Zitsanzo za Mafunso Okhudza Kuwonjezera Polymerization
Kupoletsa ndi njira yomwe ma monomers—mamolekyu ang'onoang'ono okhala ndi kapangidwe kofanana—amaphatikizika kuti apange mamolekyu akuluakulu otchedwa ma polima. Pali mitundu iwiri ikuluikulu ya polymerization: kuwonjezera polymerization ndi condensation polymerization. Nkhaniyi ikambirana za mtundu umodzi mwa mitundu iyi, kuwonjezera polymerization, ndi kutsindika pa zitsanzo ndi kukambirana kuti timvetsetse bwino lingaliro ili.
Kumvetsetsa Kuwonjezera Polima
Kuonjezera polymerization ndi njira yomwe ma monomers amaphatikizana popanda kutaya mamolekyu ang'onoang'ono monga madzi kapena HCl. Ma monomers omwe amagwiritsidwa ntchito kwambiri powonjezera polymerization ndi ma alkenes ndi ma polarized alkenes, omwe ali ndi ma double bonds a carbon-carbon (C=C). Ma monomers awa akachitapo kanthu, ma double bonds amasweka, zomwe zimapangitsa kuti ma monomers agwirizane pamodzi mu unyolo wautali.
Zitsanzo za ma polima opangidwa ndi kuwonjezera polymerization ndi monga polyethylene (PE), polypropylene (PP), polystyrene (PS), ndi polyvinyl chloride (PVC). Ma polima onsewa ndi ofunikira m'mafakitale ndi moyo watsiku ndi tsiku chifukwa cha mphamvu zawo, kukhazikika kwawo, komanso kugwiritsa ntchito kwawo kosiyanasiyana.
Njira Yowonjezerera Polima
Njira yowonjezera polymerization ingagawidwe m'magawo atatu akuluakulu:
1. Kuyambitsa: Gawo lomwe ma free radical kapena ma ion amapangidwa kuti ayambe kuchitapo kanthu.
2. Kufalikira: Gawo lomwe ma monomers amapitiliza kuphatikizana ndikupanga maunyolo ataliatali.
3. Kutha: Gawo lomwe kuyambika kwa zinthu kumasiya chifukwa maunyolo awiri a free radical amasakanikirana kapena ma free radical amakumana ndi choletsa.
Kuti timvetse bwino, apa pali kukambirana kwa zitsanzo zingapo za mafunso okhudza kuwonjezera polymerization.
Mafunso ndi Kukambirana Zitsanzo
Funso 1: Kupopera kwa Polyethylene
Funso: Fotokozani njira yowonjezera ya polymerization ya ethylene (C2H4) kuti ipange polyethylene (PE), phatikizani ndi equation ya reaction yomwe imachitika.
Kukambirana:
- Kuyambitsa:
Kuyambitsa kungatheke pogwiritsa ntchito ma catalyst kapena ma free radicals. Tiyerekeze kuti tikugwiritsa ntchito ma free radicals. Ma radical oyambitsa monga benzoyl peroxide (C14H10O4) amatha kutulutsa ma free radicals akatenthedwa.
\[
C14H10O4 \rightarrow 2C6H5COO^{\cdot}
\]
- Kufalitsa:
Ma radical awa adzaukira ma bond awiri mu ethylene monomer, ndikupanga ma radical atsopano omwe angapitirize kuukira monomer yotsatira.
\[
R^{\cdot} + CH2=CH2 \rightarrow R-CH2-CH2^{\cdot}
\]
Kenako, ma radicals kumapeto kwa unyolo adzapitiriza kuwonjezera ma ethylene monomers kuti unyolowo ukhale wautali.
\[
R-CH2-CH2^{\cdot} + nCH2=CH2 \rightarrow R-(CH2-CH2)_n^{\cdot}
\]
- Kutha kwa ntchito:
Kutha kwa ma radical kungachitike kudzera mu kuphatikiza kwa ma radical chain awiri kapena kudzera mu reaction pakati pa radical ndi inhibitor.
\[
R-(CH2-CH2)_n^{\cdot} + R-(CH2-CH2)_m^{\cdot} \rightarrow R-(CH2-CH2)_{n+m}-R
\]
Zotsatira zake ndi polyethylene (PE), polima yopangidwa mwa kuphatikiza ma monomers ambiri a ethylene (\(n\) ethylene).
Funso 2: Kupoletsa Polystyrene
Funso: Makampani opanga mankhwala akufuna kupanga polima kuchokera ku monomer styrene (C8H8). Fotokozani momwe polymerization imachitikira ndikulemba kapangidwe ka polystyrene.
Kukambirana:
- Kuyambitsa:
Monga momwe zimakhalira ndi polyethylene, ma free radicals amafunika kuti ayambe kuchitapo kanthu. Tiyerekeze kuti tikugwiritsa ntchito peroxide radicals.
\[
ROOR \rightarrow 2RO^{\cdot}
\]
- Kufalitsa:
Ma free radicals amaukira ma styrene monomers omwe ali ndi ma bond awiri a carbon-carbon.
\[
RO^{\cdot} + C6H5-CH=CH2 \rightarrow RO-C6H5-CH^{\cdot}-CH3
\]
Gawo lofalitsa lidzapangitsa kuti ma radical awa apitirize kuukira ma monomers ena a styrene.
\[
RO-C6H5-CH^{\cdot}-CH3 + n(C6H5-CH=CH2) \rightarrow RO-(C6H5-CH-CH2)_n-C6H5-CH^{\cdot}-CH3
\]
- Kutha kwa ntchito:
Kutha kumachitika pamene maunyolo awiri a polymer a radical akumana.
\[
RO-(C6H5-CH-CH2)_n^{\cdot} + RO-(C6H5-CH-CH2)_m^{\cdot} \rightarrow RO-(C6H5-CH-CH2)_{n+m}-RO
\]
Kapangidwe ka polystyrene (PS) komwe kamachokera ndi unyolo wautali wokhala ndi mayunitsi obwerezabwereza a styrene monomer.
Funso 3: Kupangidwa kwa Polyvinyl Chloride (PVC)
Funso: Fotokozani momwe polymerization yowonjezera ya vinyl chloride monomer (C2H3Cl) imagwirira ntchito, ndipo perekani zitsanzo za momwe polyvinyl chloride (PVC) imagwiritsidwira ntchito.
Kukambirana:
- Kuyambitsa:
Monga chitsanzo chapitacho, ma free radicals amapangidwa kuchokera ku peroxides.
\[
ROOR \rightarrow 2R-O^{\cdot}
\]
- Kufalitsa:
Ma free radicals amaukira ma bond awiri omwe ali mu vinyl chloride monomers.
\[
RO^{\cdot} + CH2=CHCl \rightarrow RO-CH2-CHCl^{\cdot}
\]
Kufalikira kumapitirira ndi mayunitsi a monomer olumikizana kuti awonjezere unyolo.
\[
RO-CH2-CHCl^{\cdot} + nCH2=CHCl \rightarrow RO-(CH2-CHCl)_n^{\cdot}
\]
- Kutha kwa ntchito:
Kutha kumachitika pamene maunyolo awiri a radical agwirizana.
\[
RO-(CH2-CHCl)_n^{\cdot} + RO-(CH2-CHCl)_m^{\cdot} \rightarrow RO-(CH2-CHCl)_{n+m}-RO
\]
Polyvinyl chloride (PVC) ndi polima yomwe imapangidwa ndikugwiritsidwa ntchito m'njira zosiyanasiyana monga mapaipi amadzi, zingwe zamagetsi, ndi zinthu zina zosiyanasiyana zapulasitiki.
Mapeto
Kuwonjezera polymerization ndi njira yofunika kwambiri ya mankhwala yomwe imaphatikizapo kuphatikiza kwa ma monomers popanda kutulutsidwa kwa mamolekyu ang'onoang'ono. Kumvetsetsa njira ndi momwe polymerization yowonjezera imagwirira ntchito, monga zomwe zimawonedwa mu polyethylene, polystyrene, ndi PVC, kumatithandiza kuphunzira ndikugwiritsa ntchito chidziwitsochi m'mafakitale ndi moyo watsiku ndi tsiku. Kudzera mu zitsanzo ndi zokambiranazi, titha kumvetsetsa bwino njira ndi zinthu zomwe zimachitika chifukwa cha kuwonjezera polymerization, komanso momwe imagwirira ntchito zomwe zimakhudza ukadaulo ndi moyo wamakono.
