Banca de QUALIFICAÇÃO: THAIS MARIA ALVES MARINHO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : THAIS MARIA ALVES MARINHO
DATE: 19/12/2019
TIME: 08:30
LOCAL: Sala de aulas do PPGCEM
TITLE:

EVALUATION OF THE INFLUENCE OF VARIABLES ON THE SYNTHESIS PROPERTIES OF MICROCAPSULES PUF / ENB USING PLACKETT-BURMAN PLANNING (PB)

KEY WORDS:

Self-healing, microcapsules’ synthesis, experimental design Plackett Burman, poly(urea-formaldehyde)

PAGES: 98
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

Polymers and polymer composites are constantly susceptible to damage due to the emergence of microcracks that may compromise the structure as well as the life of the material during use. Thus, self-repairing systems have been increasingly studied and the use of polymeric microcapsules is one of the effective solutions for repairing damage during application, eliminating the need to remove the component for repair and thereby reducing costs. In this work, poly (urea formaldehyde) (PUF) microcapsules with 5-ethylidene 2 norbornene (ENB) core material were prepared by in situ polymerization. For this, a Plackett-Burman (PB) experimental design was used to evaluate the effect of the synthesis process variables on the obtained microcapsule properties. Factors manipulated include stirring speed, pH, poly (ethylene-alt-maleic anhydride) (EMA) content, urea / formaldehyde (U / F) molar ratio, ammonium chloride, resorcinol and 1-octanol droplets. The responses evaluated were mean microcapsule diameter, encapsulated content, microcapsule wall roughness, thermal stability and degradation temperature. It was observed that, of all analyzed parameters, the stirring speed and the EMA content had the most significant effects on the analyzed response variables, at a confidence level of 90%. Microcapsules with larger diameters were obtained when agitation and EMA content were at the lower level of the PB planning. On the other hand, the thermal stability and degradation temperature of the microcapsules increased with agitation and the EMA content. In addition, the high significance of curvature in the Pareto graphs of some response variables analyzed indicated that microcapsules with satisfactory properties can be obtained under center point conditions. No parameters analyzed were statistically significant at a 90% confidence level for yield and encapsulated content.

BANKING MEMBERS:
Externo ao Programa - 1064594 - EVANS PAIVA DA COSTA FERREIRA
Externa à Instituição - LAURA HECKER DE CARVALHO - UFCG
Presidente - 1755267 - MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
Externa ao Programa - 1149440 - ROSANGELA DE CARVALHO BALABAN