Banca de DEFESA: CARLOS ALBERTO SOARES DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CARLOS ALBERTO SOARES DOS SANTOS
DATE: 05/06/2023
TIME: 15:00
LOCAL: UFABC - CAMPUS SANTO ANDRÉ BLOCO B - SALA A DEFINIR - DEFESA DE FORMA HÍBRIDA
TITLE:

POLIHIDROXIBUTIRATO PLASTIFICADO COM OLIGÔMERO DE POLIÉSTER

PAGES: 84
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

In 2021, global production of synthetic petroleum-based polymers exceeded 400 million tons per year. The accumulation of these non-biodegradable materials, indiscriminately discarded in the environment, has become a global problem. Polyhydroxybutyrate (PHB) offers many advantages over traditional petroleum-based polymers, as it is of biological origin, fully biodegradable, and non-toxic. PHB belongs to the class of polyhydroxyalkanoates (PHAs) and is obtained by CO2 synthesis as an energy reserve in the absence of nutrients inside the cells of numerous bacteria. This polymer has potential applications in the medical and industrial fields, with properties comparable to synthetic polymers. However, the high fragility, low thermal stability, and narrow processing window in the molten state limit the use of PHB. The use of plasticizers has been a practical and low-cost approach to increase the toughness of PHB and improve its thermal properties. This study aims to analyze the effect of two aliphatic polyester oligomers as plasticizers for PHB. The compositions of plasticized PHBs were obtained by solution and characterized by thermal analyses, mechanical tensile tests, evaluation of the crystalline structure, and migration stability. The results are discussed in relation to the interaction and miscibility of the polyesters in the PHB chain and their influences on the plasticizing effect. Both plasticizers used showed potential for use as PHB plasticizers. The polyester with a higher C-O/C=O linkage ratio showed the best interaction with PHB and, consequently, the best plasticizing effect. Its addition caused a reduction in PHB crystallinity and Tg. Additionally, it provided a reduction in the elastic modulus by up to 72% and an increase in the elongation at break by up to 467%. These results were observed at a 20% concentration of plasticizer in PHB, which was defined as an optimized concentration for plasticization, as higher concentrations of plasticizer caused phase separation between the polymer and the plasticizer, reduced migration stability, and deteriorated mechanical properties.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1961116 - DEMETRIO JACKSON DOS SANTOS
Membro Titular - Examinador(a) Interno ao Programa - 1761120 - DANILO JUSTINO CARASTAN
Membro Titular - Examinador(a) Externo à Instituição - ANA PAULA LEMES
Membro Suplente - Examinador(a) Interno ao Programa - 2347767 - MATHILDE JULIENNE GISELE CHAMPEAU
Membro Suplente - Examinador(a) Externo à Instituição - LARA TAVARES DOS SANTOS