Esfoliação e funcionalização de nanofolhas de MoS2: desenvolvimento de novos materiais elastoméricos

Detalhes bibliográficos
Ano de defesa: 2021
Autor(a) principal: Fiel, Rodrigo de Souza Penha
Orientador(a): Leite, Edson Roberto lattes
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de São Carlos
Câmpus São Carlos
Programa de Pós-Graduação: Programa de Pós-Graduação em Química - PPGQ
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Palavras-chave em Inglês:
Área do conhecimento CNPq:
Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/15615
Resumo: Two-dimensional materials, such as MoS2, have been extensively studied in recent decades due to their excellent properties in electronics, electrocatalysis, optics and mechanics. A major focus in recent research resides in the surface modification of the MoS2 structure through covalent or non-covalent functionalization for the development of new functional materials. Within this perspective, this work initially presents a simple approach of liquid phase exfoliation, assisted by an ultrasound bath, to exfoliate and functionalize, in a single step, MoS2 dispersed in a polybutadiene (PB) solution forming functionalized nanosheets (f-MoS2). In the synthesis step, the influence of the synthesis temperature on the concentration of functionalized PB was verified. Then, the functionalized nanosheets were incorporated at different loadings in a PB matrix and subsequently vulcanized only with sulfur. The elastomeric nanocomposites (f-MoS2/PB) were subjected to mechanical tests to evaluate the influence of f-MoS2 on mechanical properties such as Young's modulus and elongation at break. In addition, the rubber nanocomposites were also submitted to swelling tests in MEK and toluene and compared with the swelling of traditional rubbers (nitrile and fluorinated). Hence, the set of results allows us to conclude that it is possible to control the concentration of functionalized PB in MoS2 nanosheets by varying the ultrasound synthesis temperature. The f-MoS2 nanosheets promote a significant mechanical improvement in which it is possible to control the Young's modulus and the elongation at break of nanocomposites. Furthermore, there is a notable reduction in the swelling-ratio in MEK and toluene with the addition of f-MoS2 which can be even compared to traditional nitrile and fluorinated rubbers. The statistical results showcase that it is possible to modulate the swelling-ratio of the elastomers by varying the concentration of f-MoS2 or its synthesis temperature.