Emkhakheni kagesi, enye yezinto ezibalulekile ezintanjeni zikagesi namakhebuli i-insulating and jacketing materials.Iminyaka eminingi, izinto zokufakelwa ezivelele zamakhebuli kagesi kwakuyiphepha elifakwe uwoyela ngenxa yezakhiwo zalo ezinhle zikagesi.Futhi inamandla okumelana nezinga eliphezulu lokugcwala okushisayo ngaphandle kokuwohloka ngokweqile.Kodwa-ke, ngenxa ye-hygroscopicnature yayo, isikhwama sensimbi sinomswakama.Ngakho-ke, bekunesidingo esizwakala isikhathi eside sezinto ezifakwa kukhebula ezisebenza ngogesi, ebezinenhlanganisela yemvelo engeyona i-hygroscopic ye-thermoplasticmaterials.
Ukulungiswa kwama-polymers ahlanganisiwe kungenziwa ngezindlela ezimbili ezihlukene.Enye i-chemicalmethod kanti enye iyindlela ye-ionizing.Yize ukugcwaliseka kwalo mphumela wokuphambana kuneminyaka engaphezu kwengu-150, umthelela oxhumanisayo wemisebe ye-ionizing waboniswa okokuqala nguCharlesby.Indlela ye-radiation crosslinking ikhiqiza kakhulu izintambo ezincane nezincane futhi ngenxa yalokho izintambo ezisetshenziselwa izinto zikagesi neze-elekthronikhi zikhiqizwe indlela ye-radiation crosslinking.Le ndlela inenzuzo ngenxa yokusebenzisa amandla aphansi futhi idinga indawo encane.Inqubo yemisebe ilawulwa kalula futhi inamandla okonga amandla kanye nokulawulwa kokungcola.Izici eziqondile zokuphambana kwemisebe zifingqwa kanje:(1) Isivinini somugqa wokukhiqiza singalawulwa.Isembozo sesivinini esiphezulu (i-extrusion) singenzeka, njengoba kungekho mfuneko ye-agent yokuxhumanisa.Ngokusebenzisa i-accelerator enamandla amakhulu namandla aphansi, ukuphulukiswa okusheshayo kungafinyelelwa.(2) Ukufana kwe-Crosslinking kuhle kakhulu.Ukuxhumanisa iyunifomu ngokukhetha umshini ofanele kanye nokwamukela umklamo osezingeni eliphezulu wokuphakela ngocingo kungenziwa.(3) Izinhlobo ezihlukahlukene zamapholymer zingalungiswa, kuye ngezinga lokuxhumanisa ngenqubo yokuxhumanisa ngemisebe.Ngaphezu kwalokho, inqubo yokwelapha ngemisebe ingcono kakhulu kunenqubo yokwelapha umusi.Enqubweni yokwelapha ye-thesteam, amanzi angena kungqimba ye-polymer ngaphansi komfutho we-steam ephezulu adala inqwaba 'yama-microvoid', angabangela ukuhlukana kokukhishwa okuyingxenye okumise okwesihlahla uma ikhebula lisebenza.Nakuba lesi simo siyinkimbinkimbi kakhulu, izihlahla zingakhula futhi zibangele ukuncipha kwamandla e-dielectric ezintambo.Ngaphandle kwalokhu, inqubo yokwelapha isitimu inezihibe ezithile ngokombono wokusetshenziswa kwamandla: (a) umfutho wesitimu ophezulu uyadingeka ukuze kutholwe izinga lokushisa eliphezulu;(b) ukusebenza kahle kokushintshwa kwe-thermal okuvela ngaphandle kwekhebula kuphansi futhi (c) amandla amakhulu asetshenziswa ikhondakta yekhebula, okuholela ekusebenzeni okuphansi kokushisa kanye nesikhathi eside sokusabela kokuxhumanisa.Ukwelapha ngemisebe kuyikhandidethi lezinqubo ezomile.Kodwa-ke, kunenkinga yokuthi ukwakheka kwama-electron kumile futhi/noma ukwakhiwa kwesendlalelo sokugxilisa ngemisebe nakho kudala ukuwohloka okuyingxenye okumise okwesihlahla phakathi nangemuva kokushiswa kwemisebe.Ihluke ngokuphelele 'kwinqubo engenamanzi'.Njengoba ikhebula le-polymer liqukethe umswakama ophezulu kanye nama-voids amakhulu, inqubo yokwelapha iyadingeka.Ngaphandle kwalezi zinzuzo ezingenhla, izinto zokwakha ze-semiconductor zingethulwa kalula enqubweni yokwelapha ngemisebe okungelula uma kwenzeka inqubo yokwelapha isitimu njengoba izinto eziningi zingakwazi ukumelana nezinga lokushisa eliphezulu nokucindezela.
Inqubo yokuxhunyelelwa kwemisebe nayo idlulisela i-conductivity ku-matrix.Lena indlela eyingqayizivele yokuhlanganisa ukuqhutshwa kwe-matrix kuleyo evikelayo.Le nqubo ihilela ukuvalwa kwe-polymer yomgogodla nge-monomer efanelekile ngokuxhunyelelwa kanye nokubekwa okulandelayo kwe-polymer eqhubayo phezu kwendawo esebenzayo yomgogodla.Ngaphandle kokuziphatha kwe-insulating, kulokhu i-polymer ingaziphatha njengokuqhuba eyodwa.Yize ingakaqiniseki, ingabonisa izinhlelo zokusebenza ezingaba khona ezimbalwa ezifana nokuvikela i-EMI, ama-coatings nama-antistatic agents.Bhattacharya etal.balungise izinhlanganisela ze-polymer–FEP-g-(AA)–PPY kanye ne-polymer–FEP-g-(sty)–PPY.Ekuqaleni, i-polymer–FEP yayiyi-radiated form Co-60 futhi ifilimu yabe isicwiliswa kumaphesenti ahlukene ama-monomers.I-PPy yabe ifakwa phezu kwendawo exhunyelelwe nge-oxidative polymerisationof pyrrole kusetshenziswa i-ferric chloride njenge-oxidant.Ukumelana nobuso kunciphile futhi kungokwe-oda lika-104–105ohm/cm2.Ukumelana nendawo kuncike kumaphesenti wokuxhunyelelwa kwama-monomers.Ngokusebenzisa le nqubo, ukuqhutshwa kwe-surface conductivity esikhundleni sokuhamba ngobuningi kungandiswa.I-Photoconductingbehaviour yefilimu ingabuye idluliselwe nge-grafting technique.I-Cellulose acetate-g-(N-vinyl carbazole) kanye ne-cellulose acetate-g-(N-vinyl carbazole–methyl methacylate) yizibonelo zefilimu elenza isithombe.
Embonini yamakhebula kagesi, ikakhulukazi i-polyethylene, i-polyvinyl chloride (PVC), amarabha e-EPDM asetshenziswa.I-polyethylene isetshenziswa ngenxa yezindawo zayo ezinhle kakhulu zikagesi kanye nobude bayo besikhathi eside.I-polyethylene ene-low density ithandwa kune-high-densitypolyethylene ngenxa yezizathu ezimbalwa. Izizathu zimi kanje: (a) ukuguquguquka okwengeziwe;(b) amandla e-dielectric aphezulu kune-high-density polyethylene;(c)impilo ende kune-HDPE;(d) okunzima kakhulu ukucubungula kune-HDPE kanye (e) nengozi encane yokufakwa kwama-voids ekufakweni kwe-LDPE, okubangela i-ionization.Naphezu kwazo zonke lezi zinzuzo, i-LDPE inemikhawulo yayo njengempahla yokufaka ikhebula.Njengoba iyi-polymer ye-thermoplastic, inezinga lokushisa elithambile eliba ngu-105–115⬚C futhi inomkhuba wokuqhekeka kwengcindezi yenzeke lapho ixhumene nama-ejenti athile asebenza ebusweni.Ukuphambana kwama-molecule e-polyethylene kuthuthukisa izakhiwo ezishisayo kanye nezomzimba kuyilapho izakhiwo zawo zikagesi ngokuvamile zihlala zingashintshile.I-Crosslinked polyethylene, ngakho-ke, ayisekho i-polymer ye-thermoplastic.Ithambisa endaweni encibilikayo ye-crystalline ye-polyethylene futhi ithatha ukunwebeka, ukufana kwenjoloba, indawo eyigcinayo phakathi nokukhuphuka okwengeziwe kwezinga lokushisa, ize ibe yi-carbonise ngaphandle kokuncibilika ku-300⬚C.Ukuthambekela kokuqhekeka kwengcindezi kuyanyamalala ngokuphelele futhi ukumelana okuhle kakhulu nokuguga emoyeni oshisayo kuyatholwa.Izintambo ze-polyethylene eziphambanisiwe zikhethwa kakhulu ngenxa yezindawo zazo ezinhle kakhulu zikagesi nezomzimba.Iyakwazi ukuthwala amaza amakhulu, imelana nokugoba irediyasi encane futhi inesisindo esincane, ivumela ukufakwa kalula nokwethenjelwa, okungukuthi ayinayo imikhawulo yobude ngoba ayiqukethe noma yimaphi amafutha futhi ngaleyo ndlela ayinakho ukwehluleka ngenxa yokufuduka kukawoyela emafutheni. ikhebula lenkundla.Futhi ngokuvamile ayidingi i-metallic sheath.Ngakho-ke, ayinakho ukwehluleka okukhethekile kumakhebuli ensimbi, ukugqwala nokukhathala.Izinsuku zamanje, i-radiation crosslinking isetshenziswa ngokwezimboni ku-polyethylene kuphela kodwa nakwamanye ama-polymers afana ne-polyvinyl chloride, i-polisobutylene njll. I-PVC ngokwayo i-polymer engazinzile ngokwedlulele.Iqale ukuthola ukubaluleka kwezohwebo kuphela ngemuva kokuthuthukiswa kwezindlela ezisebenzayo zokuzinzisa.Ngosizo lwama-ejenti okuguqula (izinza, amapulasitiki, izihlungi nezinye izithasiselo), i-PVC ingenziwa ukuze ibonise izakhiwo eziningi, kusukela kokuqinile kakhulu kuye kwezivumelana nezimo kakhulu.Ukuhlukahluka kokusetshenziswa kwayo kanye nezindleko zayo eziphansi kunesibopho sokubaluleka kwayo emakethe yomhlaba.
Ukwandisa ukusebenza kahle kokuxhumanisa, ama-polymers awavamile ukusetshenziswa ngendlela yawo ehlanzekile.Amapulasitiki, ama-antioxidants, izigcwalisi zinendima yazo ngendlela yazo yokudlulisela izakhiwo ezidingekayo.I-addition iba ngcono ngesikhathi senqubo yokuxhumanisa.Amapulasitiki engezwa kuma-polymers ukunciphisa ukonakala komkhiqizo we-polymer.Zithinta ukuxhumanisa noma nini lapho zibamba iqhaza esizukulwaneni sama-freeradicals noma zifaka ukusabela okusabalalisa.I-Dibutyl phthalate, i-tritolyl phosphate ne-diallyl phosphate yizibonelo ezivamile ze-plasticiser ku-PVC.Ukuguquguquka nokunwebeka, okubaluleke kakhulu ekufakweni kukagesi, kuyathuthukiswa ngokungeza amapulasitiki ku-PVC.Empeleni uma kwenzeka i-PVC, eyi-polar ngenxa yesakhiwo esingalingani, idala amabhondi aqinile e-intermolecular, ahlanganisa amaketanga e-macromolecular ngokuqinile, ndawonye ayenze inganwebeki.Ama-Antioxidants elinye iqembu lezithasiselo, ezidingekayo kunoma iyiphi ingxube exhunywe ku-crosslink eklanyelwe injongo engokoqobo yokuqhathanisa ukuzinza okuphezulu kwe-thermooxidative emkhiqizweni we-polymer.Ngokuvamile zithinta i-crosslinking byscavenging radicals, engase yakhe izixhumanisi.I-RC (4,4-thio-bis(6-tert-butyl-3-methyl phenol), MB(Mercapto benzoimidazole) yizibonelo zama-antioxidants asetshenziswa i-Ueno et al. Ngaphezu kwamaplastiki nama-antioxidants, imibala iyadingeka, Imibala yepulasitiki ihlanganisa izinhlobonhlobo zezinto ezingaphili kanye nezinto eziphilayo.Izithasiselo eziguquliwe azikhethwa kulo mkhakha. Ama-filler ngokuvamile ayengezwa ukuze kuthuthukiswe izakhiwo zawo ze-physico-mechanical kanye nokusebenza. Kutholakala ukuthi isivuno sama-radicals ku-polyethylene senyuke ngo-50%, lapho kwengezwa inani elincane (0.05%) le-aerosil. Kucatshangwa ukuthi ukukhiqizwa okuphezulu kwama-radicals kwenzeka ku-interphase aerosil– i-polyethylene, lapho ama-macromolecules angaba sesimweni sokungalingani sezinhlobo ezinganxeshezelwanga Ngokuqukethwe okuphezulu kokugcwalisa, ukudluliswa kwamandla ukusuka ku-filler kuya esigabeni se-polymer kungenzeka futhi ngaleyo ndlela kube nomthelela ekuvunweni okuphezulu kwama-freeradicals.Ngaphezu kwalokho, inhlanganisela yokukhanya nenhlanganisela esebenzayo ingase ithinte ukwenziwa kwasendaweni kwezixhumanisi ezihambisana namaketanga e-polymer.
Kafushane, imisebe idlala indima ebalulekile ekucutshungulweni kwe-polymer esetshenziswa emkhakheni kagesi.'I-Radiation crosslinking' isenzakalo lapho izakhiwo zama-polymers zingathuthukiswa.Iyindlela ethuthuke kakhulu efana 'ne-vulcanisation' inemikhawulo ethile.Ukusebenza kahle kwe-crosslinking kungathuthukiswa ngokukhetha ama-monomer afanelekile.Enqubweni ye-radiation crosslinking, ama-plasticisers, ama-fillers kanye nokwengezwa okubushela ilangabi kusebenza kahle enqubweni yokuxhumanisa imisebe.Indlela ye-radiationcrosslinking nayo iwusizo kakhulu ekulungiseleleni izinto ezisetshenziswayo zokulinganisa i-semiconductor.Ngaphandle kwalokhu, indlela yokuxhunyelelwa ngemisebe ingabuye isetshenziswe ukuze kulungiswe ifilimu eyinhlanganisela namafilimu anokuziphatha kwe-photoconducting.
Isikhathi sokuthumela: May-02-2017