Banca de DEFESA: CARLOS HENRIQUE RODRIGUES MILFONT

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CARLOS HENRIQUE RODRIGUES MILFONT
DATE: 28/11/2025
TIME: 14:00
LOCAL: Sala de aula LIME
TITLE:

Interaction between starches from different sources and optimization of the properties of thermoplastic starch

KEY WORDS:

starch, thermoplastic starch, casting, extrusion, optimization

PAGES: 163
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

This study aimed to evaluate the influence of the interaction between corn (Mi), cassava (Ma), and potato (Ba) starches on the development of thermoplastic starch (TPS), seeking to optimize its properties. Binary and ternary mixtures were prepared based on a simplex-centroid {3,2} experimental design, and the TPS materials were obtained using casting and extrusion techniques. The starch granules presented amylose contents of 29.52 ± 0.38% (Mi), 18.19 ± 0.68% (Ma), and 34.77 ± 0.29% (Ba) and viscosity-average molar masses (M̅v) of 1.34 × 10⁶ g·mol⁻¹, 2.93 × 10⁶ g·mol⁻¹, and 6.09 × 10⁵ g·mol⁻¹, respectively. Rheological results of aqueous starch solutions, obtained using a parallel-plate rheometer, indicated that maize starch presented the highest values of apparent viscosity and thixotropy, while the mixtures showed intermediate values of G' (storage modulus), G'' (loss modulus), and |η*| (complex viscosity) compared to the individual components. In the films produced by casting, the interaction among starches influenced both crystallinity and opacity, with higher values observed in formulations dominated by potato starch. Ternary mixtures with higher proportions of Mi and Ba exhibited lower water solubility indices. Thermal analysis revealed that formulations with higher cassava starch content displayed greater thermal stability. Mechanical tests of the films indicated synergistic effects in the mixtures, with increased tensile strength compared to the individual starches. In the extruded TPS samples, increasing the Ma content resulted in smoother and glossier surfaces, although more susceptible to moisture uptake. The thermal and mechanical properties of these materials exhibited intermediate values relative to the pure starches. Overall, the results demonstrated that amylose content, starch molar mass, and processing technique significantly influenced the interaction among the components. Response surface modeling enabled the identification of optimized compositions, highlighting the potential of starch blends for the development of biodegradable materials with tunable properties.

COMMITTEE MEMBERS:
Presidente - 1639676 - EDSON NORIYUKI ITO
Interna - 1755267 - MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
Externo à Instituição - ADRIANO LINCOLN ALBUQUERQUE MATTOS - EMBRAPA
Externa à Instituição - JUCIKLÉCIA DA SILVA REINALDO - UEA
Externo à Instituição - MEN DE SÁ MOREIRA DE SOUZA FILHO - EMBRAPA