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Kungani Ukub exposure kwe-UV Kuthinta Ukulahlwa kuka-Polycarbonate
Ukulahlekelwa kwezibalo: Kani UV Radiation Kuthisha Izibhalo zika-Polycarbonate
Xa izululo ze-ultraviolet zihlaza izinhlanzi ezizulu, kwiqiniso lezo eziphakathi kwe-320 nanometers, ziqala ukuvula umongo ngendlawo yemolekiyuli. Okuqala emva koko kuyinkimbinkimbi ngempela - izibalo ze-UV zivula amakhemikhali akhe aqondene ngokuphathelene apho kumolukuli. Leli vuthi livula i-radicals esithintayo okuthandwa ukuxhumana ne-oxygen ehlabathini, libe liphindiselela okuchazwa ngabasebenzi njenge-photo oxidation. Ngemuva kwesimo sika-khemikhali sikhulisayo, sikhaqamisa ngokwempela imigqa emide ye-molecular kwindlu. Lokhu kungaba khona ukuthulaswa kwebanga elisodwa kusuku olunye nge-70% kumaphepha engaphinde aphilengi. Kunezinye izimpawu ezibonakalayo xa kufaqa kuhlala kuhlala. Iziphawu ezincane ziqala ukudala phakathi kweyafasi, zishayisa izululo zonke izindlela. Abantu abaningi bazi lokho ngokuqala njengebubi kumaplastiki ahleli. Ngokusho kwebuciko lika-Plastics Institute likhutshaziwe ngoPitsholo, lo mthubi ubonisa isikhathi sokugcina komongo.
Indima Yokuthutha kanye Nezindlela Zokudala Kwechromophore Ekubonakaleni Kwesihlangothi
Xa izimboni ziqaqazela, lezi ziphinde zihlukaniswe kumgubhu we-polymer zihlanganisa futhi ngendlela esithi izimo ezihlobene nezinhlamvu. Uma lezi ziphinde zingena kuma-7 noma 8 zinhlamvu ehlukile, into ethandwa kuqala - ziyakhula njengazo chromophores. Lezi ziphawu ezithile zomthwalo zinezindlela zokulanda amawaka esiGaba se-visible light. Phakathi kwizinhlobo ezahlukene, amagunya e-carbonyl (lezi ziphinde ze-C=O) ayehlukile njengoba angcono kunezinye. Ayisebenzisa igama elilanda igama elikhulu kwi-450 nanometer ngokusebenzisa ukuguquka kweenqwelo ye-n kuya epi-star, okwenza izinto zibukeke ngaphezulu kwe-yellow kunengcinwa. Abantu abaningi bathola ukuthi ukubuka kwe-yellow ukususwa kwe-dirt noma ukugaywa kwe-heat, kodwa yilokho ukuthi kuyachaza kakhulu. Okunempeleni kungakanani ngendlela efudumeleyo le process ikhipha. Emva kwezingu-18 ngaphansi kwezinkanyezi ze-UV, izimboni ziqashelwa ukubonisa ukubuka kwe-yellow futhi nokugaywa kwesandla nokuphula kwebalaselelwa njengoba kuchazwe kwi-Polymer Degradation Studies ngoPhephandaba last year.
Umbhalo Wokuphazanyika Kwegumbi :
- Amaphotoni ase-UV aphindzisa izinhlayiya zepolymers → Ukakamela Kwemithombo Yezinhloso
- Izinhloso + oksijini → Iihydroperoxides kanye nezigaba ze-carbonyl
- Ukugcinwa kwegumbi ye-carbonyl → Ukuthuthuka Kwesigaba Sechromophore
- Izigaba se-chromophore zizodwa izingcwele eziphansi → Ukubona Okuphuzi
Ukusungulwa Kwe-UV Akukho Mphumela Ngokusebenza Kwe-Polycarbonate Ekugcineni
Indlela Ochithezayo Lwezi-Coatings Nama-Stabilizers Ahlinzekela Ubucophele Bokugcina Kuye Namasiko
Amakhomane okhuso kanye namastabilizaya ayehlisa ukuthi izinto zihlule ngokulanda izikhangiso eziphazanyayo ze-UV kuqala ngaphambi kokuba ziye kumgodi walesi sipolomara. Uma amabhengezi akha lawa mikhakha ekukhuselekweni, bathunyelwa izinto ezilanda imithwalo ye-UV bese yabelana njengezindleko eziphathekayo ngendlela yemolekuli. Sekhona into engu-HALS (amastabilizaya okubonakala angahindiswayo) eyenziwa ngendlela eyahlukene kodwa enbalwa kangaka. Loo mzobo ihlaba ngokuxhaswa kwezimali ezimbi futhi iyadonsa ihydroperoxides engavumelekile. Ngokuphelele, lokhu kugcina kwakhiwa ukuthi izinhlelo zonke ziphume ngcono futhi zisebenze kahle ngeminyaka engaphandle. Izivivinyo zibonisa ukuthi malunga ne-90% yokulinganiso nesimo sokuqala sihlala sisungulwe noma kunjalo isibhedlela eside sesilwa. Lokhu kuyakho kakhulu izincoma zokukhuseleka lezi ngaphezu kwezinye izinto njengo-windows emakhayeni noma amathambo okuphepha apho kudingeka ukubona ngaphakathi nokugcina kakhulu.
Imininingwane Yobude Bengubo: Iziqhamo Ezithunyelwe kanye Nezithunyelwa kwiMimandla Engaqondakali
Ukubheka indlela ikhanda le-polycarbonate iba kwiiziko ezifana needeserti namazwe akwaqala kuvula kwenza kube lunge ukuthi ukukhuseleka kwe-UV kubaluleke kangakanani. I-polycarbonate ephathelene engaphantsi kokucwangciswa kuyapholile kakhulu futhi iphumelela kabini imbangela yayo yemfazwana ngomnyaka weshumi nesibini xa isetshenziselwa phakathi kwamava amagqabi. Lokhu kunguqu esilungile kowabasebenzisa lezinto phandle. Ngokuphambene, izihlangothi ezicwangciswe ngokulungisa kwe-UV zilinda ihlatywa phakade, zibonisa inkohlaka engeyiyo 3% noma ngaphezulu emva kwegama elishumi phandle. Zilinda futhi inhliziyo yazo yonke, zilindela ngaphezulu kuka-85% okwenzelwe uma zazinzuzi. Lo hlongo lwangaphandle kuthinta ukuba izindleko zokubuyisela ziphansi kakhulu futhi kunciphise ukungafanelekile. Kuma-opereyitha wegreenhouse, lokhu kubaluleke ngoba izihlangothi ezimthubiwe zivikela umlilo owudingekayo yezithixo ukuthi zifunde. Aba-architects bayakhiwa ngalo futhi ngoba izihlangothi eziphapheni zinethemba lokushisa ngemvula noma ngamaso aphapha. Lonke uhlelo lwesivikelo lusuka kuthiyolo olulodwa: ukukhuseleka kwe-UV akuyona into esingayengeza ngemuva. Kufuneka kube yinxalenye yesiqalela uma sifuna izinqumulo zethu zaphandle ukuze zibe neminyaka engaphezulu.
Iindlela eziphucwayo yokuphepha kwi-UV kumsebenzi ka-Polycarbonate
Izandla ze-UV ezingaphucanga kanye nezobuchwepheshe bazo ekusetyenzisweni kwisixeko
Kwinqobo ye-co-extrusion, abasebenzi bayakha igunya eliqinile lokuthatha UV ngokuphambene kwi-polycarbonate sheet xa bekwenza. Lo gunya uyaphanda ngokomkhuba wemolekyuli kunye nomfanekiso wokusebenza. Yintoni okwahlukileyo kumagunya ahlelweyo emva kokunyuka? Kusenokuba akukho mlando wokuphendula phantsi ngexesha futhi akukho theko ekudingayo yokulungisa. Igunya elithile lifuna njengemfihlo, likhupha i-UV A ne-UV B kodwa likuvumela kabusha ikakhulu yamandla etholeneyo esibona. Izixhelo zolabhamani ezivavanywa ukuguqulwa kwizilingo zifumanisa ukuthi lezi ziphumo eziphathelene zilapha ngamathathu amashwa kunazo ezingafundeki. Kwanjalo, ubuso bezifundo buveza ukuthi ziqinisekisa ukuba zilahlekelwa kwaye ziqinisekisa ngaphezulu kwezinyanishe eziyi-15 kwimpendulo yezinto. Ngoko ke kutheni kube lunye oluningi lamasuntswana, izinkampani ezenziwe ngamadoda, nezixhobo zangaphandle ezingcinezayo zisebenzisa lo tekinoloji xa kudinga into eyakwenzeka ngexesha lingaphaya ngaphandle kokuhlukunyana.
Ukukhetha Kwe-Additive: HALS vs. I-Absorbers Zomoya Wokubuyisa UV — Uma Kufuneka Usebenzise Yini
Abasebenzi bomongo bakhetha i-stabilizers zomoya wokubuyisa ngokuthiyingxenye kuzimpendulo eziphathelene nendlela esetshenziswa ngayo:
- I-Hindered Amine Light Stabilizers (HALS) iyehla kumasebe amakhulu, emva kwe-UV (isb., izindawo ezide, izindawo ezasendleleni), lapho umoyomelo uphinde ucindezile ukwakha kwamagxekwa. I-HALS isebenza njengesithuthi sezigaba futhi njengesithuthi sesiphazamiso—akusabi umoya wokubuyisa—kanti yilokho okufanele kusetshenziselwa uma kusekelwa kumoya wokubuyisa ngokudala.
- I-Benzotriazole UV absorbers , ngokulinganayo, ihlanya njengamabhuloyidi we-sunscreen ayothatha umoya wokubuyisa phakathi kwe-290–400 nm, ekunikeza ukuphepha okwenziwayo kakhulu kumasebe apholile phakathi kwezindlu nezintandokazi njengezindlela ezivalelwe noma izifasisi ezingaphansi kwezinye izihlahla.
Ukudiphenisa izindawo zombili kusungulwa ukusebenza okuhlanganisiwe: iHALS isondeza ubude bebuso bebenzotriazoles ngama-40% phansi kweqondo elijulile leli (Ukuchazwa Kwesayensi Kwegciwane, 2023). Kuzindlela ezihlobene nokusebenza, izilonda eziphakanyisiwe ze-polycarbonate ezigcwele ngokucophelelana kwesizinda sezindawo ezimbili zinikeza inkinobeko eningi yokuthembeka kakhulu yebusiko nesiseko sekuqhubeka.
Imibuzo Evame Ukubuzwa
Kungani kubonakala okuhlukahluka kwezibhanoyi kumagciwane?
Okuhlukahluka kwezibhanoyi kumagciwane kuchazwa ngokwanguquko kwezithunywa emva kokuxhasa kwezinhloso zomgcwabo, ekhathaza izinketho zomculi wasezinhlwini futhi kwenza ukubonakala okuhlukahluka kwebhanoyi.
Izimvushesheli ezingavikhi UV zivikela kanjani i-polycarbonate?
Izimvushesheli ezingavikhi UV zizimemeza izinketho ze-UV ukufinyelela umgcwabo, zivikela ukugaywa ngokuguqula amandla e-UV ku-heat esebenza futhi zivikela ukudalwa kwezikhumba ze-free radicals.
Ingaba ukuthi kungavikelwa kabusha ukuthintana ne-UV kumasebenzi e-polycarbonate?
Nakuba kudingeka ukuzivikela ngokugcwele kumthwalo ka-UV, ukusebenzisa izigaba ze-UV-resistant ne-stabilizers eziqashelwe ngokuphindaphindiwe zingakhipha isimo sezinto futhi zizondla ubucophe.
Kungani u-HALS nase-Benzotriazole esebenziswa ngokuhlanganisa ukuvikela kuma-UV?
Ukudibanisa u-HALS nase-Benzotriazole kusinika ukuvikela okuvamile; u-HALS uyekwa amakhono athile, wena u-Benzotriazole uyathatha umthwalo ka-UV, okwenzela ukuthuthuka kwesikhathi eside.