The initiator molecules have a certain ability to absorb light in the ultraviolet region (250-400 nm) or in the visible region (400 ~ 800 nm). After direct or indirect absorption of light energy, the initiator molecules transition from the ground state to the excited singlet state. In the excited singlet or triplet state after a single molecule or bimolecular chemistry, resulting in monomer polymerization can lead to active debris, these active fragments can be free radicals, cations, anions and so on. According to the mechanism of triggering, the photoinitiator can be divided into free radical polymerization photoinitiator and cationic photoinitiator, among which the most widely used photopolymer photoinitiator is free.
Our photoinitiator has the following advantages:
(1) cheap, simple synthesis;
(2) photoinitiator and its photolysis products should be non-toxic and tasteless;
(3) good stability, easy to store for a long time;
(4) The absorption spectrum of the photoinitiator must match the emission band of the radiation source and have a high molar extinction coefficient;
(5) Since the majority of the photoinitiator molecules absorb light energy and then transition to the excitation singlet state, the interphase channeling to stimulate the three-line state, therefore, the initiator of the inter-channel transition efficiency is higher;
(6) higher trigger efficiency.