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Frequently Asked Questions

The questions below are the ones we most frequently encounter from customers about our Vazo™ products.

Are Vazo™ free radical sources toxic?

They exhibit low to moderate toxicity. However, tetramethylsuccinonitrile (TMSN), a by-product of Vazo™ 64, is highly toxic. The properties of TMSN should be discussed with a Chemours Technical Service Representative before attempting to use Vazo™ 64. Vazo™ 67 is a safer alternative. For comparison, the oral toxicity data of Vazo™ products and their decomposition products are shown in the table below. For all grades except Vazo™ 67, the quantities represent approximate lethal dose (ALD); for Vazo™ 67, the quantities are the lethal dose for 50% of test animals.

Approximately Oral Toxicity in Rats (mg/kg) Product Azo


Product  Azo Compound  Decomposition Products 
Vazo™ 52  >5,000  5,000  
Vazo™ 64  670  60 (TMSN alone)  
Vazo™ 67  982 1,316 
Vazo™ 88  >11,800  >3,400





Is it important to store Vazo™ at or below the temperature recommended by Chemours?

Yes! Vazo™ free radical sources may decompose violently if stored above the recommended temperatures. Product quality is also maintained when Vazo™ free radical sources are stored properly.

What are the recommended storage temperatures?

For safety, the maximum storage temperatures are as follows: Vazo™ 52 (10°C [50°F]); Vazo™ 64 and Vazo™ 67 (24°C [75°F]); Vazo™ 88 (35°C [95°F]); and Vazo™ 56 WSP, Vazo™ 56 WSW, and Vazo™ 68 WSP (40°C [104°F]). These temperatures ensure a 3-month shelf life; colder temperatures will extend shelf life. Vazo™ products should never be stored at temperatures higher than those listed here.

Is there an explosion hazard with airborne dust from Vazo™ free radical sources?

Yes! Airborne dust will form explosive mixtures in air.

In emulsion polymerization processes, I normally use a persulfate. Under what circumstances might water-soluble Vazo™ be a better choice?

Among other advantages, water-soluble grades of Vazo™ (56 WSP, 56 WSW, and 68 WSP) offer narrow molecular weight distribution and minimal branching. They are also sulfur-free. Although used predominantly in an emulsion polymerization mechanism, water-soluble grades of Vazo™ can also be used in solution polymerization.