Banca de QUALIFICAÇÃO: STÉPHANIE CAVALCANTE DE MORAIS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : STÉPHANIE CAVALCANTE DE MORAIS
DATA : 07/07/2016
HORA: 14:00
LOCAL: LAPET
TÍTULO:

THERMAL STABILITY OF WATER-SOLUBLE POLYMERS

PALAVRAS-CHAVES:

Thermal stability. Kappa Carrageenan. Partially Hydrolysed Polyacrylamide. Carboxymethylcellulose. Activation energy

PÁGINAS: 92
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Polímeros e Colóides
RESUMO:

The study of thermal degradation of polymers is essential to determine the stability of the structure and depends on the state in which the polymer is. A comparative study of the thermal stability of kappa carrageenan (KC), partially hydrolyzed polyacrylamide (HPAM) and carboxymethylcellulose (CMC) was performed in an attempt to establish a correlation between the chemical structures, stability of these polymers and their activation energies in the solid state and solution. The thermal stability of the polymers in the solid state was evaluated by thermogravimetric analysis and the activation energy was calculated using the integral method Broido. As for the solution polymers, viscosity measurements were made as a function of time at the temperatures 40, 60, 80 and 100 ° C, and constructed an exponential decay model of the specific viscosity for determining the activation energy. We observed a similar stability of polymers in the solid state and in solution, with higher activation energies in the solid state due to the more efficient heat transport in solution. The results are consistent with the structural particularities of each polymer, and the polymer HPAM with greater stability compared to polysaccharides. Among the natural polymers structural rigidity played a key role, with CMC being more stable than KC. And, by the relationship between the activation energies in the solid state and in solution has been proposed the possibility of using a model for other polymers behavior prediction.

MEMBROS DA BANCA:
Interno - 1412709 - NEDJA SUELY FERNANDES
Presidente - 1149440 - ROSANGELA DE CARVALHO BALABAN
Interno - 1523912 - TATIANA DE CAMPOS BICUDO