Banca de QUALIFICAÇÃO: ANA LETICIA FERNANDES DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANA LETICIA FERNANDES DOS SANTOS
DATE: 27/11/2024
TIME: 09:00
LOCAL: meet.google.com/hzf-zekn-mxx
TITLE:

Investigation of different organosilanes on the functionalization and dispersion degree of reduced graphene oxide (rGO) in polymeric nanocomposites

KEY WORDS:

GRAPHENE; FUNCTIONALIZATION; ORGANOSILANE; POLYMERIC NANOCOMPOSITE; DISPERSION.

PAGES: 60
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

Graphene, a hexagonal structure of covalently bonded sp2 hybrid carbon atoms, is gaining more and more attention due to its unique properties. As a result, graphene has found applications in various sectors and has been widely researched as a nanofilled in polymeric matrices. Despite this, this nanomaterial faces challenges in this application due to factors that contribute to low dispersion in the polymer matrix and, consequently, lower than desired properties. For this reason, chemical modification of the surface of this nanomaterial is being researched as an alternative for expanding this application. This work aims to evaluate the degree of dispersion of reduced graphene oxide (rGO) functionalized with different organosilanes in an epoxy polymer matrix. To this end, graphene oxide (GO) was first synthesized from the chemical exfoliation of graphite based on the improved Hummers method, functionalized with 3-aminopropyltriethoxysilane (APTES), 3-aminopropyltrimethoxysilane (APTMS), 3-glycidoxypropyltrimethoxysilane (GPTMS) and triethoxymethylsilane (MTES), and then thermally reduced to produce reduced graphene oxides functionalized with the same silane agents. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), solvent dispersion stability and scanning electron microscopy (SEM) analyses were carried out to prove the successful synthesis and functionalization of these materials. The results obtained confirmed the success of covalent functionalization with all the silanes used on the surface of GO, as well as the permanence of their molecules in the basal plane of the reduced graphene oxide (rGO) carbons, showing the presence of the characteristic peaks of the silane bonds on the surface of the nanomaterials, as well as the increase in their interplanar distance due to the insertion of the organosilanes. In addition, the modification of rGO with silane coupling agents helps positively in the dispersion of these nanoparticles in ethanol when compared to pure rGO. To check the degree of dispersion in the polymer matrix, polymer nanocomposites were prepared with 0.5% by mass of each functionalized rGO. Visualization of the fracture surfaces of these materials by SEM showed that better distributions, dispersions and interfacial bonding were obtained for the nanocomposites containing functionalized rGO compared to those containing pure rGO. Among them, the nanocomposite with rGO/APTES showed a better result due to the better interaction of its organofunctionality with the epoxy matrix. This shows the high potential of covalent functionalization with rGO silanes to obtain better dispersion of these nanoparticles in polymer nanocomposites and, consequently, better properties.

COMMITTEE MEMBERS:
Presidente - 1755267 - MARIA CAROLINA BURGOS COSTA DO NASCIMENTO
Interno - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externa à Instituição - AMELIA SEVERINO FERREIRA E SANTOS - UFPB