Mmebi nke PVC bụ isi ihe na-akpata mmebi nke atọm chlorine na-arụ ọrụ na molekul n'okpuru okpomọkụ na oxygen, nke na-ebute mmepụta nke HCI. Ya mere, ihe na-eme ka okpomọkụ PVC sie ike bụ ihe ndị nwere ike ime ka atọm chlorine dị na molekul PVC sie ike ma gbochie ma ọ bụ nabata ntọhapụ nke HCI. R. Gachter et al. kewara mmetụta nke ihe na-eme ka okpomọkụ sie ike dị ka ihe mgbochi na ihe ngwọta. Nke mbụ nwere ọrụ nke ịmịkọrọ HCI, dochie atọm chlorine na-adịghị akwụsi ike, iwepụ isi mmalite ọkụ, na igbochi oxidation akpaka. Ụdị ihe na-eme ka nke ikpeazụ na-achọ ịgbakwunye na nhazi polyene, meghachi omume na akụkụ ndị na-enweghị afọ ojuju na PVC, na ibibi carbocations. Kpọmkwem, dịka ndị a:
(1) Dọpụta HC1 e si na PVC wepụta iji gbochie ọrụ ya na-akpali akpali. Ngwaahịa dịka nnu ndu, ncha ígwè acid organic, ngwakọta organotin, ngwakọta epoxy, amines, metal alkoxides na phenols, na metal thiols nwere ike imeghachi omume na HCI iji gbochie mmeghachi omume de HCI nke PVC.
Mụ (RCOO) 2+2HCI MeCl+2RCOOH
(2) Dochie ma ọ bụ wepụ ihe ndị na-adịghị agbanwe agbanwe dịka atọm allyl chloride ma ọ bụ atọm carbon chloride nke atọ dị na molekul PVC, ma wepụ ebe mmalite nke mwepụ HCI. Ọ bụrụ na atọm tin nke ihe ndị na-eme ka tin organic sie ike na-ejikọta na atọm chlorine na-adịghị agbanwe agbanwe nke molekul PVC, atọm sulfur dị na tin organic na-ejikọta na atọm carbon kwekọrọ na PVC, atọm sulfur dị na ahụ nhazi na-anọchi anya atọm chlorine na-adịghị agbanwe agbanwe. Mgbe HC1 dị, njikọ nhazi na-ekewa, otu hydrophobic na-ejikọkwa nke ọma na atọm carbon dị na molekul PVC, si otú a na-egbochi mmeghachi omume ndị ọzọ nke iwepụ HCI na ịmepụta njikọ abụọ. N'ime ncha ígwè, ncha zinc na ncha ite nwere mmeghachi omume nnọchi ngwa ngwa na atọm chlorine na-adịghị agbanwe agbanwe, ncha barium bụ nke kacha nwayọ, ncha calcium dị nwayọ, ncha ndu dịkwa n'etiti. N'otu oge ahụ, chloride metal emepụtara nwere oke mmetụta dị iche iche nke catalytic na mwepụ nke HCI, ike ha dịkwa ka ndị a:
A na-agbakwunye ZnCl>CdCl>>BaCl, CaCh>R2SnCl2 (3) na njikọ abụọ na njikọ abụọ iji gbochie mmepe nke nhazi polyene ma belata agba. Nnu acid ma ọ bụ ihe mgbagwoju anya na-enweghị afọ ojuju nwere njikọ abụọ, nke na-enweta mmeghachi omume mgbakwunye diene na molekul PVC, si otú a na-emebi nhazi covalent ha ma na-egbochi mgbanwe agba. Na mgbakwunye, ncha ígwè na-esokwa nnyefe njikọ abụọ mgbe ọ na-anọchi allyl chloride, na-emebi nhazi polyene ma si otú a na-egbochi mgbanwe agba.
(4) Jide radicals efu iji gbochie oxidation akpaka. Ọ bụrụ na itinye phenolic heat stabilizers nwere ike igbochi mwepụ nke HC1, ọ bụ n'ihi na radicals hydrogen atom free nke phenols na-enye nwere ike ijikọ na radicals macromolecular free PVC mebiri emebi, na-emepụta ihe na-enweghị ike imeghachi omume na oxygen ma nwee mmetụta nke ime ka okpomọkụ kwụsie ike. Ihe na-eme ka okpomọkụ kwụsie ike a nwere ike inwe otu ma ọ bụ ọtụtụ mmetụta.
Oge ozi: Maachị-29-2024
