Polymer composites with the addition of natural fibers have gained prominence as
a sustainable and technically viable alternative to conventional synthetic
materials, especially in applications that require a balance between mechanical
performance and environmental responsibility. This study evaluated the
mechanical behavior of composites produced with plant fibers from banana
(Musa sapientum) and sugarcane (Saccharum
officinarum L.), both sourced from the northern region of Brazil.
The fibers, used in their natural state without chemical treatment, were cut to
a uniform length of 5 mm for standardization. The polymer matrix used was
unsaturated terephthalic polyester resin, pre-accelerated and catalyzed with
methyl ethyl ketone peroxide (MEKP). The molding of test samples was performed
manually in silicone molds, according to ASTM D638 specifications, to ensure
repeatability and comparability of results. The mechanical tests revealed that
the composites made with sugarcane fibers had an average tensile strength of
17.05 (±1.41) MPa, while those with banana fibers reached 28.85 (±0.94) MPa,
compared to 26.94 (±4.60) MPa for the pure polymer matrix. These values indicate
that the addition of sugarcane fibers resulted in an approximate 36.7% reduction
in tensile strength, whereas the use of banana fibers led to an increase of
about 7.1% in this property. The results demonstrate the potential of natural
fibers added to polymer composites, especially banana fibers, which acted as
reinforcement of the matrix, proving to be a technically efficient and
environmentally promising alternative for applications in engineering
materials.