SUELLEN SIGNER BARTOLOMEI

SUELLEN SIGNER BARTOLOMEI

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Investigation on mechanical and thermal behaviours of PBAT/PLA blend reinforced with reduced graphene oxide nanosheets
2020 - BARTOLOMEI, MARCIO R.X.; CARMO, KARINA H.S.; SANTOS, BIANCA S.; BARTOLOMEI, SUELLEN S.; OLIVEIRA, RENE R.; MOURA, ESPERIDIANA A.B.
The aim of this study was to process and investigate the changes in the mechanical and morphological properties of the biodegradable nanocomposites based on polybutylene adipate-co-terephthalate (PBAT)/poly(lactic acid) (PLA) blend (PBAT/PLA blend) due to the incorporation of reduced graphene oxide (RGO) nanosheets. The biodegradable polymeric nanocomposites were prepared by melting extrusion process using a twin-screw extruder machine. The influence of the RGO nanosheets incorporation on mechanical and thermal properties of PBAT/PLA blend was investigated by tensile Thermogravimetric (TG), X-Ray diffraction (XRD), differential scanning calorimetry (DSC), and tensile test analysis. Results showed that incorporation of the small amount ofRGO(0.1wt.%) ofRGOnanosheets in the blend matrix of PBAT/PLA resulted in an important gain of mechanical properties of the blend. This result indicates that a very small amount of RGO nanosheets addition in the PBAT/PLA can lead to obtaining materials with superior properties suitable for several industrial applications.
Influence of the reduced graphene oxide incorporation on properties of acrylonitrile butadiene styrene (ABS)
2020 - SANTOS, BIANCA S.; INACIO, ANDRE L.N.; BARTOLOMEI, SUELLEN S.; SILVA, TAISE B.S.; CARMO, KARINA L.S.; OLIVEIRA, RENE R.; MOURA, ESPERIDIANA A.B.
The purpose of this study was to evaluate the influence of incorporation of the reduced graphene oxide on properties of acrylonitrile butadiene styrene (ABS). The incorporation of 0.5 and 1.5 wt% of RGO into ABS matrix was carried out by melting extrusion process using a twin-screw extruder and injection molding machine. The properties of ABS/RGO nanocomposite samples were investigated by tensile and impact Izod tests, FE-SEM, and XRD analysis. The results showed that the incorporation of small amount of RGO into ABS matrix led to obtaining of polymeric nanocomposite with superior mechanical properties when compared with original properties of ABS matrix.
Lignin‑based polyethylene films with enhanced thermal, opacity and biodegradability properties for agricultural mulch applications
2021 - CHIAPPERO, LUCIO R.; BARTOLOMEI, SUELLEN S.; ESTENOZ, DIANA A.; MOURA, ESPERIDIANA A.B.; NICOLAU, VERONICA V.
Lignins are promising alternative raw materials for biocomposites due to their renewability, low cost and abundance. In this work, the use of (softwood and hardwood) Kraft lignins in the development of LLDPE/lignin films for agricultural mulch applications is studied. Processable blends were obtained from unmodified softwood lignin (SW) and from hardwood lignin modified by esterification (HWE). LLDPE was pelletized with (2.5%, 5% and 10%) lignin with particle size between 38 and 75 μm and flexible films were blown extruded. Processable extrusion blends showed temperature differences lower than 20 °C between the Tg of lignin and the melting temperature of LLPDE. Films from neat LLPDE and with 2.5% of HWE and up to 5% SW exhibited statistically comparable (≅ 349%) values of ductility. Ester groups present in lignin improve weight loss of lignin-based blends after soil buried test.
Investigation of the effect of titanium dioxide and clay grafted with glycidyl methacrylate by gamma radiation on the properties of EVA flexible films
2020 - BARTOLOMEI, SUELLEN S.; SANTANA, JULYANA G.; DIAZ, FRANCISCO R.V.; KAVAKLI, PINAR A.; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B.
Many studies report that nanocomposites obtained by dispersion of a small amount nanofiller into the polymer have remarkable improvements achieved in the mechanical and physical properties. However, in order to achieve this great improvement in properties, it is necessary that the nanofillers be dispersed homogeneously into the polymeric matrix. Often this dispersion is difficult to achieve due to the high interfacial energy of the nanoparticles present. This study reports the effect of gamma irradiation induced graft of glycidyl methacrylate (GMA) onto the surface of TiO2 and Clay nanofillers to improve their dispersion into the EVA matrix. The physical and mechanical properties of Ethylene-vinyl acetate copolymer (EVA) flexible films with these nanoparticles were studied. EVA nanocomposite with adding of the different amount of TiO2 and modified montmorillonite clay grafted and un-grafted with glycidyl methacrylate (GMA) using gamma irradiation have been prepared by melt extrusion. The nanocomposite flexible films were produced using a flat die extrusion process. The PGMA-grafted nanofillers were characterized by XRD and TEM analysis. The flexible films were characterized by Tensile tests, ATR–FTIR, UV–VIS, XRD, TG, and FE-SEM analysis to understand the nature of the interaction between the nanofillers and EVA matrix. The results showed that the addition of PGMA-grafted TiO2 and Clay nanofillers into EVA matrix improved the bonding between the nanofillers and matrix. It was also found that the PGMA-grafted nanofillers could be well dispersed into an EVA matrix in contrast to that of un-grafted. The tensile strength and modulus of the resulting EVA/TiO2-PGMA enhanced in comparison to that of un-grafted TiO2. The EVA/Clay-PGMA had slightly decreased tensile strength comparable to that of EVA/Clay but had considerably improved elastic modulus. In addition, the flexible films based on TiO2 exhibited high UV–Vis light absorption with energy gap shifted to the visible region. The results demonstrated that TiO2 and Clay nanofillers grafted with GMA by gamma radiation can be used to prepare EVA flexible films with improved bonding between the nanofillers and matrix and, consequently, enhanced properties for food and cosmetic packaging application.
Comparative study of the use of rice husk ashes and graphite as fillers in polypropylene matrix composites
2019 - MONTEIRO, ALEX S.; BARREIRA, DAILI A.S.; BARTOLOMEI, SUELLEN S.; OLIVEIRA, RENE R.; MOURA, ESPERIDIANA A.B. de
In recent years, carbonaceous materials have been widely studied for polymer composite applications due to its capability to improve the engineering properties of the polymeric matrix. Among various carbonaceous fillers, carbon nanotube, graphene, and graphite promise to be a suitable reinforcement of polymers. Rice husk ash (RHA), a large residue rich in carbon and silica produced by the burning of rice husk offers also an immense potential as a carbonaceous filler for polymer composites on account of its lowcost, lowdensity, high strength and elastic modulus, no health risks, and renewability. This work aims at studying the effects of RHA and graphite as fillers in polypropylene (PP) matrix composites. The composites PP/RHA and PP/graphite were produced by melting extrusion process. The materials obtained were subjected to mechanical tests, XRD, TG, and FEG-SEM analyses. Comparison studies between neat PP properties and its composites were carried out.