Surface-Functionalized Carbon Nanotubes for Low-Hysteresis Elastomers
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Solution Overview
Problem
Current tire tread compounds face challenges in reducing rolling resistance while maintaining durability and wet grip, as improvements in rolling resistance often come at the expense of these properties, and the use of discrete carbon nanotubes as reinforcing fillers has been limited due to agglomeration issues and inadequate dispersion in elastomer matrices.
Innovation Solution
A composition comprising discrete carbon nanotubes with selected surface functionalization that disperses well in unsaturated molecules and crosslinks with them, reducing hysteresis and enhancing abrasion resistance, using a combination of surface modification and crosslinking agents to improve the interaction between carbon nanotubes and the elastomer matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional tire tread compounds use silica bound via organosilane to improve rolling resistance, then rolling resistance is reduced, but durability and abrasion resistance deteriorate
Solution Approach 1:
The patent uses a composite filler system combining carbon nanotubes with carbon black or silica, where carbon nanotubes provide reinforcement and durability while the carbon black/silica component manages rolling resistance. This composite approach allows simultaneous achievement of both durability and energy efficiency that single-component systems cannot achieve alone.
Solution Approach 2:
The patent changes the physical and chemical parameters of the filler system by introducing carbon nanotubes with specific aspect ratios (10-1000), surface areas (10-1000 m²/g), and functional group densities. These parameter changes enable improved tensile strength and abrasion resistance while maintaining rolling resistance performance through optimized filler-elastomer interactions.
2Reliability
If discrete carbon nanotubes are used as reinforcing fillers to improve durability, then abrasion resistance is improved, but dispersion in elastomer matrix deteriorates due to agglomeration
Solution Approach 1:
The patent uses surface functional groups (carboxyl, hydroxyl, amine) on carbon nanotubes as intermediaries that facilitate interaction between the nanotubes and elastomer matrix. These functional groups act as mediators that improve wetting and adhesion, preventing agglomeration and ensuring uniform dispersion while maintaining reinforcement effectiveness.
Solution Approach 2:
The patent modifies surface area (10-1000 m²/g) and functional group density (0.1-10 mmol/g) parameters of carbon nanotubes to optimize dispersion. By controlling these parameters, the nanotubes achieve sufficient separation to prevent agglomeration while maintaining high enough surface area for effective reinforcement and adhesion to the elastomer matrix.
3Stability of the object's composition
If carbon nanotubes are functionalized to improve dispersion, then dispersion is improved, but hysteresis increases
Solution Approach 1:
The patent optimizes functional group density (0.1-10 mmol/g) to achieve a balance where sufficient functionality provides good dispersion but excessive functionality is avoided. This parameter control ensures that hysteresis remains below 10% increase compared to unfilled elastomer, maintaining energy efficiency while achieving uniform nanotube distribution in the matrix.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves significant reductions in rolling resistance and abrasion while maintaining or improving durability and wet grip, leading to more efficient and longer-lasting tire tread formulations, particularly beneficial for electric vehicles.
Implementation Method 1
crosslinks molecules selected from the group of unsaturated monomers, unsaturated oligomers, unsaturated polymers, and any mixtures thereof
Implementation Method 2
disperses well in unsaturated molecules selected from the group of unsaturated monomers, unsaturated oligomers, unsaturated polymers, and any mixtures thereof
Data Source
AI summary
The present application is directed to novel discrete carbon nanotubes with a surface modification that disperses well in elastomers and crosslinks elastomers to the surface of the discrete carbon nanotubes, or in the vicinity of the discrete carbon nanotube surface. Significant improvements in the performance of elastomeric formulations with a plurality of discrete carbon nanotubes with a surface modification and silica and/or carbon black result, for example, improved abrasion resistance while at the same time providing a reduced hysteresis effect on cyclic deformation. These improved properties are highly desired for fuel efficient and longer wear life tire formulations.