Plexiglas: from synthetic glass to cationic exchanging resin
Plexiglas is a macromolecule (poly-methyl-methacrylate) obtained by polymerization of the Methyl Methacrylate. Cation exchanging resins have acidic groups such as COOH (carboxyl) and SO3H (sulfonic) which fix metallic cations dissolved in water releasing an equivalent of protons through the following reaction: 2 RCOOH + Me2+ (RCOO)2Me + 2 H+ Regeneration is made treating the exhausted resin with diluted hydrochloric acid (HCl) which moves the equilibrium to the left. The aim of our research is to re-use the discarded Plexiglas by transforming it into a cationic exchanging resin. Alkaline hydrolysis transforms the COOCH3 group into COO– group; the obtained group is then transformed into COOH group by means of a treatment with HCl. After the alkaline hydrolysis spectra of the solid show the characteristic band of the asymmetric stretching of the COO– (1610-1550) at 1567 (1st experiment) and at 1555 (2nd experiment). Instead after the acidic treatment the spectra of the solid show that this band has disappeared. On the contrary the characteristic band of the OH stretching of the COOH group (3300-2500) at 3228 (1st experiment) and at 3200 (2nd experiment) appears. The water hardness, due to Ca2+ and Mg2+ ions, is studied to verify the capability of the obtained resin to capture these cations. For this purpose, some mineral water is percolated through the micro-columns. There are three experimental evidences to validate the hypothesis: EDTA molecule (Ethylene Di-amino Tetra-Acetic acid, disodium salt) to estimate hardness is not required The pH of the percolated water through the column decreases from 8 of the mineral water without any treatment, to 6.3 after the treatment as expected The spectrum recorded in the visible range of the percolated mineral water through the column plus EBT (Eriochrome Black T) indicator is the same as the spectrum obtained using de-ionized water plus the same amount of EBT In conclusion, the study has provided evidence that it is possible to convert Plexiglas into cationic exchanging resin.
Beautiful Butterfly: The Physics Behind The Colors
Even as a child, I was fascinated by the colors in nature, such as rainbows, butterflies and flowers. This fascination developed into curiosity with age, and as my school studies developed, I became particularly interested in the scientific aspects of the origin and development of colors. I wanted to answer the question: How are the different colors of the butterfly wings related to the nanostructures of scales and pigments? The color on the butterfly wings results either from the pigmentation (chemical color) or from the structure (physical color) of the wing scales. Colors such as yellow, black, red and brown are mainly created by pigments. The interaction of light and structures in and on the surface of butterfly wings, often the size of the wavelength of the light, results in physical colors. These colors are usually bright and dependent on the viewing angle (unlike chemical pigments that spread light diffusely). The colors produced here are usually golden, green, purple and blue. But, where do these colors come from and why do certain species dazzle more than others? To get to the heart of the matter, I identified two key questions: • How are the different colors of the butterfly wings related to the nanostructures of scales and to the pigments? • Using the nanostructure, can you find out the wavelength of the reflected light? In this work, I focus on the structural colors of butterflies and study the physics behind them. This includes parachuting in areas such as diffraction gratings, scattering of light, interference in thin films, and multilayer interference. In order to experience the greatest possible diversity, I selected butterflies from different species for the measurements. Using the spectrometer, I measured the light reflected from butterflies. High-resolution microscopes such as the laser microscope and the scanning electron microscope gave me the opportunity to study the detailed nanostructures of the wing. In addition, I was able to analyze and evaluate my results using existing physical models and MATLAB simulations (Maxwell equations).