New carbazole-indan-1,3-dione- based host materials for phosphorescent organic light emitting diodes

New carbazole- and indan-1,3-dione -based low molecular weight derivatives were synthesized and characterized by mass spectrometry and 1H NMR spectroscopy. Thermal behaviour of the derivatives was demonstrated by thermo-gravimetric analysis and differential scanning calorimetry. The materials were found to show very high thermal stability having initial thermal degradation temperatures in the range of 398- 401°C. Glass transition temperatures of the amorphous molecular materials were in the rage of 80–114°C. The derivatives were tested as host materials in blue phosphorescent organic light emitting diodes with iridium(III)[bis(4,6-difluorophenyl)- pyridinato-N,C2 ]picolinate as the guests. One of the blue OLED devices demonstrated rather low turn-on voltage of 5.0 V, a maximum luminance efficiency of 2.73 cd/A and maximum brightness of about 220 cd/m2Kauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij

Alkali-free method of hide preparation for tanning

Usually, beamhouse processes are carried out by varying a medium from strongly alkaline (unhairing-liming) up to strongly acid (pickling). This study is designed to develop a preparation of hide for tanning via processes that avoid a sharp change of hide pH. Enzymes active in acid medium are employed for hide unhairing in a buffer system containing 2.5% acetic acid and 0.3% sodium acetate. An oxidative treatment with peracetic acid then allows the complete removal of residual hair and scud. During both processes, unhairing and oxidative treatment, the opening of the derma structure occurs: 13.3-14.6g of non-collagen proteins are removed and amount of dermatan sulphate decreases by 35%. The hide obtained can be chromed directly after the above processes and subsequent treatment with sodium chloride solution omitted conventional pickling. The pH of the hide varies in the range of 8.3-3.7 during the processes of preparation for tanning