Ulwazi Lwezinto Zokupakisha-Yintoni Ebangela Ukutshintsha Kombala WeeMveliso zePlastiki?

• Ukuthotywa kwe-oxidative yemathiriyeli ekrwada kunokubangela ukuguquka kombala xa kubumba kwiqondo lobushushu eliphezulu;
• Ukuguquka kombala kwiqondo lobushushu eliphezulu kuya kubangela ukuguquka kwemibala yeemveliso zeplastiki;
• Ukusabela kweekhemikhali phakathi kombala kunye nemathiriyeli ekrwada okanye izongezo ziya kubangela ukujika kombala;
• Ukusabela phakathi kwezongezo kunye ne-oxidation ngokuzenzekelayo yezongezo ziya kubangela utshintsho lombala;
• I-Tautomerization yemibala yombala phantsi kwesenzo sokukhanya kunye nobushushu kuya kubangela utshintsho lombala weemveliso;
• Izingcolisi zomoya zinokubangela utshintsho kwiimveliso zeplastiki.

1. Ibangelwa yiPlastiki yokuBumba

I-1) Ukutshatyalaliswa kwe-oxidative yezinto eziluhlaza kunokubangela ukuguquka kombala xa kubumba kwiqondo lokushisa eliphezulu

Xa umsesane wokufudumeza okanye ipleyiti yokufudumala yezixhobo zokubumba zeplastiki zihlala zikwisimo sokufudumeza ngenxa yokungalawuleki, kulula ukubangela ukuba ukushisa kwendawo kuphakame kakhulu, okwenza ukuba i-oxidize i-oxidize kwaye ibole kwiqondo lokushisa eliphezulu. Kwezo iiplastiki ezingevani nobushushu, ezifana nePVC, kulula ukuba Xa le nto isenzeka, xa inzulu, iya kutshisa kwaye ijike ibe tyheli, okanye ibe mnyama, ikhatshwa sisixa esikhulu se-volatiles ephantsi yemolekyuli ephuphumayo.

Oku kuthotywa kubandakanya ukusabela okunjei-depolymerization, i-random chain scission, ukususwa kwamaqela ecala kunye nezinto eziphantsi ze-molecular weight.

• I-Depolymerization

I-cleavage reaction yenzeke kwikhonkco lekhonkco le-terminal, ibangela ukuba ikhonkco letsheyini liwe nganye nganye, kwaye i-monomer eyenziwe iguquke ngokukhawuleza. Ngeli xesha, ubunzima bemolekyuli butshintsha kancinci kakhulu, njengenkqubo ebuyela umva ye-polymerization yekhonkco. Njenge-thermal depolymerization ye-methyl methacrylate.

• Random Chain Scission (Ukuthotywa)

Ekwabizwa ngokuba zikhefu random okanye amatyathanga ezaphukileyo random. Ngaphantsi kwesenzo samandla omatshini, i-radiation-energy high-energy, amaza e-ultrasonic okanye i-reagents yekhemikhali, i-polymer chain iphula ngaphandle kwendawo echanekileyo yokuvelisa i-polymer ephantsi-molekyuli. Yenye yeendlela zokuthotywa kwepolymer. Xa i-polymer chain iyancipha ngokungaqhelekanga, ubunzima be-molecular buyancipha ngokukhawuleza, kwaye ukulahlekelwa kwesisindo sepolymer kuncinci kakhulu. Umzekelo, indlela yokuthotywa kwe-polyethylene, i-polyene kunye ne-polystyrene ikakhulu kukuthotywa kwe-random.

Xa iipolymers ezifana ne-PE zibunjwe kumaqondo aphezulu, nasiphi na isikhundla sekhonkco eliphambili sinokuphulwa, kwaye ubunzima be-molecular buyancipha ngokukhawuleza, kodwa isivuno se-monomer sincinci kakhulu. Olu hlobo lokusabela lubizwa ngokuba yi-random chain scission, ngamanye amaxesha kuthiwa yi-degradation, i-polyethylene I-radicals yamahhala eyenziwe emva kwe-chain scission isebenza kakhulu, ijikelezwe yi-hydrogen engaphezulu kwesibini, ixhomekeke kwiimpendulo zokudluliselwa kwekhonkco, kwaye phantse akukho monomers ziveliswayo.

• Ukususwa kwezinto ezibambeleyo

I-PVC, i-PVAc, njl. Xa i-polyvinyl chloride, i-polyvinyl acetate, i-polyacrylonitrile, i-polyvinyl fluoride, njl. Ukuthatha i-polyvinyl chloride (PVC) njengomzekelo, i-PVC icutshungulwa kwiqondo lobushushu elingaphantsi kwe-180 ~ 200 ° C, kodwa kubushushu obuphantsi (obufana ne-100 ~ 120 ° C), iqala ukukhupha i-dehydrogenate (HCl), kwaye ilahlekelwe yi-HCl kakhulu. ngokukhawuleza malunga ne-200 ° C. Ngoko ke, ngexesha lokucubungula (180-200 ° C), i-polymer ivame ukuba mnyama ngombala kwaye iyancipha ngamandla.

I-HCl yamahhala inempembelelo ye-catalytic kwi-dehydrochlorination, kunye nee-chloride zetsimbi, ezifana ne-ferric chloride eyenziwe yisenzo se-hydrogen chloride kunye nezixhobo zokusebenza, zikhuthaza i-catalysis.

Iipesenti ezimbalwa ze-absorbents ze-asidi, ezifana ne-barium stearate, i-organotin, i-lead compounds, njl., kufuneka zongezwe kwi-PVC ngexesha lokulungiswa kwe-thermal ukuphucula ukuzinza kwayo.

Xa intambo yonxibelelwano isetyenziselwa ukufaka umbala kwintambo yonxibelelwano, ukuba i-polyolefin layer kwi-copper wire ayizinzile, i-carboxylate yobhedu eluhlaza iya kwenziwa kwi-polymer-copper interface. Ezi mpendulo zikhuthaza ukusasazwa kobhedu kwipolymer, kukhawulezisa i-catalytic oxidation yobhedu.

Ngoko ke, ukuze kuncitshiswe izinga lokuthotywa kwe-oxidative ye-polyolefins, i-phenolic okanye i-aromatics ye-amine antioxidants (AH) ihlala yongezwa ukuphelisa le mpendulo ingentla kwaye yenze i-radicals engasebenziyo engasebenziyo A·: ROO·+AH-→ROOH+A·

• Ukuthotywa kwe-Oxidative

Iimveliso zePolymer ezivezwe emoyeni zifunxa ioksijini kwaye zingene kwi-oxidation ukuze zenze i-hydroperoxides, zibole ngakumbi zenze amaziko asebenzayo, zenze iiradicals zasimahla, kwaye emva koko zingene kwi-free radical chain reactions (okt, inkqubo ye-auto-oxidation). Iipolymers zibonakaliswe kwi-oksijini emoyeni ngexesha lokucubungula kunye nokusetyenziswa, kwaye xa ishushu, ukuchithwa kwe-oxidative kuyakhawuleza.

I-oxidation ye-thermal ye-polyolefins yeye-free radical chain reaction mechanism, ene-autocatalytic behaviour kwaye inokohlulwa ibe ngamanyathelo amathathu: ukuqaliswa, ukukhula kunye nokupheliswa.

I-chain scission ebangelwa liqela le-hydroperoxide ikhokelela ekunciphiseni ubunzima be-molecular, kwaye iimveliso eziphambili ze-scission zi-alcohols, i-aldehydes, kunye ne-ketones, ekugqibeleni i-oxidized kwi-carboxylic acids. I-Carboxylic acids idlala indima enkulu kwi-catalytic oxidation yesinyithi. Ukuthotywa kwe-oxidative sesona sizathu siphambili sokuwohloka kweempawu zomzimba kunye noomatshini beemveliso zepolymer. Ukuchithwa kwe-oxidative kuyahluka kunye nesakhiwo se-molecular ye-polymer. Ubukho beoksijini bunokonyusa umonakalo wokukhanya, ubushushu, imitha yemitha kunye namandla omatshini kwiipolymers, okubangela ukusabela okuntsonkothileyo kokuthotywa. Ii-Antioxidants zongezwa kwiipolymers ukucothisa ukuthotywa kwe-oxidative.

2) Xa iplastiki icutshungulwa kwaye ibunjwe, umbala uyabola, uphelelwe kwaye utshintshe umbala ngenxa yokungakwazi ukumelana nokushisa okuphezulu.

I-pigments okanye idayi esetyenziselwa ukufaka imibala yeplastiki inomlinganiselo wokushisa. Xa lo mlinganiselo wobushushu ufinyelelwe, ii-pigments okanye iidayi ziya kutshintsha imichiza ukuze zivelise iikhompawundi ezahlukeneyo zobunzima bemolekyuli, kwaye iifomula zazo zokusabela zintsokothile; ii-pigments ezahlukeneyo zineempendulo ezahlukeneyo. Kwaye iimveliso, ukumelana nobushushu bemibala eyahlukeneyo kunokuvavanywa ngeendlela zokuhlalutya ezifana nokuncipha kobunzima.

2. IiColourants Zisabela ngeMathiriyeli ekrwada

Ukusabela phakathi kwemibala kunye nemathiriyeli ekrwada kubonakaliswa ikakhulu ekulungisweni kwemibala ethile okanye idayi kunye nemathiriyeli ekrwada. Ezi mpendulo zeekhemikhali ziya kukhokelela ekutshintsheni i-hue kunye nokuthotywa kwee-polymers, ngaloo ndlela kutshintshe iimpawu zeemveliso zeplastiki.

• Ukunciphisa Ukusabela

Ezinye iipolymers eziphezulu, ezifana nenayiloni kunye ne-aminoplasts, zi-asidi ezomeleleyo zokunciphisa i-asidi kwindawo etyhidiweyo, ezinokunciphisa kunye nokucima i-pigments okanye idayi ezinzile kwiqondo lokushisa.

• Utshintshiselwano ngealkaline

Iintsimbi zomhlaba zealkaline kwiipolima ze-emulsion zePVC okanye iipolypropylene ezithile ezizinzileyo “zinokutshintshiselana ngesiseko” kunye nesinyithi somhlaba sealkaline kwimibala yokutshintsha umbala ukusuka oluhlaza-bomvu ukuya kuorenji.

I-PVC emulsion polymer yindlela apho i-VC ipholymerized ngokuvuselela kwi-emulsifier (njenge-sodium dodecylsulfonate C12H25SO3Na) isisombululo samanzi. Ukusabela kuqulethe iNa +; ukwenzela ukuba kuphuculwe ukushisa kunye nokuchasana kwe-oksijeni ye-PP, i-1010, i-DLTDP, njl. I-oksijeni, i-antioxidant ye-1010 yi-transesterification reaction eyenziwa yi-3,5-di-tert-butyl-4-hydroxypropionate methyl ester kunye ne-sodium pentaerythritol, kwaye i-DLTDP ilungiselelwe ngokusabela isisombululo se-Na2S samanzi kunye ne-acrylonitrile Propionitrile i-hydrolyodized ekugqibeleni ukuvelisa i-asidi kunye ne-asidi. efunyenwe nge-esterification kunye ne-lauryl alcohol. Ukusabela kwakhona kuqulethe iNa +.

Ngexesha lokubunjwa kunye nokusetyenzwa kweemveliso zeplastiki, i-Na+ eshiyekileyo kwi-raw material iya kusabela nge-pigment yechibi equlethe i-ion zetsimbi ezifana ne-CIPigment Red48: 2 (BBC okanye i-2BP): XCa2++2Na+→XNa2+ +Ca2+

• Ukusabela phakathi kwePigments kunye neHydrogen Halides (HX)

Xa izinga lokushisa liphakama ukuya kwi-170 ° C okanye phantsi kwesenzo sokukhanya, i-PVC isusa i-HCI ukuze yenze i-conjugated double bond.

I-halogen-equlathe i-pololefin e-retardant-flame-retardant okanye iimveliso zeplastiki ezingenakunqandwa ngumlilo zikwayi-dehydrohalogenated HX xa ibunjwe kubushushu obuphezulu.

1) Ultramarine kunye ne-HX yokusabela

I-ultramarine blue pigment esetyenziswa kakhulu kumbala weplastiki okanye ukuphelisa ukukhanya okutyheli, yikhompawundi yesulfure.

2) I-pigment yobhedu yegolide yobhedu ikhawulezisa ukubola kwe-oxidative ye-PVC ekrwada.

Ii-pigments zobhedu zinokuxutywa kwi-Cu + kunye ne-Cu2 + kwiqondo lokushisa eliphezulu, eliya kukhawulezisa ukubola kwe-PVC.

3) Ukutshatyalaliswa kwee-ion zetsimbi kwiipolymers

Ezinye ii-pigments zinempembelelo eyingozi kwiipolymers. Umzekelo, i-pigment ye-manganese yechibi i-CIPigmentRed48:4 ayifanelekanga ukubunjwa kweemveliso zeplastiki zePP. Isizathu kukuba ixabiso eliguquguqukayo le-ion yensimbi ye-manganese i-catalyze i-hydroperoxide ngokugqithiswa kwee-electron kwi-oxidation ye-thermal okanye i-photooxidation ye-PP. Ukubola kwePP kukhokelela ekugugeni okukhawulezileyo kwePP; ibhondi ye-ester kwi-polycarbonate kulula ukuba i-hydrolyzed kwaye ihlanjululwe xa ishushu, kwaye emva kokuba kukho i-ion zetsimbi kwi-pigment, kulula ukukhuthaza ukubola; ion zentsimbi ziya kukhuthaza kwakhona ukubola thermo-oksijini PVC kunye nezinye izinto ekrwada, kwaye kubangele utshintsho umbala.

Ukushwankathela, xa uvelisa iimveliso zeplastiki, yeyona ndlela inokwenzeka kwaye isebenzayo yokuphepha ukusetyenziswa kwee-pigments ezinemibala eziphendula ngezinto eziluhlaza.

3. Ukusabela phakathi kwemibala kunye nezongezo

1) Ukusabela phakathi kwee-pigments ezinesulfure kunye nezongezo

I-Sulfur-containing pigments, efana ne-cadmium yellow (isisombululo esiqinileyo se-CdS kunye ne-CdSe), ayifanelekanga kwi-PVC ngenxa yokunganyangeki kwe-asidi, kwaye akufanele isetyenziswe kunye ne-additives equkethe i-lead.

I-2) Ukuphendulwa kweekhompawundi ezine-lead ezine-sulfur-containing stabilizers

Umxholo okhokelayo kwi-chrome pigment emthubi okanye i-molybdenum ebomvu iphendula kunye ne-antioxidants efana ne-thiodistearate DSTDP.

3) Ukusabela phakathi kwe-pigment kunye ne-antioxidant

Kwizinto eziluhlaza ezine-antioxidants, ezifana ne-PP, ezinye ii-pigments nazo ziya kusabela kunye ne-antioxidants, ngaloo ndlela zenza buthathaka umsebenzi we-antioxidants kunye nokwenza ukuzinza kwe-oksijini ye-thermal yezinto eziluhlaza kubi nakakhulu. Ngokomzekelo, i-phenolic antioxidants itsalwa lula yikhabhoni emnyama okanye isabelana nabo ukuze ilahlekelwe ngumsebenzi wabo; i-phenolic antioxidants kunye ne-titanium ion kwiimveliso zeplastiki ezimhlophe okanye ezinombala okhanyayo zenza i-phenolic aromatics hydrocarbon complexes ukuze zenze ukuba tyheli kweemveliso. Khetha i-antioxidant efanelekileyo okanye ungeze izongezo ezincedisayo, ezifana netyuwa ye-zinc ye-anti-acid (i-zinc stearate) okanye i-P2 yohlobo lwe-phosphite ukukhusela ukuguqulwa kombala we-pigment emhlophe (TiO2).

4) Ukusabela phakathi kwe-pigment kunye ne-stabilizer yokukhanya

Impembelelo ye-pigments kunye ne-stabilizers yokukhanya, ngaphandle kokuphendula kwee-pigments ezinesulfure kunye ne-nickel-containing stabilizers yokukhanya njengoko kuchazwe ngasentla, ngokubanzi kunciphisa ukusebenza kwe-stabilizers yokukhanya, ngakumbi umphumo wokuthintela ukukhanya kwe-amine kunye ne-azo yellow and red pigments. Umphumo wokuhla okuzinzile ubonakala ngakumbi, kwaye awuzinzile njenge-uncolored. Akukho ngcaciso icacileyo yale nto.

4. Ukusabela Phakathi Kwezongezo

Ukuba izongezo ezininzi zisetyenziswa ngokungafanelekanga, ukusabela okungalindelekanga kunokwenzeka kwaye imveliso iya kutshintsha umbala. Umzekelo, i-retardant ye-Sb2O3 idibana ne-anti-oxidant enesulfure ukuze ivelise i-Sb2S3: Sb2O3+–S–→Sb2S3+–O–

Ngoko ke, kufuneka kuthathelwe ingqalelo ekukhetheni izongezo xa kuqwalaselwa uqulunqo lwemveliso.

5. I-Auxiliary Auto-oxidation IiMbangela

I-oxidation ngokuzenzekelayo ye-phenolic stabilizers yinto ebalulekileyo yokukhuthaza ukuguqulwa kombala weemveliso ezimhlophe okanye ezikhanyayo. Olu tshintsho ludla ngokubizwa ngokuba “yiPinking” kumazwe angaphandle.

Idityaniswe ngeemveliso ze-oxidation ezifana ne-BHT antioxidants (2-6-di-tert-butyl-4-methylphenol), kwaye imile njenge-3,3′,5,5′-stilbene quinone ukukhanya kwemveliso ebomvu yokusabela, Oku kuguquguquka kwenzeka. kuphela xa kukho ioksijini kunye namanzi kunye nokungabikho kokukhanya. Xa ibonakaliswe kukukhanya kwe-ultraviolet, ukukhanya okubomvu kwe-stilbene quinone ukubola ngokukhawuleza ibe yimveliso yeringi enye emthubi.

6. I-Tautomerization yeePigments eziMbala Ngaphantsi kwesenzo sokukhanya kunye nokushisa

Ezinye ii-pigments ezinemibala zifumana i-tautomerization ye-molecular configuration phantsi kwesenzo sokukhanya kunye nobushushu, njengokusetyenziswa kwe-CIPig.R2 (BBC) ii-pigments ukutshintsha ukusuka kuhlobo lwe-azo ukuya kuhlobo lwe-quinone, olutshintsha isiphumo sokuqala sokudibanisa kwaye sibangele ukubunjwa kwe-conjugated bonds. . kuncipha, okukhokelela kutshintsho lombala ukusuka kumbala oluhlaza okwesibhakabhaka-obomvu obomvu ukuya kobomvu orenji.

Ngelo xesha, phantsi kwe-catalysis yokukhanya, ibola ngamanzi, iguqula i-co-crystal yamanzi kwaye ibangele ukubola.

7. Okubangelwa ziZingcolisi zoMoya

Xa iimveliso zeplastiki zigcinwa okanye zisetyenziswa, ezinye izinto ezisebenzayo, nokuba yimathiriyeli ekrwada, izongezo, okanye ii-pigments zombala, ziya kusabela ngokufuma emoyeni okanye kungcoliseko lweekhemikhali ezinjengeeasidi kunye nealkali phantsi kokukhanya nobushushu. Iintlobo ezahlukeneyo zeekhemikhali ezintsonkothileyo ziyabangelwa, nto leyo eya kukhokelela ekuphelelweni okanye ekutshintsheni kombala ekuhambeni kwexesha.

Le meko inokuphetshwa okanye incitshiswe ngokongeza i-oxygen stabilizers efanelekileyo ye-thermal, i-stabilizers yokukhanya, okanye ukhethe izongezo zokumelana nemozulu ephezulu kunye nee-pigments.