Abstract: A contradiction every tire compounder knows but rarely states out loud: To pass electrostatic (surface resistivity <10⁶ Ω), you add conductive carbon black – typically 10 – 20 phr. At that loading, tan δ @60°C goes up – rolling resistance (RR) deteriorates. This white paper demonstrates how High performance CNT rubber additive manufacturers have broken this tire industry deadlock using <2 phr of Multi walled carbon nanotubes for rubber reinforcement. By understanding the Benefits of using CNT in new energy vehicle tires, engineers can finally move beyond the physical limit of spherical-particle percolation.
- How long have we been trapped in the conductive carbon black path? First, a fact: passing the factory resistivity spec has never been hard. What is hard is keeping RR under control, preserving processability, and ensuring the tire remains safe after 30,000 km. The conductive network of high-structure conductive blacks relies on physical interparticle contacts. Once the tire enters dynamic flexure, contacts constantly break and reform, leading to extra energy loss and resistivity drift. There’s a dark joke in our industry: We solve static electricity with carbon black, then RR, wear, and fatigue life pay the bill. This is why the Benefits of using CNT in new energy vehicle tires are becoming the new standard for electric drivetrains that are sensitive to static buildup.
- Why can carbon nanotubes escape this logic? Multiwalled carbon nanotubes (MWCNTs) are not “better carbon black.” They are a different physical mechanism based on Specialty CNT conductive agents for elastomers. Their 1D nanofiber geometry (aspect ratio >1000:1) forms a continuous fibrous network. As an Anti static carbon nanotube for EV tires, it provides reinforcement through stress transfer and load bearing rather than simple filling.
Comparison of Technical Aspects:
| Aspect | Conductive Carbon Black (high structure) | Carbon Nanotubes (MWCNT) |
| Conduction mechanism | Particle-chain physical contacts | Fibrous network, long-range electron pathways |
| Typical loading for antistatic | 10–20 phr | 1–2 phr |
| Impact on RR (tan δ @60°C) | Significantly increases | Controllable at low loading |
| Reinforcement efficiency | Particulate reinforcement, modulus increases | Nanofiber reinforcement, tensile & tear strength improve |
| Conductive stability (fatigue) | Poor – contacts break, resistivity rises | Fibrous network adapts, more durable |
| Thermal conductivity gain | Negligible | Measured increase >10% |
- Data: How to replace conductive carbon black with carbon nanotubes Data from a tire undertread formulation [test methods ISO 1853/ASTM D991] confirms the effectiveness of Improving tire wear resistance with carbon nanotube tecnología.
Formulation and Performance Data:
| Formulación | Volume resistivity (Ω·cm) | Modulus @300% (MPa) | Resistencia a la tracción (MPa) | Alargamiento a la rotura (%) | DIN abrasion (mm³) | tan δ @60°C |
| S1 (Carbon black ref) | 1.18×10⁵ | 11.9 | 17.4 | 434 | 131 | 0.163 |
| S2 (+2 phr CNT, -6 phr CB) | 2.61×10⁴ | 11.6 | 18.7 | 469 | 129 | 0.179 |
| S3 (+3 phr CNT, -6 phr CB) | 1.01×10⁴ | 11.5 | 18.3 | 473 | 115 | 0.192 |
| S4 (+4 phr CNT, no CB red) | 1.18×10³ | 14.2 | 19.5 | 425 | 104 | 0.198 |
When researching How to replace conductive carbon black with carbon nanotubes, we see a nearly 10× drop in resistivity at 2 phr even after removing 6 phr of carbon black. Furthermore, DIN abrasion improves significantly (131 → 104), proving that Improving tire wear resistance with carbon nanotube is a tangible benefit for tire life extension.
- Why I don’t fully trust standard tests: Conductive stability of carbon nanotubes under dynamic flexure Does the resistivity measured by ISO 1853 represent safety after 30,000 km? The honest answer is no. For conductive carbon black, particle-chain contacts fail progressively under fatigue. However, Conductive stability of carbon nanotubes under dynamic flexure ensures safety. Internal tests show the CNT fibrous network increased resistivity by less than 30% after 5,000 cycles, compared to a 3-5 fold increase in carbon black systems. Passing the spec is not the same as knowing the degradation trajectory.
- Most “CNT didn’t work” cases: Dispersion challenges of carbon nanotubes in rubber mixing The formulation is only 20% of the outcome; the rest happens in the mixing room. Dispersion challenges of carbon nanotubes in rubber mixing arise because van der Waals forces cause them to tangle and agglomerate. If dispersion fails, these become micron-sized stress concentrators. To succeed, one must use high shear, staged addition, and monitor the filler dispersion rating (DISPERGRADER). Aligned multiwalled CNTs are also easier to disperse than randomly entangled forms.
- Total cost of ownership: Sustainable carbon nanotube fillers for tire industry While CNT costs more per kg, Sustainable carbon nanotube fillers for tire industry redefine the performance boundary. By Reducing power consumption in electric vehicles with CNT tires, the value in WLTP/CLTC range extension far outweighs the material cost.
Aspects of TCO Comparison:
| Aspect | Carbon black solution | CNT solution (2–3 phr) |
| Total filler loading | Mayor | Can be reduced |
| Net impact on RR | Significant penalty | Controllable increase |
| Wear life improvement | — | DIN abrasion -21% |
| Conductivity stability | Drops fast | Drops much slower |
| Thermal management | Negligible | >10% thermal conductivity gain |
- Three questions compound engineers ask most often Q1: What is the Effect of carbon nanotubes on rubber Mooney viscosity? At 2–3 phr, the Effect of carbon nanotubes on rubber Mooney viscosity is manageable, moving from 63 to 69–71. At 4 phr, however, it jumps to 88, which is a real challenge.
Q2: Will CNT work in silica-filled tread? Yes, but since silica is an insulator, you may need 3–4 phr CNT to reach target resistivity compared to 2 phr in all-carbon-black compounds.
Q3: Can I use it without special equipment? Possibly, but a simple two-roll mill will struggle to break down agglomerates. Without high shear and temperature control, the value of the material will be diluted.
Resources & Contact: As one of the Leading carbon nanotube chemical suppliers in China, we offer grade selection and process validation. For more info on our Powerflex CNT44G, contact the technical team at High performance CNT rubber additive manufacturers : yorichen@sanezen.com or visit www.sanezenrubber.com.
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