Ulwazi malunga nokuguga kwerabha

1. Yintoni ukuguga kwerabha?Ibonisa ntoni le nto kumphezulu?
Kwinkqubo yokucubungula, ukugcinwa kunye nokusetyenziswa kwerabha kunye neemveliso zayo, ngenxa yesenzo esibanzi sezinto zangaphakathi nangaphandle, iimpawu zomzimba kunye neekhemikhali kunye neepropati zemishini yerabha ngokuthe ngcembe ziwohloka, kwaye ekugqibeleni zilahlekelwa yixabiso labo lokusetyenziswa.Olu tshintsho lubizwa ngokuba kukuguga kwerabha.Kumphezulu, ibonakala njengeentanda, ukuncamathela, ukuqina, ukuthamba, ukutshova, ukujika kombala, kunye nokukhula kokungunda.
2. Ziziphi izinto ezichaphazela ukuguga kwerabha?
Izinto ezibangela ukuguga kwerabha zezi:
(a) Ioksijini kunye neoksijini kwirabha zingena kwi-radical chain reaction yasimahla kunye neemolekyuli zerabha, kwaye ikhonkco lemolekyuli yaphukile okanye idityaniswe ngokugqithisileyo, okukhokelela kutshintsho kwiipropathi zerabha.I-oxidation sesinye sezizathu ezibalulekileyo zokuguga kwerabha.
(b) Imichiza ye-ozone ne-ozone iphakame kakhulu kunomoya weoksijini, yaye iyingozi ngakumbi.Ikwaphula ikhonkco le-molecular, kodwa umphumo we-ozone kwi-rubber uyahluka kunye nokuba irabha ikhubazekile okanye ayikho.Xa isetyenziselwa irabha ekhubazekileyo (ikakhulukazi irabha engaxutywanga), iintanda ezixhomekeke kwicala lesenzo soxinzelelo zivela, oko kukuthi, okubizwa ngokuba "yi-ozone crack";xa isetyenziswe kwirabha ekhubazekileyo, kuphela ifilimu ye-oxide eyenziwa phezu komhlaba ngaphandle kokuqhekeka.
(c) Ubushushu: Ukuphakamisa iqondo lobushushu kunokubangela ukuqhekeka kwe-thermal okanye i-thermal crosslinking yerabha.Kodwa isiphumo esisisiseko sobushushu sisebenza.Ukuphucula isantya sokusasazwa kwe-oksijini kwaye uvule ukusabela kwe-oxidation, ngaloo ndlela kukhawulezisa isantya sokusabela kwe-oxidation yerabha, into eqhelekileyo yokuguga - ukuguga kwe-oxygen eshushu.
dUmonakalo kwirabha yimitha ye-ultraviolet enamandla aphezulu.Ukongezelela ekubangeleni ngokuthe ngqo ukuphuka kunye nokudibanisa kwe-rubber ye-molecular chain, imisebe ye-ultraviolet ivelisa i-radicals yamahhala ngenxa yokutshatyalaliswa kwamandla okukhanya, okuqalisa kunye nokukhawulezisa inkqubo ye-oxidation chain reaction.Ukukhanya kwe-Ultraviolet kusebenza njengokufudumeza.Olunye uphawu lwesenzo sokukhanya (esihluke kwisenzo sokushisa) kukuba sivela ikakhulu phezu kwerabha.Kwiisampuli ezinomxholo ophezulu weglue, kuya kubakho ukuqhekeka kwenethiwekhi kumacala omabini, oko kukuthi, okubizwa ngokuba "yi-optical yangaphandle ye-cracks".
(e) Uxinzelelo lomatshini: Ngaphantsi kwesenzo esiphindaphindiweyo soxinzelelo lomatshini, i-raber molecular chain iya kuphulwa ukuze ivelise i-radicals yamahhala, eya kubangela i-oxidation chain reaction kwaye yenze inkqubo ye-mechanochemical.I-Mechanical scission yamaketanga eemolekyuli kunye nokusebenza komatshini kweenkqubo ze-oxidation.Yiyiphi enesandla esiphezulu ixhomekeke kwiimeko apho ibekwe khona.Ukongezelela, kulula ukubangela ukuqhekeka kwe-ozone phantsi kwesenzo soxinzelelo.
(f) Ubumanzi: Isiphumo sokufuma sinemiba emibini: Irabha yonakala ngokulula xa ibekwe emvuleni emoyeni ofumileyo okanye intywiliselwa emanzini.Oku kungenxa yokuba izinto ezinyibilikayo emanzini kunye namaqela amanzi acocekileyo kwirubha akhutshwa kwaye anyibilikiswe ngamanzi.Ibangelwa yi-hydrolysis okanye ukufunxa.Ngokukodwa phantsi kwesenzo esitshintshileyo sokuntywiliselwa kwamanzi kunye nokuvezwa kwe-atmospheric, ukutshatyalaliswa kwerubha kuya kukhawuleziswa.Kodwa kwezinye iimeko, umswakama awulonakalisi i-rubber, kwaye unomphumo wokulibazisa ukuguga.
(g) Ezinye: Kukho imidiya yekhemikhali, i-valence metal ion, i-high-energy radiation, umbane kunye nebhayoloji, njl., ezichaphazela irabha.
3. Ziziphi iintlobo zeendlela zokuvavanya ukuguga kwerabha?
Inokwahlulwa ibe ngamacandelo amabini:
(a) Indlela yokuvavanya ukwaluphala ngokwendalo.Ikwahlulahlulwe kwakhona ibe luvavanyo lokuguga olusemoyeni, uvavanyo lokuguga olukhawulezileyo lomoya, uvavanyo lokuguga olugcinwe kwindawo yendalo, indawo yendalo (kubandakanywa nomhlaba ongcwatywe, njl.njl.) kunye novavanyo lokuguga lwebhayoloji.
(b) Indlela yokuvavanya ukuguga okukhawulezileyo.Ukuguga okushushu, ukuguga kwe-ozone, ukufota, ukuguga kwemozulu eyenziweyo, ukuguga kwe-photo-ozone, ukuguga kwebhayoloji, imitha ye-eneji ephezulu kunye nokuguga kombane, kunye nokuguga kwemidiya yekhemikhali.
4. Liliphi ibakala lobushushu elimele likhethelwe uvavanyo lokuguga komoya oshushu kwiikhompawundi ezahlukeneyo zerabha?
Kwirabha yendalo, ubushushu bovavanyo buqhele ukuba yi-50 ~ 100℃, kwirabha yokwenziwa, iqhele ukuba yi-50~150℃, kwaye ubushushu bovavanyo kwezinye iirubha ezikhethekileyo buphezulu.Umzekelo, irabha ye-nitrile isetyenziswa kwi-70 ~ 150 ℃, kwaye irabha ye-silicone fluorine isetyenziswa ngokubanzi kwi-200 ~ 300 ℃.Ngamafutshane, kufuneka kumiselwe ngokovavanyo.