Iintshukumo eziqaliswe kumitha zingahlelwa ngokwezintlu ezimbini: (1) ukudibanisa kunye ne-scission kunye (2) nokuxhunyelelwa kunye nokunyanga.
I-Crosslinking yi-intermolecular bond formation of polymer chain.Iqondo lokuxhumanisa lilingana nethamo lemitha.Ayifuni amaqela angaxutywanga okanye asebenze ngakumbi.Ngaphandle kwezinye izinto (njengakwiipolymers eziqulethe aromatics), ayihlukanga kakhulu kunye nesakhiwo sekhemikhali.Ayihlukanga kakhulu ngamaqondo obushushu.Nangona indlela yokunxibelelana ngemitha iye yaphononongwa ukusukela ekufumaneni kwayo okokuqala, akukabikho sivumelwano sibanzi malunga nobume bayo.Indlela yokudibanisa ngokubanzi iyahluka kunye neepolymers ezichaphazelekayo.Indlela eyamkeleke kwihlabathi jikelele ibandakanya ukucandeka kweqhina le-C-H kwitsheyini yepolymer enye ukuze yenze iathom yeathom yehydrogen, kulandele ukutsalwa kweathom yehidrojeni yesibini kwikhonkco elingummelwane ukuvelisa imolekyuli yehydrogen.Emva koko ii-radicals ezimbini ezikufutshane ze-polymeric zidibanisa zenze i-crosslink.Isiphumo esipheleleyo se-crosslinking kukuba ubunzima be-molecular ye-polymer bukhula ngokuthe ngcembe kwi-dose ye-radiation, okukhokelela kumatyathanga e-branched de, ekugqibeleni inethiwekhi ye-polymer ye-dimensional ye-three-dimensional xa ikhonkco ngalinye le-polymer lidityanisiwe. kwelinye ikhonkco.
Ngokwahlukileyo, i-scission yinkqubo echaseneyo yokudibanisa apho ukuphuka kwe-C-C bondsoccurs.I-Crosslinking inyusa umndilili wobunzima bemolekyuli ngelixa inkqubo yokugqibela iyayinciphisa.Ukuba amandla osasazo lwemitha aphezulu, ukuqhawuka kwamakhonkco kwenzeka ngokucandeka kwebhondi ye-C–C.Kwi-aeratedsolution medium, nangona kunjalo, indlela yobuchwephesha yescission iqhubeka ngendlela engathanga ngqo.I-radicals yamahhala ye-Thepolymeric yenziwa ngama-radicals angenayo i-solvent, esele yenziwe yi-radiation.Ukongezwa kwe-oksijini kunye ne-polymeric free radicals zenza iintlobo ze-peroxy, ezithi kwi-decom-position zenze iimolekyuli ezincinci.Ukuthotywa kwe-oxidative yeepholima kuxhomekeke kwi-solventus kwi-system.Ngokwenyani, ukuthotywa kwepolymer kukhuphisana ne-oxidation yesinyibilikisi.
I-Grafting yindlela apho ii-monomers ziziswa ecaleni kwikhonkco le-polymer apho i-ascuring yi-polymerisation ekhawulezayo yomxube we-oligomer monomer ukuze yenze i-coating, e-essen-tially eboshwe ngamandla omzimba kwi-substrate.Ngeyona ndlela ilula, ezo ndlela zibandakanya iinkqubo ezingafaniyo, isubstrate iyifilim, ifayibha okanye umgubo, kunye nemonomer njengolwelo oluneat, umphunga okanye isisombululo.Kukho unxulumano olusondeleyo phakathi kokuxhunyelelwa kunye nokunyanga nangona kukho iiyantlukwano ezithile.Ngokwenyani, akukho mda wexesha lenkqubo yokuxhunyelelwa.Kungathatha imizuzu, iiyure okanye iintsuku, ngelixa ukunyanga kuyinkqubo eqhelekileyo ekhawulezayo eyenzeka kwiqhezu lesibini.Ekufakeleni, iibhondi ze-C-C ezihlangeneyo ziyenziwa ngelixa ekunyangeni, ukudibanisa kudla ngokubandakanya i- weakervan der Waals okanye i-London dispersion forces.van der Waals bonding isebenza kumgama apho kukho ukudityaniswa okuncinci okanye kungabikho utshintshiselwano kwaye idityaniswa ngokubanzi namandla amancinci.Nangona kunjalo, i-covalentbonding, iyasebenza kumgama omncinci we-internuclear kwaye inxulunyaniswa nokudibana kwe-electron, utshintshiselwano, kwaye ngenxa yoko amandla aphezulu.Omnye umba obalulekileyo wokunyangwa kweempendulo kukuba kungenzeka ukuba kuhlonyelwe ngaxeshanye kunye nokunyanga kwenzeke okukhokelela kuphuculo lweempawu zemveliso egqityiweyo, ingakumbi ekuncamatheleni kunye nokuba bhetyebhetye.
Ukuxhunyelelwa kuqhubeka ngeendlela ezintathu ezahlukeneyo: (a) phambi kokukhanya;(b) i-peroxidation kunye (c) nobugcisa be-mutual irradia-tion.Kwi-pre-irradiation technique, i-polymer backbone yokuqala ifakwe kwi-vacuum okanye kubukho begesi engasebenziyo ukwenza i-radicals yamahhala.I-substrate ye-polymer ene-irradiated iphathwa nge-monomer, enokuba ngulwelo okanye umphunga okanye njengesisombululo kwi-solvent efanelekileyo.Nangona kunjalo, kwindlela yokuxutywa kwe-peroxidation, i-polymer ye-trunk iphantsi kwemitha ephezulu yamandla xa kukho umoya okanye i-oxygen.Isiphumo kukubunjwa kwee-hydroperoxides okanye i-diperoxides ngokuxhomekeke kubume bepolymeric backbone kunye neemeko zokurhawuzelela.Iimveliso ze-peroxy, ezizinzileyo, ziphathwa nge-monomer kwiqondo lobushushu eliphezulu, apho iiperoxides zingena kwi-radicals yokubola, ezithi ziqalise ukuxhunyelelwa.Inzuzo yolu buchule kukuba i-peroxyproducts ephakathi ingagcinwa ixesha elide ngaphambi kokuba yenze inyathelo lokuxhunyelelwa.Kwelinye icala, ngeteknoloji ye-irradiation ehambelanayo i-polymer kunye ne-monomers zifakwa kwimitha ngaxeshanye ukwenza i-radicals yasimahla kwaye ke ukongeza kwenzeka.Kuba iimonomers zingavezwanga kwiradiation kwi-pre-irradiation technique, ingenelo ecacileyo yaloo ndlela kukuba ikhululekile noko kwingxaki yokwenziwa kwehomopolymer eyenzeka ngobuchule obungaxeshanye.Nangona kunjalo, i-addivantaged egqitywe kwi-pre-irradiation technique kukukrazula kwe-polymer yesiseko ngenxa ye-directradiation yayo, evelisa ubukhulu becala ukusekwa kwee-copolymers zebhloko kune-graftcopolymers.
Ixesha lokuposa: May-03-2017