BARBOSA, R.; http://lattes.cnpq.br/4917843873626040; BARBOSA, Renata.
Résumé:
High density polyethylene (HDPE)/Bentonite clay nanocomposites were prepared
by the melt intercalation technique. The clay was organically modified with different
quaternary salts of ammonium to obtain the organoclay. Chemical analysis, X-ray
fluorescence (XRF), infrared spectroscopy by Fourier Transform (FTIR), X-ray diffraction
(XRD), thermogravimetry (TG) and scanning electron microscopy (SEM) were used to
characterize the clays. The unmodified and modified clays with the quaternary salts of
ammonium were introduced in several quantities in a HDPE matrix using a twin screw
extruder. The thermal stability and the flammability of the systems were investigated by
thermogravimetry and UL-94HB standard, respectively. The dispersion analysis and the
interlayer distance (dooi) of the clay particles were obtained by XRD and transmission
electron microscopy (TEM). Mechanical properties of tensile and impact of the
nanocomposites were studied too. The results showed that the salts were incorporated in the
clay structure, confirming the organophilization. The organoclay presence in the polymer
matrix increased the systems degradation temperature in relation to the pure polymer. In
general, the mechanical properties of the systems presented superior values compared to the
matrix and the modified clay type affected the properties. The systems showed a reduction
on the burning rate, indicating that the flammability resistance of nanocomposites was
improved. For comparison, two types of commercial flame retardants were used in HDPE
to evaluate the flammability and they showed that the HDPE/organoclay system was more
efficient.