In this report, indium-tin-oxide (ITO)-layer extraction from end-of-life (EOL) Liquid Crystal Displays (LCDs) was discussed by sulfuric acid leaching with simultaneous application of ultrasonication on the ITO-side of glass/ITO panels, exhibiting various dimensions. Applying this technique presents several advantages compared to the traditional leaching process such as fast and controllable kinetics, high extraction yield of indium and tin, selective recovery of these two metals possible, and the opportunity to recycle the neat glass separately avoiding additional separation processes. ITO-dissolution kinetics from EOL LCD panels were investigated as function of leaching time and acidity of sulfuric acid. At a temperature of 60°C, a nearly quantitative indium yield was obtained using an acid concentration of 18mol/L by simultaneous application of ultrasonication, whereas only 70% were recovered in the absence of ultrasound. Results from ICP-AES agreed well with SEM/BSE observations demonstrating the high efficiency of the ultrasound assisted process since only 3-4min were required to obtain maximum ITO recovery.
This study investigates the use of low molecular weight poly(ethylene glycol) (PEG) as a plasticizer for poly(lactic acid) (PLA). PLA/PEG blend films were prepared using the solvent casting method with varying mixing ratios. The films were analyzed using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and dynamic rheological analysis. The results indicate that the addition of PEG as a plasticizer affects the thermal and mechanical properties of the PLA/PEG blend films. The study found that the glass transition and cold crystallization temperatures decreased with increasing PEG content up to 20 wt%, while the crystallinity and crystallization rate increased. The blends with up to 20 wt% PEG were miscible, but phase separation occurred when the plasticizer content was increased to 30 wt%. Subsequently, amorphous samples of neat PLA and PLA plasticized with 10 wt% of PEG underwent annealing at various temperatures (Ta = 80–120 °C) for durations ta of 1 and 24 h. The samples were then analyzed using DSC and DMA. The addition of PEG to PLA altered the content of α′ and α crystalline forms compared to neat PLA at a given (Ta; ta) and favored the formation of a mixture of α′ and α crystals. The crystallinity achieved upon annealing increased with increasing Ta or ta and with the incorporation of PEG.
6 September 2000 in Journal of Applied Polymer Science
Phase diagrams of unpolymerized and UV-polymerized 2-ethyl hexyl acrylate (EHA) mixtures with the liquid crystal E7 are established using optical microscopy and differential scanning calorimetry. Both diagrams show upper critical solution temperature behavior. From 50 to 90 wt % liquid crystal (LC), the phase located between the and (I) phases was clearly shown. The nematic phase inside the droplets exhibits a twisted radial structure indicating that homeotropic anchoring occurs at the polymer interface. The experimental phase diagrams were successfully analyzed using a model based on the Flory-Huggins theory of isotropic mixing supplemented with the Maier-Saupe theory of nematic order. The LC solubility limit in the polymer matrix and the fractional amount of LC contained in the droplets were deduced from the calorimetric measurements. For the specific composition EHA/E7 (50:50), the scattering and morphological properties of the films were studied as a function of time elapsed after UV exposure. Drastic changes in the size, shape, spatial distribution, and number density of nematic droplets were observed and analyzed in terms of coalescence/diffusion phenomena.