GEISE RIBEIRO
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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.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.Artigo IPEN-doc 15176 Post irradiation effects on the graft of poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA) films2009 - GERALDES, ADRIANA N.; ZEN, HELOISA A.; RIBEIRO, GEISE; FERREIRA, HENRIQUE P.; SOUZA, CAMILA P.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.Radiation induced grafting of monomers into fluorinated polymers was designed as an alternative route to polymer modification. In this work, grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) was studied. Radiation-induced grafting of styrene onto PFA films was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. The films of PFA were irradiated at 20, 40, 80 and 100 kGy doses at room temperature and chemical changes were monitored after contact with styrene for grafting. The post-irradiation time was established between 7 and 28 days when films of PFA were maintained in styrene/toluene 1:1 v/v solution at room temperature. After these periods the grafting degrees were evaluated in the samples. The highest degree of grafting was achieved after 14 days. Chemical modifications were evaluated by infrared spectroscopic analysis (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC) and also by scanning electron microscopy (SEM). The degree of grafting (DOG) was determined gravimetrically. The results showed that irradiated PFA films at 100 kGy exhibited higher grafting degree. Surface analysis by SEM technique of irradiated, grafted and original films have presented an homogeneous surface.