AUREA BEATRIZ CERQUEIRA GERALDO
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Licenciada e bacharel em Química pela Universidade Federal do Paraná (1991), mestre em Físico-Química pela Universidade Estadual de Campinas (1993) e doutora em Engenharia Metalúrgica e de Materiais pela Universidade Federal do Rio de Janeiro (1998). Atualmente é tecnologista do Instituto de Pesquisas Energéticas e Nucleares. Atua principalmente nos seguintes temas: a) eletroquímica: eletroanalítica, eletrodissolução/eletrodeposição, b) materiais modificados por radiação: modificação e caracterização de materiais poliméricos, caracterização de materiais ligados a radioisótopos, estudo e caracterização de materiais para a produção de radioisótopos primários e c) ensino de química (Texto extraído do Currículo Lattes em 4 out. 2021)
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Resumo IPEN-doc 26563 Mechanical evaluation of PVC films modified by electron beam irradiation2011 - CARDOSO, J.R.; MOURA, E.; SOMESSARI, E.S.R.; SILVEIRA, C.G.; PAES, H.A.; SOUZA, C.A.; MANZOLI, J.E.; GERALDO, A.B.C.The polyvinyl chloride (PVC) is a technological and low cost polymer. Although this polymer is weather resistant, it presents high sensitivity to high energy irradiation because of the weakness of carbon-chloride bond face to carbon-carbon and carbon-hydrogen bonds [1]. Upon exposure to high energy irradiation, some carbon-chloride bonds are broken to give rise radicals like chlorine and organic chloride that are initiators of two concurrent processes: degradation and crosslinking. The degradation process on PVC is macroscopically observed by discoloration effects, where the material tends to darken or to turn yellow, mainly at a typical sterilization dose of 25 kGy [2]; this process yields hydrogen chloride as a byproduct, it is autocatalytic and it continues after irradiation exposure. By other way, the crosslinking leads to an improvement in thermal resistance and mechanical properties. The aim of this work is to evaluate the mechanical properties of PVC irradiated by electron beam to verify the degradation process. Also, mechanical properties are investigated on styrene grafted PVC by electron beam irradiation using mutual and pre-irradiation methods to verify the mechanical resistance changes of obtained product if grafting process is applied from non-irradiated and from pre-irradiated substrates. The PVC commercial film samples with 210 jam thickness were cut into a dumbbell-shape (gauge length: 25 mm, width: 4.10 mm, area: 0.86 mm2). The grafting media was styrene /butanol-1 mixture in several monomer concentrations (from 10% to 100%). The samples were irradiated on a Job 188 Dynamitron® Electron Beam Accelerator with 1.5 MeV energy. All irradiation procedures were performed in atmosphere air and the irradiation conditions comprised doses from 10 kGy to 100 kGy and dose rates of 2.2 kGy/s and 22.4 kGy/s. The styrene grafted samples were analyzed by gravimetry to determinate the grafting yield; the final values have been averaged from a series of three measurements. The Mid-ATR-FTIR was the spectrophotometer technique used for qualitative/semi-quantitative analysis of grafted samples. The Young's module and tensile strength of pre-irradiated and grafted PVC samples at both methods were measured at a Lloyd LXR tensile tester at a crosshead speed of 10.00 mm/min. We observed the decrease of Young's module and tensile strength with the increase of absorbed dose at pre-irradiated PVC samples, that it indicates degradation process. These mechanical parameters results are discussed to styrene grafted PVC samples.Artigo IPEN-doc 24186 Electron beam irradiation process applied to primary and secondary recycled high density polyethylene2017 - CARDOSO, JESSICA R.; MOURA, EDUARDO de; GERALDO, AUREA B.C.Plastic bags, packaging and furniture items are examples of plastic utilities always present in life. However, the end-of-life of plastics impacts the environment because of this ubiquity and also often their high degradation time. Recycling processes are important in this scenario because they offer many solutions to this problem. Basically, four ways are known for plastic recycling: primary recycling, which consists in re-extrusion of clean plastic scraps from a production plant; secondary recycling, that uses end-of-life products that generally are reduced in size by extrusion to obtain a more desirable shape for reprocessing (pellets and powder); tertiary recover which is related to thermo-chemical methods to produce fuels and petrochemical feedstock; and quaternary route, that is related to energy recovery and it is done in appropriate reactors. In this work, high density polyethylene (HDPE) was recovered to simulate empirically the primary and secondary recycling ways using materials which ranged from pristine to 20-fold re-extrused materials. The final 20-fold recycled thermoplastic was irradiated in an electron beam accelerator under a dose rate of 22.4 kGy/s and absorbed doses of 50 kGy and 100 kGy. The characterization of HDPE in distinct levels of recovering was performed by infrared spectroscopy (FTIR) and thermogravimetric degradation. In the HDPE recycling, degradation and crosslinking are consecutive processes; degradation is very noticeable in the 20-fold recycled product. Despite this, the 20-fold recycled product presents crosslinking after irradiation process and the post-irradiation product presents similarities in spectroscopic and thermal degradation characteristics of pristine, irradiated HDPE. These results are discussed.Resumo IPEN-doc 23064 Recycled HDPE/Vulcanized EPDM mixtures obtained by irradiation processes2017 - CARDOSO, J.; GERALDO, A.; MOURA, E.Recycling polymers process includes techniques that present solutions to the problem of plastic waste in the environment. This process is important to improve the economic sector in many countries, like cooperative societies. Primary recycling is related to the reuse of plastic waste directly from the production site in the industry, that carry on some advantages besides the low cost involved in the reuse of this waste: the raw material is free from dust of many kinds (metals, different powders and plastics). Among this polymeric waste, packaging dominates this scenario, covering 62:2% of the total, where polyolefins account more than 50% of the packaging production. In the same way, the recovering of sulfur-cured rubber contribute to release the environment from this almost non-degradable rubber. The goal of this work is to produce an alternative recycled product composed by mixing twenty-times reused HDPE (by primary recycling process) with vulcanized EPDM rubber. The twenty-times recycled thermoplastic was reached by extrusion, which intention was to simulate a polyolefin like a scrap. The EPDM rubber was fragmented and incorporated to the thermoplastic matrix in proportions of 1% and 5% w/w, from both kinds of rubber, like received and after a thermal treatment. One of the thermal treatment of rubber consisted in an oven ageing in the temperature of 100 C; the other was a simultaneous heating under irradiation process by electron beam at 130 C and at 100 kGy absorbed dose (at 22:4 kGy/s dose rate). The final mixture was obtained by injection molding and specimens from injection process were -irradiated at 50 kGy and at 100 kGy. Mechanical analysis of stress-strain, infrared FTIR spectra and thermogravimetric degradation were performed to evaluate the final product. The obtained product showed heterogeneous; the rubber without thermal treatment was better incorporated to thermoplastic matrix and the irradiated samples present mechanical resistance that suggests this new material intended to be viable to industrial use.Artigo IPEN-doc 21149 Evaluation of electron beam irradiation under heating process on vulcanized EPDM2015 - GABRIEL, LEANDRO; CARDOSO, JESSICA R.; MOURA, EDUARDO; GERALDO, AUREA B.C.Artigo IPEN-doc 21092 Characteristics of recycled and electron beam irradiated high density polyethylene samples2015 - CARDOSO, JESSICA R.; GABRIEL, LEANDRO; GERALDO, AUREA B.C.; MOURA, EDUARDOArtigo IPEN-doc 17168 Mechanical behavior of styrene grafted PVC films by electron beam irradiation2011 - CARDOSO, JESSICA R.; MOURA, EDUARDO; SOMESSARI, ELISABETH S.R.; SILVEIRA, CARLOS G.; PAES, HELIO A.; SOUZA, CARLOS A.; MANZOLI, JOSE E.; GERALDO, AUREA B.C.