Loading...

Synthesis and Characterization of 2-dimensional Carbides (MXenes), and Fabrication of 3D Printed MXene-Polylactic Acid Nanocomposites

Mohammadi, Hamid Reza | 2024

0 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56880 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Alizadeh, Reza
  7. Abstract:
  8. A decade after discovery of graphene, the unique properties and characteristics of two-dimensional materials, particularly an emerging family of carbides and nitrides (MXenes), have attracted the attention of researchers. MXenes are two-dimensional structures of two or more layers of transition metals, with interstitial carbon and/or nitrogen atoms, with exceptional properties such as high specific surface area, excellent elastic modulus, metallic conductivity, and various termination groups. These properties can be altered by various factors, including chemical composition and synthesis processes, and any changes in these factors significantly affect the properties of MXene sheets. In this study, two different synthesis routes were investigated to examine the effect of process methods on MXene flakes properties. The first method involved the use of 30% HF to etch MAX phase particles, and in the second method, a mixture of 5 % HF, HCl, and DI water was carried out. The experimental results showed that the lateral size of the MXene sheets obtained through the second method were much larger compared to the first method, and the fluorine ion content on their surface was lower. Additionally, accordion-like morphology was not observed in the multilayer MXene sheets obtained through the second method. Overall, it was concluded that MXene sheets synthesized through the second method are suitable fillers for composite fabrication. In the next step of this research, MXene sheets were utilized to reinforce polylactic acid with concentrations of 0.1, 0.3, and 0.5 % and prepared using a solvent casting method. After the extrusion of appropriate filaments, various samples were 3D-printed using the Fused Deposition Modeling (FDM) technique to evaluate their properties. Initially, the dispersion and distribution of MXne sheets were examined using XRD and FE-SEM analysis, resulting in an excellent dispersion and distribution of MXene sheets in the matrix. Afterward, the tensile test showed that MXene sheets led to a significant improvement in the mechanical properties of the nanocomposite, tensile strength and elastic modulus improving by 55 and 43% respectively, compared to neat PLA. The addition of hydrophilic MXene sheets enhanced the hydrophilicity of the matrix due to the presence of polar groups, such as hydroxyl groups. Furthermore, the degradation rate of polylactic acid improved by adding MXene sheets due to increased hydrophilicity. In summary, it can be concluded that the synthesis of MXene sheets using a mixture solution of HCl, DI water, and HF is an appropriate method for the fabrication of nanocomposites. Moreover, MXene sheets, as a filler, have significant effects on the mechanical properties, hydrophilicity, degradation rate, and crystallinity of polylactic acid
  9. Keywords:
  10. MXene Nanosheets ; Two Dimentional Materials ; Synthesis ; Additive Manufacturing ; Nanocomposite ; Polylactic Acid

 Digital Object List

 Bookmark

No TOC