Benzoyl peroxide
The radical initiator that cures MMA floors and many polyester and vinyl ester resins, usually as a stabilized powder or paste.
Benzoyl peroxide (molecular weight about 242.2 g/mol) is an organic peroxide whose weak O–O bond splits to form free radicals. In construction resins it is supplied phlegmatized (diluted and stabilized) as a powder or paste for safer handling.
BPO initiates the free-radical cure of MMA floor and deck systems, unsaturated polyester and vinyl ester resins, gelcoats and some adhesives. The dose is adjusted for temperature to control pot life and cure time.
On its own, BPO decomposes slowly at room temperature. An amine accelerator in the resin, often an aromatic tertiary amine, speeds decomposition so radicals form quickly, start polymerization of the C=C double bonds and cure the resin within about an hour.
BPO is an organic peroxide and an oxidizer: heat, friction, contamination or mixing with accelerators can cause rapid, violent decomposition. Store cool, away from accelerators, metals and combustibles, and add it only to the resin as instructed, never directly to the accelerator.
Radical formation slows at low temperatures, so more initiator (within the manufacturer’s range) keeps cure time practical. Too much can make the cure too fast or brittle.
No. Combining peroxide directly with amine accelerators can cause a violent reaction. Always follow the component order on the product instructions.
