(PVC) yog cov thermoplastic nrov uas tsis muaj ntxhiab, khoom, nkig, thiab feem ntau yog xim dawb.Tam sim no nws tau suav tias yog qhov thib peb feem ntau siv yas hauv ntiaj teb (tom qab polyethylene thiab polypropylene).PVC feem ntau yog siv rau hauv cov kav dej thiab cov dej siv, txawm hais tias nws tseem muag hauv daim ntawv pellets lossis li resin hauv nws daim ntawv hmoov.
Kev siv ntawm PVC
Kev siv PVC yog qhov tseem ceeb hauv kev lag luam hauv tsev.Nws tau ua haujlwm tsis tu ncua los yog hloov pauv rau cov kav hlau hlau (tshwj xeeb yog tooj liab, galvanized steel, lossis cam khwb cia hlau), thiab hauv ntau daim ntawv thov uas corrosion tuaj yeem cuam tshuam kev ua haujlwm thiab nce nqi kho.Ntxiv rau cov ntawv thov nyob hauv tsev, PVC kuj tseem siv niaj hnub rau hauv nroog, kev lag luam, tub rog, thiab kev lag luam.
Feem ntau, PVC yog qhov yooj yim dua los ua haujlwm nrog ntau dua li cov yeeb nkab hlau.Nws tuaj yeem txiav mus rau qhov xav tau ntev nrog cov cuab yeej siv tes yooj yim.Fittings thiab cov yeeb nkab txuas tsis tas yuav tsum tau welded.Cov kav dej yog txuas nrog kev siv cov pob qij txha, hnyav cement, thiab cov kua nplaum tshwj xeeb.Lwm qhov zoo ntawm PVC yog tias qee cov khoom uas cov yas tau muab ntxiv yog softer thiab hloov tau yooj yim dua, tsis zoo li nruj, ua rau lawv yooj yim rau nruab.PVC kuj tau siv dav hauv ob qho tib si hloov tau thiab cov ntaub ntawv nruj raws li rwb thaiv tsev rau cov khoom siv hluav taws xob xws li xaim thiab cable.
Hauv kev lag luam kev noj qab haus huv, PVC tuaj yeem pom nyob rau hauv daim ntawv ntawm cov raj pub mis, cov hnab ntim ntshav, cov hnab ntim (IV), cov khoom siv lim ntshav, thiab lwm yam khoom.Nws yuav tsum raug sau tseg tias cov ntawv thov no tsuas yog ua tau thaum phthalates-cov tshuaj uas tsim cov qib hloov pauv ntawm PVC thiab lwm yam yas-yog ntxiv rau cov qauv PVC.
Cov khoom siv dav siv xws li cov tsho tiv nag, hnab yas, cov khoom ua si menyuam yaus, daim npav rho nyiaj, lub vaj hoses, lub qhov rooj thiab qhov rais, thiab cov ntaub thaiv da dej - rau npe rau ob peb yam uas koj yuav pom hauv koj tsev neeg - kuj yog tsim los ntawm PVC hauv ib daim ntawv los yog lwm yam.
Yuav ua li cas PVC ua
Txawm hais tias cov yas yog cov khoom siv tib neeg, ob lub ntsiab lus tseem ceeb uas nkag mus rau hauv PVC - ntsev thiab roj - yog cov organic.Ua PVC, thawj qhov uas koj yuav tsum tau ua yog cais ethylene, ib qho roj av derivative, los ntawm qhov hu ua "feedstock."Hauv kev lag luam chemical, roj av yog cov khoom noj uas xaiv rau ntau cov tshuaj, suav nrog methane, propylene, thiab butane.(Natural feedstocks muaj xws li algae, uas yog ib qho khoom noj rau hydrocarbon fuels, nrog rau pob kws thiab qab zib, uas yog ob qho tib si lwm feedstocks rau ethanol.)
Txhawm rau cais cov ethanol, cov roj av ua kua yog rhuab rau hauv lub cub tawg thiab muab tso rau hauv qhov kub siab (tus txheej txheem hu ua thermal cracking) kom coj tau cov kev hloov pauv ntawm qhov hnyav molecular ntawm cov tshuaj hauv cov khoom noj.Los ntawm kev hloov kho nws qhov hnyav molecular, ethylene tuaj yeem txheeb xyuas, sib cais, thiab sau.Thaum ua tiav, nws txias rau nws lub xeev ua kua.
Cov txheej txheem tom ntej no suav nrog kev rho tawm cov tshuaj chlorine los ntawm cov ntsev hauv dej hiav txwv.Los ntawm kev hla cov hluav taws xob muaj zog los ntawm cov dej ntsev (electrolysis), ib qho hluav taws xob ntxiv ntxiv rau cov tshuaj chlorine molecules, dua, tso cai rau lawv txheeb xyuas, sib cais, thiab muab rho tawm.
Tam sim no koj muaj cov khoom tseem ceeb.
Thaum ethylene thiab chlorine sib ntsib, cov tshuaj tiv thaiv lawv tsim tsim ethylene dichloride (EDC).EDC tau dhau los ua cov txheej txheem thermal tawg thib ob, uas dhau los, tsim cov yas chloride monomer (VCM).Tom ntej no, VCM tau dhau los ntawm cov khoom siv hluav taws xob uas muaj cov khoom siv hluav taws xob, uas ua rau VCM cov molecules txuas ua ke (polymerization).Thaum VCM molecules txuas, koj tau txais PVC resin-lub hauv paus rau tag nrho cov khoom siv yas.
Kev cai nruj, yoog raws, lossis sib xyaw cov yas sib xyaw yog tsim los ntawm kev sib xyaw ntawm cov resin nrog cov formulations sib txawv ntawm cov yas, stabilizers, thiab cov kev hloov kho kom ua tiav cov khoom xav tau uas suav nrog txhua yam ntawm xim, kev ntxhib los mos, thiab yoog mus rau cov kav ntev hauv huab cua huab cua thiab UV.
Qhov zoo ntawm PVC
PVC yog cov khoom siv uas tsis tshua muaj nqi uas yog lub teeb yuag, tuaj yeem yooj yim, thiab feem ntau yooj yim los tuav thiab nruab.Piv rau lwm hom polymers, nws cov txheej txheem tsim khoom tsis txwv rau kev siv roj av lossis roj av.(Ib txhia sib cav hais tias qhov no ua rau PVC ua "sustainable yas" vim nws tsis nyob ntawm cov ntaub ntawv uas tsis muaj zog.)
PVC kuj tseem ruaj khov thiab tsis cuam tshuam los ntawm corrosion los yog lwm yam kev degradation, thiab yog li ntawd, nws tuaj yeem khaws cia rau lub sijhawm ntev.Nws cov formulation tuaj yeem hloov pauv tau yooj yim rau hauv ntau hom kev siv thoob plaws ntau yam kev lag luam thiab kev siv, uas yog qhov tseeb ntxiv.PVC kuj muaj tshuaj lom neeg ruaj khov, uas yog ib qho tseem ceeb thaum PVC cov khoom siv nyob rau hauv ib puag ncig nrog ntau hom tshuaj.Cov yam ntxwv no tau lees paub tias PVC tuav nws cov khoom yam tsis muaj kev hloov pauv tseem ceeb thaum cov tshuaj tau qhia.Lwm qhov zoo muaj xws li:
● Biocompatibility
● Qhov tseeb thiab pob tshab
● Resistance rau tshuaj lom neeg kev nyuaj siab tawg
● Tsawg thermal conductivity
● Yuav tsum tau me ntsis kom tsis muaj kev saib xyuas
Raws li cov thermoplastic, PVC tuaj yeem rov ua dua thiab hloov mus rau hauv cov khoom tshiab rau kev lag luam sib txawv, txawm hais tias vim muaj ntau cov qauv siv los tsim PVC, nws tsis yog ib qho yooj yim txheej txheem.
Disadvantages ntawm PVC
PVC tuaj yeem muaj li 57% chlorine.Cov pa roj carbon - muab los ntawm cov khoom siv roj av - feem ntau yog siv hauv nws cov khoom siv.Vim tias muaj cov co toxins uas tuaj yeem tso tawm thaum lub sijhawm tsim khoom, thaum raug hluav taws kub, lossis thaum nws decomposes hauv qhov chaw pov tseg, PVC tau raug dubbed los ntawm qee cov kws tshawb fawb kho mob thiab cov kws tshawb fawb ib puag ncig ua "cov tshuaj lom yas."
Kev txhawj xeeb txog kev noj qab haus huv ntawm PVC tseem tsis tau muaj pov thawj, txawm li cas los xij, cov co toxins no tau txuas nrog rau cov xwm txheej uas suav nrog tab sis tsis txwv rau kev mob qog noj ntshav, kev loj hlob ntawm tus menyuam hauv plab, kev cuam tshuam endocrine, mob hawb pob, thiab lub ntsws ua haujlwm tsis zoo.Thaum cov tuam ntxhab taw qhia rau PVC cov ntsiab lus ntsev siab uas yog ntuj thiab tsis muaj teeb meem, kev tshawb fawb qhia tias sodium - nrog rau kev tso tawm ntawm dioxin thiab phthalate - qhov tseeb muaj peev xwm ua rau muaj kev phom sij rau ib puag ncig thiab kev noj qab haus huv PVC poses.
Yav tom ntej ntawm PVC yas
Kev txhawj xeeb txog kev pheej hmoo ntsig txog PVC thiab tau ua rau muaj kev tshawb fawb txog kev siv qab zib ethanol rau feedstock es tsis yog naphtha (cov roj flammable tau los ntawm qhuav distillation ntawm thee, shale, los yog roj av).Cov kev tshawb fawb ntxiv tau ua los ntawm bio-based plasticizers nrog lub hom phiaj ntawm kev tsim phthalate-dawb lwm txoj hauv kev.Thaum cov kev sim no tseem nyob rau hauv lawv cov theem pib, kev cia siab yog los tsim cov ntaub ntawv muaj txiaj ntsig zoo ntawm PVC kom txo tau qhov cuam tshuam tsis zoo rau tib neeg kev noj qab haus huv thiab ib puag ncig thaum lub sijhawm tsim khoom, siv, thiab pov tseg.
Post lub sij hawm: Apr-07-2022