LUIS FILIPE CARVALHO PEDROSO DE LIMA
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Resumo IPEN-doc 24340 Glass transition temperature determination on cross-linked polyethylene by dynamic mechanical analysis2001 - SEGURA PINO, E.; LIMA, L.F.C.P.The Glass Transition Temperature, Tg, was determined on electron beam cross-linked low- density polyethylene, using the dynamic mechanical analysis technique. The measurements were carried out over a temperature range of -170 to -100 deg.C, at frequencies of 0.5, 1.0, 2.0, 5.0 and 10.0 Hz and at an average heating rate of 1.83 deg. C/min. The radiation dose was 50, 100, 150, 200, 300 and 400kGy that corresponded to about a cross-linking degree from 20 to 80%. The experimental results have shown that Tg changed about 10 degrees as a function of frequency but for each frequency the value of Tg remained constant as a function of the irradiation dose. At the fixed frequency of 1.0 Hz Tg had a value of-139.4±0.1 deg. C and the activation energy was 51.2±0.7kJ.mol-1. These experimental results have shown that the presence of a three-dimensional interconnected structures and increase in molecular weight, due to the cross-linking effect, had not affected the Tg value at each frequency. It was expected that these molecular modifications could hinder, in some way, the molecular rotational motion, changing this Tg value.Capítulo IPEN-doc 23237 Contribution to the β relaxation study of the HDPE, LDPE and LLDPE2017 - OLIANI, WASHINGTON L.; PARRA, DUCLERC F.; LIMA, LUIS F.C.P.; OTAGURO, HARUMI; FERRETO, HELIO F.R.; LUGAO, ADEMAR B.The activation of three polyethylenes, the low density, the high density and the linear low density polyethylene, was determined by means of dynamic mechanical analysis (DMA). Storage modulus and tan δ spectra were obtained as a function of the temperature from −60 to 50 °C with a heating rate of 2° min−1 at frequencies of 1, 2 and 5 Hz and measurement strain amplitude of 10−5. In the tan δ spectra, a small peak in the β region of the three polyethylenes was found and substantiated by subtracting the growing exponential background. This procedure was based on a model that associates the dislocation motion on metals under cyclic stress to vibrating strings and considering the same for the polymeric chains. For the determination of the activation energy we have utilized the frequency versus the reciprocal of the absolute temperature peak of the tan δ. The values obtained for the three polyethylenes, the low density, the high density and the linear low density were, 362 ± 12, 266 ± 9 and 197 ± 6 kJ mol−1, respectively, which were compared with those presented in the literature.Artigo IPEN-doc 16354 Effects of accelerated thermal aging on polypropylene modified by irradiation process2015 - OLIANI, WASHINGTON L.; FERMINO, DANILO M.; LIMA, LUIS F.C.P. de; LUGAO, ADEMAR B.; PARRA, DUCLERC F.Artigo IPEN-doc 21248 Development of a nanocomposite of polypropylene with biocide action from silver nanoparticles2015 - OLIANI, WASHINGTON L.; PARRA, DUCLERC F.; LIMA, LUIS F.C.P.; LINCOPAN, NILTON; LUGAO, ADEMAR B.Artigo IPEN-doc 20835 AgNPs polypropylene gel films-thermal study and antibacterial activity2015 - OLIANI, WASHINGTON L.; LIMA, LUIS F.C.P. de; ROGERO, SIZUE O.; RIELLA, HUMBERTO G.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.Artigo IPEN-doc 20523 Filme de polipropileno com nanoargila e nanopartículas de prata visando à ação biocida2014 - OLIANI, W.L.; FERMINO, D.M.; DIAZ, F.R.V.; LIMA, L.F.C.P.; LINCOPAN, N.; SANTOS, P.M. dos; LUGAO, A.B.; PARRA, D.F.Artigo IPEN-doc 20445 Bidodegradability and mechanical properties of sugarcane bagasse filled PP/HMSPP structural foams biocomposites treated with gamma-irradiation2013 - CARDOSO, ELISABETH C.L.; SCAGLIUSI, SANDRA R.; LIMA, LUIS F.C.P.; BUENO, NELSON R.; PARRA, D.F.; LUGAO, ADEMAR B.Capítulo IPEN-doc 04120 Preparation and characterization of stainless steel filters1992 - AMBROZIO FILHO, F.; LIMA, L.F.C.P.; MOURISCO, A.J.; BARBOSA, L.P.; POLA, E.J.G.; NEVES, M.D.M.Capítulo IPEN-doc 05541 Utilizacao de tecnicas de atrito interno no estudo de gases em metais1994 - LIMA, L.F.C.P.Resumo IPEN-doc 17347 Polypropylene nanogel 'Myth or Reality'2011 - OLIANI, W.L.; PARRA, D.F.; RIELLA, H.G.; LIMA, L.F.C.P.; LUGAO, A.B.