Cov txheej txheem thermal degradation ntawm PVC yog qhov nyuaj heev, thiab ntau cov tshuaj tiv thaiv cov txheej txheem tuaj yeem ua tiav tib lub sijhawm: molecular saw decomposition los ntawm HCL, oxidation chain breaking thiab cross-linking, nrog rau tsawg tus qauv ntawm cov ntxhiab tsw thiab cov tshuaj tiv thaiv. ntawm loj molecular saw tawg los tsim hydrocarbons, uas cov laus los yog carbonization ntawm PVC tshwm sim los ntawm HCL yog lub ntsiab kev ua tau zoo ntawm thermal degradation.
Raws li cov txiaj ntsig kev tshawb fawb tam sim no, cov txheej txheem ua haujlwm ntawm cov cua sov stabilizer tuaj yeem muab faib ua pawg hauv qab no:
1) Absorb HCI tsim nyob rau hauv cov txheej txheem thermal degradation ntawm resin thiab inhibit nws qhov tsis siv neeg catalytic degradation. Xws li txhuas ntsev, organic acid hlau xab npum, organotin tebchaw, hlau alkol thiab lwm yam inorganic los yog hlau-organic tebchaw, cov tsis muaj zog lub hauv paus ntsev thiab hlau soaps yog ib qho yooj yim rau react nrog HCI, hloov dua siab tshiab rau hauv cov hlau chloride, mus cuag lub hom phiaj ntawm txiav los yog inhibiting decomposition ntawm polyvinyl chloride; Epoxides thiab amines kuj tuaj yeem hnov mob nrog decomposed HCL los tsim cov sib txuas; Phosphite esters thiab mercaptan tebchaw tuaj yeem ua lub luag haujlwm antioxidant, yog li inhibiting degradation thiab nce thermal stability.
2) Hloov qhov tsis ruaj tsis khov allyl chloride atom lossis txiv ntxawm carbon chloride atom hauv polyvinyl chloride molecule kom tshem tawm lub luag haujlwm ntawm qhov chaw degradation. Piv txwv li, cov tshuaj ntxuav tes nrog cadmium thiab zinc, organotin, mercaptan thiab antimony tuaj yeem khi rau cov tshuaj chlorine tsis ruaj khov hauv polyvinyl chloride molecules.
3) Ntxiv cov tshuaj tiv thaiv nrog cov qauv polyene los tiv thaiv kev tsim cov kab ke loj thiab txo cov xim. Yog hais tias unsaturated acid ntsev los yog ester muaj ob daim ntawv cog lus, lub diene ntxiv cov tshuaj tiv thaiv tshwm sim nrog lub conjugated ob daim ntawv cog lus nyob rau hauv lub polyvinyl chloride molecule, yog li rhuav tshem nws conjugated qauv thiab inhibiting xim hloov.
