Woyambitsa kuwala

Woyambitsa kuwala

Mu dongosolo photocurable, kuphatikizapo UV guluu, UV ❖ kuyanika, UV inki, etc., kusintha kwa mankhwala kumachitika atalandira kapena kuyamwa mphamvu kunja, ndi kuwola kukhala ma radicals ufulu cations, motero kuyambitsa polymerization anachita.

Photoinitiators ndi zinthu zomwe zimatha kutulutsa ma free radicals ndikuyambitsanso ma polymerization powunikira.Ma monomers ena akaunikiridwa, amayamwa ma photon ndi kupanga chisangalalo M* : M+ HV →M*;

Pambuyo pa homolysis ya molekyulu yoyendetsedwa, chowonjezera chaulere M *→ R·+R '· chimapangidwa, kenako polymerization ya monomer imayambika kupanga polima.

Ukadaulo wochiritsa ma radiation ndiukadaulo watsopano wopulumutsa mphamvu ndi chitetezo cha chilengedwe, womwe umayatsidwa ndi kuwala kwa ultraviolet (UV), mtengo wa elekitironi (EB), kuwala kwa infrared, kuwala kowoneka, laser, fluorescence yamankhwala, ndi zina zambiri, ndipo imakumana ndi "5E" Makhalidwe: Zothandiza, Zothandizira, Zachuma, Zopulumutsa Mphamvu, ndi Zogwirizana ndi Zachilengedwe. Chifukwa chake, amadziwika kuti "Green Technology".

Photoinitiator ndi chimodzi mwazinthu zofunika kwambiri zomatira zojambulidwa, zomwe zimagwira ntchito yayikulu pakuchiritsa.

Pamene photoinitiator ndi kuwala ndi kuwala kwa ultraviolet, imatenga mphamvu ya kuwala ndikugawanika kukhala ma radicals awiri ogwira ntchito, omwe amayamba ndi unyolo wa polymerization wa photosensitive resin ndi diluent yogwira, kupanga zomatirazo zimagwirizanitsidwa ndi kulimba. Photoinitiator ili ndi mawonekedwe achangu, kuteteza chilengedwe komanso kupulumutsa mphamvu.

Mamolekyu oyambitsa amatha kuyamwa kuwala kudera la ultraviolet (250 ~ 400 nm) kapena dera lowoneka (400 ~ 800 nm). Pambuyo poyamwa mphamvu yowunikira mwachindunji kapena mosadziwika bwino, mamolekyu oyambitsa amasintha kuchokera pansi kupita ku dziko losangalatsa la singlet, ndiyeno kupita ku dziko losangalatsa la katatu kupyolera mu kusintha kwa intersystem.

Pambuyo pa singlet kapena triplet state kusangalala kudzera mu monomolecular kapena bimolecular chemical reaction, zidutswa zogwira ntchito zomwe zimatha kuyambitsa polymerization ya monomer zitha kukhala ma radicals aulere, ma cations, anions, ndi zina zambiri.

Malinga ndi njira zosiyanasiyana zoyambira, ma photoinitiators amatha kugawidwa kukhala free radical polymerization photoinitiator ndi cationic photoinitiator, pomwe ma free radical polymerization photoinitiator ndi omwe amagwiritsidwa ntchito kwambiri.