Authors:M. Fook, A. Souza, M. Trindade, M. Conceiçăo, J. Santos, S. Prasad, V. Fernandes, and S. Crispim
The high-density polyethylene, thermoplastic widely-used in the production of industrial domestic utilities, was collected
in two situations: virgin high-density polyethylene (JV 060) and post-consumption high-density polyethylene (with features
of low-density polyethylene). After collecting the samples, they were submitted to natural aging with the quantification of
the incident solar radiation for 180 days. The samples were characterized by melt flow index, differential scanning calorimetry,
tensile strength, rupture load, elongation at break and infrared. The results showed that after 180 days of exposure the virgin
high-density polyethylene presented physical properties similar to the post-consumption polyethylene.
Authors:M. Bernardi, S. Crispim, A. Maciel, A. Souza, M. Conceiçăo, E. Leite, and E. Longo
The synthesis and the characterization of Al2O3-based nanocrystalline inorganic pigments are reported. The pigments were synthesized by the polymeric precursor (Pechini
method) using Cr2O3 as chromophore. XRD results only evidenced the corundum phase. The average particle size was about 34 nm. The samples were
also characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG), and CIE-L*a*b* calorimetry. The pigments
obtained in this work presented different colors, ranging from green to rose.
Authors:C. Xavier, C. Costa, S. Crispim, M. Bernardi, M. Maurera, M. Conceiçăo, E. Longo, and A. Souza
The pigments used in ceramic applications are of nature predominantly inorganic and they should be thermally stable, insoluble
in glazing, resistant to the chemical and physical agents' attacks. This work aimed at the synthesis by the polymeric precursor
method of ZrO2-based inorganic pigments, doped with Fe, Ni, Co, Cr and Cu cations. The fired pigments were characterized by thermogravimetry
(TG), differential thermal analysis (DTA) and X-ray diffraction (XRD). Among the metals used to zirconium-doping, the best
result was achieved with the cations Cu, which presented the monophase pigment, even as 20 mol% of dopant. Up to the temperature
of 1000C the pigments presented a good thermal stability.