{"id":8837,"date":"2025-09-05T10:08:44","date_gmt":"2025-09-05T10:08:44","guid":{"rendered":"https:\/\/changhongchemical.com\/?p=8837"},"modified":"2026-04-27T11:16:00","modified_gmt":"2026-04-27T11:16:00","slug":"what-is-a-photoinitiator","status":"publish","type":"post","link":"https:\/\/changhongchemical.com\/pt\/what-is-a-photoinitiator\/","title":{"rendered":"O que \u00e9 um fotoiniciador\uff1f"},"content":{"rendered":"

What is a photoinitiator<\/strong>\uff1f<\/strong><\/h1>\n

photoinitiator, also known as (photosensitizer) or (photocuring agent),<\/p>\n

\"\"These compounds absorb specific wavelengths of light energy in the ultraviolet (250-420 nm) or visible (400-800 nm) regions, generating reactive species such as free radicals or cations, which then initiate polymerization, crosslinking, and curing. They play a key role in photocuring systems and are widely used in UV adhesives, UV coatings, UV inks, and gel polishes.<\/p>\n

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01 Principle of Action<\/b><\/strong><\/p>\n

After absorbing light energy, photoinitiator molecules transition from the ground state to an excited state, undergoing chemical changes via singlet or triplet states to generate active fragments (such as free radicals and cations) that can initiate polymerization. Based on their mechanism, they can be categorized as follows:<\/p>\n

– Free radical photoinitiators: <\/b><\/strong>These generate free radicals through cleavage or hydrogen abstraction reactions, initiating free radical polymerization.<\/p>\n

– Cationic photoinitiators: <\/b><\/strong>After photolysis, they generate a strong proton acid (such as a Br\u00f8nsted acid), initiating cationic polymerization.<\/p>\n

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02 Classification & Typical Representatives<\/b><\/strong><\/p>\n

Free Radical Photoinitiators:<\/p>\n

(1) Cleavage-Type Initiators<\/b><\/strong><\/p>\n

After absorbing light energy, a Norrish I reaction occurs, and the bond breaks to generate free radicals:<\/p>\n