Ukuwohloka kwe-PVC kubangelwa ikakhulukazi ukubola kwama-athomu e-chlorine asebenzayo ku-molecule ngaphansi kokushisisa nomoya-mpilo, okuholela ekukhiqizeni i-HCI. Ngakho-ke, iziqinisi zokushisa ze-PVC ziyinhlanganisela ngokuyinhloko ekwazi ukuzinzisa ama-athomu e-chlorine kuma-molecule e-PVC futhi avimbele noma amukele ukukhululwa kwe-HCI. R. Gachter et al. ihlukanise imiphumela yezinzisi zokushisa njengokuvimbela nokulungisa. Eyokuqala inemisebenzi yokumunca i-HCI, ishintsha ama-athomu e-chlorine angazinzile, isuse imithombo yokuthungela, futhi ivimbele i-oxidation ezenzakalelayo. Uhlobo lwakamuva lokulungisa luhlose ukwengeza esakhiweni se-polyene, ukuphendula ngezingxenye ezingagcwele ku-PVC, nokucekela phansi ama-carbocation. Ngokuqondile, kanje:
(1) Absorb HC1 ekhishwe ku-PVC ukuze uvimbele umsebenzi wayo wokuzisiza. Imikhiqizo efana nosawoti oholayo, insipho yensimbi ye-organic acid, izinhlanganisela ze-organotin, izinhlanganisela ze-epoxy, ama-amine, ama-alkoxide ensimbi nama-phenols, nama-metal thiols konke kungasabela nge-HCI ukuvimbela ukusabela kwe-HCI kwe-PVC.
Mina (RCOO) 2+2HCI MeCl+2RCOOH
(2) Faka esikhundleni noma susa izinto ezingazinzile njengama-athomu e-alyl chloride noma ama-athomu ekhabhoni chloride ephakeme kuma-molecule e-PVC, futhi uqede indawo yokuqala yokususwa kwe-HCI. Uma ama-athomu kathayela we-organic tin stabilizers ehlangana nama-athomu e-chlorine angazinzile wama-athomu e-PVC, kanye nama-athomu esibabule ku-organic tin exhumanisa nama-athomu e-carbon ahambisanayo ku-PVC, ama-athomu esibabule emzimbeni wokuxhumanisa athatha indawo yama-athomu e-chlorine angazinzile. Uma i-HC1 ikhona, isibopho sokuxhumanisa siyahlukana, futhi iqembu le-hydrophobic libopha ngokuqinile nama-athomu ekhabhoni kuma-molecule e-PVC, ngaleyo ndlela livimbele ukusabela okwengeziwe kokususwa kwe-HCI nokwakhiwa kwamabhondi aphindwe kabili. Phakathi kwezinsipho zensimbi, insipho ye-zinc nensipho yebhodwe inokusabela okushesha kakhulu esikhundleni nama-athomu e-chlorine angazinzile, insipho ye-barium ihamba kancane, insipho ye-calcium ihamba kancane, futhi insipho yomthofu iphakathi. Ngasikhathi sinye, ama-chloride ensimbi akhiqizwayo anamazinga ahlukahlukene omphumela we-catalytic ekususweni kwe-HCI, futhi amandla awo ami kanje:
ZnCl>CdCl>>BaCl, CaCh>R2SnCl2 (3) yengezwa kumabhondi aphindwe kabili kanye ne-co conjugated double bond ukuvimbela ukuthuthukiswa kwezakhiwo ze-polyene nokunciphisa umbala. Osawoti be-asidi engagcwalisiwe noma ama-complexes anamabhondi aphindwe kabili, abhekana nokusabela kokwengezwa kwe-diene nama-molecule e-PVC, ngaleyo ndlela aphazamise ukwakheka kwawo okuhlangene futhi avimbele ukushintsha kombala. Ngaphezu kwalokho, insipho yensimbi ihambisana nokudluliswa kwesibopho esiphindwe kabili ngenkathi ishintsha i-alyl chloride, idala umonakalo esakhiweni se-polyene futhi ngaleyo ndlela ivimbele ukushintsha kombala.
(4) Thwebula ama-radicals mahhala ukuvimbela i-oxidation ezenzakalelayo. Uma ukungeza ama-phenolic heat stabilizers kungavimba ukukhishwa kwe-HC1, kungenxa yokuthi ama-radicals mahhala e-athomu ye-hydrogen ahlinzekwa ama-phenol angabhangqwana nama-radicals amahhala e-PVC acekeleke phansi, enze into engakwazi ukusabela nge-oxygen futhi inomphumela wokuzinzisa okushisayo. Lesi siqinisi sokushisa singaba nomphumela owodwa noma eminingana.
Isikhathi sokuthumela: Mar-29-2024
