Novel thermal radical initiators based on a triazene moiety for radical polymerization

In this study, we designed and synthesized novel thermal radical initiators of BTAP (1-phenyl-3,3-dipropyltriazene), BTACP (1-(phenyldiazenyl)pyrrolidine), BTACH (1-(phenyldiazenyl)piperidine), and BTACH7 (1-(phenyldiazenyl)azepane) based on a triazene moiety to provide a thermal initiator for radical polymerization. The synthetic method is valuable due to the simplicity. In addition, the synthesized thermal initiator did not affect the color of the polymer. Among the four initiators, the polymerization time for the BTACH of the 6-membered ring decreased by 67%, as opposed to the polymerization time without initiator. Conversion after polymerization was over 92%. DSC experiments also showed that the initiator with hexagonal rings had the lowest peak polymerization temperature of $160^{\circ}C$. Our study suggests a promising new initiator system that is effective for radical polymerization.