Kushatisa kwePVC kunonyanya kukonzerwa nekuparara kwemaatomu anoshanda eklorini mumorekuru pasi pekudziya uye okisijeni, zvichikonzera kugadzirwa kweHCI. Naizvozvo, PVC heat stabilizers akanyanya makomisheni anogona kudzikamisa maatomu eklorini muPVC mamorekuru uye kudzivirira kana kubvuma kuburitswa kweHCI. R. Gachter et al. yakarongedza mhedzisiro yekushisa stabilizer sekudzivirira uye kugadzirisa. Iyo yekutanga ine mabasa ekutora HCI, kutsiva isina kugadzikana maatomu eklorini, kubvisa zvitubu zvemoto, uye kudzivirira oxidation otomatiki. Iyo yekupedzisira kugadzirisa mhando ine chinangwa chekuwedzera kune iyo polyene chimiro, kuita neunsaturated zvikamu muPVC, uye kuparadza carbocations. Kunyanya, sezvinotevera:
(1) Bvisa HC1 yakatorwa muPVC kuti inhibidze yayo yega inokonzeresa kuita. Zvigadzirwa zvakadai semunyu wekutungamirira, organic acid simbi sipo, organotin compounds, epoxy compounds, amines, metal alkoxides uye phenols, uye metal thiols zvose zvinogona kuita neHCI kuvharidzira maitiro eHCI yePVC.
Ini (RCOO) 2+2HCI MeCl+2RCOOH
(2) Tsiva kana kubvisa zvinhu zvisina kugadzikana senge allyl chloride maatomu kana tertiary kabhoni chloride maatomu muPVC mamorekuru, uye bvisa nzvimbo yekutanga yekubvisa HCI. Kana maatomu emarata eorganic tin stabilizers akabatana nemaatomu eklorini asina kugadzikana emamorekuru ePVC, uye maatomu esarufa ari muorganic tin akabatana nemaatomu ekabhoni anoenderana muPVC, maatomu esarufa ari mumuviri wekubatanidza anotsiva nemaatomu echlorine asina kugadzikana. Kana HC1 iripo, iyo coordination bond inotsemuka, uye boka rehydrophobic rinosunga zvakasimba nekabhoni maatomu muPVC mamorekuru, zvichivharisa mamwe maitiro ekubviswa kweHCI uye kuumbwa kwemabhondi maviri. Pakati peSipo dzesimbi, sipo yezingi uye sipo yepoto ine kukurumidza kutsiva kuita nemaatomu echlorine asina kugadzikana, sipo yebarium ndiyo inononoka, sipo yecalcium inononoka, uye sipo yemutobvu iri pakati. Panguva imwecheteyo, iyo yakagadzirwa nesimbi chlorides ine madhigirii akasiyana e catalytic mhedzisiro pakubviswa kweHCI, uye simba rawo rakaita seizvi:
ZnCl>CdCl>>BaCl, CaCh>R2SnCl2 (3) inowedzerwa kumabhondi maviri uye co conjugated double bonds kudzivirira kusimukira kwe polyene zvimiro uye kuderedza coloring. Unsaturated acid salts kana macomplexes ane ma bond maviri, ayo anopinda diene ekuwedzera reaction nePVC molecules, zvichikanganisa chimiro chavo checovalent uye kuvharira shanduko yeruvara. Uye zvakare, sipo yesimbi inoperekedzwa nekaviri chisungo chekufambisa uchitsiva allyl chloride, zvichikonzera kukuvadzwa kweiyo polyene chimiro uye nekudaro ichivharira shanduko yeruvara.
(4) Bata emahara radicals kudzivirira otomatiki oxidation. Kana kuwedzera phenolic heat stabilizers kunogona kuvharidzira kubviswa kweHC1, imhaka yekuti hydrogen atomu isina radicals inopiwa ne phenols inogona kubatana neyakaora PVC macromolecular free radicals, ichigadzira chinhu chisingakwanisi kuita neokisijeni uye ine thermal stabilization effect. Iyi inopisa stabilizer inogona kuva neimwe kana akati wandei mhedzisiro.
Nguva yekutumira: Mar-29-2024
