TY - JOUR
T1 - Nylon-6/Ti3C2Tz MXene Nanocomposites Synthesized by in Situ Ring Opening Polymerization of ϵ-Caprolactam and Their Water Transport Properties
AU - Carey, Michael
AU - Hinton, Zachary
AU - Sokol, Maxim
AU - Alvarez, Nicolas J.
AU - Barsoum, Michel W.
N1 - Funding Information:
*E-mail: barsoumw@drexel.edu. ORCID Michel W. Barsoum: 0000-0001-7800-3517 Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Funding This work was funded by the Army Research Office (69521MSII). Notes The authors declare no competing financial interest.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/6/5
Y1 - 2019/6/5
N2 - Clay-reinforced nylon-6 nanocomposites (NCs)-characterized by the full exfoliation of the nanoreinforcement-were introduced in the marketplace in the 1990s. Herein, we demonstrate, for the first time, that Ti3C2Tz MXene can be incorporated into nylon-6 to synthesize melt-processable nanocomposites with excellent water barrier properties (94% reduction in water vapor permeation). To intercalate the ϵ-caprolactam monomer between the MXene multilayers, the latter were first treated with 12-aminolauric acid, a low-cost, nontoxic, biodegradable, and long shelf life compound. Upon heating to 250 °C, in the presence of 6-aminocaproic acid, in situ polymerization occurred, yielding melt-processable nylon-6/MXene NCs that were, in turn, studied by thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, scanning and transmission electron microscopy, infrared spectroscopy, and dynamic vapor sorption analysis. Using the latter, moisture-sorption isotherms of a neat and a 1.9 vol % NC, at 60 °C, were fit to the Guggenheim, Anderson, and de Boer equation. Solubility, permeation, and diffusion coefficients of water through the NCs were measured as a function of temperature and found to be the lowest ever reported for nylon-6, despite the fact that, at 1.9 and 5.0 vol %, the MXene loads were relatively low. This record low diffusivity is ascribed to the very large aspect ratios-500 to 1000-of Ti3C2Tz flakes and their dispersion. The water permeation rate is a factor of 5 lower than the best reported in the much more mature nylon/clay field, suggesting lower values can be achieved with further optimization. Lastly infrared spectroscopy spectra of neat and NC samples suggest the surface terminations of the 12-Ti3C2Tz flakes bind with nylon-6, limiting water adsorption sites, resulting in reduced solubility in the NC films.
AB - Clay-reinforced nylon-6 nanocomposites (NCs)-characterized by the full exfoliation of the nanoreinforcement-were introduced in the marketplace in the 1990s. Herein, we demonstrate, for the first time, that Ti3C2Tz MXene can be incorporated into nylon-6 to synthesize melt-processable nanocomposites with excellent water barrier properties (94% reduction in water vapor permeation). To intercalate the ϵ-caprolactam monomer between the MXene multilayers, the latter were first treated with 12-aminolauric acid, a low-cost, nontoxic, biodegradable, and long shelf life compound. Upon heating to 250 °C, in the presence of 6-aminocaproic acid, in situ polymerization occurred, yielding melt-processable nylon-6/MXene NCs that were, in turn, studied by thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, scanning and transmission electron microscopy, infrared spectroscopy, and dynamic vapor sorption analysis. Using the latter, moisture-sorption isotherms of a neat and a 1.9 vol % NC, at 60 °C, were fit to the Guggenheim, Anderson, and de Boer equation. Solubility, permeation, and diffusion coefficients of water through the NCs were measured as a function of temperature and found to be the lowest ever reported for nylon-6, despite the fact that, at 1.9 and 5.0 vol %, the MXene loads were relatively low. This record low diffusivity is ascribed to the very large aspect ratios-500 to 1000-of Ti3C2Tz flakes and their dispersion. The water permeation rate is a factor of 5 lower than the best reported in the much more mature nylon/clay field, suggesting lower values can be achieved with further optimization. Lastly infrared spectroscopy spectra of neat and NC samples suggest the surface terminations of the 12-Ti3C2Tz flakes bind with nylon-6, limiting water adsorption sites, resulting in reduced solubility in the NC films.
KW - MXene
KW - polyamides
KW - polymer nanocomposites
KW - water diffusion coefficients
KW - water permeation
UR - http://www.scopus.com/inward/record.url?scp=85066485390&partnerID=8YFLogxK
U2 - 10.1021/acsami.9b05027
DO - 10.1021/acsami.9b05027
M3 - Article
C2 - 31071257
AN - SCOPUS:85066485390
SN - 1944-8244
VL - 11
SP - 20425
EP - 20436
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 22
ER -