HANKEN, R. B. L.; http://lattes.cnpq.br/4979828962131919; HANKEN, Ruth Barreto Leite.
Resumo:
Polymers derived from oil have caused environmental impact due to its
inappropriate disposal. An alternative is the use of biopolymers like
biopolyethylene (bioPE). Polymer/clay nanocomposites have attracted great
interest of researchers around the world since they present good thermal and
barrier properties, flame retardance, strength and high modulus. In this work
BioPE/vermiculite organophilic clay bionanocomposites were developed using
the melt intercalation method. The effect of the vermiculite clay content on the
mechanical and rheological properties was evaluated. The amount of the
surfactant used to organically modify the vermiculite clay was based on the
Cation Exchange Capacity (CEC) of the clay. The bionanocomposites were
prepared by extrusion followed by injection molding. The vermiculite clay was
characterized by X-Ray Diffraction (XRD), Infrared Spectroscopy (FTIR), X-Ray
Fluorescence (XRF), and particle size anatyses by laser diffraction (AG) while
the bionanocomposites were characterized by XRD, FTIR, Scanning Electron
Microscopy (SEM), thermal and mechanical properties melt flow índex (MFI)
and rheological measurements under low and high shear rates, and oscillatory
shear flow. XRD and FTIR results showed that the surfactant was incorporated
to the vermiculite structure confirming its organophilization. XRF result indicated
a possible substitution of vermiculite exchangeable cátions with the ions present
in the surfactant. The AG analysis evidenced that the organophilization process
led to a decrease in the particles average size and doubled the clay fraction
below 2\im. The increase in the organophilic vermiculite clay content favored
the increase in the modulus and the decrease in the MFI, impact strength, and
hardness, while the tensile strength remained almost unchanged. The
rheological measurements indicated that the viscosity increased with the clay
content. This variation was observed at low frequencies, where the storage
modulus was higher when compared to pure BHDPE for ali compositions
studied. For the rheological measurements at higher frequencies, the viscosity
decreased with the increase in the clay content.