In this work, composite materials of polyester matrix reinforced by short sisal
fiber, by residue of wood and by hybrid system for sisal / residue of wood, arranged
randomly, were produced using the minimum stages of technology processing in the
productive step, with views to produce a composite material easy technically to
produce. The polyester matrix used was a pre-accelerated tereftálica with cobalt
naftenato and cured at room temperature with methyl ethyl ketone peroxide (MEK) in
different proportions in relation to the resin, 0.33%, 1.66%, 3.33% and 5.00% by
volume in order to evaluate the influence on mechanical properties. The sisal fibers
were manually cut in lengths of 5, 10 and 15 mm and used in the way purchased and
surface untreated. The residue of wood powder was used of maçaranduba wood.
The composites were produced by manual moulding, without pressure and room
temperature. Specimen were manufactured for evaluated matrix, composites
reinforced by sisal, ranging of the length of the fibres, composites reinforced by
maçaranduba residue and strengthening of hybrid composites, sisal / wood residue,
in different proportions of the constituents. Mechanical properties were evaluated by
tests of traction and Charpy impact and the areas of fracture generated were
evaluated by scanning electron microscopy in order to correlate aspects of fracture
with the mechanical properties. It was determined the specific mass of each series of
specimen of each manufactured, and the volume fraction of the composite material.
The results showed that the increase in the length of the sisal fiber, tensile strength
and impact of composites has been increased, reaching the composite of sisal fibre,
15 mm, the best performance with the specimen series tested. The heterogeneity of
size maçaranduba residue was negative effect on the mechanical properties of
composites. The hybrid composites materials sisal / wood residue with higher content
of fibers elevated in 80% of the mechanical properties obtained for the composite
material reinforced only by sisal fiber.
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