Tsebo ea Thepa ea Packaging - Ke Eng e Bakang Phetoho ea 'Mala oa Lihlahisoa tsa Plastiki?

• Ho senyeha ha oxidative ea lisebelisoa tse tala ho ka 'na ha etsa hore ho be le mebala ha ho thehoa mocheso o phahameng;
• Ho fifala ha colorant ka mocheso o phahameng ho tla baka ho fifala ha lihlahisoa tsa polasetiki;
• Karabelo ea lik'hemik'hale lipakeng tsa 'mala le lisebelisoa tse tala kapa li-additives li tla baka ho fetoha ha mmala;
• Karabelo lipakeng tsa li-additives le oxidation ea othomathike ea li-additives e tla baka liphetoho tsa mebala;
• Tautomerization ea mebala ea mebala tlas'a ketso ea leseli le mocheso e tla baka liphetoho tsa 'mala oa lihlahisoa;
• Lintho tse silafatsang moea li ka baka liphetoho lihlahisoa tsa polasetiki.

1. E Bakiloeng ke Polasetiki ea Mould

1) Ho senyeha ha oxidative ea lisebelisoa tse tala ho ka baka ho fifala ha ho bopeha ka mocheso o phahameng

Ha lesale la ho futhumatsa kapa poleiti e futhumatsang ea lisebelisoa tsa ho sebetsa ka polasetiki e lula e le sebakeng sa ho futhumatsa ka lebaka la ho tsoa taolong, ho bonolo ho etsa hore mocheso oa sebaka o be o phahameng haholo, e leng se etsang hore thepa e tala e oxidize le ho senyeha ha mocheso o phahameng. Bakeng sa li-plastiki tse nang le mocheso, tse kang PVC, ho bonolo ho Ha ketsahalo ena e etsahala, ha e le e tebileng, e tla chesa 'me e fetohe mosehla, kapa e be e ntšo, e tsamaeang le palo e kholo ea li-volatiles tse tlaase tsa limolek'hule tse phallang.

Ho nyenyefatsa hona ho kenyelletsa likarabelo tse kangdepolymerization, random chain scission, ho tlosoa ha lihlopha tsa mahlakoreng le lintho tse tlaase tsa boima ba limolek'hule.

• Depolymerization

Karabelo ea cleavage e etsahala ho sehokelo sa ketane ea terminal, e etsang hore sehokelo sa ketane se theohe ka bonngoe, 'me monoma e hlahisitsoeng e fetoha ka potlako. Ka nako ena, boima ba limolek'hule bo fetoha butle haholo, joalo ka ts'ebetso e fapaneng ea polymerization ea ketane. Joalo ka thermal depolymerization ea methyl methacrylate.

• Random Chain Scission (Degradation)

E boetse e tsejoa e le khefu e sa reroang kapa liketane tse robehileng. Tlas'a ketso ea matla a mechine, mahlaseli a matla a matla, maqhubu a ultrasonic kapa lik'hemik'hale tsa lik'hemik'hale, ketane ea polymer e senya ntle le ntlha e tsitsitseng ho hlahisa polymer e tlaase ea molek'hule. Ke e 'ngoe ea mekhoa ea ho senyeha ha polymer. Ha ketane ea polymer e senyeha ka mokhoa o sa reroang, boima ba molek'hule bo theoha ka potlako, 'me tahlehelo ea boima ba polymer e nyenyane haholo. Ka mohlala, mokhoa oa ho senya oa polyethylene, polyene le polystyrene ke haholo-holo ho senyeha ho sa tloaelehang.

Ha li-polymers tse kang PE li bōptjoa ka mocheso o phahameng, boemo leha e le bofe ba ketane e kholo bo ka 'na ba robeha,' me boima ba limolek'hule bo theoha ka potlako, empa chai ea monomer e nyenyane haholo. Mofuta ona oa ho itšoara o bitsoa random chain scission, ka linako tse ling o bitsoa degradation, polyethylene Li-radicals tsa mahala tse entsoeng ka mor'a ketane scission li sebetsa haholo, li pota-potiloe ke hydrogen e eketsehileng ea bobeli, e atisang ho ba le liphetoho tsa ketane, 'me hoo e ka bang ha ho na monomers e hlahisoang.

• Ho tlosoa hoa tse ling

PVC, PVAc, joalo-joalo e ka ba le maikutlo a ho tlosoa ha sebaka ha e futhumetse, kahoo sehlaba se atisa ho hlaha mokokotlong oa thermogravimetric. Ha li-polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, polyvinyl fluoride, joalo-joalo li futhumatsoa, ​​li-substitute li tla tlosoa. Ho nka mohlala oa polyvinyl chloride (PVC), PVC e sebetsoa ka mocheso o ka tlase ho 180 ~ 200 ° C, empa ka mocheso o tlase (joalo ka 100 ~ 120 ° C), e qala ho dehydrogenate (HCl), 'me e lahleheloa ke HCl haholo. ka potlako e ka bang 200 ° C. Ka hona, nakong ea ts'ebetso (180-200 ° C), polymer e atisa ho ba lefifi ka 'mala le ho fokotseha ka matla.

HCl e sa lefelloeng e na le phello ea catalytic ho dehydrochlorination, 'me li-chloride tsa tšepe, tse kang ferric chloride e entsoeng ke ketso ea hydrogen chloride le lisebelisoa tsa ho sebetsa, li khothalletsa catalysis.

Liphesente tse 'maloa tsa li-absorbents tsa acid, tse kang barium stearate, organotin, metsoako ea lead, joalo-joalo, li tlameha ho kenngoa ho PVC nakong ea ho sebetsa ha mocheso ho ntlafatsa botsitso ba eona.

Ha thapo ea puisano e sebelisoa ho mebala thapo ea puisano, haeba lesela la polyolefin holim'a terata ea koporo le sa tsitsa, ho tla thehoa carboxylate ea koporo e tala holim'a sebopeho sa polymer-copper. Lits'ebetso tsena li khothalletsa ho ata ha koporo ka har'a polymer, e leng ho potlakisa khase ea koporo.

Ka hona, molemong oa ho fokotsa sekhahla sa ho senyeha ha oxidative ea polyolefin, phenolic kapa amine antioxidants (AH) hangata e eketsoa ho felisa karabelo e kaholimo le ho theha li-radicals tsa mahala tse sa sebetseng A·: ROO·+AH-→ROOH+A·

• Ho senyeha ha Oxidative

Lihlahisoa tsa polymer tse pepeselitsoeng moeeng li monya oksijene ebe li kenella ka har'a oxidation ho etsa hydroperoxides, ho tsoela pele ho bola ho hlahisa litsi tse sebetsang, ho etsa li-radicals tsa mahala, ebe li kena ka har'a ketane ea mahala (ke hore, auto-oxidation process). Li-polymers li pepesehela oksijene moeeng nakong ea ts'ebetso le ts'ebeliso, 'me ha li futhumala, ho senyeha ha oxidative ho potlakisa.

Thermal oxidation ea polyolefin ke ea free radical chain reaction mechanism, e nang le boitšoaro ba autocatalytic mme e ka aroloa ka mehato e meraro: ho qala, ho hola le ho felisoa.

The scission ketane e bakoang ke sehlopha sa hydroperoxide e lebisa ho fokotseha ha boima ba limolek'hule, 'me lihlahisoa tse ka sehloohong tsa scission ke li-alcohol, aldehydes le ketone, tseo qetellong li nang le oxidized ho carboxylic acid. Li-carboxylic acid li bapala karolo e kholo ho oxidation ea tšepe. Ho senyeha ha oxidative ke lebaka le ka sehloohong la ho senyeha ha thepa ea 'mele le ea mechine ea lihlahisoa tsa polymer. Ho senyeha ha oxidative ho fapana le sebopeho sa limolek'hule tsa polymer. Ho ba teng ha oksijene ho ka boela ha matlafatsa ts'enyo ea leseli, mocheso, mahlaseli le matla a mochine ho li-polymers, tse bakang liphetoho tse rarahaneng tsa ho senyeha. Li-Antioxidants li kenngoa ho li-polymers ho liehisa ho senyeha ha oxidative.

2) Ha polasetiki e sebetsoa le ho bōptjoa, 'mala oa bola, oa fifala le ho fetola' mala ka lebaka la ho sitoa ho mamella mocheso o phahameng.

Li-pigments kapa dae tse sebelisetsoang mebala ea polasetiki li na le moeli oa mocheso. Ha mocheso ona o lekanyelitsoeng o fihleloa, li-pigments kapa dae li tla fetoha lik'hemik'hale ho hlahisa metsoako e sa tšoaneng ea boima ba limolek'hule, 'me mekhoa ea bona ea ho itšoara e batla e rarahane; mebala e fapaneng e na le karabelo e fapaneng. 'Me lihlahisoa, ho hanyetsa mocheso oa li-pigments tse fapaneng ho ka lekoa ka mekhoa ea ho hlahloba e kang ho theola boima ba' mele.

2. Li-colorants li sebetsana le lisebelisoa tse tala

Boitšoaro pakeng tsa li-colorants le lihlahisoa tse tala bo bonahala haholo-holo ha ho etsoa li-pigments kapa li-dae le lisebelisoa tse tala. Liphetoho tsena tsa lik'hemik'hale li tla lebisa liphetohong tsa 'mala le ho senyeha ha li-polymers, ka hona ho fetola thepa ea lihlahisoa tsa polasetiki.

• Phokotso Karabelo

Li-polymer tse ling tse phahameng, joalo ka nylon le li-aminoplasts, ke lisebelisoa tse matla tse fokotsang asiti sebakeng sa ho qhibiliha, tse ka fokotsang le ho fifatsa li-pigments kapa lidae tse tsitsitseng mochesong oa ho sebetsa.

• Alkaline Exchange

Litšepe tsa lefats'e tsa alkaline ka li-polymers tsa emulsion tsa PVC kapa li-polypropylene tse tsitsitseng li ka "phapanyetsano ea motheo" ka litšepe tsa alkaline tsa lefats'e ka mebala ho fetola 'mala ho tloha bofubelu bo boputsoa ho ea ho lamunu.

PVC emulsion polymer ke mokhoa oo VC e entsoeng ka polymerized ka ho hlohlelletsa ka emulsifier (e kang sodium dodecylsulfonate C12H25SO3Na) tharollo ea metsi. Karabelo e na le Na+; e le ho ntlafatsa ho hanyetsa mocheso le oksijene ea PP, 1010, DLTDP, joalo-joalo hangata li eketsoa. Oxygen, antioxidant 1010 ke transesterification reaction catalyzed by 3,5-di-tert-butyl-4-hydroxypropionate methyl ester le sodium pentaerythritol, 'me DLTDP e lokisoa ka ho arabela tharollo ea metsi a Na2S ka acrylonitrile Propionitrile ke hydrolyodized ho hlahisa asiti. e fumanoang ka esterification ka joala ba lauryl. Karabelo e boetse e na le Na+.

Nakong ea ho bōptjoa le ho sebetsa ha lihlahisoa tsa polasetiki, Na+ e setseng ka thepa e tala e tla itšoara ka pigment ea letša e nang le li-ion tsa tšepe tse kang CIPigment Red48:2 (BBC kapa 2BP): XCa2++2Na+→XNa2+ +Ca2+

• Karabelo lipakeng tsa Pigments le Hydrogen Halides (HX)

Ha mocheso o nyolohela ho 170 ° C kapa tlas'a ketso ea leseli, PVC e tlosa HCI ho theha tlamahano e habeli ea conjugated.

Polyolefin e nang le halogen e thibelang malakabe kapa lihlahisoa tsa polasetiki tse mebala-bala tse thibelang malakabe le tsona ke dehydrohalogenated HX ha e bōptjoa ka mocheso o phahameng.

1) Karabelo ea Ultramarine le HX

Ultramarine blue pigment e sebelisoang haholo ho mebala ea polasetiki kapa ho tlosa leseli le mosehla, ke motsoako oa sebabole.

2) Pigment ea phofo ea koporo e potlakisa ho bola ha oxidative ea lisebelisoa tse tala tsa PVC.

Li-pigments tsa koporo li ka oxidized ho Cu + le Cu2 + ka mocheso o phahameng, o tla potlakisa ho bola ha PVC.

3) Ho senyeha ha li-ion tsa tšepe ho li-polymers

Li-pigment tse ling li na le phello e senyang ho li-polymers. Mohlala, pigment ea letša la manganese CIPigmentRed48: 4 ha e loketse ho etsoa ha lihlahisoa tsa polasetiki tsa PP. Lebaka ke hore li-ion tsa tšepe tsa manganese tse feto-fetohang li etsa hore hydroperoxide e be teng ka ho fetisoa ha li-electrone ka har'a oxidation ea mocheso kapa photooxidation ea PP. Ho senyeha ha PP ho lebisa botsofaling bo potlakileng ba PP; tlamo ea ester ka polycarbonate e bonolo ho hydrolyzed le ho senyeha ha e futhumala, 'me hang ha ho e-na le li-ion tsa tšepe ka har'a pigment, ho bonolo ho khothalletsa ho bola; li-ion tsa tšepe li tla boela li khothaletse ho bola ha thermo-oksijene ea PVC le lisebelisoa tse ling tse tala, 'me li etse hore 'mala o fetohe.

Ho akaretsa, ha ho etsoa lihlahisoa tsa polasetiki, ke tsela e ka khonehang le e sebetsang ka ho fetisisa ea ho qoba tšebeliso ea li-pigments tse mebala-bala tse sebetsanang le lihlahisoa tse tala.

3. Boitšoaro pakeng tsa li-colorants le li-additives

1) Boitšoaro pakeng tsa li-pigment tse nang le sebabole le li-additives

Li-pigment tse nang le sebabole, tse kang cadmium yellow (solid solution ea CdS le CdSe), ha li tšoanelehe bakeng sa PVC ka lebaka la ho hanyetsa acid e fokolang, 'me ha lia lokela ho sebelisoa le li-additives tse nang le loto.

2) Karabelo ea metsoako e nang le loto e nang le li-stabilizer tse nang le sebabole

Likahare tsa lead tse ka har'a chrome yellow pigment kapa molybdenum red li sebetsana le li-antioxidants joalo ka thiodistearate DSTDP.

3) Karabelo lipakeng tsa pigment le antioxidant

Bakeng sa lisebelisoa tse tala tse nang le li-antioxidants, tse kang PP, li-pigments tse ling li tla boela li sebetsane le li-antioxidants, kahoo li fokolise mosebetsi oa li-antioxidants le ho etsa hore botsitso ba oksijene bo chesang ba lintho tse tala bo be bobe le ho feta. Ka mohlala, li-antioxidants tsa phenolic li kenngoa habonolo ke carbon black kapa li itšoara le tsona ho lahleheloa ke mosebetsi oa tsona; phenolic antioxidants le li-ion tsa titanium ka lihlahisoa tsa polasetiki tse tšoeu kapa tse bobebe li etsa li-phenolic aromatics hydrocarbon complexes ho baka hore lihlahisoa li be mosehla. Khetha e loketseng ea antioxidant kapa u kenye li-additives tse thusang, tse kang letsoai la zinki la anti-acid (zinc stearate) kapa P2 mofuta oa phosphite ho thibela ho fifala ha pigment e tšoeu (TiO2).

4) Karabelo pakeng tsa pigment le leseli stabilizer

Phello ea li-pigments le li-stabilizers tse khanyang, ntle le karabelo ea li-pigments tse nang le sebabole le li-stabilizer tse nang le nickel tse nang le leseli joalokaha ho hlalositsoe ka holimo, ka kakaretso li fokotsa katleho ea li-stabilizers tsa leseli, haholo-holo phello ea li-stabilizers tse thibelang amine le li-pigments tse mosehla le tse khubelu. Phello ea ho fokotseha ho tsitsitseng e totobetse haholoanyane, 'me ha e tsitsa joaloka e sa tsitsang. Ha ho na tlhaloso e hlakileng ea ketsahalo ena.

4. Karabelo Pakeng Tsa Li-additives

Haeba li-additives tse ngata li sebelisoa ka mokhoa o sa lokelang, ho ka 'na ha etsahala lintho tse sa lebelloang' me sehlahisoa se tla fetola 'mala. Mohlala, se thibelang lelakabe Sb2O3 se sebetsana le sebolaea-lik'hemik'hale se nang le sebabole ho hlahisa Sb2S3: Sb2O3+–S–→Sb2S3+–O–

Ka hona, tlhokomelo e tlameha ho nkoa ha ho khethoa li-additives ha ho nahanoa ka metsoako ea tlhahiso.

5. Thuso ea Auto-oxidation Lisosa

The automatic oxidation ea phenolic stabilizers ke ntlha ea bohlokoa ho khothaletsa ho fifala ha lihlahisoa tse tšoeu kapa tse bobebe. Ho fifala hona hangata ho bitsoa "Pinking" linaheng tse ling.

E kopantsoe ke lihlahisoa tsa oxidation tse kang BHT antioxidants (2-6-di-tert-butyl-4-methylphenol), 'me e bōpehile joaloka 3,3',5,5'-stilbene quinone leseli le lefubelu sehlahisoa sa karabelo e khubelu, 'mala ona oa fetoha. feela ka boteng ba oksijene le metsi le ho ba sieo ha leseli. Ha e pepeselitsoe khanya ea ultraviolet, khanya e khubelu ea stilbene quinone e bola ka potlako ho ba sehlahisoa se mosehla sa reng e le 'ngoe.

6. Tautomerization ea Mebala e Mebala Tlas'a Ketso ea Leseli le Mocheso

Li-pigments tse ling tsa mebala li na le tautomerization ea tlhophiso ea limolek'hule tlasa ts'ebetso ea khanya le mocheso, joalo ka ts'ebeliso ea mebala ea CIPig.R2 (BBC) ho fetoha ho tloha mofuteng oa azo ho ea ho mofuta oa quinone, e fetolang phello ea conjugation ea mantlha mme e baka ho thehoa ha litlamo tse kopaneng. . ho fokotseha, ho bakang phetoho ea 'mala ho tloha ho boputsoa bo lefifi bo bofubelu ho ea ho bofubelu bo khanyang ba lamunu.

Ka nako e ts'oanang, tlas'a catalysis ea leseli, e senya ka metsi, e fetola metsi a kristale ea co-crystal le ho baka ho fela.

7. E Bakiloeng ke Litšilafatso Tsa Moea

Ha lihlahisoa tsa polasetiki li bolokoa kapa li sebelisoa, lisebelisoa tse ling tse sebetsang, ebang ke lintho tse tala, li-additives, kapa li-pigments tsa mebala, li tla itšoara ka mongobo sepakapakeng kapa lintho tse silafatsang tsa lik'hemik'hale tse kang li-acid le alkali tlas'a ketso ea khanya le mocheso. Liphetoho tse fapaneng tse rarahaneng tsa lik'hemik'hale li bakoa, tse tla lebisa ho fifala kapa ho fifala ha nako e ntse e ea.

Boemo bona bo ka qojoa kapa ba fokotsoa ka ho eketsa li-stabilizers tse loketseng tsa mocheso oa oksijene, li-stabilizers tse bobebe, kapa ho khetha li-additives le li-pigments tsa boleng bo holimo tsa boemo ba leholimo.