Nucleation and growth mechanism of iron oxide nanoparticles on zeolite template and their stability dependence are reported. Hyperfine field resulting from the variation of particle size indicates the effect of zeolite on particles growth; particle size decreases at lower concentration of zeolite. At higher concentration, a fraction of nano Fe3O4 experiences hyperfine field (45 and 49 T) similar to bulk particles. Effect of incubation and digestion time on the particles growth and the binding effect with zeolite are discussed. Annealing treatments show that the binding of nanoparticles with zeolite stabilizes the nanoparticles with regard to agglomeration and structural transformation. Thermogravimetry-differential thermal analysis (TG-DTA) shows that increase in dehydration temperature from 335.1 to 351.7 K results in zeolite content increasing from 0 to 1000 mg. Weight loss of the particles prepared in incubation time of 0.5 min is 9.46% and reaches 13.9% in 240 min. The weight loss remains practically constant at ca. 9% irrespective of the digestion method.

Poly(o-methoxyaniline) (POMA) was synthesized by oxidative polymerization of the monomer o-methoxyaniline. POMA/poly(methyl methacrylate) (PMMA) blends were produced by dissolving both polymers in chloroform (CHCl3).The amount of camphor sulfonic acid (CSA) used as dopant of POMA was different, providing two methods for preparation of the blends. Solutions were analyzed by Fourier transform infrared spectroscopy (FTIR) and then deposited on glass substrate by spin coating for characterization by atomic force microscope (AFM) and current versus voltage (I × V) curves. FTIR spectra of solutions were similar as expected. In the AFM images a reduction and/or loss of globules common in conducting polymers (CP) such as polyaniline (PANI) and its derivatives was observed. Films produced with different amounts of CSA presented distinct, linear and non-linear I × V curves.

Poliestireno (PS) é um dos materiais descartáveis mais usados no nosso cotidiano, mas ele não se decompõe facilmente. A adição de amido de mandioca ao PS pode melhorar a sua degradabilidade, tendo em vista ser o amido um polímero biodegradável. O objetivo deste trabalho foi desenvolver blendas de PS e (amido termoplástico) TPS usando dois diferentes plastificantes: glicerol e óleo de buriti, sendo esse óleo um plastificante natural e original para o amido. As blendas PS/TPS foram preparadas em diversas composições por casting e em seguida caracterizadas por termogravimetria (TG), calorimetria exploratória diferencial (DSC), análise termomecânica (TMA) e ressonância magnética nuclear (RMN) 13C. As blendas PS/TPS com óleo de buriti apresentaram uma contínua redução em suas Tg e Ta. Nas blendas com glicerol esses parâmetros permaneceram praticamente constantes. As blendas também foram submetidas a testes de degradação no solo e depois analisadas por TG e RMN. A análise das blendas PS/TPS com óleo de buriti mostrou que houve um aumento da perda de massa nas curvas TG. Nos espectros de RMN 13C, todos os picos referentes ao amido desapareceram, depois do teste de aterro, sugerindo que houve consumo do amido das blendas por microorganismos. De acordo com as análises realizadas, a adição do TPS produzido com óleo de buriti pode melhorar a degradabilidade do PS.

Polystyrene (PS) is one of the most used disposable materials in our daily life, but it does not decompose easily. The addition of cassava starch to PS can improve its degradability since starch is a biodegradable polymer. The aim of this work was to develop blends of PS and thermoplastic starch (TPS) using two different plasticizers: buriti glycerol and buriti oil, a novel and natural plasticizer for starch. PS/TPS blends were prepared in various contents with the casting technique and analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and 13C nuclear magnetic resonance (NMR). PS/TPS blends with buriti oil presented a continuous reduction in Tg and Ta. For blends with glycerol these parameters remained practically constant. PS/TPS blends were submitted to degradation by soil burial testing and then analyzed by TG and 13C NMR. The analysis of PS/TPS blends with buriti oil indicated an increase in weight loss in the TG curves. All NMR peaks associated with starch disappeared after the soil burying test, probably due to the consumption of starch by microorganisms. The results showed that addition of TPS produced with buriti oil to PS can probably improve its degradability.