Ukwengeza i-Polymerization: Indlela, Izicelo, kanye Nezinzuzo Embonini
I-Pendahuluan
I-polymerization iyindlela yokusabela kwamakhemikhali lapho ama-molecule amancane e-monomer ehlangana khona ukuze akhe ama-macromolecule amakhulu aziwa ngokuthi ama-polymer. Enye yezinhlobo ezivame kakhulu ze-polymerization i-add-polymerization. Lesi sihloko sihlose ukuchaza indlela eyisisekelo ye-add-polymerization, ukusetshenziswa kwayo okuhlukahlukene okubalulekile kwezimboni, kanye nezinzuzo ezinikezayo.
Indlela Yokwengeza I-Polymerization
I-polymerization eyengeziwe, eyaziwa nangokuthi i-chain polymerization, inqubo lapho ama-monomer anezibopho eziphindwe kabili noma amaqembu asebenzayo asebenzayo ehlangana khona ngochungechunge lwezimpendulo zokwengeza ukuze akhe i-polymer. Le nqubo ingahlukaniswa ngezigaba ezintathu eziyinhloko: ukuqaliswa, ukusabalala, kanye nokuphela.
1. Ukuqaliswa
Ukuqaliswa kuyisigaba sokuqala se-polymerization lapho ama-free radical noma ama-ion akhiwa khona njengezinhlobo ezisabelayo. Lawa ma-free radical ngokuvamile akhiqizwa ngokubola kokushisa noma kwe-photochemical kwama-initiators afana nama-peroxide noma ama-azo compounds. Isibonelo, ekuqhekekeni kwama-peroxide:
\[ ROOR \umcibisholo ongakwesokudla 2RO\cdot \]
I-free radical RO• ingaqala ukusabela nge-monomer (isb., i-ethylene):
\[ RO\cdot + CH_2=CH_2 \umcibisholo ongakwesokudla RO-CH_2-CH_2\cdot \]
2. Ukusabalala
Esigabeni sokusabalala, ama-free radical akhiqizwa esigabeni sokuqala asabela namanye ama-monomer ukuze akhe amaketanga amade e-polymer. Isikhathi ngasinye lapho i-free radical ixhumana ne-monomer entsha, iketanga le-polymer liyanwetshwa:
\[ RO-CH_2-CH_2\cdot + CH_2=CH_2 \umcibisholo ongakwesokudla RO-CH_2-CH_2-CH_2-CH_2\cdot \]
Le nqubo iyaqhubeka kuze kube yilapho amakhulu kuya ezinkulungwaneni zama-monomer ehlanganiswa abe amaketanga amade e-polymer.
3. Ukuqeda
Ukuphela kwesigaba sokugcina se-polymerization lapho ukukhula kwe-polymer chain kuyeka khona. Ukuphela kwesigaba kungenzeka ngezindlela ezahlukene, njengokuhlanganiswa noma ukungahleleki. Ngokuhlangana, ama-free radical amabili ahlangana ukuze akhe i-molecule eyodwa ye-polymer:
\[ RO-CH_2-CH_2\cdot + \cdot CH_2-CH_2-RO \rightarrow RO-CH_2-CH_2-CH_2-CH_2-RO \]
Ngokungalingani, ama-free radical aseduze ashintshana ngama-athomu e-hydrogen ukuze akhiqize ama-molecule amabili angagcwali:
\[ RO-CH_2-CH_2\cdot + \cdot CH_2-CH_2-RO \rightarrow RO-CH_2-CH_3 + CH_2=CH-RO \]
Izicelo ze-Addition Polymerization
Inqubo yokufaka i-polymerization isetshenziselwa ukukhiqiza izinhlobo ezahlukene zama-polymer anezinhlobo eziningi zezicelo kuzo zonke izimboni. Ezinye zezicelo eziyinhloko zifaka phakathi ipulasitiki, irabha yokwenziwa, kanye nemicu.
1. Ipulasitiki
Amapulasitiki ayimikhiqizo eyinhloko yokwenza i-polymerization eyengeziwe. I-Polyethylene, i-polypropylene, i-polystyrene, kanye ne-polyvinyl chloride (PVC) yizibonelo ezivamile zamapulasitiki akhiqizwa yi-polymerization eyengeziwe:
– I-Polyethylene (PE): Isetshenziswa emikhiqizweni yansuku zonke njengezikhwama zepulasitiki, amathoyizi ezingane, namabhodlela eziphuzo.
– I-Polypropylene (PP): Isetshenziswa kabanzi ekukhiqizeni ifenisha yasekhaya, ukupakishwa kokudla, kanye nezingxenye zezimoto.
– I-Polystyrene (PS): Isetshenziselwa ukwenza imikhiqizo efana nezitsha zokudla, imishini yelabhorethri, kanye nokushisa.
– I-Polyvinyl chloride (PVC): Isetshenziswa ekwenziweni kwamapayipi, izintambo, nezinto zokwakha.
2. Irabha Yokwenziwa
Amarabha okwenziwa afana ne-polybutadiene kanye ne-styrene-butadiene (SBR) nawo akhiqizwa ngokusebenzisa i-polymerization eyengeziwe. Lawa marabha okwenziwa asetshenziswa ekwenziweni kwamathayi ezimoto, ama-foot ezicathulo, kanye neminye imikhiqizo yerabha ehlukahlukene.
3. Ifayibha
Ezinye izintambo zokwenziwa ezisetshenziswa embonini yezindwangu nazo zikhiqizwa ngokusebenzisa i-polymerization eyengeziwe. Izibonelo zifaka phakathi i-acrylic ne-polypropylene, ezisetshenziswa ekwenziweni kwezingubo, amakhaphethi, nezinye izindwangu.
Izinzuzo Zokwengeza i-Polymerization
Ukwengeza i-polymerization kuletha izinzuzo eziningana ezenza kube nenzuzo enkulu ezisetshenziswa ezimbonini.
1. Ukusebenza Kahle Kokukhiqiza
Ukwengeza i-polymerization kuvumela ukukhiqizwa kwama-polymer amakhulu ngokulawula okuncane ubude beketanga kanye nokusatshalaliswa kwesisindo sama-molecule. Le nqubo ishesha futhi kulula ukuyilungisa, inezimo ezingalungiswa ukuze kukhiqizwe izinhlobo eziningi zama-polymer.
2. Izindleko Eziphansi
Ama-monomer asetshenziswa ngaphezu kwalokho i-polymerization ngokuvamile ashibhile futhi atholakala kabanzi. Ngaphezu kwalokho, le ndlela ingasetshenziswa ngokusetshenziswa kwamandla okuncane, okufaka isandla ekusebenzeni kahle kwezindleko zenqubo yokukhiqiza.
3. Ukuguquguquka Kwezinto Ezibonakalayo
Ukwengeza i-polymerization kungakhiqiza ama-polymer anezakhiwo eziningi zomzimba nezemishini. Ngokushintsha uhlobo lwe-monomer noma ngokulawula izimo zokusabela, abakhiqizi bangakha ama-polymer aklanyelwe izidingo ezithile.
4. Ukuqina Nokuzinza
Ama-polymer akhiqizwa ngokwengeza i-polymerization avame ukumelana kakhulu nezici ezahlukahlukene zemvelo, okuhlanganisa izinga lokushisa, amakhemikhali, kanye nokucindezeleka ngokomzimba. Lokhu kuwenza afaneleke kakhulu ekusetshenzisweni okudinga ukuqina okuphezulu, njengezinto zokwakha kanye nemishini yezimboni.
5. Ukusebenziseka kabusha
Ama-polymer amaningi engeziwe, njenge-polyethylene ne-polypropylene, angasetshenziswa kabusha, asekela imizamo yokuzinza kanye nokunciphisa imfucuza yemvelo. Lokhu kubaluleke kakhulu uma kucatshangelwa ukwanda kokuqwashisa ngomthelela wemfucuza yepulasitiki emvelweni.
Izinselele Nezixazululo
Naphezu kwezinzuzo eziningi ezinikezayo, ukwenziwa kwe-polymerization kubhekene nezinselele eziningana okudingeka kubhekwane nazo ukuze kuthuthukiswe ukusebenza kahle kwayo kanye nokusimama kwayo.
1. Ukulawulwa Kwezakhiwo Ze-Polymer
Ukulawula isakhiwo kanye nezakhiwo zama-polymer atholakalayo kuvame ukuba yinselele. Abacwaningi kumele baqhubeke nokuthuthukisa izindlela zokulawula ukusatshalaliswa kwesisindo sama-molecule kanye nokucushwa kwe-stereochemical ukuze kufezwe ukusebenza okuhle kakhulu.
2. Umthelela Wezemvelo
Ukukhiqizwa kwe-polymer kuvame ukuba nemiphumela ebalulekile kwezemvelo. Ukusetshenziswa kwezinsiza kusebenza kahle kanye nobuchwepheshe obunobungani nemvelo kumele kuthuthukiswe njalo ukuze kuncishiswe ukusabalala kwekhabhoni kwezinqubo zokukhiqizwa kwe-polymer.
3. Imisebenzi Yokuvuselela
Ukuthuthukisa ubuchwepheshe bokuvuselela obusebenza kahle futhi obusebenza kahle ngokwezomnotho kubalulekile ekuphatheni inani elikhulayo lemfucuza ye-polymer. Ukuthuthukiswa ekuhlungeni nasekucutshungulweni kwemfucuza yepulasitiki kungadlala indima ebalulekile kulo mzamo.
Isiphetho
Ukwengeza i-polymerization kudlala indima ebalulekile ekukhiqizweni kwezinhlobo eziningi zama-polymer asekela izici eziningi zempilo yanamuhla. Kusukela kumapulasitiki nerabha kuya kumafayibha endwangu, le ndlela ivumela ukukhiqizwa kwezinto ezisebenza kahle nezingabizi. Ngenkathi ibhekene nezinselele ezithile, intuthuko kwezobuchwepheshe kanye nocwaningo inganqoba lezi zithiyo futhi ikhulise izinzuzo zokwengeza i-polymerization. Ngokuqhubeka nokuthuthukiswa kwesicelo kanye nokwenza ngcono inqubo, ukwengeza i-polymerization kuzohlala kuyisici esibalulekile embonini yamakhemikhali kanye nokukhiqiza, kusekela ukuthuthuka komphakathi ozinzile.
