pulasitiki imapangidwa ndi zinthu ziti?
Monga chinthu chofunikira m'moyo wamakono, mapulasitiki amagwiritsidwa ntchito kwambiri m'magawo ambiri monga kulongedza, zida zamagetsi, magalimoto, ndi zomangamanga. Kodi mapulasitiki amapangidwa ndi zinthu ziti? Izi zikuphatikiza sayansi yovuta ya ma polima mumakampani opanga mankhwala. Pulasitiki amapangidwa kuchokera ku ma polima osiyanasiyana opangidwa kapena opangidwa ndi semi-synthetic, ndipo zopangira za polima izi zimakonzedwa kudzera munjira zinazake kukhala zinthu zatsiku ndi tsiku zomwe timadziwa. M'munsimu, tidzasanthula mwatsatanetsatane kapangidwe ka pulasitiki ndi ndondomeko ya kukonzekera kwawo.
1. Zigawo zoyambirira za mapulasitiki: ma polima
Kodi mapulasitiki amapangidwa ndi chiyani? Yankho lapakati ndi ma polima. Polima ndi unyolo wa mamolekyu apamwamba opangidwa ndi kuchuluka kwa ma monomers obwerezabwereza olumikizidwa ndi polymerization reaction. Ma polima wamba amaphatikizapo polyethylene (PE), polypropylene (PP), polystyrene (PS) ndi polyvinyl chloride (PVC). Mitundu yosiyanasiyana ya mapulasitiki imawonetsa zinthu zosiyanasiyana zakuthupi ndi zamankhwala kutengera mtundu wa monomer womwe umagwiritsidwa ntchito, njira ya polymerization ndi kapangidwe ka maselo.

Polyethylene (PE): polymerised kuchokera ku ethylene monomer, yomwe imagwiritsidwa ntchito kwambiri popanga matumba apulasitiki, mafilimu opangira chakudya, etc.
Polypropylene (PP): polymerisation ya propylene monomer, yokhala ndi kukana kwabwino kwa kutentha, imagwiritsidwa ntchito kwambiri muzovala zamabotolo apulasitiki, ziwiya zapakhomo.
Polystyrene (PS): polymerized kuchokera ku styrene monomer, yowonekera komanso yosavuta kupanga, yomwe imagwiritsidwa ntchito kwambiri popanga zida zotayira, zoyikapo.

2. Zowonjezera zomwe zimagwiritsidwa ntchito popanga mapulasitiki
Kuphatikiza pa ma polima, mapulasitiki ali ndi zowonjezera zosiyanasiyana zomwe zimagwiritsidwa ntchito kukulitsa katundu wawo kapena kuchepetsa ndalama zopangira. Zowonjezera izi zimaphatikizapo antioxidants, plasticizers, stabilizers, coloring agents, fillers ndi zina zotero. Mtundu ndi kuchuluka kwa zowonjezera zimakhudza mwachindunji katundu wakuthupi ndi ntchito za pulasitiki.

Plasticisers: onjezerani kusinthasintha kwa mapulasitiki ndikupangitsa kuti zikhale zosavuta kuzikonza ndi kuumba. Nthawi zambiri amagwiritsidwa ntchito popanga PVC.
Ma Antioxidants: amaletsa pulasitiki kuti isakalamba chifukwa cha okosijeni pakupanga ndikugwiritsa ntchito, ndikupangitsa kuti ikhale yolimba.
Zodzaza: monga calcium carbonate, talcum powder, zomwe zimagwiritsidwa ntchito kuonjezera kuuma ndi kukhazikika kwa pulasitiki, pamene kuchepetsa ndalama zopangira.

3. Pulasitiki kupanga ndondomeko: polymerization anachita ndi akamaumba luso
Kupanga mapulasitiki kumagawidwa m'magawo awiri: polymerization reaction ndi kuumba. Ma monomers amasinthidwa kukhala ma polima kudzera muzochita zamakemikolo. Kutengera ndi njira ya polymerisation, imatha kugawidwa mu polymerization yaulere, polymerization ya anionic, polymerization ya cationic ndi copolymerization. Kenako, polima ndi kukonzedwa mu mankhwala a mawonekedwe ankafuna ndi jekeseni akamaumba, extrusion, kuwomba-akaumba ndi njira zina.

Kuumba jekeseni: Pulasitiki yosungunuka yotenthedwa imakanikizidwa mu nkhungu ndi mawonekedwe, omwe amagwiritsidwa ntchito popanga zinthu zapulasitiki zomwe zimagwiritsidwa ntchito tsiku ndi tsiku.
Extrusion: Pulasitiki imatenthedwa kenako imapangidwa ndi extrusion, yoyenera kupanga zinthu zopitirira monga mapaipi ndi mafilimu.
Kuwomba: Pulasitiki wosungunuka amawumbidwa ndipo amagwiritsidwa ntchito popanga zinthu zopanda kanthu monga mabotolo.

4. Chitukuko cha mapulasitiki okonda zachilengedwe
Ndi kukwera kwa chidziwitso cha chilengedwe, anthu ayika patsogolo zofunikira za chilengedwe pakupanga ndi kugwiritsa ntchito mapulasitiki. Mapulasitiki owonongeka, mapulasitiki opangidwa ndi bio ndi mapulasitiki obwezerezedwanso akukhala njira yatsopano yachitukuko.

Mapulasitiki owonongeka: monga polylactic acid (PLA), amatha kuchepetsedwa pang'onopang'ono kukhala carbon dioxide ndi madzi m'chilengedwe.
Mapulasitiki opangidwa ndi bio: ma polima opangidwa kuchokera kuzinthu zopangira mbewu, monga chimanga ndi nzimbe, zomwe zimapezeka kudzera mukusintha kwachilengedwe.
Mapulasitiki obwezerezedwanso: pokonzanso zinthu zakale zamapulasitiki, poyeretsa, kuphwanya ndi kukonzanso, amagwiritsidwanso ntchito kupanga zatsopano.

Mapeto
Kupyolera mu kusanthula pamwambapa, tikhoza kuyankha momveka bwino funso la "pulasitiki yopangidwa ndi zinthu ziti": pulasitiki imapangidwa makamaka ndi ma polima opangidwa ndi zinthu zosiyanasiyana, zomwe zimagwiritsidwa ntchito popanga njira zosiyanasiyana. Ndi kupita patsogolo kwa sayansi ndi ukadaulo, chitukuko cha mapulasitiki ochezeka ndi chilengedwe chikusintha pang'onopang'ono kudalira kwathu mapulasitiki achikhalidwe, ndikulimbikitsa chitukuko chamakampani apulasitiki m'njira yobiriwira komanso yokhazikika.