Ukuhlanya Kwesikhathi Somphakathi Wase-Polycarbonate: Kuhlinza Amaphetha Ase-UV

Kungani Ukuthinteka Kwesithunzi Se-UV Kuyisisekelo Sokuphila Kwemifanekiso Yezinkundla Zasepolycarbonate

Indlela Othunzi Lwe-UV Lwesolile Lisibonisa Ukubhala, Ukukhanya Okungafanele, Nokuphatha Kwemithambo Yomkhakha

Uma imisebe yelanga ye-UV ishaya amashidi ophahla e-polycarbonate angavikelekile, iqala inqubo yokuqhekeka kwamakhemikhali ebangela umonakalo ohlala njalo ngezindlela eziningana ezixhunyiwe. Ukukhanya kwe-UV empeleni kuphula izibopho zama-molecule kulezi zinto ze-polymer, ikakhulukazi kuqondiswe kulezo zakhiwo zendandatho ezinuka amakhambi ezimunca amandla e-UV kodwa azikwazi ukuzisusa ngempumelelo. Lokhu kuholela kulokho okubizwa ngokuthi i-chain scission ezingeni lama-molecule. Okokuqala sibona lo monakalo njengokwephuzi kanye nokufiphala ebusweni, okunciphisa inani lokukhanya okudlula cishe ngo-40% ngemuva kweminyaka emihlanu kuphela lapho kuhlolwa ngokwezindinganiso ze-ISO ezifana ne-4892-1 kusukela ngo-2016. Ngesikhathi esifanayo, imifantu emincane iqala ukwakheka ebusweni ngoba ama-plasticizers ahamba noma aqhekeke ngokuhamba kwesikhathi. Le mifantu ivumela umswakama ungene ngokushesha futhi inciphise isakhiwo sonke. Njengoba izinyanga ziphenduka iminyaka, kokubili amandla okudonsa kanye nekhono lokugoba ngaphandle kokuqhekeka kwehla endaweni ethile phakathi kuka-15% no-25%. Ukuhlolwa kwelebhu kubonisa ukuthi ngemva kokuchayeka cishe ku-10,000 kJ ngemitha yesikwele yemisebe ye-UV (njengoba kulinganiswe yi-ISO 4892-3:2016), le nto igcina cishe u-60% wamandla ayo okuqala okugoba. Okwenza lokhu kube yinto ekhathazayo kakhulu ukuthi lokhu kubuthakathaka kwenzeka kancane kancane nangokuthula, isikhathi eside ngaphambi kokuba noma ubani abone noma yiziphi izimpawu ezisobala zokwehluleka.

Ukubizwa Kwemibuzo: Ukuhambisana Kwezindawo Zokusebenza Okwanele Nokuvulwa Kwemithombo Yokuqala Kwamaphethini Angafunywa

I-Polycarbonate inokumelana okumangalisayo komthelela, cishe izikhathi ezingu-250 kunengilazi evamile ngokwezindinganiso ze-ASTM D256. Kodwa kunenkinga efihliwe akekho okhuluma kakhulu ngayo. Indlela ama-molecule e-polycarbonate ahlelwe ngayo iwenza abe sengozini enkulu lapho evezwa ekukhanyeni kwe-UV okuvela elangeni. Uma ubheka kuqala konke kubukeka kulungile ngoba izinto zisazizwa ziqinile futhi ziqinile. Kodwa-ke, ngemva kweminyaka emi-3 kuya kwemi-5 ngaphandle, kwenzeka into engavamile. Amandla epulasitiki okwelula ngaphambi kokuphuka ehla ngaphezu kuka-80%. Kungani lokhu kwenzeka? Nokho, umonakalo we-UV usebenza ezingeni elincane kakhulu, wephula kancane kancane izibopho zamakhemikhali ku-polymer chain ngaphandle kokwenza iphaneli libukeke lonakele ebusweni. Ngakho-ke noma ishidi le-polycarbonate lingase libukeke lilihle ngokuphelele, empeleni lingase lifihle ubuthakathaka obukhulu ngaphakathi. Lokhu kusho ukuthi amaphaneli angaqhekeka ngokuzumayo, aqhekezeke, noma ahluleke ngokuphelele lapho ebhekene nokushintsha kokushisa noma imimoya enamandla, okuyilokho kanye okungekho muntu ofuna kwenzeke ekufakweni kwawo okubizayo.

Ngaphezu kwe-UV: Ukuphatha Kwezinye Izimo Zokuzimela Kwesikhumba Sekhanda Sasezulwini

Nakuba ukuphatha kwe-UV kuyisibonelo esiphambili, ubukhulu bekho polycarbonate kubukhulu bekho ukuphatha kwezinye izimo zokuzimela—kubonisiwe ngokuvamile kumathuluzi asezingeni elizwe nasezindaweni zokusebenza.

Ukuchitha Kwezinhlobo Zokuzimela, Ukugcina Kwemithandane, Nokuphatha Kwezinhlobo Zokuzimela Kwemithandane (Kubonisiwe ngu-ASTM/ISO)

I-polycarbonate isebenza kahle nakuba izintemperetsha zihamba kusukela ku-40° Celsius futhi zihamba kude ku-120° Celsius. Ayikwazi ukuzimisa, ukuzinga kakhulu, noma ukuthakazela ngalokho. Uma kubhekwa emfanekisweni, leli khilomu likhuluma izikhumba ezinkulu zezinyoka zezibambo ezingama-25 millimeters ngaphansi kwemilinganiso yazo ngaphandle kokukhona kwezikhumba. Lokhu kukhona kubantu abaningi abaningi ngoba bahlupha kahle. Izifundo zezimpahla zika-ASTM ne-ISO zibonisa ukuthi izipaneli zika-polycarbonate ziyakwazi ukubuka izivuthi ezihamba ngemvelo kude kwe-150 km/h. Kulezi zindawo ezizimele ngamaphepho amakhulu noma ezindaweni zezihloko eziphakeme lapho imete zihamba kakhulu, lokhu kuyisibonelo esikhulu. Ukuthi lokhu kufuna izimo eziningi zokubeka kumkhiqizo kuyabonisa ukuthi izindawo ezenza izipaneli zika-polycarbonate ziyadinga ukugcina okuncane kanye nokudala kakhulu kulokho okungafani nalo.

Ukuthatha kwamanzi nokuchitha kwezinsuku zokuphupha kanye nokuvutha kwezinsuku zokuvutha kusukela ekuphupheni kuya ekuvutheni kumlinganiso wokuhambisa

Ngokufihla kwe-moisture absorption emzini wakhe engaphezu kwe-0.2%, ipolycarbonate iyaphikisa i-hydrolysis, i-swelling, noma i-creep yeminyaka—izindlela zokuphulukana ezithile kwezinye i-thermoplastics. I-low coefficient of thermal expansion yakhe (65 × 10⁻⁶/K) iyanciphisa i-stress yangaphakathi ngemikhatsi yokuqhubeka kwesikhathi sokuhlala kwezinkathi zokuphupha nokuchitha, ikhathazisa ukulinganiswa kwezibhodi, ukuthinteka kwezinyangoma, nokubamba kwezinkambo ngeminyaka—kodwa futhi ekuseni esinamandla okuhlanza noma emakhaya apho amandla okuhlala akhona.

Izindlela Zokuhlinzekisa UV Kwi-Roof Sheet Yasepolycarbonate: Izicabangi, Izinkambo Ezifakelwe, Nokuchitha Kweminyaka

Izilayiya Zokuhlinzekisa UV Zokufakwa Kusinye vs. Izisolution Zokucabangwa Kusuka Kusuka Kwenyanga: Idatha Yokudura Kwesikhathi Sokusebenza

Kodwa abahleli bapakisha izikhathi zokuphatha kwe-UV ngokujabulisa ku-prosesi yokwenza i-sheet njengoba yisikhathi esibonakalayo sokusebenza ngokuthinta isikhathi esingama-50 ukuya ku-80 microns, lezi zinhlobo zezinto zinakho ukuvikela kahle kusukela kusukela. Lokhu kungani? Lezi zinhlobo zezinkampani zokuvikela kwe-UV zihlanganiswa ngqo ku-materiale yepolymers, akuzange zibe yisikhathi esihlukanisiweyo esiyakwenzeka ngaphandle kokubhalwa ngaphezulu apho kuzothatha amandla okuhlela kwezinye izinqumo, amasikhali, noma ukubuka kwezinto ezingafanele. Iziphakamiso zokusebenza kwiziprojekthi zonke ezaseNorth America, e-Australia, futhi naseMiddle East zibonisa ukuthi lezi zikhathi zokuphatha kwe-UV zilungiselela ngaphezulu kwe-90% yezinhlobo zokubuyela kwabantu babo ngaphandle kokuthi zibonakale kahle ukuthi zihlukile kancane ekuthinteni isikhathi esingaphezu kwe-decade. Kodwa izikhathi zokuphatha kwe-surface zibonisa isiphakamiso esahlukile. Izininzi zibegina ukufihla noma ukubona izindlebe zokugcina zokubonakala ngokushesha ngaphakathi kwe-5 ukuya ku-7 iminyaka ngoba kunezimboni zokuguqula kwezintemperatura nezimboni zokuhlaziyelwa ngokwemisebenzi nokubhala. Nakuba lezi zikhathi zokuphatha kwe-surface zingabonakala zingabi ngezimali ngaphakathi, ukunqoba kwezikhathi zokubuyisela kuzoba yinkululeko eyinkulu eminyakeni eyisikhathi esingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimali ngaphakathi kwezindawo ezingabi ngezimal......

Amthwasa we-UV, Amstabilayizwe we-HALS, kanye nezinkomponente ezingaphansi zokubuyela — Imisebenzi kanye nezinkinga

Ukuhlanganisa izinkampani zokuvikela UV kubalulekile ukuthi zihlangane ngokuhlanganisa izinkampani eziningi zokuvikela ezenza njengoba zihlangane. Izinkampani zokuthintela UV zithatha amagama okuthintela okungafanele okusuka ku-290 ku-400 nanometres futhi ziyabuyisa kakhulu ngokuthintela kwezinto ezingavumelekile. Kwenza kakhulu kuzo izinkampani zokuvikela umshilo wokuhlakaza kwezindawo (Hindered Amine Light Stabilizers), okwenzelwa ngokujwayelekile nge-HALS, ozokukhuluma nezinkampani ezibomvu ezilungile (free radicals) okuzalwa uma izinto zihlwa emshilweni. Futhi kwenza kakhulu kuzo izinkampani ezisemthwakathini ezinokubuyisa UV (reflective nanocomposites) ezisemthwakathini okwenzelwa ngokuphelele nge-silica noma i-cerium oxide ozokubuyisa amagama okuthintela UV kabusha ngaphambi kokuthi zizame ukufika kwezinye izindawo. Kodwa akukho lezi zinhlobo zezinkampani zokuvikela ziyisodwa. Izinkampani zokuthintela UV zihlala zihlukana ngokugcwele emva kwezinsuku eziningi futhi zidinga ukuthi zifakwe ngokulinganayo ukuze zingakwazi ukuthi zibe yisodwa. I-HALS ayisebenzi kahle emazini apho amasimu ayisodwa noma amadwaba ayisodwa. Futhi lezi zinkampani ezisemthwakathini? Uma azifakwanga ngokulinganayo kwezinye izindawo zezinto ngokusebenzisa izindlela zokufaka (extrusion processes), zingabeka izindawo ezingavumelekile kwezinye izindawo. Uma abasebenzi bakwenza ukuthi isibonelo sikhona ngokulinganayo, ikakhulu kumaqembu okufaka kabanjwe (co-extrusion applications), izinto zingahamba ngeminyaka eyisikhombisa noma kude kakhulu. Kodwa uma bahlukanisa isibonelo sokufaka, izinkinga njengekukhanya kwezinto (yellowing) nokuba kwezinto ziyisodwa (brittle) ziyafika kancane kakhulu kunezidingo, lokhu kuyakhiwa kakhulu emazini apho uv exposure kuyisodwa noma kumazini apho amasimu ayisodwa.

Imibuzo Evame Ukubuzwa

Kungani ubukhulu be-UV buyisisekelo kubhodi zokuphepha zesiqephu?

Ubukhulu be-UV buyisisekelo kubhodi zokuphepha zesiqephu ngoba kusiza ekunakweni kwezinkinga zokuphepha kwe-UV njengekuvula, ukukhanya kwezinye izikhathi, nokuhlula kwezinkinga zokusebenza, ngakho kuyenza ukuthi leli sikhundla siyadlula isikhathi eside.

Ubukhulu be-UV buyiphinda kanjani kubhodi zokuphepha zesiqephu?

Ubukhulu be-UV buyiphinda kubhodi zokuphepha zesiqephu ngokuhlanza izihlobo zezinkampani, okubangela ukuvula, ukunciphisa ukuthi kwenzeka ukubonwa kwezilumko, izibhadi zemboni, nokunciphisa ubukhulu bezinkinga zokusebenza ngaphakathi kwezikhathi eziningi.

Izilayiya zokuphepha kwe-UV zokufanana kahle ziyini?

Izilayiya zokuphepha kwe-UV zokufanana kahle ziyizilayiya zokuphepha ozokwenzeka kubhodi zesiqephu ngokugcina kuzo izinhlobo zokulungisa ngokugcina kuzo ngokugcina kuzo kubhodi yezinkampani.

Ukuchaza kwezilayiya zokuphepha kwe-UV zemboni kuyaphakanyiswa kanjani ngezilayiya zokuphepha kwe-UV zokufanana kahle?

Izinkundla zokufaka amaphepha kusuka emhlabeni zihlukana kahle, kubonakala ukuthi zihlukana nokubhujwa ngaphansi kweminyaka eyi-5-7, futhi izinkundla zokugcina uvuvu zokuphathwa kusuka kuzo zinconywa ngokwanele ukuthi zilindelele ukuthi zihlukane kwezinye izinto ezivamile, zikhubaza izinto eziqondile ngaphezu kweyishumi yeminyaka.