Banca de DEFESA: PAULO RENIERE SILVA DE SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : PAULO RENIERE SILVA DE SOUZA
DATA : 22/07/2016
HORA: 09:00
LOCAL: Sala 3F1
TÍTULO:

NANOPARTICLES FROM COMPLEXATION OF CHITOSAN AND POLY(SODIUM METHACRYLATE): light scattering studies

PALAVRAS-CHAVES:

Interpolyelectrolyte complexes, dynamics light scattering, small angle X-ray scattering, chitosan.

PÁGINAS: 50
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Química de Interfaces
RESUMO:

Interpolyelectrolyte complex (IPEC) dispersions were prepared from chitosan and poly(sodium acrylate), NaPMA, by mixing their solutions., at different carboxyl to aminium molar ratio, . Gyration radius was determined by SAXS and showed that, as   increased, IPEC dimensions decreased and reached a minimum at , which was considered the ratio at which IPEC cluster dimensions was minimum, following collapse and growth of larger particles. Pair distance distributions, ,  became narrower up to , increasing its width from this point. Relaxation-related parameters from DLS intensity correlation functions (ICF) identified three main relaxation process. The fast process, related to free polyelectrolyte molecules random motion disappeared as  was increased. The other two relaxation process were a function of  and presented marked changes at . At the same value of the energy of activation for the average relaxation rate showed the occurrence of a clear change in the nature of IPEC-related interactions. As hydrodynamic diameter, determined by DLS was much larger than the gyration radius determined by SAXS, IPEC particles could be described as being composed by a core, rich in segregated, insoluble material, enveloped by IPEC soluble clusters, possibly in the form of water-rich gels.

MEMBROS DA BANCA:
Interno - 1753094 - ALCIDES DE OLIVEIRA WANDERLEY NETO
Externo à Instituição - ELIZABETE FERNANDES LUCAS - UFRJ
Interno - 1803692 - FABRICIO GAVA MENEZES
Presidente - 1198847 - JOSE LUIS CARDOZO FONSECA