Detonation nanodiamonds for doping Kevlar.

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Kevlar is a high-strength synthetic fiber known for its rigidity.
• Nanoparticle reinforcement typically enhances material properties.
• The interaction between nanoparticles and polymer matrices is crucial for composite performance.

Purpose of the Study:

• To investigate the creation of a novel Kevlar-nanodiamond nanocomposite.
• To understand the interfacial interactions between nanodiamonds and Kevlar.
• To evaluate the impact of nanodiamond inclusion on Kevlar's mechanical properties.

Main Methods:

• Nanocomposite preparation via precipitation from an acidic Kevlar solution with dispersed nanodiamonds.
• Characterization of nanodiamond surface functional groups using Boehm's titration.
• Assessment of macroscopic hardness of the nanocomposite and pure Kevlar.

Main Results:

• Diamond nanoparticles (4 nm) were successfully encapsulated within a 1 nm Kevlar layer.
• Nanodiamond surfaces exclusively featured carboxyl groups, interacting with Kevlar's amide groups.
• This interaction disrupted Kevlar's structure, forming submicrometric assemblies with a fractal-like "cauliflower" morphology.
• The resulting nanocomposite exhibited significantly lower hardness (1.03 GPa) than pure Kevlar (2.31 GPa).

Conclusions:

• The study presents the first instance of Kevlar being doped with nanodiamonds.
• Nanoparticle-induced structural changes in Kevlar led to a counterintuitive decrease in macroscopic hardness.
• This work demonstrates a novel mechanism affecting mechanical properties through nanoparticle-polymer interactions.