Polyvinyl chloride (PVC) nws tus kheej muaj ntau cov tshuaj chlorine atoms hauv nws cov qauv molecular. Thaum tshav kub kub, nws tso tawm cov roj hydrogen chloride, uas muaj qee yam inhibitory cuam tshuam rau combustion.Txawm li cas los xij, nws cov txheej txheem combustion tseem tuaj yeem tsim cov tee dej, cov pa luam yeeb, thiab cov pa phem, txwv tsis pub nws siv ntxiv hauv kev tsim kho, hluav taws xob, kev thauj mus los, thiab cov chaw pej xeem. Txhawm rau txhim kho combustion kev ua tau zoo, nplaim retardant additives ua lub luag haujlwm tseem ceeb hauv PVC formulations. Lawv txoj kev xaiv thiab kev sib raug zoo ncaj qha cuam tshuam rau cov khoom siv hluav taws xob hluav taws xob, cov yam ntxwv ntawm cov pa taws, thiab kev nyab xeeb ntawm cov khoom siv hluav taws xob, ua ib qho tseem ceeb rau kev txhim kho hluav taws kev nyab xeeb ntawm cov khoom.
Los ntawm kev xav txog kev sib txuas ntawm kev sib txuas, PVC combustion muaj ntau theem: thermal decomposition, roj-theem combustion, thiab condensed-theem nplaim taws retardancy. Thaum ntxov ntawm thermal decomposition, cov hydrogen chloride tso tawm tuaj yeem dilute qhov concentration ntawm cov pa roj carbon monoxide thiab inhibit dawb radical chain reactions. Txawm li cas los xij, ntawm qhov kub thiab txias, tsis txaus cov pa roj carbonization yooj yim ua rau tsim cov molten droplets, ua kom cov nplaim hluav taws xob nrawm. Lub luag haujlwm ntawm cov nplaim hluav taws xob ntxiv yog los hloov cov txheej txheem combustion los ntawm kev nqus cua sov thiab cua txias, txhawb kev tsim char, cais cov pa oxygen, thiab quenching nplaim dawb radicals. Piv txwv li, inorganic nplaim taws retardants xws li txhuas hydroxide thiab magnesium hydroxide decompose thiab tso dej ntawm crystallization thaum rhuab, absorbing ib tug loj npaum li cas ntawm tshav kub thiab txo qhov kub ntawm cov khoom, thaum ib txhij generating dej vapor rau dilute flammable gases. Phosphorus-raws li cov nplaim hluav taws tuaj yeem txhawb nqa lub cev qhuav dej thiab charring ntawm PVC, tsim cov txheej txheem ntom ntom uas thaiv cov cua sov thiab huab cua hloov pauv. Boron-raws li cov tebchaw tuaj yeem tsim cov iav npog txheej hauv cov theem condensed, inhibiting kev khiav tawm ntawm cov nplaim hluav taws kub.
Raws li kev tswj hwm kev ua tau zoo, cov nplaim hluav taws sib txawv muaj txoj hauv kev sib txawv thiab muaj kev cuam tshuam los ntawm kev txhim kho cov kev sib txuas ntawm PVC. Inorganic hlau hydroxides muaj hluav taws kub retardant efficiency, tsis tshua muaj toxicity, thiab kuj tsis tshua muaj pa luam yeeb ntau lawm, tab sis loj ntxiv tuaj yeem cuam tshuam rau cov neeg kho tshuab lub zog thiab ua fluidity ntawm cov resin, yuav tsum tau synergistic optimization nrog plasticizers thiab kev pab los txo cov kev cuam tshuam tsis zoo. Phosphorus-Nitrogen intumescent nplaim retardants tuaj yeem tsim cov txheej txheem intumescent char thaum combustion, muab cov rwb thaiv tsev kub, oxygen barrier, thiab cov pa luam yeeb, ua rau lawv tsim nyog rau cov ntawv thov nrog cov pa luam yeeb nruj, xws li subway, qhov, thiab siab - nce cov khoom siv sab hauv tsev. Thaum halogenated nplaim taws retardants (xws li bromine-raws li thiab chlorine-raws li halogenated sawv daws yuav) muaj cov nplaim hluav taws kub retardancy thiab xav tau me me xwb, lawv yuav tsim cov tshuaj lom hydrogen halides thiab dioxins thaum combustion lossis siab -kub decomposition. Lawv daim ntawv thov raug txwv vim muaj kev tswj hwm ib puag ncig thiab kev nyab xeeb, thiab lawv tau maj mam hloov los ntawm qis- tshuaj lom, qis- cov pa luam yeeb.
Kev ua tau zoo ntawm cov pa luam yeeb yog lwm qhov tseem ceeb rau kev ntsuas kev nyab xeeb ntawm kev sib txuas ntawm PVC. Ntxiv nrog rau hom nplaim hluav taws kub, kev siv cov pa taws ua ke tuaj yeem txo qhov concentration ntawm cov pa taws pom thiab tsim cov roj corrosive thaum lub sij hawm combustion. Molybdenum compounds, zinc compounds, thiab qee cov hlau oxides tuaj yeem hnov mob nrog hydrogen chloride los ua kom tsawg - volatility ntsev, inhibiting pa taws particle tsim thiab txo corrosivity, uas yog ib qho tseem ceeb heev rau cov neeg khiav tawm thiab cawm hluav taws. Lub synergistic tsim ntawm cov pa taws retardancy thiab nplaim retardancy yuav tsum tau soj ntsuam systematic nyob rau hauv lub formulation theem kom sib npaug ntawm kev sib raug zoo ntawm nplaim taws retardancy efficiency, pa taws retardancy nyhuv, thiab cov khoom ua tau zoo.
Kev ntsuam xyuas ntawm kev ua tau zoo combustion yuav tsum tau ua raws li cov qauv txheej txheem, xws li kev txiav txim siab oxygen (LOI), kev ntsuas hluav taws xob ntsug / kab rov tav, lub khob hliav qab calorimetry, thiab kev ntsuas pa luam yeeb. Cov ntaub ntawv no tsis yog siv los txiav txim siab seb cov ntaub ntawv puas ua tau raws li qhov yuav tsum tau ua ntawm cov nplaim hluav taws kub nyhiab rau kev siv lub tsev, hluav taws xob, lossis kev thauj mus los, tab sis kuj tseem muab cov ntsiab lus ntau rau kev ua kom zoo dua qub. Nyob rau hauv cov khoom tsim, kev siv hluav taws xob hluav taws xob siv hluav taws xob, qhov cua qhov cua, thiab qhov muaj peev xwm ignition qhov chaw ntawm cov kev siv sib txawv yuav tsum tau txiav txim siab los xaiv cov nplaim hluav taws xob tsis zoo, zam kev ua raws li qhov muaj txiaj ntsig zoo rau ib qho kev qhia uas tuaj yeem ua rau muaj kev cuam tshuam ntawm lwm yam kev ua haujlwm lossis kev nce nqi hauv cov nqi.
Zuag qhia tag nrho, kev tswj hwm kev ua tau zoo ntawm PVC additives txhim kho kev nyab xeeb ntawm PVC cov ntaub ntawv nyob rau hauv hluav taws kub los ntawm kev sib koom ua ke ntawm cov nplaim hluav taws kub hnyiab, hluav taws kub hnyiab, thiab char tsim mechanisms. Kev xaiv kev tshawb fawb ntawm qis- toxicity, tsawg- pa luam yeeb, thiab cov nplaim hluav taws kub hnyiab tau zoo thiab cov pa luam yeeb- cov tshuab hluav taws xob tsis tuaj yeem txhim kho cov hluav taws kub tsis zoo ntawm cov khoom thiab txo qis kev sib kis ntawm hluav taws thiab kev phom sij ntawm cov pa phem, tab sis kuj ua raws li cov cai tswj kev nyab xeeb ntsuab, muab kev ruaj ntseg rau kev nthuav dav thiab kev siv hluav taws xob PVC {{1} .