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Hydrophobic bio-composites of stearic acid starch esters and micro fibrillated cellulose processed by extrusion

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Autor(es):
Lozano, Karen Paola Contreras ; Mendes, Juliana Farinassi ; Ferreira, Laura Fonseca ; Martins, Maria Alice ; Mendoza, Jairo Salcedo ; Mendes, Rafael Farinassi
Número total de Autores: 6
Tipo de documento: Artigo Científico
Fonte: INDUSTRIAL CROPS AND PRODUCTS; v. 221, p. 13-pg., 2024-08-07.
Resumo

Fatty acid starch esters are potential candidates for obtaining hydrophobic starch-based materials. The objective was to evaluate thermoplastic bio-composites with stearic acid cassava starch esters (SAE) as matrices reinforced with micro fibrillated cellulose (MFC). SAE with 0.11 and 0.14 of DS and native cassava starch were processed with 5% and 10% MFC by extrusion and then thermo-compression to obtain bio-composite films. Performance of bio-composites as a function of the degree of substitution (DS) of starch esters and the content of MFC, was evaluated. Starch esterification reduced the crystalline phase and glass transition temperature of bio-composites, as confirmed by structural and thermal analysis. The increase of DS reduced the degradation temperature, which was compensated by adding MFC, favoring thermal stability. The hydrophobicity of films increased with the degree of starch esterification. Treatments with 0.14 DS formed stiffer and less tensile strength films. There was an increase in the modulus of elasticity and a reduction in elongation by increasing MFC. Fracture microscopy of films showed defects by incomplete starch melting and lack of interfacial adhesion with MFC caused by starch esterification. Starch esterification and MFC dispersion were determinants in the performance of bio-composites. In consequence, starch esterification with stearic acid reduces the compatibility with the MFC and, consequently, the performance of composites. (AU)

Processo FAPESP: 19/26622-4 - Desenvolvimento de curativos nanoestruturados contendo agentes antimicrobianos visando aplicações de engenharia de tecido em bovinos
Beneficiário:Juliana Farinassi Mendes
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado