GEISE RIBEIRO
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Resumo IPEN-doc 13463 Styrene grafted onto polypropylene and polytetrafluoroethylene films2008 - FERREIRA, H.P.; SOUZA, C.P. de; ZEN, H.A.; GERALDES, A.N.; RIBEIRO, G.; PARRA, D.F.; LUGAO, A.B.The objective of this work is to present results of radiation-induced grafting polymerization of styrene onto polypropylene (PP) films with 0.04 mm thickness and polytetrafluoroethylene (PTFE) films with 0.2 mm thickness. Both films were processed in the same method. The films were placed in a glass tube in contact with styrene monomer/toluene (1:1, v/v) solution and nitrogen was bubbled to guarantee inert atmosphere. The films were irradiated at 20, 40, 80 and 100 kGy doses at room temperature in cobalt–60 source. After irradiation process the samples were kept in the solution and at room temperature to 7, 14, 21 and 28 days in order to evaluate the grafting behavior. Another aspect studied was the effect of radiation dose on the grafting yield. The samples were characterized by Thermogravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC) and Infrared Spectroscopy (FTIR). The degree of grafting (DOG) was calculated gravimetrically. The DOG results revealed that after 21 days at 100 kGy is achieved the higher grafting in the films (table 1). By TG is verified that PTFE grafted exhibit two steps of degradation and the PP grafted only one step of degradation.Resumo IPEN-doc 16635 Small ange X-ray scattering of polystyrene grafted and sulfonated poly(ethylene-co-tetrafluoroethylene) membranes2010 - RIBEIRO, GEISE; ZEN, HELOISA A.; GERALDES, ADRIANA N.; PARRA, DUCLERC F.; WESTFAHL JUNIOR, HARRY; LUGAO, ADEMAR B.Resumo IPEN-doc 16174 Effect of radiation induced crosslinking and degradation of ETFE films2010 - ZEN, HELOISA A.; RIBEIRO, GEISE; GERALDES, ADRIANA N.; SOUZA, CAMILA P.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.Resumo IPEN-doc 16208 Solvent effect on post-irradiation grafting of styrene onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) films2010 - GERALDES, ADRIANA N.; ZEN, HELOISA A.; RIBEIRO, GEISE; SOUZA, CAMILA P.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.Resumo IPEN-doc 13572 Polypropylene films grafted with styrene using PCBTF as solvent2008 - RIBEIRO, G.; ZEN, H.A.; GERALDES, A.N.; FERREIRA, H.P.; SOUZA, C.P. de; PARRA, D.F.; LUGAO, ADEMAR B.In this study, radiation-induced grafting of styrene (S) onto polypropylene (PP) 0.1 µm thickness was investigated with respect to: the effect of irradiation dose (40 and 80 kGy); reaction time of post simultaneous irradiation process (7 and 15 days) and using 4- chlorobenzotrifluoride (PCBTF) as solvent. PCBTF is potentially useful for organic and fluorous synthesis. Despite these favorable characteristics, PCBTF is unknown as solvent for polymer modification using radiation. The ratio of monomer:solvent, S:PCBTF, used was 4:1 (v/v). The degree of grafting (DOG) was obtained gravimetrically by measuring the weight of the film before and after the radiation-induced grafting at pos simultaneous irradiation using the following equation: DOG (%) = [(Wg - Wo)/Wo] x 100 Where Wg and Wo are the weights of the grafted and original PP film, respectively. The behavior of styrene grafting was found to be very similar for both reaction times. However, the DOG obtained at 80 kGy was higher than 40 kGy. This result can be attributed to the fact that the increase in the radiation dose leads to generation of more radicals in the grafting system, consequently, more radicals contribute to the grafting reaction, table 1. The thermogravimetric (TGA) curves for grafted PP films showed that the mass loss begins at low temperatures (25°C) reaching the total of ~100% mass loss at about 600 °C. Two stages can be considered. The first ranges from 25 to about 100 °C that corresponds at about 1% weight loss assigned to water molecules. The second stage, 350 – 500 °C, gives about 98% weight loss, corresponding to PP grafted decomposition. The DSC thermogram of original PP shows a strong transition (endothermic peak) at 162 °C which corresponds to the melting temperature (Tm).The incorporation of styrene onto PP film does not change significantly Tm value, for example, the modified film with 80 kGy after 15 days of reaction shows Tm in 163 °C. By means of the FT-IR it was observed that the monomer was grafted into the PP film.Resumo IPEN-doc 13494 The effect of different solvents in the grafting of styrene into ETFE films via gamma radiation2008 - GERALDES, ADRIANA N.; ZEN, HELOISA A.; RIBEIRO, GEISE; FERREIRA, HENRIQUE P.; PARRA, DUCLERC F.; ETT, GERHARD; LUGAO, ADEMAR B.Resumo IPEN-doc 13492 Radiation grafting of styrene/divinylbenzene onto PP film2008 - RIBEIRO, GEISE; ZEN, HELOISA A.; GERALDES, ADRIANA N.; FERREIRA, HENRIQUE P.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.Resumo IPEN-doc 13491 Polypropylene films modified by radiation induced graft polymerization2008 - ZEN, HELOISA A.; GERALDES, ADRIANA N.; RIBEIRO, GEISE; FERREIRA, HENRIQUE P.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.Artigo IPEN-doc 15205 The effect of peroxidation method on polypropylene film using gamma radiation2009 - ZEN, HELOISA A.; RIBEIRO, GEISE; GERALDES, ADRIANA N.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.Artigo IPEN-doc 14220 Desenvolvimento de membranas para celula a combustivel por enxertia de estireno via radiacao em filmes de ETFE2009 - GERALDES, ADRIANA N.; ZEN, HELOISA A.; RIBEIRO, GEISE; SOUZA, CAMILA P.; FERREIRA, HENRIQUE P.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.