Title: On the Effect of Ultralow Loading of Microwave-Assisted Bifunctionalized Graphene Oxide in Stereolithographic 3D-Printed Nanocomposites

Abstract

Surface functionalization of graphene oxide (GO) is one of the best ways to achieve homogeneous dispersions of GO within polymeric matrices and composites. Nonetheless, studies regarding how the level of GO functionalization affects the macroscopic properties of three-dimensional (3D) printed nanocomposites are still few. Furthermore, the bifunctionalization of GO with the NH₂/NH₃⁺ groups to obtain improved thermomechanical macroscopic properties at ultralow loads has not been reported. In this paper, fast and straightforward surface bifunctionalization of GO with a controlled ratio of NH₂/NH₃⁺ groups at low, medium, and high functionalization levels (AGOL, AGOM, and AGOH) in a one-step microwave-assisted synthesis is reported for the first time. The functionalization mechanism was disclosed, wherein three graft densities (Gφ) were obtained. A plateau of maximum functionalization (G_φ = 4.9 μmol/m² = 2.9 molecules/nm²) was reached, suggesting that full coverage of the GO surface is achievable. Also, an increase in the exfoliation of functionalized layers was obtained, ranging from d002 = 8.6 Å up to d₀₀₂ = 15.8 Å. X-ray photoelectron spectroscopy (XPS) reveals the successful functionalization of GO, as well as an atomic relationship NH₂/NH₃⁺ of about 50/50% in all functionalized samples. Stereolithographic (SLA) 3D-printed nanocomposites (AGOL/R, AGOM/R, and AGOH/R) were obtained using ultralowmore » loads (0.01 wt %) of each bifunctionalized material. This ultralow amount was sufficient to enhance thermal stability (up to 4 °C) and a significant increase in the glass transition temperature (93 °C ≤ T_g ≤ 120 °C). Interestingly, we found that low and medium grafting density promotes a ductile material (ε > 5%); meanwhile, a high graft density produces brittle materials. Also, we observe that the toughness can be tuned as a function of the graft density (AGOH: 24 MPa, AGOM: 342 MPa, AGOL: 562 MPa) at ultralow loadings. The 3D-printed nanocomposites using GO with low graft density (AGOL) increase their tensile strain by 90% in comparison with the control sample (without filler). Finally, the underlying mechanisms were discussed to explain the findings.« less

Authors:

Ramirez-Soria, Edgar Homero  ^[1];

• Search DOE PAGES for author "Ramirez-Soria, Edgar Homero"
• Search DOE PAGES for ORCID "0000-0003-3605-0918"

Bonilla-Cruz, Jose  ^[1];

• Search DOE PAGES for author "Bonilla-Cruz, Jose"
• Search DOE PAGES for ORCID "0000-0001-8575-5637"

Flores-Amaro, Monica Gabriela  ^[2];

• Search DOE PAGES for author "Flores-Amaro, Monica Gabriela"
• Search DOE PAGES for ORCID "0000-0002-2079-822X"

Garcia, Vincent Joseph ^[3]; Lara-Ceniceros, Tania E.  ^[1];

• Search DOE PAGES for author "Lara-Ceniceros, Tania E."
• Search DOE PAGES for ORCID "0000-0001-6403-6705"

Elizondo, Perla  ^[2];

• Search DOE PAGES for author "Elizondo, Perla"
• Search DOE PAGES for ORCID "0000-0001-8215-8677"

Advincula, Rigoberto  ^[4]

• Search DOE PAGES for author "Advincula, Rigoberto"
• Search DOE PAGES for ORCID "0000-0002-2899-4778"

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+ Show Author Affiliations

1. CIMAV-Unidad Monterrey (Mexico)
2. Autonomous University of Nuevo Leon (Mexico)
3. Case Western Reserve Univ., Cleveland, OH (United States)
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Publication Date:

Mon Oct 19 00:00:00 EDT 2020

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1814303

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 12; Journal Issue: 43; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; bifunctionalization; graphene oxide; 3D printing; ductile−brittle nanocomposites; toughness; Functionalization; Organic polymers; Layers; Nanocomposites; Materials