Dynamic mechanical characterization of CNT-PP nanocomposites

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Polymer nanocomposites (PNCs) offer enhanced properties but their dynamic mechanical behavior requires detailed understanding.
• Single-walled carbon nanotubes (SWCNTs) are crucial nanofillers influencing polymer chain dynamics.

Purpose of the Study:

• To investigate the dynamic mechanical analysis and relaxation behavior of polypropylene (PP) and SWCNT nanocomposites.
• To elucidate the role of SWCNTs and free volume on polymer chain mobility and stress relaxation.

Main Methods:

• Molecular dynamic simulations were employed for dynamic mechanical analysis.
• Quasistatic loading and relaxation tests were performed on composite unit cells.
• Time-temperature superposition was used to generate a master curve.

Main Results:

• Nano-level polymer chain readjustments were observed during relaxation, reducing stress.
• Free volumes and voids around SWCNTs facilitated polymer chain mobility.
• Nano relaxation parameters were deduced by fitting standard relaxation curves.

Conclusions:

• SWCNTs significantly influence the relaxation behavior of polypropylene nanocomposites.
• Understanding chain mobility is key to predicting the long-term performance of PNCs.
• The study provides a method for characterizing dynamic mechanical properties of nanocomposites over extended timescales.