Benzoyl Peroxide, 70% active (water wet) is a thermal free-radical initiator used in compatible polymerization systems. Product 21446 is supplied as a water-wet white powder or granules with a benzoyl peroxide assay of 67.0–71.0%.
Synonym: Dibenzoyl Peroxide.
When heated under suitable reaction conditions, benzoyl peroxide decomposes to generate free radicals that can initiate polymerization. The appropriate concentration and processing conditions depend on the monomer system, temperature profile, formulation composition, and required polymer properties.
The water-wet form helps maintain the product in its supplied condition. It does not mean that benzoyl peroxide is dissolved in water. Formulators should confirm that the water content is compatible with the intended polymerization process.
Key Properties
- Thermal free-radical polymerization initiator
- Benzoyl peroxide assay: 67.0–71.0%
- Active oxygen: 4.3–4.8%
- Appearance: white powder or granules
- CAS number: 94-36-0
- Molecular formula: C14H10O4
- Molecular weight: 242.23 g/mol
- Product number: 21446
Applications
Thermal Polymerization
Benzoyl peroxide is used as a source of free radicals in compatible thermally initiated polymerization reactions.
Vinyl Monomer Polymerization
May be evaluated as an initiator for compatible vinyl monomer systems when the formulation and process can accommodate a water-wet initiator.
Resin & Polymer Research
Suitable for laboratory research involving polymer and resin formulations that use benzoyl peroxide initiation chemistry.
Process Development
May be used in small-scale polymerization studies to evaluate initiator concentration, reaction temperature, conversion, and final material properties.
Compatibility & Polymerization Considerations
- Use only in polymerization systems compatible with benzoyl peroxide initiation
- Confirm that the formulation can tolerate the product’s water content
- Initiation behavior depends on temperature, concentration, monomer composition, and reaction conditions
- Evaluate compatibility with monomers, solvents, accelerators, pigments, fillers, and other formulation components
The required initiator concentration and reaction temperature must be established for the specific polymerization system. Small-scale trials are recommended before increasing batch size.
Application Tips
- Keep the material in its supplied water-wet condition
- Use controlled addition and mixing procedures appropriate for organic peroxides
- Avoid grinding, shock, friction, and localized heating
- Monitor reaction temperature carefully during polymerization trials
- Confirm conversion and final polymer properties using suitable analytical methods
Handling & Storage
- Store at room temperature in a cool, well-ventilated location
- Keep away from heat, hot surfaces, sparks, open flames, and other ignition sources
- Do not subject the product to grinding, shock, or friction
- Keep the material wetted and the container securely closed
- Wear protective gloves, protective clothing, and safety glasses
- Use only with adequate ventilation and avoid breathing dust or mist
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FAQ
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1. What is Benzoyl Peroxide, 70% active used for?
It is used as a thermal free-radical initiator in compatible polymerization systems. Reaction conditions must be established for the specific monomers, formulation, and process.
2. What does “70% active, water wet” mean?
It means the product contains approximately 70% benzoyl peroxide and is supplied wetted with water. Product 21446 has a benzoyl peroxide assay specification of 67.0–71.0%.
3. Is benzoyl peroxide soluble in water?
The term “water wet” describes how the product is supplied and does not mean that benzoyl peroxide is dissolved in water. Evaluate the complete formulation to confirm that the water content is acceptable for the intended process.
4. What is the molecular weight of benzoyl peroxide?
Benzoyl peroxide has a molecular weight of 242.23 g/mol and the molecular formula C14H10O4.
5. How should product 21446 be stored?
Store it at room temperature in a cool, well-ventilated location. Keep it wetted, securely closed, and away from heat, sparks, open flames, shock, friction, and other ignition sources.
6. What safety precautions are required?
Wear protective gloves, protective clothing, and safety glasses. Use adequate ventilation, avoid breathing dust or mist, and do not grind or subject the product to shock or friction. Review the Safety Data Sheet before handling.
Safety & Documentation
This product is an organic peroxide with fire, blast, and projection hazards. It is harmful if inhaled, causes skin and eye irritation, may cause an allergic skin reaction, and is very toxic to aquatic life. Keep it wetted and away from heat, ignition sources, grinding, shock, and friction. Review the Safety Data Sheet, product specification, and lot-specific Certificate of Analysis before use.
