Ukusabela kwe-polymerization
I-Pendahuluan
Ama-polymer ayizinhlanganisela zamakhemikhali ezakhiwe ngama-molecule amakhulu, anochungechunge olude akhiwe ngamayunithi aphindaphindayo abizwa ngokuthi ama-monomers. I-polymerization inqubo yamakhemikhali la ma-monomers ahlangana ngayo ukuze akhe ama-polymer. Le nqubo ibalulekile embonini yamakhemikhali futhi inegalelo ekwakhiweni kwezinto ezihlukahlukene eziyigugu, okuhlanganisa amapulasitiki, irabha, kanye nemicu yokwenziwa.
Lesi sihloko sihlose ukuchaza izindlela, izinhlobo, kanye nokusetshenziswa kwezindlela zokusabela kwe-polymerization. Izinqubo ze-polymerization zingenzeka ngezindlela ezahlukene, ngezigaba ezimbili eziyinhloko: ukwengeza i-polymerization kanye ne-condensation polymerization.
Izinhlobo ze-Polymerization
Ukwengeza i-Polymerization
Ukwengeza i-polymerization kuyinqubo lapho ama-monomer anezibopho eziphindwe kabili noma kathathu esabela khona ekwakheni i-polymer ngaphandle kokukhiqiza imikhiqizo elandelanayo. Ama-polymer akhiqizwa yilolu hlobo lwe-polymerization abizwa ngokuthi ama-polymer angeziwe.
I-Langkah-langkah:
1. Ukuqaliswa: Ukusabela kuqala lapho isiqalo sikhiqiza ama-free radical, ama-ion, noma ama-catalyst angaphula izibopho eziphindwe kabili kuma-monomers.
2. Ukusabalala: Ama-free radical noma ama-ion akhekile asabela nama-monomer, adale iziphetho ezintsha ezisebenzayo ezingasabela namanye ama-monomer.
3. Ukuphela: Ukusabela kuyama lapho ama-free radical amabili ehlangana futhi akha isibopho esihambisanayo, noma lapho enye indlela imisa ukusabalala.
Isibonelo:
– I-Poly(ethylene): I-ethylene monomer (C2H4) isabela ngochungechunge lwama-free radicals ukuze yakhe i-poly(ethylene).
– I-Poly(vinyl chloride) (PVC): Ama-monomer e-vinyl chloride (C2H3Cl) ahlanganiswa ngokuqaliswa, ukusabalala, kanye nokuphela.
Ukwakheka kwe-Condensation Polymerization
I-polymerization ye-condensation ihilela ama-monomers anamaqembu okungenani amabili asebenzayo asebenzayo futhi akha i-polymer enomkhiqizo ophumayo, njengamanzi noma i-methanol.
I-Langkah-langkah:
1. Ukuqaliswa: Ama-monomer anamaqembu asebenzayo asabelanayo ayasabelana.
2. Ukwakheka: Ukwakheka kwezibopho phakathi kwama-monomers, okuhambisana nokukhululwa kwama-molecule okukhanya, njenge-H2O noma i-HCl.
3. Ukukhula Kweketanga: Le nqubo iyaqhubeka kuze kube yilapho ama-monomer ephela noma izimo zokusabela zingasasebenzi.
Isibonelo:
– Inayiloni-6,6: Yenziwe ngokusabela phakathi kwe-hexamethylenediamine ne-adipic acid, ekhiqiza amanzi njengomkhiqizo ophumayo.
– I-Polyester: Yakhiwe ngokusabela phakathi kwe-terephthalic acid ne-ethylene glycol, ngamanzi njengomkhiqizo ophumayo.
Indlela Yokwenza I-Polymerization
I-Radical Polymerization yamahhala
I-polymerization yama-free radical ingenye yezindlela ezivame kakhulu zokwengeza i-polymerization. Le nqubo iqala ngokwakhiwa kwama-free radical asabela kakhulu, ngokuvamile ngokushisa noma ngokukhanya kwelanga.
1. Ukuqaliswa: Ama-molecule okuqala njenge-benzoyl peroxide noma i-azobisisobutyronitrile (AIBN) ayahlukaniswa ukuze akhiqize ama-free radical.
\[ \text{(Qaphela, AIBN) → 2 \cdot (Okukhulu, )} \]
2. Ukusabalala: Ama-free radical asabela nama-monomer ukuze akhe ama-extended monomer radicals:
\[ \text{(Radical + Monomer) → (R-Polymer)} \]
3. Ukuphela: Ama-free radical amabili ahlangana ukuze akhe i-molecule engeyona i-radical futhi amise ukusabela kwe-chain:
\[ \text{(R + R ) → Okungakhiqizi Kakhulu} \]
I-Ionic Polymerization
Lokhu kwakheka kwe-polymer kuhilela ukwakheka kwama-ion (ama-cation noma ama-anion) njengezinhlobo ezisabelayo. Ukwakheka kwe-polymer kwe-Ionic kungahlukaniswa futhi ngezinhlobo ezimbili eziyinhloko, okungukuthi:
– I-Cationic Polymerization: Ihilela uhlobo lwe-cationic njengesiqalisi. Ngokuvamile isetshenziswa nama-monomers anamaqembu anikela ngama-electron njenge-isobutylene.
– I-Anionic Polymerization: Ihilela ama-ion ashajeke kabi (ama-anion) njengeziqalisi. Isetshenziswa kuma-monomers anamaqembu amukela ama-electron njenge-styrene.
Ukuhlanganiswa kwe-Polymerization
Lolu hlobo lwe-polymerization luqondiswa yi-transition metal complex catalysts, isibonelo yi-Ziegler-Natta polymerization esetshenziswa ukwenza i-stereo-regular polyethylene kanye ne-polypropylene.
1. Ama-Catalyst: Izinsimbi eziguqukayo ezifana ne-titanium chloride zisetshenziswa kanye nama-organometallic compounds afana ne-aluminium triethyl (AlEt3).
2. Ukusabela: Ama-monomer ahlangana endaweni esebenzayo yesakhiwo sensimbi.
Izicelo Zokwenza I-Polmerization
Imboni Yepulasitiki
Amapulasitiki ayimikhiqizo ye-polymer eyaziwa kakhulu futhi esetshenziswa kabanzi. Enziwa ngezinqubo zokwengeza kanye nokuqinisa i-polymer. Izibonelo zemikhiqizo ye-polymer yepulasitiki evamile zifaka i-polyethylene, i-polypropylene, i-PVC, kanye ne-PET (i-polyethylene terephthalate). Amapulasitiki asetshenziswa ekwenziweni kokupakisha, amathoyizi, amapayipi, kanye neminye imikhiqizo ehlukahlukene yabathengi.
Izinto ze-Fiber
Imicu yokwenziwa efana ne-nylon kanye ne-polyester iwumphumela we-condensation polymerization. Isetshenziswa ekwenziweni kwezindwangu, izingubo, nezinto zasekhaya ezifana namakhaphethi nezintambo. Imicu ivame ukukhethwa ngenxa yamandla ayo, ukumelana nokuguguleka, kanye nokuqina.
Irabha Yokwenziwa
Amarabha okwenziwa, njenge-polybutadiene kanye ne-styrene-butadiene (SBR), ayimikhiqizo ye-polymerization eyengeziwe yama-monomer aqukethe i-diene. Lawa marabha asetshenziswa ekwenziweni kwamathayi ezimoto, izivalo, kanye nezinhlelo zokusebenza ezahlukahlukene zezimboni ngenxa yokumelana kwawo nokuguguleka kanye nokuguquka.
Ama-Epoxy Resins nama-Thermosetting Polymers
Ama-resin e-epoxy awumphumela we-condensation polymerization eyenzeka ekushiseni kwegumbi noma ngokushisa. Asetshenziswa kuma-adhesive, opende, nezinto ezihlanganisiwe ezidinga ukumelana nokushisa namakhemikhali. Lawa ma-polymer e-thermosetting awakwazi ukuncibilikiswa kabusha ngemva kokuqina, ngokungafani nama-polymer e-thermoplastic.
I-Biomedis
Ama-polymer asetshenziswa ekusetshenzisweni kwezokwelapha afaka phakathi i-polylactide (PLA) kanye ne-poly(tetrahydrofurane) (PTHF), asetshenziselwa ukudala izinto zokufakelwa ezingaphili. Lawa ma-polymer aklanyelwe ukubola emzimbeni, okunciphisa isidingo sokususwa kwesibili ngokuhlinzwa.
Izinto Ezisebenza Ngogesi
Ama-polymer asebenza ngogesi angama-polymer ashintsha isimo ngaphansi kwethonya lensimu kagesi, ngokuvamile asetshenziswa kuma-actuator nama-sensor. Izibonelo zifaka phakathi i-poly(3,4-ethylenedioxythiophene) (PEDOT), esetshenziswa kumadivayisi kagesi njengesikrini sokuthinta.
Isiphetho
Ukusabela kwe-polymerization kuyizinqubo zamakhemikhali eziyisisekelo embonini yamakhemikhali yanamuhla, okuvula indlela yemikhiqizo eminingi kanye nezinhlelo zokusebenza eziguqula izimpilo zethu zansuku zonke. Ngokuqonda izindlela nezinhlobo ze-polymerization, kanye nezinhlelo zokusebenza zazo, singakha izinto ezintsha ezinezakhiwo ezithuthukisiwe zezidingo zesikhathi esizayo. Ukwengeza i-polymerization kanye ne-condensation polymerization ngayinye idlala indima ehlukile ekwakhiweni kwalezi zinto, futhi isayensi iyaqhubeka nokuthuthuka ukuthola izindlela ezintsha zokwenza ngcono lezi zinqubo nokuthola izinhlelo zokusebenza ezintsha zama-polymer.
