MARCUS VINICIUS DE SOUZA

MARCUS VINICIUS DE SOUZA

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Preparation and characterization of nanocellulose from sugarcane bagasse
2017 - SEIXAS, MARCUS V. de S.; RANGARI, VIJAYA K.; MOURA, ESPERIDIANA A.B.; WIEBECK, HELIO
Nanocellulose is steadily gaining attention since this material is a renewable alternative to reinforce polymers. Research and development of materials obtained from renewable natural sources have been the focus of attention in various engineering applications. The residues from different kinds of lignocellulosic materials has great potential for production of biocomposites, which are applied in optoelectronic devices, packaging, and building. The main object of this work was study of nanocellulose preparation from sugarcane bagasse and its characterization. The sugarcane bagasse was submitted to chemical treatment for separating of the cellulose from the lignocellulosic material, bleaching with hydrogen peroxide followed by sonication treatment for obtaining nanocellulose. Sonication treatment solution was prepared with a cellulosic material in water/DMF(dimethylformamide)/ethanol. Sonication treatment was done in a DES500 ultrasonic cell tip/horn sonicator with a 20 kHz ultrasonic frequency. The nanocellulose samples were characterized by FTIR, XRD, FE-SEM and TEM analysis. According to the results, the methodology used in this work presented a great potential to the obtaining of nanocellulose for applications in the development of new nanocomposite materials.
Effects on Clay addition on properties of LDPE flexible films
2017 - SANTANA, JULYANA G.; SEIXAS, M.V. de S.; ARANTES, MARIANA; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B.
Studies have indicated that the addition of nanoparticles in flexible films improves performance flexible packaging, leading to better mechanical, thermal and barrier properties. Clay is an abundant mineral, inexpensive, easy to process, and provide considerable enhancements on the properties of polymers. Titanium dioxide (TiO 2 ) is widely used for its efficiency in scattering visible light, and imparting whiteness, brightness, and high opacity when incorporated into a plastic formulation. Low density polyethylene (LDPE) is generally used as a packaging material due to its good resistance, easy processing, low cost and high hardness. The objective of this study was to evaluate the effects of clay and TiO 2 nanoparticles addition on the properties of LDPE flexible films. LDPE with 1 wt % of TiO 2 addition and 1-3 wt. % of green Brazilian Clay, from Cubati, Pb, Brazil were prepared by melt extrusion process, using a twin-screw extruder Haake Rheomex P332 with 16 mm and L/D = 25, from Thermo Scientific. Then the LDPE/Clay nanocomposite was transformed into thin films using an extrusion blown film, single screw machine with 25 mm diameter and specimen test samples were obtained. The specimen samples were characterized by mechanical tests, UV-VIS, DSC, TG and FE-SEM analysis.
Structure and thermal/mechanical properties of poly (ϵ‐caprolactone)‐clay blend
2017 - LODIS, ALINE M.; SEIXAS, M.V. de S.; VALENZUELA-DIAZ, FRANCISCO; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B.
In the area of nanotechnology, polymer matrix based on nanocomposites have generated a significant amount of attention in the recent literature. The achieved results were at least initially viewed as unexpected (‘‘nano-effect’’) offering improved properties over that expected from thermal and mechanics predictions. This work presents the synthesis and characterization of EVA/Clay flexible films treated by electron beam radiation. EVA with 0.5 -3 wt.% of green Brazilian Clay addition were prepared by melt extrusion process, using a twin-screw extruder Haake Rheomex P332 with 16 mm and L/D = 25, from Thermo Scientific. Then, EVA/Clay nanocomposite was transformed into flexible films using a single-screw extruder with 25 mm diameter equipped with a flat die (laboratory line) and specimen test samples were obtained. Part of flexible film samples was submitted at electron beam radiation dose range 25-100 kGy using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. The irradiated and non-irradiated samples were submitted to mechanical tests, XRD, UV-VIS, DSC, TG and FE-SEM analysis. The results showed significant changes in mechanical and thermal properties of EVA/CLAY flexible film due to clay addition and electron-beam irradiation. These results showed that it is possible to get interesting property in EVA flexible films by clay addition and electron-beam radiation treatment
Influence of electron-beam irradiation on the properties of LDPE/EDPM blend foams
2018 - SANTANA, JULYANA; SEIXAS, MARCUS V. de S.; RANGARI, VIJAY; VALENZUELA-DIAZ, FRANCISCO; WIEBECK, HELIO; MOURA, ESPERIDIANA
Closed-cell polyethylene (PE) foams have been extensively used in many applications such as packaging, transportation, sports, construction, and agriculture because of their variety of properties including light weight, chemical resistance, thermal and electrical insulation. The objective of this study is to evaluate the influence of electron-beam irradiation on the properties of LDPE/EPDM blend foams. The LDPE/EPDM blend (80/20 wt%) were prepared by melt extrusion, using a twin-screw extruder machine. The foam structure of LDPE/EPDM blends was obtained by melt extrusion process, using a special single screw for foaming with 1.5 wt% of foaming agent as blowing agent. The foam samples were irradiated by electron-beam at radiation dose of 25, 50, 75 and 100 kGy and submitted to heating in an oven at 100 °C. The specimen tests samples of irradiated and non-irradiated foams were submitted to mechanical tests, DSC, TG analysis and density measurement.