LEITE, A. M. D.; http://lattes.cnpq.br/3077817092155432; LEITE, Amanda Melissa Damião.
Abstract:
Asymmetric microporous membranes were prepared by precipitation immersion
technique, from polyamide 6 nanocomposites with national clays. The clay was
used as non-treated (MMT) and treated (OMMT) with ammonium quaternary
salts. To confirm the presence of the salt groups of chemicals in the clay, it was
done the test with X-ray diffraction (XDR) and X-ray fluorescence (XRF). After, it
was prepared a master of PA 6/clay in the proportion of 1:1 and added to a
polyamide 6 matrix in a counter-rotating twin-screw extruder, with clay content
of 3 and 5% in weight. The nanocomposites were characterized by XRD,
thermogravimetric analysis (TG) and differential scanning calorimetry (DSC).
From the results of XRD it was observed a morphological structure with
lamellae of clay exfoliated/partially exfoliated in the PA 6 matrix. Also the
nanocomposite presented thermal stability and in general the presence of clay
does not cause significant change in the crystallinity of polyamide 6. The
membranes were prepared by phase inversion technique, changing the
synthesis conditions and it was characterized by XRD, DSC and scanning
electron microscopy (SEM). The XRD patterns from the membranes show
indicated a structure that is in accordance with the results obtained to
nanocomposites. From DSC it was observed that there was no significant
change in the crystallinity with the presence of clay. Also it was observed from
DSC and from DRX the presence of two crystalline phases of PA 6 for all
compositions. From SEM it was showed an asymmetric morphology, consisting
of skin film and a porous layer for all membranes. The content of polymer
solution, presence of clay and the use of successive exchanges of non-solvent
cause changes in the morphology of the membranes and in the pore formation.
From wetting test and mercury porosimetry it was observed that the presence of
clay changes the wetting and significantly reduced the average pore diameter of
the membranes.