Banca de DEFESA: AMANDA NASCIMENTO BRAGA SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : AMANDA NASCIMENTO BRAGA SANTOS
DATE: 20/04/2023
TIME: 14:00
LOCAL: Sala 302A do Bloco B do Campus de Santo André da Universidade Federal do ABC
TITLE:

ISOCYANATE MICROENCAPSULATION FOR POLYURETHANE-BASED ADHESIVE APPLICATIONS

PAGES: 146
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

The high toxicity presented by the reactive component isocyanate (-NCO) has stimulated the creation of restrictive regulations for its use in several industries. Aiming to overcome these restrictions, the footwear industry seeks solutions to increase the bonding performance of its polyurethane-based adhesives without using isocyanate in its free form. The solution found to this problem was the microencapsulation of this component. This way, it is protected by a polymeric shell, and at the right time, it must be activated by the action of temperature and pressure, allowing the occurrence of the curing reaction, which guarantees the proper performance of the adhesive. The purpose of this work is to obtain poly (methyl methacrylate) (PMMA) microcapsules containing active -NCO groups in the core through solvent evaporation technique in oil-in-water emulsions to obtain one-component polyurethane-based adhesives for application in the footwear industry. Seeking to tailor the final properties of the microcapsules for the application in question, the influence of surfactant concentration, stirring speed, initial volume of isocyanate, initial mass of PMMA, and temperature and time in the system were studied. Among the parameters studied, only surfactant concentration, agitation speed and temperature had a statistically significant influence on the response variables. Depending on the combination of parameters applied (7 wt.% of surfactant, 1920 rpm, 4 mL of isocyanate, 1g of PMMA, at temperature of 50°C for 2h), spherical shaped microcapsules were obtained, presenting core-shell morphology, with approximately 13 wt.% of active isocyanate in the core, an average diameter of 50.3 µm, and thermal stability superior to the pure component. The analysis of the content of -NCO groups over time indicated that the microcapsules have low stability. Microcapsules were dispersed in a polyurethane adhesive matrix to obtain a single component adhesive. Analyzes carried out by rheology, TMOR and peeling indicate that the microcapsules are efficient in releasing the active isocyanate and in promoting the cross-linking reaction. FTIR indicated low stability of the adhesive over time.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1761120 - DANILO JUSTINO CARASTAN
Membro Titular - Examinador(a) Interno ao Programa - 052.991.506-52 - JULIANA DA SILVA BERNARDES - UFABC
Membro Titular - Examinador(a) Externo ao Programa - 1730526 - SUEL ERIC VIDOTTI
Membro Titular - Examinador(a) Externo ao Programa - 1762438 - JEAN JACQUES BONVENT
Membro Titular - Examinador(a) Externo à Instituição - GUILHERMINO JOSÉ MACÊDO FECHINE - UPM
Membro Suplente - Examinador(a) Interno ao Programa - 1763443 - MARCIA APARECIDA DA SILVA SPINACE
Membro Suplente - Examinador(a) Interno ao Programa - 2347767 - MATHILDE JULIENNE GISELE CHAMPEAU
Membro Suplente - Examinador(a) Externo ao Programa - 2352281 - LIGIA PASSOS MAIA OBI
Membro Suplente - Examinador(a) Externo à Instituição - ADRIANA MARTINELLI CATELLI DE SOUZA - FEI