SANTOS, T. T.; SANTOS, TIAGO T.; http://lattes.cnpq.br/7231093946602329; SANTOS, Tiago Tibério dos.
Resumo:
In this work, PBAT/organoclay nanocomposites with 2.5; 5,0 e 7,5% filler content
were prepared by two routes: (I) direct mixing in an internal mixer, operating at
180°C for 15 minutes at speeds of 60, 120 and 180 rpm, and (II) preparation of a
masterbatch (1:1 PBAT/organophilic clay) processed at 180°C, 120 rpm for 15
minutes followed by dilution with the matrix in a double screw corrotational
extruder to the desired concentrations. Nanocomposites PBAT/C20A organoclay
prepared by route (I), were analyzed by torque rheometry and the formulations
thus processed were ground, injected and characterized by X-ray Diffraction
(XRD), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and
parallel plate rheometry. PBAT/organoclay masterbatches containing three
different organophilic clays (C10A, C20A and C30B) were prepared by route (II).
The masterbatches were ground and extruded in co-rotational twin-screw
extruder and matrix diluted to the desired concentrations. The neat matrix was
processed under the same conditions. The systems obtained by this route were
characterized by XRD, DSC, TG, Dynamic-Mechanical Analysis (DMA),
Transmission Electron Microscopy (TEM) and Parallel Plate Rheometry. Results
show the processing condition in the internal mixer that led to nanocomposites
with higher degree of mixing and better thermal and rheological properties was
at 120 rpm and that, although both routes generated nanocomposites with
intercalated structures, route II led to structures with greater basal interplanar
distance and a slight increase in the degree of crystallinity. Nanocomposites
prepared by route II displayed a slight increase in thermal stability which
increased with clay content. The elastic modulus, obtained by DMA, varied with
clay concentration and was independent of the type of organophilic clay. The
glass transition temperature (Tg) is also independent of clay content and identity.