HELOISA AUGUSTO ZEN
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Resumo IPEN-doc 27675 Effect of molecular sieve incorporation into fluoroelastomer on the mechanical properties2020 - ZEN, H.A.; LUGAO, A.B.The nanoparticle incorporation improves mechanical and thermal properties, and also improve gas barrier property in a polymeric matrix. This incorporation can be facilitated by elastomer solubility, which permits a homogeneous distribution of the nancoparticle. In this work molecular sieve with 3A was incorporated into fluoroelastomer matrix at 0.5, 1, 2 and 5% weight. In a Banbury equipment was carried the nanoparticle and fluoroelastomer, in order to obtain nanocomposites. After that was performed the vulcanization process to obtain films with 0.5mm of thickness. The films were characterized by mechanical tests and swelling degree to determine the modification on mechanical properties of the fluoroelastomer matrix. The results showed an increase in the stiffness and in the tension at break values although the swelling values didn’t suffer drastic changes.Artigo IPEN-doc 24322 Effect of clay incorporation in the dimensional stability of FKM nanocomposite2017 - ZEN, HELOISA A.; LUGAO, ADEMAR B.In this work was studied the effect of nanoparticle incorporation in the dimensional stability of elastomer matrix. To avoid excessive swelling and consequently dimensional instability in the films, crosslinking has been shown to be an efficient and simple method for achieve the reducing membrane swelling and improving mechanical stability. The elastomer used was a fluorinated type, with 70% of fluor in its composition and commercial clay (Cloisite®) was the nanofiller used. The nancomposites with 0.5, 1 or 2% (wt%) of nanoclay were prepared in a open two roll mill. The fluoroelastomer was a type of Viton® (DuPont) which has low fuel permeation and suitable for use as sealant mainly for o-ring production. The incorporation of clay in the polymer matrix aimed to avoid excessive swelling and to maintain the material dimensional stability. The nanocomposites were characterized by stress–strain test to evaluated elongation and tension at break, by rheometry to analyzed maximum and minimum torques, and degree of swelling to follow dimensional size modification of nanocomposites films. There were a decreasing of the elongation at break and of degree of swelling values what can be correlated to an increase of crosslinking, and consequently formation of a networking in the nanocomposites matrix in the films evaluatedResumo IPEN-doc 23744 Effect of radiation on mechanical properties of FKM rubber before and after vulcanization2016 - ZEN, HELOISA A.; LUGAO, ADEMAR B.Artigo IPEN-doc 22625 Effect of clay incorporation in the dimensional stability of FKM nanocomposite2016 - ZEN, HELOISA A.; LUGAO, ADEMAR B.In this work was studied the effect of nanoparticle incorporation in the dimensional stability of elastomer matrix. The elastomer used was a fluorinated type, with 70% of fluor in its composition and commercial clay (Cloisite®) was the nanofiller used. The nancomposites with 0.5, 1 or 2% (wt%) of nanoclay were prepared in a open two roll mill. The fluoroelastomer was a type of Viton® (DuPont) which has low fuel permeation and suitable for use as sealant mainly for o-ring production. The incorporation of clay in the polymer matrix aimed to avoid excessive swelling and to maintain the material dimensional stability. The nanocomposites were characterized by stress–strain test to evaluated elongation and tension at break, by rheometry to analyzed maximum and minimum torques, and degree of swelling to follow dimensional size modification of nanocomposites films. There were a decreasing of the elongation at break and of degree of swelling values what can be correlated to an increase of crosslinking, and consequently formation of a networking in the nanocomposites matrix in the films evaluated.Artigo IPEN-doc 22009 Prevention of degradation of 'gamma'-irradiated EPDM using phenolic antioxidants2016 - ZAHARESCU, TRAIAN; ZEN, HELOISA A.; MARINESCU, MADALINA; SCAGLIUSI, SANDRA R.; CARDOSO, ELISABETH C.L.; LUGAO, ADEMAR B.Artigo IPEN-doc 21178 Efeito da incorporação de poss em elastômero2015 - ZEN, HELOISA A.; OLIVEIRA, JONATHAN P. de; LUGAO, ADEMAR B.Artigo IPEN-doc 21025 The effect of clay incorporation on the mechanical properties of fluoroelastomer2015 - ZEN, HELOISA A.; OLIVEIRA, JONATHAN P. de; LUGAO, ADEMAR B.Tese IPEN-doc 20774 Desenvolvimento de elastômeros fluorados multifuncionais baseados em nanocompósitos2015 - ZEN, HELOISA A.Os polímeros fluorados são conhecidos por suas ótimas propriedades mecânicas, pela alta estabilidade térmica e pela resistência a ambientes químicos agressivos, e por causa destas propriedades são muito utilizados em indústrias automobilística, petroquímica, de manufatura, dentre outras. Para aprimorar as propriedades térmicas e de barreira a gases da matriz polimérica, é muito utilizado a incorporação de nanopartículas nesta matriz, pois após a incorporação o nanocompósito permanece com suas próprias características e adquire novas propriedades devido a presença da nanopartícula. Devido as características dos fluoropolímeros, sua modificação estrutural e morfológica é muito difícil de ser obtida por técnicas tradicionais e para transpor essa dificuldade a radiação ionizante é uma técnica muito utilizada e eficaz para a alteração estrutural de polímeros fluorados. Neste trabalho foram desenvolvidos nanocompósitos poliméricos à base de fluoroelastômero (FKM) incorporado com quatro diferentes nanopartículas: argila Cloisite 15A, POSS 1159, POSS 1160 e POSS 1163. Após obtenção dos filmes de nanocompósitos foi realizado o processo de enxertia de estireno induzida por radiação ionizante, seguida de sulfonação para obtenção de membrana trocadora de íons. O efeito da incorporação de nanopartículas e da radiação ionizante nos filmes desenvolvidos foram caracterizados por difração de raios X, análise térmica, análise mecânica, microcospia eletrônica de varredura e intumescimento; enquanto que as membranas obtidas foram avaliadas quanto ao grau de enxertia, capacidade de troca iônica e intumescimento. Após a caracterização os filmes, foi verificado que a reticulação foi o efeito predominante nos nanocompósitos irradiados antes da vulcanização, enquanto que a degradação foi o efeito predominante nos nanocompósitos irradiados após a vulcanização.Resumo IPEN-doc 20593 Thermal resistance of EPDM/IIR systems under 'gamma'-irradiation2014 - SCAGLIUSI, SANDRA R.; ZAHARESCU, TRAIAN; ZEN, HELOISA A.; CARDOSO, ELIZABETH L.C.; JIPA, SILVIU; LUGAO, ADEMAR B.Resumo IPEN-doc 20592 Influence of antioxidant loading on the 'gamma'-exposure of ethylene-propylene terpolymer2014 - ZEN, HELOISA A.; ZAHARESCU, TRAIAN; MARINESCU, MARIANA M.; SCAGLIUSI, SANDRA R.; CARDOSO, ELIZABETH C.L.; LUGAO, ADEMAR B.