Banca de DEFESA: TALITA ANGELICA DOS SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : TALITA ANGELICA DOS SANTOS
DATA : 11/12/2020
HORA: 14:00
LOCAL: “por participação remota”
TÍTULO:

BIOCOMPOSITES OF THERMOPLASTIC STARCH REINFORCED WITH BACTERIAL CELLULOSE

PÁGINAS: 180
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Polímeros, Aplicações
RESUMO:

Partial replacement of conventional polymers in applications with a short life span with biodegradable polymers is advantageous due to their shorter degradation period. Among biodegradable polymers, starch stands out due to its low cost and abundance, and bacterial cellulose (CB) due to its high crystallinity and high tensile strength values. Starch consists of the polysaccharides amylose and amylopectin, and can be transformed into thermoplastic starch (TPS) which has properties similar to thermoplastics. In this work, samples of native starch from potatoes and corn, were transformed into TPS by extrusion and compression molding using different levels of glycerol, water and citric acid as a plasticizer. Starch, CB and TPS were characterized by thermal, morphological and mechanical analysis. Biocomposites were obtained in the “sandwich” panel format using TPS films as a matrix and CB films as a dispersed phase by means of compression molding and were characterized. Finally, CB, TPS and the biocomposite that showed better mechanical properties were subjected to biodegradation tests due to loss of mass, release of carbon dioxide (CO₂), hygrothermal aging and environmental degradation. The results indicated that TPS from corn with 20 % by weight (w/w) of glycerol, 20 % (w/w) of water and 0.6 % (w/w) of citric acid showed the best mechanical properties ( Maximum stress = 5.22 MPa). The biocomposite using corn TPS (20 % water and 20 % glycerol) and water as a coupling agent showed the best mechanical properties (Maximum stress = 13.87 MPa). The mass loss biodegradation test for this biocomposite showed that 90% of its degradation occurred in 70 days and the CO₂ release tests showed that complete degradation occurred in periods greater than 120 days ago. Hygrothermal aging showed that TPS dissolves in water in 26 days and that CB only absorbs water for a period of 126 days. After 326 days of aging test in the environment, the materials did not present visual degradation, which indicates that they can be used in this period. The suggested application of the biocomposite in the area of disposable packaging for hygiene products and dry foods.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1763443 - MARCIA APARECIDA DA SILVA SPINACE
Membro Titular - Examinador(a) Interno ao Programa - 1761120 - DANILO JUSTINO CARASTAN
Membro Titular - Examinador(a) Externo ao Programa - 2347767 - MATHILDE JULIENNE GISELE CHAMPEAU FERREIRA
Membro Titular - Examinador(a) Externo à Instituição - MARIANA AGOSTINI DE MORAES - UNIFESP
Membro Titular - Examinador(a) Externo à Instituição - MARIA ISABEL FELISBERTI - UNICAMP
Membro Suplente - Examinador(a) Interno ao Programa - 1671298 - RENATO ALTOBELLI ANTUNES
Membro Suplente - Examinador(a) Externo ao Programa - 2604737 - EVERALDO CARLOS VENANCIO
Membro Suplente - Examinador(a) Externo ao Programa - 2352281 - LIGIA PASSOS MAIA OBI
Membro Suplente - Examinador(a) Externo ao Programa - 1850090 - ANNE CRISTINE CHINELLATO