fotoiniciált

Fotoiniciált is a term used in chemistry to describe a substance that initiates a chemical reaction upon exposure to light. These compounds, known as photoinitiators, absorb light energy and subsequently undergo a process that generates reactive species, such as free radicals or cations. These reactive species then trigger the polymerization of monomers or other chemical transformations.

The mechanism typically involves the photoinitiator molecule absorbing photons of specific wavelengths. This absorption excites the molecule to a higher energy state. From this excited state, the molecule can undergo fragmentation, electron transfer, or energy transfer processes, leading to the formation of initiating species. For example, some photoinitiators cleave upon irradiation to form two free radicals. Others abstract a hydrogen atom from a co-initiator to generate radicals.

Photoinitiators are crucial components in various applications, most notably in photopolymerization. This process is widely employed in UV-curable coatings, inks, adhesives, and 3D printing. The rapid curing afforded by photoinitiators under UV or visible light allows for faster production cycles and enables the creation of complex three-dimensional structures. The selection of a photoinitiator depends on factors such as the light source used, the desired curing speed, and the compatibility with the specific monomers and other components in the formulation.