Di(3,5,5-trimethylhexanoyl) peroxide

Di(3,5,5-trimethylhexanoyl) peroxide (CAS 3851-87-4) is an organic peroxide initiator commercially available under trade names including Trigonox 36, Trigonox 36C75, Lup 219, USP 355M, and Peroyl 355. It carries EC number 223-356-0 and has the molecular formula C18H34O4. No E-code designation applies to this substance.

In plastics and polymer manufacturing, this peroxide functions as a free-radical initiator for the polymerization of vinyl monomers such as vinyl acetate and acrylates, decomposing thermally to generate reactive radicals that drive chain growth. It is also employed as a cross-linking agent in rubber compounding, where radical generation creates covalent bonds between polymer chains, improving mechanical strength and heat resistance.

This compound is subject to REACH registration requirements within the European Union and must be handled in accordance with applicable peroxide transport and storage regulations. It is typically supplied in liquid concentrate form, with diluted grades such as the 75% formulation available to meet handling and safety requirements.