Sulfur-Modified Carbon Nanotubes for the Development of Advanced Elastomeric Materials

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Carbon nanotubes (CNTs) offer exceptional properties but face limitations in rubber matrices, particularly for high-performance tire treads.
• Issues include CNT agglomeration, interference with vulcanization, and strong filler-rubber interactions, leading to increased energy dissipation and limited rolling resistance.
• These factors hinder the effective utilization of CNTs in demanding applications like tire compounds.

Purpose of the Study:

• To overcome limitations of CNTs in rubber compounds for tire treads.
• To improve key properties of rubber-CNT composites by surface-modifying CNTs.
• To investigate the effects of functionalized CNTs on viscoelastic behavior and network structure.

Main Methods:

• Surface modification of CNTs with oxygen-bearing groups and sulfur.
• Incorporation of functionalized CNTs into rubber matrices for tire tread compounds.
• Characterization using mechanical tests, equilibrium swelling experiments, and low-field Nuclear Magnetic Resonance (NMR).

Main Results:

• Surface modification, particularly sulfur introduction, enabled covalent bonding between CNTs and the rubber matrix.
• This resulted in a decreased loss factor at 60 °C, indicating reduced rolling resistance.
• The study observed a reduction in non-elastic defects and an increase in crosslink density.

Conclusions:

• Surface modification of CNTs with sulfur is an effective strategy to enhance rubber compounds for tire treads.
• Covalent bonding improves viscoelastic properties and network structure, leading to better performance.
• The modified CNTs offer a promising solution for reducing rolling resistance in tires.