Rosana Lopes Lima Fialho

El objetivo de este trabajo es desarrollar un modelo fenomenológico dinámico de un sistema de desalinización solar térmica que funciona mediante evaporación a presión atmosférica, diseñado para regiones aisladas con escasez de agua. Para describir el balance de masa y energía y evaluar los fenómenos de transferencia de calor y masa, se formuló un sistema de ecuaciones diferenciales. La simulación del modelo se llevó a cabo en Python para analizar el comportamiento de variables del proceso de desalinización, tales como el nivel de agua, concentración de sal, temperatura y producción de agua desalinizada. Los resultados muestran que es posible evaporar el 26,67 % del agua salada suministrada en una hora. Asimismo, se evaluó la capacidad de condensación, en la que se produjo la condensación de todo el vapor. El estudio destaca por su enfoque sostenible, que integra la energía solar térmica, y por su sencillez operativa, lo que lo hace adecuado para ubicaciones remotas.

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The thermoplastic injection moulding process is very important in the plastics industry, as it enables automated production, supports high productivity and allows the production of plastic parts with complex geometries. It is possible to split in two large groups of polymers: amorphous and semicrystalline. Cooling rate and other injection moulding parameters have great influence over the final properties of the plastic part. Regarding the use of aluminium as cavity material in injection moulds, new variables must be included in the analysis, since its thermal properties are significantly different from those presented by steels, which are traditionally used. In this way, the purpose of this study was to evaluate the effect of aluminium and steel cavities on different types of thermoplastics belonging to the two classes of polymers by assessing the injection parameters of a high-production part (automotive cup holder). In terms of productivity factors, moulds made of aluminium using semicrystalline polymers showed more significant reductions in cycle time compared to amorphous materials. Specifically, polypropylene exhibited a cycle time reduction between 40.6% and 52.5% when compared to steel moulds, while polyamide showed an even more substantial reduction, ranging between 56% and 63.5%. As for warpage, the amorphous materials displayed the lowest values for both types of moulds, but they also exhibited greater variations in isothermal simulations compared to semicrystalline materials. In relation to the mould materials, aluminium mould exhibited the lowest warping results and smaller variations compared to the isothermal analyses for all polymers.

Polybutylene succinate (PBS) is a biodegradable polymer that has the potential to replace conventional plastic, however it has limitations such as processing viscosity and high cost. In this work, melt flow index index (MFR) measurements were used to evaluate the influence of the way PBS was packaged before processing and whether this condition could influence the rheological characteristics of the polymer. For this purpose, samples of PBS packaged by the manufacturer (humid PBS) and after drying for 5 hours at 70°C (dry PBS) were evaluated. The results confirmed the degradation condition of the PBS, before being submitted to drying, since the MFR of the sample presented a reduction of 75% of the value indicated by the manufacturer. The melt flow index, obtained from the variation in weight, was used to evaluate the rheological curve of the PBS and a pseudoplastic behavior was verified that did not vary with the form of packaging.

Fiberglass is the most commonly used material in the manufacturing process of wind turbine components, as it meets the basic requirements of the final product. However, as the market for wind turbines expands, industries must keep up with the demands of increasing blade efficiency at a reduced cost. As a replacement for fiberglass, poly (ethylene terephthalate) - PET textile fiber is an option, which has better tensile strength, elongation rate, and low density. However, it has low wettability and poor interfacial bonding with resin matrices. This study aims to perform a literature review of existing scientific studies using PET fiber from the tire industry or not applied as reinforcement in structural composites.

The development of green synthesized polymeric nanoparticles with anticancer studies has been an emerging field in academia and the pharmaceutical and chemical industries. Vegetable oils are potential substitutes for petroleum derivatives, as they present a clean and environmentally friendly alternative and are available in abundance at relatively low prices. Biomass-derived chemicals can be converted into monomers with a unique structure, generating materials with new properties for the synthesis of sustainable monomers and polymers. The production of bio-based polymeric nanoparticles is a promising application of green chemistry for biomedical uses. There is an increasing demand for biocompatible and biodegradable materials for specific applications in the biomedical area, such as cancer therapy. This is encouraging scientists to work on research toward designing polymers with enhanced properties and clean processes, containing oncology active pharmaceutical ingredients (APIs). The nanoencapsulation of these APIs in bio-based polymeric nanoparticles can control the release of the substances, increase bioavailability, reduce problems of volatility and degradation, reduce side effects, and increase treatment efficiency. This review discusses the use of green chemistry for bio-based nanoparticle production and its application in anticancer medicine. The use of castor oil for the production of renewable monomers and polymers is proposed as an ideal candidate for such applications, as well as more suitable methods for the production of bio-based nanoparticles and some oncology APIs available for anticancer application.

Latterly, the development of green synthesized polymeric nanoparticles with anticancer studies has been an emerging field in academia, and in the pharmaceutical and chemical industry. Vegetable oils are potential substitutes for petroleum derivatives, as they present themselves as a clean and environmentally friendly alternative and are available in high quantities at relatively low prices. Biomass-derived chemicals can be converted into monomers with unique structures, generating materials with new properties for the synthesis of sustainable monomers and polymers. In this way, the production of bio-based polymeric nanoparticles appears as a great application of green chemistry for biomedical uses. There is an increasing demand for biocompatible and biodegradable materials for specific applications in biomedical as cancer therapy, encouraging scientists in working on research towards designing polymers, with enhanced properties and clean processes, containing oncology active pharmaceutical ingredients (APIs). The nanoencapsulation of these APIs in bio-based polymeric nanoparticles can control the release of the substances, increase bioavailability, reduce problems with volatility and degradation, reduce side effects, and increase treatment efficiency. Thus, this review aims to discuss the use of green chemistry for bio-based nanoparticle production and its application in anticancer medicine. The use of vegetable oils for the production of renewable monomers and polymers will be discussed, bringing castor oil as an ideal candidate for such application, as well as more suitable methods for the production of bio-based nanoparticles and some oncology APIs available for anticancer application.

In the recent years, the growing amounts and incorrect disposal of solid wastes have created serious negative environmental impacts, including land and water pollution. Chicken litter (CL) is a type of solid waste which is generated during chicken production, the appropriate final destination of which is still subject to technical discussion. Because CL is composed mostly of fibers, proteins, carbohydrates, and different minerals, the use of this material as a filler for the manufacture of polymer materials has been suggested. The main objective of the present work is the manufacture of polymer composites in situ polymerization using CL as a filler and succinic acid and 1,4‐butanediol as monomers, considering that the fiber content in CL is ≈20 wt%. The obtained poly(butylene succinate) (PBS) composites are characterized by Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), degradability in distilled water, and compression analyses. The results show that the addition of CL to the mixture do not affect the course of the polycondensation reaction significantly. Furthermore, compression tests show that the compressive strength of test pieces increases with the CL content.