Silane functionalization of WS₂ nanotubes for interaction with poly(lactic acid)

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Nanofiller functionalization is crucial for strong interfacial interactions in polymer nanocomposites.
• Tungsten disulfide nanotubes (WS2 NTs) offer unique properties but require surface modification for effective integration into polymer matrices.

Purpose of the Study:

• To functionalize WS2 NTs using (3-aminopropyl) triethoxysilane (APTES).
• To prepare and characterize poly(lactic acid) (PLA) composites reinforced with functionalized WS2 NTs.
• To evaluate the impact of functionalized WS2 NTs on the mechanical properties of PLA.

Main Methods:

• WS2 NTs were functionalized with APTES at various ratios (1:1, 1:2, 1:4).
• Surface modification was confirmed using X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and zeta potential measurements.
• Composites of PLA and functionalized WS2 NTs were prepared and subjected to mechanical testing.

Main Results:

• Successful grafting of APTES onto WS2 NTs was confirmed by spectroscopic and microscopic analyses, showing changes in surface chemistry and charge.
• APTES functionalization rendered WS2 NTs organophilic and improved their dispersion in PLA.
• The inclusion of 0.5 wt% APTES-modified WS2 NTs (with 2.0 wt% APTES) in PLA resulted in a 600% increase in elongation at break and tensile toughness, without compromising stiffness or strength.

Conclusions:

• APTES functionalization effectively modifies WS2 NTs, promoting strong interfacial adhesion with PLA.
• The developed WS2 NTs/PLA nanocomposites exhibit significantly enhanced ductility and toughness.
• This study demonstrates a viable strategy for creating high-performance polymer nanocomposites using functionalized WS2 NTs.