The present work studies the mechanical behavior of rice husk as a reinforcement element in mixtures of polyolefins. The composites were made by polyolefin mixtures of 30% LDPE, 40% HDPE and 30% PP, rice husk and Polybond as a compatibilizer. Samples for the tensile test were prepared by injection and compressive methods. The results confirm that rice husk alongside the compatibilizer bring about positively in the strength of composites. In reference to the adherence of rice husk to the mixture of polyolefins, which was studied from the microstructure of composites, the addition of compatibilizer improves the adherence between the polyolefins and rice husk, and thereby the quality in the fracture surface. These composites are considered to be a good alternative for the recovery of plastic agricultural waste.

This current work has focused on the evaluation of the hexavalent chromium – Cr (VI) adsorption carried out by a biocomposite based on rice husk and chitosan. The chromium IV is an agro industrial contaminant residual while chitosan is a natural biopolymer with a great adsorption of heavy metals. Conditions for the biosorption such as concentrations of rice husk and Cr (VI) alongside the contact time, were identified in order to achieve the highest biosorpion of the heavy metal – Cr (VI). The morphology of rice husk, carried out in a Scanning Electron Microscopy (SEM), showed a porous surface which can allow the adherence of chitosan. Different concentrations of rice husk (10, 20, 30, 40, 50 ) were used for the synthesis of the biopolymer. Furthermore, the capacity of Cr (VI) adsorption of the biocomposite based on rice husk and chitosan was evaluated throughout the contact time, resulting in a 68.28 % of Cr (IV) removal at 120 minutes. Additionally, the results of the experimental design consistent with the adsorption kinetic designs are shown in this work.

In this study, the degree of acetylation (DA) and degree of deacetylation (DDA) were determined by Fourier Transform Infrared Spectroscopy (FT-IR) analysis, and their viability was evaluated by the cytocompatibility test with L132 epithelial cells, from samples of chitin and chitosan extracted of Cryphiops caementarius. FT-IR measurements resulted in the successful determination of DA and DDA. Particularly the results showed that, the chitosan CHT-C has the highest DDA (93%), while viability tests employed to determine the cytotoxicity of chitin and chitosan showed that the cell survival rate of CH-C and CHT-C are 130% and 75% respectively while commercial CHT has a rate of 80% approximately, demonstrating that the CH-C (chitin) a favorable behavior against L132 cell.

In this research work, the corrosion resistance of plate steel used in the construction of cylindrical container tanks of seawater was evaluated. These container tanks are usually used for fighting fires on the coast of the Arequipa-Peru region, where the shortage of drinking water is significant. The study was based on immersion tests of 2 × 2 cm square test plates in 3.5 wt.% NaCl solution. Five paint systems were studied, varying only in the primers: P1-860 (inorganic zinc silicate); P1-ZC (epoxy-zinchromate); P1-850 (organic rich in zinc); P1-600 (reinforced inorganic zinc) and P1-SP1000 (high solids epoxy-amine). All systems consisted of a primer coat, an epoxy middle coat and a polyurethane topcoat. To characterize the behaviour of each system, the electrochemical impedance spectroscopy (EIS) was mostly used. In addition, the scanning Kelvin probe (SKP) and scanning electro­che­mical microscopy (SECM) were used as local techniques. The first three paint systems (P1-860, P1-ZC and P1-850) showed an invariable value of impedance modulus up to 3360 h of immersion in NaCl. The last two paint systems (P1-600 and P1-SP1000) showed a decrease in impedance modulus by more than one order of magnitude. This research provides a clear contribution of results obtained by global electrochemical techniques such as EIS, estab­lishing excellent tools for monitoring the performance of organic anticorrosive coatings.

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