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The great concern for environmental problems, as well as the need for polymeric materials with more versatile properties for their application, currently lead to a growing interest in the development of polymeric composites based on agro-industrial waste. In this work, novel composites of poly(3-hexylthiophene-2,5-diyl)/natural-silicon dioxide (P3HT/N-SiO2) were synthesized by extracting SiO2 from an agro-industrial waste (rice husk), they were characterized and applied to electrochromic devices (ECD). Composites were prepared by in-situ polymerization of 3HT monomer in the presence of N-SiO2. To evaluate the effect of the incorporation of N-SiO2 in P3HT on its physicochemical properties and its application in electrochromic devices, the N-SiO2 concentration was varied. The results revealed improved properties of P3HT with the addition of N-SiO2, such as higher crystallinity and decreased bandgap. Likewise, it was determined that the presence of N-SiO2 in P3HT increases the optical contrast in single ECD (glass/ITO/composite/polymeric electrolyte/ITO/glass architecture design) in a certain wavelength range. The procedure for obtaining P3HT/N-SiO2 composites is simple and inexpensive, which in addition to their interesting properties makes them potential candidates for their application in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals were extracted from cotton. The cellulose nanocrystals made a self-assembly structure when dried under slow conditions, as it was revealed by the characterization made to the material. The AFM images of the nanocrystals showed that they had a changing local orientation, pointing in a preferred direction that underwent a periodic change. This periodic change resembles the orientation of a chiral nematic phase. The TEM images showed that the nanocrystals had a rod-like appearance with average length size of 98.5 nm and a diameter of 4.7 nm. The TEM characterization showed the nanocrystals with more details than AFM. In this paper, the self-assembling of CNC was observed by AFM, and further investigations were done by TEM, deconvoluting the process of CNC nanorods aggregation. [ABSTRACT FROM AUTHOR]

Transformers are very expensive apparatuses and are vital to make the whole power system run normally. The failures in such apparatuses could leave them out of service, causing severe economic losses. The life of a transformer can be effectively determined by the life of the insulating paper. In the present work, we show an alternative diagnostic technique to determine the ageing condition of transformer paper by the use of FTIR spectroscopy and an empirical model. This method has the advantage of using a microsample that could be extracted from the transformer on-site. The proposed technique offers an approximation quantitative evaluation of the degree of polymerization of dielectric papers and could be used for transformer diagnosis and remaining life estimation. [ABSTRACT FROM AUTHOR]