(PVC) yi-thermoplastic ethandwayo engenavumba, eqinileyo, ebhityileyo, kwaye emhlophe ngokubanzi ngombala.Okwangoku ibekwe njengeyesithathu iplastiki esetyenziswa kakhulu kwihlabathi (emva kwepolyethylene kunye ne-polypropylene).I-PVC idla ngokusetyenziswa kwimibhobho yamanzi nakwimibhobho yamanzi, nangona ikwathengiswa ngohlobo lweepellets okanye njengentlaka ekwimo yomgubo.
Ukusetyenziswa kwePVC
Ukusetyenziswa kwePVC yeyona nto iphambili kushishino lokwakha amakhaya.Isetyenziswa rhoqo njengendawo yokutshintsha okanye enye indlela yemibhobho yentsimbi (ingakumbi ubhedu, intsimbi ekhandisiweyo, okanye intsimbi ekhandiweyo), kwaye kwizicelo ezininzi apho umhlwa unokubeka esichengeni ukusebenza kwaye unyuse iindleko zokuyilungisa.Ukongeza kwizicelo zokuhlala, iPVC ikwasetyenziswa rhoqo kumasipala, kushishino, emkhosini, nakwiiprojekthi zorhwebo.
Ngokubanzi, i-PVC ilula kakhulu ukusebenza kunombhobho wensimbi.Inokunqunyulwa ubude obufunwayo kunye nezixhobo ezilula zesandla.Izinto zokufakelwa kunye nemibhobho yokuhambisa akufuneki ukuba zidityaniswe.Imibhobho idibene nokusetyenziswa kwamalungu, i-samente ye-solvent, kunye neglue ezikhethekileyo.Enye inzuzo ye-PVC kukuba ezinye iimveliso ezifakwe kwi-plasticizers zithambile kwaye ziguquguqukayo, ngokuchasene nokuqina, okwenza kube lula ukuzifaka.I-PVC ikwasetyenziswa ngokubanzi kuzo zombini iifom eziguquguqukayo neziqinileyo njengokugquma kumacandelo ombane afana nocingo kunye nentambo.
Kwishishini lezempilo, i-PVC inokufumaneka kwimibhobho yokutya, izikhwama zegazi, iingxowa ze-intravenous (IV), iinxalenye zezixhobo ze-dialysis, kunye nezinye izinto ezininzi.Kufuneka kuqatshelwe ukuba izicelo ezinjalo zinokwenzeka kuphela xa i-phthalates-iikhemikhali ezivelisa amabakala aguquguqukayo ePVC kunye nezinye iiplastiki-zongezwa kwi-PVC formulation.
Iimveliso eziqhelekileyo zabathengi ezifana neengubo zemvula, iingxowa zeplastiki, izinto zokudlala zabantwana, amakhadi okuthenga ngetyala, imibhobho yegadi, iicango kunye neefestile zefestile, kunye namakhethini eshawa-ukukhankanya nje izinto ezimbalwa onokuthi uzifumane kwindlu yakho-nazo zenziwe ngePVC ifom enye okanye enye.
Yenziwa njani iPVC
Nangona iiplastiki ngokuqinisekileyo ziyizinto ezenziwe ngabantu, izithako ezibini eziphambili ezingena kwi-PVC-ityuwa kunye neoli-zizinto eziphilayo.Ukwenza i-PVC, into yokuqala okufuneka uyenze kukwahlula i-ethylene, i-derivative yegesi yendalo, kwinto eyaziwa ngokuba yi "feedstock."Kwishishini lemichiza, i-petroleum yeyona nto ikhethwayo kwiikhemikhali ezininzi, kubandakanya imethane, ipropylene, kunye nebutane.(Izondlo zendalo zibandakanya i-algae, esisisondlo esixhaphakileyo samafutha e-hydrocarbon, kunye nombona kunye nommoba, zombini ezizezinye iindlela zokutya ze-ethanol.)
Ukwahlula i-ethanol, i-petroleum engamanzi ifudunyezwa kwiziko lomphunga kwaye ibekwe phantsi koxinzelelo olugqithisileyo (inkqubo ebizwa ngokuba yi-thermal cracking) ukuzisa utshintsho kubunzima bemolekyuli beekhemikhali ezikwi-feedstock.Ngokuguqula ubunzima bayo bemolekyuli, i-ethylene inokubonwa, yohlulwe, kwaye ivunwe.Yakube yenziwe loo nto, ipholiswe kwimeko yolwelo.
Inxalenye elandelayo yenkqubo ibandakanya ukukhupha inxalenye yeklorine kwityuwa emanzini olwandle.Ngokugqithisa umbane onamandla ngokusebenzisa isisombululo samanzi etyuwa (i-electrolysis), i-electron eyongezelelweyo yongezwa kwii-molecule ze-chlorine, kwakhona, zivumela ukuba zichongwe, zihlulwe kwaye zikhutshwe.
Ngoku unamalungu aphambili.
Xa i-ethylene kunye neklorini zidibana, ukusabela kweekhemikhali ezivelisayo kudala i-ethylene dichloride (EDC).I-EDC ifumana inkqubo yesibini yokuqhekeka kwe-thermal, eya kuthi ivelise i-vinyl chloride monomer (VCM).Emva koko, i-VCM idluliselwa kwi-reactor equkethe i-catalyst, ebangela ukuba ii-molecule ze-VCM zidibanise kunye (i-polymerization).Xa iimolekyuli zeVCM zidibanisa, ufumana i-PVC resin-isiseko sayo yonke i-vinyl compounds.
Iikhompawundi zevinyl eziqhelekileyo, eziguquguqukayo, okanye ezidityanisiweyo zenziwa ngokuxuba i-resin kunye neendlela ezahlukeneyo zeplastiki, izinzile, kunye neziguquli ukuze kuphunyezwe iipropathi ezinqwenelekayo ezibandakanya yonke into ukusuka kumbala, ukuthungwa, kunye nokuguquguquka kokuqina kwimozulu embi kunye neemeko ze-UV.
Izinto eziluncedo zePVC
I-PVC yimathiriyeli enexabiso eliphantsi ekhaphukhaphu, ithambileyo, kwaye kulula ukuyiphatha nokuyifaka ngokubanzi.Xa kuthelekiswa nezinye iintlobo zeepolymers, inkqubo yayo yokuvelisa ayikhawulelwanga ekusebenziseni ioli ekrwada okanye igesi yendalo.(Abanye baphikisa ngelithi oku kwenza iPVC ibe “yiplastiki ezinzileyo” kuba ingaxhomekekanga kwiindlela ezingahlaziyekiyo zamandla.)
I-PVC yomelele kwaye ayichatshazelwa kukuhlwa okanye ezinye iindlela zokuthotywa, kwaye ngenxa yoko, inokugcinwa ixesha elide.Ukuqulunqwa kwayo kunokuguqulwa ngokulula kwiifom ezahlukeneyo zokusetyenziswa kwiindidi ezahlukeneyo zamashishini kunye nezicelo, ezidityanisiweyo ezicacileyo.I-PVC nayo inozinzo kwiikhemikhali, eyona nto ibalulekileyo xa iimveliso zePVC zisetyenziswa kwindawo eneentlobo ezahlukeneyo zeekhemikhali.Olu phawu luqinisekisa ukuba i-PVC igcina iipropati zayo ngaphandle kokwenza utshintsho olubalulekileyo xa kuqaliswa iikhemikhali.Olunye uncedo lubandakanya:
● Biocompatibility
● Ukucaca nokungafihlisi
● Ukumelana nokuqhekeka koxinzelelo lweekhemikhali
● I-conductivity ephantsi ye-thermal
● Ifuna isondlo encinane okanye ingabikho
Njenge-thermoplastic, i-PVC inokuphinda isetyenziswe kwaye iguqulelwe kwiimveliso ezintsha kumashishini ahlukeneyo, nangona ngenxa yeendlela ezininzi ezahlukeneyo zokwenziwa kwe-PVC, akusoloko kuyinkqubo elula.
Ukungalungi kwePVC
I-PVC inokuqulatha ukuya kuthi ga kwi-57% yeklorini.Ikhabhoni—ephuma kwimveliso yepetroleum—nayo ngokufuthi isetyenziswa ekwenzeni kwayo.Ngenxa ye-toxins enokuthi ikhutshwe ngexesha lokwenziwa, xa ibonakaliswe emlilweni, okanye njengoko ibola kwiindawo zokulahla inkunkuma, i-PVC iye yabizwa ngabaphandi bezonyango kunye nabagcini bendalo njenge "plastiki yetyhefu."
Iinkxalabo zempilo ezinxulumene ne-PVC ziseza kuqinisekiswa ngokweenkcukacha-manani, nangona kunjalo, ezi tyhefu ziye zadibaniswa neemeko ezibandakanya kodwa azikhawulelwanga kumhlaza, ukuphazamiseka kokuphuhliswa komntwana, ukuphazamiseka kwe-endocrine, i-asthma, kunye nokunciphisa ukusebenza kwemiphunga.Ngelixa abavelisi bekhomba kwi-PVC ephezulu yetyuwa njengendalo kwaye ayinabungozi, isayensi ibonisa ukuba i-sodium-kunye nokukhululwa kwe-dioxin kunye ne-phthalate-enyanisweni zinokuba negalelo kwizinto ezinobungozi bendalo kunye nempilo ye-PVC.
Ikamva lePVC yePlastiki
Iinkxalabo malunga nemingcipheko enxulumene ne-PVC kwaye ibangele uphando malunga nokusetyenziswa kwe-ethanol yommoba kwisondlo kune-naphtha (i-oyile evuthayo efunyenwe ngokuxutywa kwe-distillation eyomileyo yamalahle, i-shale, okanye i-petroleum).Uphononongo olongezelelweyo lwenziwa kwiiplastiki ze-bio-based ngenjongo yokudala ezinye iindlela ezingenazo i-phthalate.Ngelixa olu vavanyo lusekwinqanaba labo lokuqala, ithemba kukuphuhlisa iindlela ezizinzileyo zePVC ukunciphisa ifuthe elibi elinokubakho kwimpilo yabantu kunye nokusingqongileyo ngexesha lokwenziwa, ukusetyenziswa, kunye nezigaba zokulahla.
Ixesha lokuposa: Apr-07-2022