strength of the solvent, intermolecular association through hydrophobic lactic acid units was observed for the copolymers of high lactic acid unit content.
COBISS.SI-ID: 4117274
In this work we report the preparation and physical–chemical characterization of Liquid Single Crystal Elastomers (LSCEs) containing azobenzene derivative side-chain mesogens as co-monomer. The interplay between the orientational ordering and mechanical response in the nematic phase is investigated by thermomechanical measurements as well as by deuteron NMR spectroscopy.
COBISS.SI-ID: 22867751