Manufacturing of Epoxy Composites Incorporated with Buriti Fibers and Evaluation of Thermogravimetric Behavior

The thermal resistance of natural fibers is a relevant property for technical application associated with relatively high temperature levels. In polymer composites manufacturated with natural fibers the resistance to thermal degradation may become a critical factor not only with respect to processing temperature but also in-service heating operational conditions. In the present work, epoxy composites incorporated with up to 30 vol% of fibers extracted from the petiole of the buriti palm tree were manufactured and evaluated by thermogravimetric analysis, by means of the TG, and its derivative, DTG, curves from room temperature to 700°C. The results showed thermal resistances above 200°C for both the isolated buriti fibers and its manufactured composites.

Preparation of Hydroxylated Carbon Nanotubes/Magnetic Iron Oxide Compound Particles

In this paper, hydroxylated CNTs/Fe2O3 precursors were prepared on the basis of Fenton reagent treatment using aqueous ammonia (NH3H2O), sodium carbonate (Na2CO3) and urea (CO(NH2)2) as precipitants. And then three kinds of hydroxylated CNTs/Fe2O3 compound particles were obtained by calcining the precursors at 523K for 2h. The change of hydroxyl group, phase structure, morphology, thermogravimetric behavior, magnetic property and electrical conductivity of the compound particles were investigated, respectively. The results show that hydroxyl groups exist on surface of CNTs, and Fe2O3 particles in composite particles exhibit high purity and integrated crystalline structure. For NH3H2O precipitant, α-Fe2O3 particles is produced with crystallite size of 62.5nm and no saturation magnetization (Ms). For Na2CO3 precipitant, γ-Fe2O3 is produced with crystallite size of 37.6nm and Ms of 10.5emug-1, and the compound particles are drastically agglomerated. For CO(NH2)2 precipitant, γ-Fe2O3 is produced with crystallite size of 35.1nm and Ms is 9.7 emug-1, and the compound particles are homogeneous with the lowest volume resistivity of 100 Ωcm.

Influence of Zeolite NaA on Thermogravimetric Behavior of Sodium Alginate for the Purpose of Processing Plastic Wastes

Thermogravimetric behavior of sodium alginate with incorporation of zeolite 4A has been studied. The experiments were performed at air flow rate of 30 ml/min, under heating rates of 5 ~ 30 K/min and up to 1250 K. Kinetic parameters for the main degradation phase thus were estimated by using the pseudo first-order assumption. The results have shown that the introduced zeolite as well as its content has obviously affected thermal properties of sodium alginate.