Imibuzo Yezibonelo kanye Nengxoxo Yezinhlobo Zama-Polymers
I-polymer iyi-molecule enkulu eyakhiwe ngamayunithi amancane ama-molecule abizwa ngokuthi ama-monomers. Ama-polymer asetshenziswa ezinhlobonhlobo zezicelo, kusukela kumapulasitiki nerabha kuya kumafayibha okwenziwa nezinto zokwakha. Ukuqonda ama-polymer kubalulekile kumakhemikhali, isayensi yezinto zokwakha, kanye nezimboni ezahlukahlukene. Lesi sihloko sizoxoxa ngezibonelo eziningana zezinkinga mayelana nezinhlobo zama-polymer futhi sinikeze izixazululo ezijulile zalezi zinkinga.
Imibuzo Eyisibonelo Nengxoxo
Umbuzo 1:
Qamba izinhlobo ezintathu zama-polymers ngokusekelwe emthonjeni wazo wokuqala bese unikeza isibonelo sazo.
Ingxoxo:
1. Ama-polymer emvelo:
Ama-polymer emvelo angama-polymer ayenzeka ngokwemvelo endaweni ezungezile. Izibonelo zama-polymer emvelo zifaka:
– I-Cellulose: Itholakala ezindongeni zamaseli ezitshalo.
– Irabha Yemvelo: Itholakala emanzini esihlahla se-Hevea brasiliensis.
– Amaprotheni: Njenge-collagen etholakala esikhumbeni nasezicutshini ezixhumene nezilwane.
2. Ama-polymer okwenziwa:
Ama-polymer okwenziwa angama-polymer akhiqizwa ngezinqubo zamakhemikhali zokwenziwa ngabantu. Izibonelo zama-polymer okwenziwa zifaka:
– I-Polyethylene (PE): Isetshenziswa ekwenziweni kwezikhwama zepulasitiki.
– I-Polypropylene (PP): Isetshenziswa embonini yezimoto kanye nokupakisha ukudla.
– I-Polyvinyl Chloride (PVC): Isetshenziswa ekwakhiweni kwamapayipi nezintambo.
3. Ama-Polymer angenziwanga kahle:
Ama-polymer angenziwe ngokwengxenye ayizinguquko zama-polymer emvelo ukuze kuthuthukiswe izakhiwo zawo. Izibonelo zama-polymer angenziwe ngokwengxenye zifaka:
– I-Cellulose Acetate: Yenziwe nge-cellulose eshintshiwe kusetshenziswa i-acetic acid, esetshenziswa efilimini yezithombe.
– I-Nitrocellulose: Itholakala nge-nitration ye-cellulose, esetshenziswa ekwenziweni kwezinto eziqhumayo kanye nezingubo.
Umbuzo 2:
Chaza umehluko phakathi kwama-polymer e-thermoplastic kanye nama-polymer e-thermoset, bese unikeza izibonelo ezimbili zazo.
Ingxoxo:
1. Ama-polymer e-Thermoplastic (ama-Thermoplastic):
Le polymer iyathamba uma ishiswa futhi iqine uma ipholisiwe, futhi ingadlula kule nqubo ngokuphindaphindiwe. Lokhu kwenza kube lula ukuyiphinda isetshenziswe. Isibonelo:
– I-Polyethylene (PE): Isetshenziswa ekwenziweni kwezikhwama zepulasitiki namabhodlela.
– I-Polystyrene (PS): Isetshenziswa ekwenziweni kwezinto zokuvikela ukushisa kanye nokupakisha ukudla.
2. Ama-polymer e-Thermosetting (ama-Thermosets):
Lawa ma-polymer, uma esenziwe ngokushisa nokupholisa, awakwazi ukuncibilikiswa futhi. Anesakhiwo esiqinile futhi awakwazi ukuphinda asetshenziswe ngendlela efanayo ne-thermoplastics. Isibonelo:
– I-Bakelite: Itholakala kumaswishi kagesi kanye nezibambo zemishini yokupheka.
– I-Epoxy: Isetshenziswa ekunamathiseleni, ekumbozeni, nasezihlanganisweni ezihlala isikhathi eside.
Umbuzo 3:
Chaza inqubo yokwengeza i-polymerization bese unikeza izibonelo zama-polymer akhiqizwa ngale nqubo.
Ingxoxo:
Ukwengeza i-polymerization inqubo yokwakha ama-polymer ngokusebenzisa ukusabela kweketanga lapho ama-monomer aqukethe ama-double bond (ngokuvamile ama-carbon-carbon double bond) ahlangana ngaphandle kokukhiqiza imikhiqizo engezansi.
Izigaba ezengeziwe ze-polymerization zifaka:
1. Ukuqaliswa: Ukwakheka kwama-free radical noma ama-ion aqala ukusabela.
2. Ukusabalala: Ama-free radical noma ama-ion asabela nama-monomers, akha amaketanga amade e-polymer.
3. Ukuphela: Ukusabela kuphela lapho kuhlangana ama-free radical amabili.
Izibonelo zama-polymers okwengeza:
– I-Polyethylene (PE): Ikhiqizwa nge-ethylene monomer (C2H4).
– I-Polypropylene (PP): Yenziwe nge-propylene monomer (C3H6).
Umbuzo 4:
Kusho ukuthini ukupholimitha komoya futhi unikeze izibonelo ezimbili zama-polymer akhiqizwa ngale nqubo.
Ingxoxo:
I-polymerization ye-condensation inqubo ye-polymerization lapho ama-monomer ehlangana khona ngokususa ama-molecule amancane njengamanzi noma i-methanol.
Izibonelo ze-polymerization ye-condensation yilezi:
1. Ukwakheka kwe-Nylon:
Inayiloni 6,6 yakhiwa ngokusabela phakathi kwe-hexamethylenediamine ne-adipic acid, okukhiqiza amanzi njengomkhiqizo ophumayo.
\[ \umbhalo{H}_2\umbhalo{N}-(\umbhalo{CH}_2)_6\umbhalo{NH}_2 + \umbhalo{HOOC}-(\umbhalo{CH}_2)_4\umbhalo{COOH} \rightarrow (-\umbhalo{NH}-(\text{CH}_2)_6\text{NH-CO}-(\) COOH}__text \umbhalo{H}_2\umbhalo{O} \]
2. Ukwakheka kwePolyester:
Ama-polyester afana ne-polyethylene terephthalate (PET) akhiwa ngokusabela phakathi kwe-terephthalic acid ne-ethylene glycol, okukhiqiza amanzi njengomkhiqizo ophumayo.
\[ \umbhalo{HOOC-}\umbhalo{C}_6\umbhalo{H}_4\umbhalo{COOH} + \umbhalo{HO-CH}_2\umbhalo{CH}_2\umbhalo{OH} \umcibisholo wangakwesokudla (-\umbhalo{O-CH}_2\umbhalo{CH}_2-\umbhalo{OCO-}\umbhalo{C}_6\umbhalo{H}_4) +_umbhalo{H}_4 \umbhalo{H}_2\umbhalo{O} \]
Umbuzo 5:
Izakhiwo zomzimba zama-polymer zingashintshwa kanjani ngokusebenzisa ama-plasticizer? Nikeza isibonelo.
Ingxoxo:
Ama-plasticizer ayizithasiselo ezingezwe kuma-polymer ukuze kwandiswe ukuguquguquka, kuncishiswe ukuphuka, futhi kwehliswe izinga lokushisa lokuguquka kwengilazi (Tg). Ama-plasticizer asebenza ngokunciphisa amandla ezibopho eziphakathi kwama-molecule ngaphakathi kwe-polymer, okuvumela amaketanga e-polymer ukuthi ahambe ngokukhululeka futhi andise ukuqina kwezinto.
Izibonelo zokusebenzisa ama-plasticizer:
– Ama-PVC nama-plasticizer: Ekwenzeni izintambo zikagesi, i-PVC ixutshwa nama-plasticizer afana nama-phthalates ukuze iguquguquke futhi iqine kakhudlwana.
– I-cellulose acetate kanye ne-plasticizers: Isetshenziswa ekukhiqizweni kwamafilimu kanye nama-lacquer ukwenza imikhiqizo ingabi lukhuni.
Isiphetho
Ama-polymer ayizinto eziguquguqukayo ngendlela emangalisayo ezidlala indima ebalulekile empilweni yansuku zonke kanye nobuchwepheshe besimanje. Ngokuqonda izinhlobo zama-polymer kanye nezinqubo ze-polymerization, singakha izinto ezintsha ezinezakhiwo ezifiselekayo futhi sithuthukise ukusetshenziswa kwazo emikhakheni eyahlukahlukene. Imfundo yama-polymer iqala ngokubhekana nalezi zinkinga nokuthola ukuqonda okujulile kwezimiso eziyisisekelo eziyisisekelo zesayensi yama-polymer. Lesi sihloko sihlose ukunikeza ukuqonda kokuqala kwezinhlobo zama-polymer nokukhuthaza abafundi ukuthi baqhubeke nokufunda nokuhlola ngokujulile ngama-polymer kanye nezinhlelo zokusebenza zawo.
