Lipotso tsa Mehlala le Puisano ea Likarabelo tsa Polymerization
Likarabelo tsa polymerization ke sehlooho sa bohlokoa k'hemistri ea lintho tse phelang. Ts'ebetso ena e kenyelletsa ho kopanngoa ha limolek'hule tsa monomer ho etsa limolek'hule tse kholo tse bitsoang li-polymer. Li-polymer li bohlokoa bophelong ba letsatsi le letsatsi, ho tloha linthong tse tala tse sebelisoang ho etsa polasetiki le rabara ho ea ho likhoele tsa masela. Sehloohong sena, re tla tšohla mehlala e 'maloa ea likarabelo tsa polymerization le litharollo tsa tsona.
Mefuta ea Polymerization
Ka kakaretso, polymerization e ka aroloa ka mefuta e 'meli e meholo:
1. Ho eketsa polymerization – Ts'ebetso ena e kenyelletsa ho kopanya li-monomer tse nang le litlamo tse habeli kapa tse tharo ho etsa polymer ntle le ho hlahisa lihlahisoa tse ling. Mohlala o tloaelehileng oa polymer e eketsehileng ke polyethylene, e entsoeng ka ethylene (CH₂=CH₂).
2. Ho polima ha condensation – Ts'ebetsong ena, karabelo pakeng tsa li-monomer tse peli tse nang le lihlopha tse itseng tse sebetsang e hlahisa polymer hammoho le lihlahisoa tse ling tse kang metsi kapa methanol. Mohlala o tloaelehileng ke nylon, e entsoeng ka diamine le diacid.
Mohlala oa Bothata ba ho Eketsa Polymerization
Potso ea 1:
Ethylene (CH₂=CH₂) ke monomer e etsang polymer ho etsa polyethylene. Hlalosa karabelo ea polymerization 'me u bolele lihlahisoa tse hlahang.
Puisano:
Polyethylene ke polymer e entsoeng ka li-monomers tsa ethylene ka karabelo ea polymerization e eketsehileng. Karabelo ena e ka ngoloa ka tsela e latelang:
\[ n \text{(CH₂=CH₂)} \rightarrow \text{ -[CH₂-CH₂]- }_n \]
Moo \( n \) e leng palo ea li-unit tsa monomer. Polyethylene e entsoeng ke ketane e telele ea li-monomer tsa ethylene tse se nang lihlahisoa tse ling.
Lipotso tsa Mohlala oa Polymerization ea Condensation
Potso ea 2:
Polima ea nylon-6,6 e thehoa ke karabelo pakeng tsa hexamethylenediamine le adipic acid. Ngola karabelo 'me u thathamise lihlahisoa tse setseng.
Puisano:
Nylon-6,6 ke polymer e entsoeng ka karabelo pakeng tsa hexamethylenediamine (\( \text{H₂N-(CH₂)₆-NH₂} \)) le adipic acid (\( \text{HOOC-(CH₂)₄-COOH} \)). Karabelo ea sebopeho e ka etsoa ka tsela e latelang:
\[ \mongolo{n (H₂N-(CH₂)₆-NH₂) + n (HOOC-(CH₂)₄-COOH)} \mongolo o nepahetseng \mongolo{-[NH-(CH₂)₆-NH-CO-(CH₂)₄-CO]- }_n {H] 2n \ sengoloa
Sehlahisoa se setseng ke metsi (H₂O).
Lipotso tse ling tsa Polymerization
Potso ea 3:
Polyethylene terephthalate (PET) e sebediswa tlhahisong ya dibotlolo tsa polasetiki le masela. Di-monomer tse etsang PET ke ethylene glycol (\( \text{HOCH₂CH₂OH} \)) le terephthalic acid (\( \text{HOOC-C₆H₄-COOH} \)). Hlalosa tshebetso ya ho thehwa ha PET mme o bale palo ya sehlahiswa se setseng haeba re qala ka di-mole tse 5 tsa monomer ka nngwe.
Puisano:
Karabelo ea polymerization ea condensation bakeng sa ho thehoa ha PET ke:
\[ n \text{(HOCH₂CH₂OH)} + n \text{(HOOC-C₆H₄-COOH)} \rightarrow \text{ -[OOC-C₆H₄-COO-CH₂CH₂O]- }_n + 2n \text{H₂O} \]
Moo \( n \) e leng palo ea li-mol tsa monomer. Haeba re qala ka li-mol tse 5 tsa ethylene glycol le li-mol tse 5 tsa terephthalic acid, joale lihlahisoa tse latelang ke 5 × 2 = 10 li-mol tsa H₂O.
Likarolo tsa Kinematic ho Polymerization
Likarabelong tsa polymerization, kinetics ea karabelo ke taba ea bohlokoa. Sekhahla sa polymerization se ka susumetsoa ke lintlha tse fapaneng tse kang mocheso, khatello le mahloriso a monomer.
Potso ea 4:
Haeba sekgahla sa polymerization ya karabelo se bolelwa e le \( k [M]^x \), moo k e leng sekgahla se sa fetoheng, [M] ke sekgahla sa monomer, mme x ke tatellano ya karabelo mabapi le monomer, hlalosa kamoo phetoho ya sekgahla sa monomer e tla ama sekgahla sa karabelo haeba x = 2.
Puisano:
Haeba x e le 2, joale sekhahla sa karabelo ke \( k [M]^2 \). Sena se bolela hore sekhahla sa karabelo se lekana ka ho toba le sekwere sa khatello ea monomer. Haeba khatello ea monomer e imena habeli, sekhahla sa karabelo se tla eketseha ka makhetlo a mane (2² = 4).
Ho lokisa 'mele ka Redox
Mofuta o mong oa karabelo ea polymerization ke redox polymerization. Sena se kenyelletsa karabelo ea redox pakeng tsa lintho tse peli tse qalang polymerization.
Potso ea 5:
Polima e thehoa ka karabelo ea redox pakeng tsa benzoyl peroxide le styrene. Ngola karabelo ea qalo e hlahang.
Puisano:
Karabelo ea ho qala pakeng tsa benzoyl peroxide le styrene e hlahisa li-free radicals tse qalang polymerization. Karabelo ke e latelang:
\[ \text{(C₆H₅CO)₂O₂} \rightarrow 2 \text{C₆H₅COO·} \]
Benzoyloxyl radical (\( \text{C₆H₅COO·} \)) ebe e arabela ka styrene, e qalang karabelo ya ketane ya polymerization.
\[ \text{C₆H₅COO· + CH₂=CHC₆H₅} \rightarrow \text{C₆H₅COOCH₂-CH·C₆H₅} \]
Karabelo ena e tswela pele ho fihlela styrene e setseng tsamaisong e arabela ho foromo ya polystyrene.
Qetello
Ho utloisisa dikarabelo tsa polymerization le mekgwa e ka morao ho tsona ho bohlokwa ho mang kapa mang ya amehang khemistring kapa saenseng ya thepa. Ka mehlala e tshohlwang ka hodimo, babali ba lebelletswe ho utlwisisa mekgwa ya motheo ya polymerization ya ho eketsa le ho kolobisa, hammoho le dintlha tse ding tse tswetseng pele jwalo ka kinetics ya karabelo le polymerization ya redox. Ka motheo o tiileng, re ka utlwisisa hantle karolo ya bohlokwa ya di-polymers dikarolong tse fapaneng tsa bophelo ba sejwalejwale.
