Preparation and characterization of biodegradable composites based on Brazilian cassava starch, corn starch and green coconut fibers

Abstract

Increasing search for new materials with high premium on eco-friendliness, new trend is emerging in materials development such as composites, which are well established for a wide variety of applications. With growing interest and importance of renewable bioresources has led to more stress on the use of locally available materials. This paper presents preliminary results on the preparation and characterization of composites based on Brazilian coconut fibers and starches of cassava and corn. The raw materials were characterized for their morphology, chemical composition, and thermal properties and X-ray diffraction studies. Coir fibers were also tested for their tensile properties showing increasing strength and Young`s modulus with decreasing diameter, while the % elongation remaining constant. Lignin content of coir was found to be 35%. Structure and properties of composites containing 0, 5 10, 15% fibers in both the matrices and prepared by compression molding would be compared. For the 2 types of starch, there was an increase in the tensile strength by the increasing proportion of fiber. The effect of moisture in the composite stress affects the strength and percentage elongation. The water absorption was higher in the composites made from cassava starch.

Cassava: Its polymer, fiber, composite, and application

“…Foam obtained from a mixture of cassava starch and 4% chitosan and 30% kraft fiber had elongation of starch of 2.43% and tensile strength of 944.4 kPa that was similar to that obtained for polystyrene foam. The foam obtained was quite similar in properties to polystyrene foam but the water solubility index (WSI) and water absorption index (WAI) were found to be in increased amount as compared to their value in polystyrene foam . Another study conducted by Teixeira et al used cassava starch and cassava bagasse to develop fiber‐reinforced thermoplastic starch (TPSB and TPSI, respectively).…”

“…The strength of cassava PVA showed the same trend as in water absorption with an increase of about 70 wt% on increase on fiber loading . Table bellow reported the work of cassava based composite .…”

“…The study conducted by Kaisangsri al. used cassava starch incorporated with natural polymers of chitosan and kraft fiber to obtain biodegradable foam trays. The starch/ fiber and chitosan mixture was made in the ratio of 1 : 1 and chitosan solution at 0, 2, 4, and 6% (w/v) were used.…”

Influência de ciclos molhagem-secagem em fibras de sisal sobre a aderência com matrizes de cimento Portland

“…Ensaio de arrancamento: a) configuração; b) detalhe do sistema de fixação do amostra; c) detalhe da fibra presa à garra A partir da carga de arrancamento P, obtida experimentalmente, é possível calcular a tensão de aderência média entre a fibra e a matriz utilizando a equação (2): (2) onde l é o comprimento de embebimento da fibra e r é o raio da fibra calculado através de imagem obtida por microscopia eletrônica de varredura. …”

“…Na linha de desenvolvimento de materiais reforçados com fibras vegetais, muitas pesquisas vêm sendo desenvolvidas sobre compósitos de matriz cimentícia ou matriz polimérica e resultados promissores têm sido alcançados, mostrando uma melhoria da durabilidade, resistência e ductilidade [1][2][3]. A opção pelo uso de fibras vegetais como reforço mostra-se benéfica sob vários aspectos, incluindo o da sustentabilidade, uma vez que elas são biodegradáveis e demandam pequena quantidade de energia, quando comparadas com as fibras poliméricas.…”