Effect of exfoliation medium on the morphology of multi-layer graphene oxide and its importance for Poly(Ethylene terephthalate) based nanocomposites

Autor(es)

Pinto, Gabriel M. ^[1] ; Silva, Giovanna da C. ^[1] ; Fechine, Guilhermino J. M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Prebiteriana Mackenzie, Mackenzie Inst Res Graphene & Nanotechnol MackGra, Rua Consolacao 896, BR-01302907 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Polymer Testing; v. 90, OCT 2020.
• Citações Web of Science: 1

Resumo

Poly(ethylene terephthalate) (PET)/multi-layer graphene oxide (mGO) nanocomposites were produced using the melt compounding technique, with the aid of a twin-screw extruder. The main goal was to investigate the effect of different exfoliation media on the morphology of graphene oxide and its effects, mainly on the mechanical performance of PET/mGO based polymer nanocomposites. Two different exfoliation media (water and ethanol) were used for the mGO synthesis. Based on each medium, nanocomposites with three different mGO contents (0.05 wt%, 0.1 wt%, and 0.3 wt%) were produced. When exfoliated in water, mGO sheets present larger lateral dimensions, i.e., higher surface area available to interact with polymer chains. All nanocomposites presented similar crystallinity, but with a slight increase related to the neat PET, indicating the nucleating effect of mGO. A theoretical model was used to predict the nanocomposites elastic modulus, justifying the experimental results. The biggest mechanical improvement was presented by a composite with low content of water-exfoliated mGO (0.1 wt%). The polymer tensile strength, strain at break, and toughness were improved by 19%, 238% and 590%, respectively. A significant reduction in the polymer dissipation factor (Milo) with mGO content was also verified, indicating some confinement of polymeric chains due to interactions with the mGO sheets. The different surface fracture mechanisms presented by the nanocomposite with 0.1 wt% water-exfoliated mGO were verified, in which a good interface allowed greater release of strain energy. The XR-MT data confirmed that differences in mGO morphology can sensitively affect the final composite properties, characterising it as the driving force for mechanical improvements. Therefore, a melt compounded PET/graphene derivative composite is presented, exhibiting more promising results than what is already reported by solution mixed and in-situ polymerised composites. It was possible due to the strategic processing route utilised, in which the exfoliated mGO was premixed with the polymer powder using the SSD technique. (AU)

• Processo FAPESP: 18/05440-2 - Propriedades mecânicas e de barreira de nanocompósitos formados por politerftalato de etileno e óxido de grafeno (PET/GO)
• Beneficiário: Gabriel Matheus Pinto
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 18/10910-8 - Fotodegradação e fotoestabilização de nanocompósitos poliméricos a base de cargas bidimensionais
• Beneficiário: Guilhermino José Macêdo Fechine
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/50259-8 - Grafeno: fotônica e opto-eletrônica: colaboração UPM-NUS
• Beneficiário: Antonio Helio de Castro Neto
• Modalidade de apoio: Auxílio à Pesquisa - Programa SPEC
• Processo FAPESP: 18/18055-0 - Investigação das propriedades de barreira de nanocompósitos PET/GO para a indústria de embalagens
• Beneficiário: Giovanna da Cruz Silva
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica