Banca de DEFESA: MARCELLA MATOS CORDEIRO BORGES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARCELLA MATOS CORDEIRO BORGES
DATE: 07/06/2023
TIME: 13:30
LOCAL: Online
TITLE:

Development of chitosan-based stimulus-responsive materials for adsorption and controlled release studies

KEY WORDS:

Chitosan. Stimuli-responsive polymers. Adsorption. Controlled release.

PAGES: 159
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Polímeros e Colóides
SUMMARY:

The main approach of this work was the development of new materials based on a natural polymer, chitosan (CS), and synthetic polymers, poly-(2-diethylaminoethyl methacrylate) (PDEAEMA) and polypyrrole (PPy), to verify their applicability in adsorption and controlled release studies. The first material to be synthesized was a responsive composite, consisting of a magnetic particle coated with CS and PDEAEMA, called Fe₃O4/SiO₂/PDEAEMA/CS. This material was used as a fipronil adsorbent in adsorption studies in aqueous media. For this, batch experiments were carried out as a function of pH, contact time, concentration, and temperature. The best results were found at pH 4, using 25 mg of adsorbent and agitation for 60 s, reaching ~80% adsorption capacity. Fipronil adsorption was well interpreted by pseudo-second order kinetic model (R² = 0.928) and dual-site Langmuir-Freundlich isotherm model (R² = 0.984). Then, a pH-responsive controlled-release nanocarrier consisting of CS and PPy, called CS/PPy, was synthesized. Subsequently, to obtain improved properties, CS/PPy was cross-linked with glutaraldehyde, obtaining a new material called CS/PPy@GA. In order to develop promising materials capable of encapsulating peryl alcohol (POH) for application in the treatment of cancer, a material with a magnetic core coated with CS/PPy, called Fe₃O₄/SiO₂/CS/PPy, was also synthesized. The CS/PPy, CS/PPy@GA and Fe₃O₄/SiO₂/CS/PPy materials showed high values of encapsulation efficiency of POH. The POH release assay was performed at pH 4.5, 6.0 and 7.4. The POH release rate was higher in acid medium (pH 4.5) than in neutral/basic medium (pH 7.4). The release mechanism for CS/PPy and Fe₃O₄/SiO₂/CS/PPy was Korsmeyer-Peppas for all pH. CS/PPy@GA presented Korsmeyer-Peppas as a model only at pH 4.5 and 6.0, and Higuchi was better adjusted to pH 7.4.

BANKING MEMBERS:
Presidente - 1727278 - LUIZ GUSTAVO DE LIMA GUIMARAES
Interno - 1942302 - VICTOR AUGUSTO ARAUJO DE FREITAS
Externa ao Programa - 1954071 - MARIA CRISTINA SILVA
Externa à Instituição - SARA SILVEIRA VIEIRA BERTOLI
Externo à Instituição - EDUARDO COSTA DE FIGUEIREDO