Raws li qhov sib txawv ntawm txoj kev taw qhia, cov nplaim hluav taws xob tuaj yeem muab faib ua cov nplaim hluav taws xob ntxiv thiab cov nplaim hluav taws xob hluav taws xob. Cov nplaim hluav taws xob ntxiv feem ntau yog muab tso rau hauv cov polymers hauv lub cev, uas yog kev lag luam thiab siv tau yooj yim, tab sis lawv feem ntau muaj kev sib raug zoo nrog cov polymers. Qhov tsis xws luag hauv cov khoom siv hluav taws xob ntawm cov khoom siv polymer.
Sib txawv ntawm lub hauv paus ntsiab lus ntawm cov nplaim hluav taws kub retardants, reactive nplaim retardants tuaj yeem tsim cov copolymer nrog monomers lossis ua cov tshuaj tiv thaiv kab mob ntawm cov polymers, kom cov ntaub ntawv tuaj yeem muaj cov nplaim hluav taws xob ruaj khov. Ntxiv mus, reactive nplaim retardants muaj me ntsis cuam tshuam rau cov neeg kho tshuab thiab mechanical zog ntawm cov ntaub ntawv polymer, thiab tsuas yog ib tug me me npaum li cas yuav ua tau ib tug zoo dua nplaim retardant nyhuv, uas yog ib tug kub lub ntsiab lus nyob rau hauv tam sim no nplaim retardant kev tshawb fawb. Daim ntawv no tsuas yog qhia txog cov nplaim hluav taws kub nyhiab ntawm cov nplaim hluav taws kub nyhiab thiab cov ntawv thov txheej txheem ntawm epoxy resin, polyurethane, paj rwb ntaub thiab nplaim hluav taws retardant ntawv.
Nplaim Retardant Mechanism ntawm Reactive Flame Retardants
Cov txheej txheem combustion ntawm cov ntaub ntawv polymer yog txheej txheem nyuaj nrog cov tshuaj tiv thaiv multiphase, uas yog nrog los ntawm kev hloov pauv ntawm lub cev thiab tshuaj lom neeg. Reactive nplaim retardants qhia txawv nplaim retardant mechanisms nyob rau hauv txawv nplaim retardant systems, uas yog tshwm sim los ntawm qhov sib txawv nyob rau hauv cov muaj pes tsawg leeg ntawm cov nplaim retardants lawv tus kheej thiab cov khoom ntawm txawv polymers. Tab sis feem ntau, cov nplaim retardant mechanism ntawm reactive nplaim retardants yuav muab faib ua ob pawg: roj theem mechanism thiab condensed theem mechanism.
1. Gas theem mechanism
Ua raws li cov txheej txheem combustion, cov roj theem nplaim hluav taws xob retardant mechanism ntawm reactive nplaim retardants suav nrog cov teebmeem ntawm lub cev thiab tshuaj lom neeg, thiab ntau dua yog cov nyhuv synergistic ntawm ob. Cov nyhuv ntawm lub cev feem ntau yog tshwm sim nyob rau hauv hais tias ib nrab reactive nplaim retardant tuaj yeem nqus tau cov cua sov hauv ib puag ncig, decompose thiab tso tawm cov pa roj tsis zoo xws li nitrogen, ammonia thiab carbon dioxide, uas feem ntau tuaj yeem dilute cov nkev nplaim taws ntawm qhov tawg ntawm cov khoom siv polymer lossis nyob hauv nruab nrab ntawm cov nplaim taws. Nws txo cov concentration ntawm cov roj tsis hloov mus rau qis dua qhov kev txwv kev sib txuas, thiaj li tiv thaiv cov khoom siv txuas ntxiv mus. Qee lub sij hawm qee cov roj uas tsis muaj hluav taws kub kuj muaj cov txiaj ntsig ntawm cov cua kub dissipation, uas tuaj yeem txo qhov kub ntawm ib puag ncig ib puag ncig.
Cov nyhuv tshuaj feem ntau yog tshwm sim hauv kev ntes cov dawb radicals. Piv txwv li, qee cov phosphorus-raws li nplaim hluav taws tuaj yeem tso cov dawb radicals cuam tshuam rau hauv qhov kub thiab txias thiab hnov mob H. thiab O H. uas ua rau combustion. Nyob rau hauv rooj plaub no, cov saw hlau cov tshuaj tiv thaiv ntawm combustion tuaj yeem tiv thaiv tau, thiab cov cua kub tawm los ntawm cov nplaim hluav taws tuaj yeem txo qis heev.
2. Condensation mechanism
Cov nplaim retardant mechanism ntawm reactive nplaim retardants muaj ntau hom kev txiav txim nyob rau hauv lub condensed theem, thiab carbon tsim yog feem ntau hom. Reactive nplaim retardants feem ntau tuaj yeem ua rau muaj qhov tsim ntawm cov khoom siv polymers, tshwj xeeb tshaj yog cov polymers uas muaj oxygen, xws li epoxy resin, cellulose, thiab lwm yam.
Cov txheej txheem carbon feem ntau yog tsim nyob rau hauv thaj tsam ntawm cov roj theem thiab cov theem condensed, thiab muaj kev tiv thaiv zoo. Nws tuaj yeem suav tias yog kev tiv thaiv kev tiv thaiv los tiv thaiv kev sib kis ntawm cov pa oxygen thiab kev xa hluav taws xob hauv huab cua, thiab ua tiav cov txiaj ntsig ntawm inhibiting tiam ntawm cov roj hluav taws xob. Kev siv cov nplaim hluav taws kub nyhiab ntawm cov ntaub paj rwb ua piv txwv, nws hloov cov txheej txheem thermal cracking cov tshuaj tiv thaiv ntawm fiber ntau macromolecular saw nyob rau hauv cov theem condensed, thiab txhawb lub cev qhuav dej, kev sib txuas thiab lwm yam kev cuam tshuam, thiab maj mam tsim cov pa roj carbon txheej. Tus nqi ntawm cov pa roj carbon residue tau nce thiab cov roj combustible txo qis hauv cov txheej txheem.
condensed theem charcoal nplaim retardant
Cov nplaim hluav taws kub hnyiab tuaj yeem tsis tsuas yog nce cov pa roj carbon monoxide, tab sis kuj txhawb kev tiv thaiv oxidation ntawm cov pa roj carbon monoxide thiab tiv thaiv cov pa roj carbon monoxide kom tsis txhob muaj cov pa roj carbon dioxide, yog li txo cov cua sov tawm los ntawm oxidation. Ntxiv nrog rau kev tsim cov char, hom kev ua haujlwm ntawm cov nplaim hluav taws xob reactive nyob rau hauv lub condensed theem kuj muaj xws li dawb radical inhibition, lub zog mechanism ntawm molten polymer viscosity, thiab cov nyhuv ntawm txheej txheej.
Schematic daim duab ntawm nplaim retardancy xws li inhibition ntawm dawb radicals thiab char tsim
Feem ntau, lub luag haujlwm tseem ceeb ntawm cov nplaim hluav taws kub nyhiab hauv cov khoom siv hluav taws xob yog tsim cov roj uas tsis muaj hluav taws xob thaum lub polymer raug hlawv, dilute lub concentration ntawm cov roj combustible, txo cov thermal nyhuv ntawm cov khoom thaum lub sij hawm combustion thiab decomposition, thiab ua rau kom cov pa roj carbonization. . tus nqi, cuam tshuam kev hloov pauv ntawm oxygen thiab cua sov. Tsis tas li ntawd, tom qab qee cov ntaub ntawv polymer raug kho nrog cov nplaim hluav taws kub nyhiab, qhov kub ntawm qhov hluav taws kub tau nce siab, thiab cov nyhuv ntawm cov nplaim hluav taws kuj ua tiav.
Nws Daim Ntawv Thov hauv Polyurethane
Polyurethane (PU) yog ib qho polymer uas muaj cov organic sib txuas los ntawm urethane, thiab muaj ntau yam zoo heev xws li suab nrov zoo, rwb thaiv tsev kub thiab hnav tsis kam. Yog tsis muaj nplaim hluav taws kev kho mob, qhov limiting oxygen Performance index (LOI) ntawm cov khoom siv polyurethane yog li 18 feem pua, uas yooj yim rau hlawv thiab tso tawm ntau cov cua sov thiab cov pa roj carbon monoxide uas tsim kev puas tsuaj rau tib neeg lub cev. Tam sim no, polyurethane reactive nplaim retardants feem ntau qhia cov pab pawg nrog nplaim taws retardant ua haujlwm rau hauv cov qauv molecular ntawm polyurethane los ntawm grafting cov tshuaj tiv thaiv, thiaj li los txhim kho cov nplaim retardant nyhuv thiab thermal stability ntawm polyurethane cov ntaub ntawv nyob rau hauv kub kub ib puag ncig.
Nyob rau hauv cov nplaim retardant hloov pauv ntawm cov ntaub ntawv polyurethane, phosphorus-muaj nplaim retardants feem ntau yog siv, tsis tsuas yog muaj cov nplaim hluav taws zoo tab sis kuj muaj cov pa taws tsawg thiab kev tiv thaiv ib puag ncig. Lub hauv paus ntsiab lus yog los qhia phosphorus rau hauv polyurethane hauv daim ntawv cog lus tshuaj xws li PO lossis PC bonds. Nyob rau hauv cov ntaub ntawv cov qauv, cov covalent daim ntawv cog lus muaj loj zog daim ntawv cog lus thiab muaj zog stability.
Nitrogen-muaj reactive nplaim taws retardant nplaim retardant polyurethane cov ntaub ntawv feem ntau qhia melamine pawg rau hauv cov qauv polyurethane los ntawm covalent bonds. Melamine yog ib qho ruaj khov crystalline compound uas muaj 67 feem pua ntawm nitrogen atoms. Qhov kub nce mus txog 350 degree. Nws sublimates, absorbs ntau lub zog, thiab txo qhov kub thiab txias. Thiab ntawm qhov kub siab dua, melamine decomposes los tsim nitrogen thiab tsim ib qho thermally ruaj khov condensate.
Piv nrog rau kev taw qhia ntawm ib qho hluav taws kub retardant, lub reactive nplaim retardant nrog ob los yog ntau dua nplaim retardant ntsiab yog zoo dua nyob rau hauv cov nqe lus ntawm nplaim retardant nyhuv thiab thermal stability.
