LARANJEIRA, E.; http://lattes.cnpq.br/3574545531102928; LARANJEIRA, Edilâne.
Abstract:
The present work deals with the properties of polyester/jute composites; of the
systems polyester/bentonite and polyester/jute/bentonite. The mechanical
performance (tensile and impact properties) of these composites was investigated
as a function of fiber content and orientation; clay content and chemical
modification and system composition. The influence of a flame retarding system
addition on the mechanical, thermal and burning characteristics of selected
composites was also analyzed. The water sorption characteristics of some of
these systems were determined. The clay was modifiied with hydrochloric acid
(0.3N) and with two different quaternary ammonium salts (Dodigen and
Cetremide). Both natural and modified clays were characterized by chemical
analysis, FTIR spectroscopy, X ray diffraction and thermogravimetry which
indicated that acid activation promoted exfoliation while quaternary ammonium salt
modifications promoted organophilization. The results show composite properties
to be strongly dependent on fiber orientation, being much higher in composites
tested along the jute fiber axis direction. Mechanical properties higher than those
of the matrix were achieved at fiber contents as low as 10% in weight. It was
shown that composite properties, mainly those of elongation at break and impact
strength, were dependent on clay modification. Better toughness was displayed by
polyester/bentonite and polyester/jute/bentonite systems with HCI and Dodigen
modified clays at 2% w/w clay contents. X ray diffraction data showed that a
polyester/bentonite nanocomposite was obtained with the cetremide modified clay
incorporation which led to an increase in flame resistance of the system. Only the
matrix and the composite Polyester/bentonite 5% w/w with the Cetremide modified
clay having 5, 6, 7,5% and 5% w/w bromine in the flame retardant system,
respectively, achieved V-0 classification on the UI-94V test. The system
polyester/5%bentonite natural and 5% w/w bromine in the flame retardant system
achieved V-1 classification. The remainder did not achieve classification. Water
sorption increased with jute fiber and with clay addition in the matrix.