LEANDRO GABRIEL
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Resumo IPEN-doc 26956 Crystallinity and mechanical properties of recycled, gamma irradiated HDPE/EPDM blends2017 - GABRIEL, LEANDRO; MOURA, EDUARDO; GERALDO, AUREA B.C.High Density Polyethylene (HDPE) is a commodity and its wide range of uses comprises several plastic processing in the industry due its conformability, high thermal and chemical resistance and a relative low cost [1]. Also, this material can be recycled many times, which is an important characteristic to decrease the environmental impact when plastic goods reach their end of life. EPDM is one of thermosetting elastomers widely applicated in automotive industry because of its high mechanical, thermal and ageing resistance [2]. The mixture of this both components generate a material with high impact resistance and tensile strength at break [3]. HDPE/EPDM blends are obtained by extrusion of these polymeric components with addition of compatibilizers agents to achieve a homogenous and compatible mixture [4]. In this work the High Density Polyethylene (HDPE) matrix has been recycled four times from original substrate and mixed to non-vulcanized EPDM rubber in proportions from 1 % to 10 % with no addition of compatibilizer agents. The gamma irradiation process was applied at 50 kGy and 100 kGy to both original and recycled blend samples. Characterization of samples was performed by X-ray diffraction and stress-strain assay. These results showed an increase of degree of crystallinity at recycled non-blended HDPE compared to this same parameter to pristine HDPE. It was also observed that crystallinity decreases as EPDM concentration increases. In irradiated samples, this parameter increase with high absorbed doses. The crystallite grain size increases in EPDM concentration from 1 % to 5 %; however, this parameter decreases in blends with 10 % of EPDM contents. This behavior suggests a co-crystallization effect on each polymeric component present in the blend and it may explain the miscibility and compability of both components in this material without addition of other agglutinative substances. The parameter stress at yield is high in pristine HDPE and low in recycled HDPE; this parameter decreases with as EPDM concentration increases in the non-irradiated polymeric blend. In irradiated blends the stress at yield increases in high doses. The irradiation process promotes blend crosslinking, and it is evident in blends with high EPDM concentration where high stress at 100 % strain is observed.Resumo IPEN-doc 23065 Obtention and characterization of gamma-irradiated recycled HDPE/EPDDM blends2017 - GERALDO, A.; MOURA, E.; GABRIEL, L.Elastomeric materials have specific properties that allow the development and use of a variety of products. The application of elastomeric compounds in the automotive industry has increased considerably; due this, high volume of parts are disposal and among these, thermosetting materials, that are not easily recyclable. High density polyethylene (HDPE) is a commodity material with a wide range of uses in the industry. What make this polymeric material so interesting to the market are its unique properties such as good conformability, high resistance to heat and chemicals, and a relative low cost. Another characteristic for this material is its good reprocessability, which is the ability of being recycled many times. Thus, the environmental impact of both materials is evident, thereby promoting essential damage. In the present work the HDPE matrix has been recycled four times from original substrate and mixed to EPDM rubber not vulcanized in proportions from 1% to 10%. The -irradiation process was applied at 50 kGy and 100 kGy in both original and recycled blend samples; in this way, mechanical properties and morphologic characteristics were evaluated. The results shown EPDM in quantities of 1% bring high tensile strength and yield strength to recycled non-irradiated blends compared to higher concentration of 10%, that present high impact resistance. Irradiation process applied to these samples carried an increase in these parameters and the recycled blends presented higher tensile strength values than pristine HDPE samples. Blends are homogeneous and presented no specific morphologic aspects that suggests HDPE and EPDM are miscible and compatible components; crystallinity is higher in low EPDM content blend and at a dose value of 50 kGy the crystallinity reached the maximum value of 79:5% compared to 72:2% for pristine HDPE. These results suggest irradiated blends formed by recycled HDPE with 1% of EPDM present high viability for industrial use due its high mechanical performance compared its low production cost.Dissertação IPEN-doc 22024 Preparação, irradiação e caracterização de blendas PEAD reciclado/EPDM2016 - GABRIEL, LEANDROA reciclagem de refugos é um processo estratégico que viabiliza a expansão do mercado de plásticos, podendo gerar novos produtos. A obtenção de blendas poliméricas é uma alternativa nesse processo, já que é conhecida a perda de propriedades mecânicas dos termoplásticos nas etapas de reprocessamento. Neste trabalho, o polietileno de alta densidade (PEAD) reciclado teve adições de borracha do monômero etileno-propileno-dieno (EPDM) puro em baixos teores (1 %, 5 % e 10 %), cujo objetivo foi formar blendas miscíveis e um produto final mais resistente ao impacto. O PEAD foi submetido a quatro ciclos de moagem, extrusão e injeção (reprocessamento) e misturado ao EPDM puro por extrusão sem o uso de qualquer aditivo. Os grânulos da blenda formada foram usados para confeccionar os corpos-de-prova por injeção para seu uso nas distintas metodologias analíticas. O processo de irradiação gama foi aplicado nas doses de 50 kGy e 100 kGy e os parâmetros físico-químicos e mecânicos dessas amostras foram comparados aos das não irradiadas. Tanto as blendas irradiadas como as não irradiadas mostraramse visualmente e microscopicamente homogêneas, indicando a compatibilidade da mistura, que também é verificada por seu comportamento térmico. Os parâmetros mecânicos provenientes dos ensaios de tração e flexão, foram semelhantes nas amostras do termoplástico virgem e do reciclado; o processo de irradiação nas blendas gerou sua reticulação, sendo esta verificada não só pelo aumento dos valores desses parâmetros como também pelo aumento da fração gel. A resistência ao impacto aumentou cerca de duas vezes e meia nas amostras com maior teor de EPDM e cerca de 6 a 7 vezes nestas mesmas amostras irradiadas a 50 kGy e 100 kGy respectivamente. O novo material obtido tem fortes indicativos para a sua utilização na pequena e média indústria de plástico, uma vez que já com 1 % de EPDM apresentam melhores características mecânicas em relação ao termoplástico reciclado quatro vezes e essas características foram incrementadas após o processo de irradiação gama.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, EDUARDOResumo IPEN-doc 20480 Blendas pead/epdm de matéria-prima reciclada: preparação, irradiação e caracterização2014 - GABRIEL, LEANDRO