DIONE PEREIRA DE CASTRO

DIONE PEREIRA DE CASTRO

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Reuse of textile waste with nano reinforcement for the development of materials incorporated with nanocomposites
2023 - SARTORI, MARIANA do N.; CASTRO, DIONE P. de; SILVA, LEONARDO G. de A. e
The use of plastics in Brazil and the world has shown a growing demand due to their qualities, ease of obtaining, and low cost, and, consequently, produces an increase of these plastics in solid urban waste. The destination of these materials, especially in Brazil, is summarized in sending to landfills, incineration and, mechanical and chemical recycling. This study evaluates the possibility of using polyamide textile waste with elastane discarded by the textile industry, as reinforcement for the development of a polymer-clay composite, on a nanometric scale, and develop a recycling route for these materials. In that, the nanocomposite technology adds value to this material. This work used polyamides from textile waste of the industry. These materials were first processed in a compacting machine. Afterward the composites with 1, 2, and 3% in mass of Verde Clara clay/polyamide were prepared in a double screw extruder. The composites were characterized by techniques of X-ray diffraction (XRD), tensile, flexural, impact tests and thermogravimetric analysis (TGA). Results obtained were compared with the properties of the standard samples. As a conclusion of this study, it can be stated that the polyamide textile scraps with elastane can be reused forming nanocomposites with Verde Clara clay. Verde Clara clay in the proportion of 1% already confers gains in the properties of these nanocomposites.
Thermal degradation and spectroscopy analysis of TPS/PBAT blends irradiated by Cobalt-60 source
2022 - CASTRO, D.P.; ANDRADE e SILVA, L.G.
This study aimed to prepare blends of natural polymers of TPS with PBAT by reactive extrusion that were subsequently subjected to the irradiation process and evaluated for their thermal and chemical properties. The blends were incorporated with plasticizers (glycerol, castor oil and surfactant) and submitted to the irradiation process using a Cobalt-60 source at a 25 kGy dose and then characterized by FTIR and DSC. The results obtained in the FTIR analysis, the blends did not undergo chemical changes during the irradiation process and thus, maintained their properties. In the DSC analysis, it was observed that the blends F2 (castor oil) and F3 (castor oil and TWEEN® 80) showed higher values of heat flow for degradation than the samples F0 (glycerol) and F1 (glycerol and TWEEN® 80), probably due to the chemical interaction of castor oil and its constituents. There was no thermal variation in the irradiation process between blends F0 and F1 or F2 and F3. It was concluded that it is feasible to replace castor oil with glycerol in TPS/PBAT blends, and that irradiation using a Cobalt-60 source did not change the properties analyzed and contributed to microbiological protection.
The incorporation of the Light Green clay in the textile polyamide residues
2021 - SARTORI, M.N.; CASTRO, D.P.; VALENZUELA-DIAZ, F.R.; SILVA, L.G.A.
The aim of this work is to evaluate the possibility to use textile residues of polyamide with elastane that are discarded by the industry as a matrix of a new polymer-clay composite material, evaluated on a manometric scale, and to propose a way of recycling for these materials. At the same time, with nanocomposite technology, value is added to this material. In this work, polyamide of textile residues from industrywas used. These materials were first processed in a compacter machine. Composites at 1, 2, and 3% by weight of Light Green clay/polyamide were prepared by double screw extrusion. The properties of the composite were characterized by X-ray diffraction (XRD), tensile, flexural, impact tests, and thermogravimetric analysis (TGA). Results obtained were compared with the neat textile polyamide properties. It was concluded that it is feasible to recycle the textile residues of polyamide, and that the addition of clay, at the doses studied in this work, could lead to the obtaining of composite materials with better mechanical than untreated ones.
Characterization of TPS/PBAT blends irradiated by ionizing radiation
2021 - CASTRO, DIONE P. de; SILVA, LEONARDO G. de A. e
The use of biodegradable polymers is an important alternative today for both the environment and industry. However, when compared to conventional polymers, biodegradables are more expensive. The development of polymeric blends using matrices of biodegradable and synthetic polymers with natural additives are less damaging to the environment and more cost efficient. This study aimed to prepare natural blends of thermoplastic starch (TPS) with poly(butylene adipate-co-terephthalate) (PBAT) by reactive extrusion. The blends were submitted to the irradiation process using a Cobalt-60 source at a 25 kGy dose and then characterized by Fourier-transform infrared spectroscopy (FTIR) and differential heat flow scanning calorimetry (DSC). According to the results obtained in the FTIR tests, the blends did not undergo chemical changes during the irradiation process and, thus, maintained their properties. In the DSC tests, it was observed that the blends F2 (composed of castor oil) and F3 (composed of castor oil and TWEEN® 80) showed higher values of heat flow for degradation than the samples F0 (composed of glycerol) and F1 (composed of glycerol and TWEEN® 80), probably due to the chemical interaction of castor oil and its constituents. There was no thermal variation in the irradiation process between blends F0 and F1 or F2 and F3 . It was concluded that it is feasible to replace castor oil with glycerol in TPS/PBAT blends.
Characterization using X-ray diffraction and study of the crystallinity of the thermoplastic starch/poly(butylene adipate-co-terephthalate) blends irradiated by gamma rays
2020 - CASTRO, DIONE P. de; GARCIA, RAFAEL H.L.; SILVA, LEONARDO G. de A. e
The aim of this study was to analyze the changes in the structure and crystallinity of non-irradiated and irradiated thermoplastic starch blends (TPS)/poly (butylene adipate-co-terephthalate) - PBAT and also to evaluate the behavior of castor oil replacing glycerol. In this work, the characterization was performed by using X-ray diffraction (XRD), in which the crystallinity index (IC) of non-irradiated and irradiated blends of TPS/PBAT was calculated, through the software Bruker DIFFRAC.EVA® v4.22. For the plastification of the TPS, glycerol, castor oil and TWEEN® 80 were used to verify their compatibility and establish a comparison among the blends. The samples were prepared by extrusion and irradiated at 25 kGy with gamma rays with a 60Co source. However, the crystallinity indexes of the blends were altered according to the plasticizer used and the use of TWEEN® 80. Thus, it was concluded that replacing glycerol with castor oil is feasible in TPS/PBAT blends.