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        # Carbon Black in Polymers: Conductive Grade vs. Reinforcing Grade Performance

        

**Topic:** Explainer

        

Carbon black is the primary colorant, reinforcing filler, and conductive agent in rubber and plastics compounding. Selecting the correct grade (reinforcing N330/N220 vs. high-structure conductive black) is critical to achieving target electrical percolation or mechanical wear resistance.

        
        
        
        
        
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          ## Frequently Asked Questions

          
### Why does a high-structure black make a compound conductive at lower loading?

High-structure carbon blacks have highly branched aggregate shapes. These branches contact each other easily, forming conductive networks at much lower concentrations (typically 8-15% loading) compared to low-structure blacks.

### How does carbon black provide UV protection in plastics?

Carbon black is an exceptionally efficient UV absorber. It absorbs UV radiation across the entire solar spectrum and converts it to thermal energy, protecting the host polymer from photo-oxidation.

### What is the difference between OAN and COAN?

Oil Absorption Number (OAN/DBP) measures the structure of the raw carbon black. Compressed Oil Absorption Number (COAN) measures the structure after mechanical compression, representing the structure that survives polymer mixing.

### What is the CAS number for Carbon Black?

The CAS registry number for Carbon Black is 1333-86-4.

        
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By NBT Technical Desk · Updated 2026-07-04

        

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