SÍNTESE DE POLI (ÁCIDO LÁTICO-CO-ÁCIDO GLICÓLICO) ATRAVÉS DE POLICONDENSAÇÃO CATALISADA POR RESINA DE TROCA IÔNICA CONTENDO ÓXIDO DE ESTANHO COMO CO-CATALISADOR.
Carregando...
Data
2008-11-27
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
In this study PLGA copolymers were synthesized with molecular
weight above 10 kDa through direct polycondensation of L-lactic acid and
glycolic acid monomers. Catalysts based on sulfonated styrenedivinylbenzene
copolymer (SC) containing or not Sn2+ íons adsorbed as
SnCl2.H2O colloidal particles from neutral solution or [SnCl3]- complex anions
from acid solution were prepared. All catalysts were evaluated by specific
surface area and pore volume measurements, infrared spectroscopy, X-ray
diffraction, atomic absorption spectrophotometry and ion exchange capacity.
The obtained PLGA copolymers were characterized by infrared
spectroscopy, X-ray diffraction and inherent viscosity measurements.
Independent of pH solution of the adsorptions, it was observed that Sn2+
ions were oxidized to Sn4+ forming SnO2. This oxidation probably occurred
during catalysts drying process in the presence of oxygen. The PLGA
copolymers with highest inherent viscosities, i.e., highest molecular weights
were obtained with SC catalyst containing SnO2 prepared by adsorption of
SnCl2.H2O colloidal particles in neutral solution. It was estimated that the
highest PLGA molecular weights were equal or larger than 35 kDa. The
produced PLGA presented white or lightly yellow color and Sn contamination
less than 1 ppm which is below the limit allowed by the Brazilian legislation
Descrição
Citação
OLIVEIRA, Leonardo François de. SYNTHESIS OF POLY (lactide-co-glycolic acid)
BY Polycondensation Catalyzed by
ION EXCHANGE RESIN CONTAINING OXIDE
TIN AS CO-CATALYST. 2008. 25 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2008.