Ukususela ekuqaleni kwayo ngexesha nasemva kweMfazwe Yehlabathi II, ishishini lezorhwebo lee-polymers-i-long-chain synthetic molekyuli apho "iplastiki" iligama elibi eliqhelekileyo-likhule ngokukhawuleza.Ngo-2015, ngaphezulu kwe-320 yezigidi zeetoni zeepolymers, ngaphandle kweentsinga, zenziwe kwihlabathi jikelele.
[Itshathi: Incoko] Ukuya kuthi ga kwiminyaka emihlanu edlulileyo, abaqulunqi bemveliso yepolymer abakhange bayithathele ingqalelo into ezakwenzeka emva kokuphela kobomi bokuqala bemveliso.Oku kuyaqala ukutshintsha, kwaye lo mba uya kufuna ukugxila okwandisiweyo kwiminyaka ezayo.
Ishishini lePlastiki
"Iplastiki" iye yaba yindlela ephosakeleyo yokuchaza iipolymers.Ngokuqhelekileyo zivela kwi-petroleum okanye igesi yendalo, ezi zimolekyuli zekhonkco elide elinamakhulu ukuya kumawaka amakhonkco kwikhonkco ngalinye.Amatyathanga amade adlulisela iimpawu ezibalulekileyo zomzimba, ezinjengokomelela kunye nokuqina, ukuba iimolekyuli ezimfutshane azikwazi ukuhambelana.
"Iplastiki" ngokwenene luhlobo olufutshane lwe "thermoplastic," igama elichaza izinto zepolymeric ezinokubunjwa kwaye ziphinde zenziwe ngokutsha ngokusebenzisa ubushushu.
Ishishini langoku lepolymer lenziwe ngokufanelekileyo nguWallace Carothers eDuPont ngeminyaka yoo-1930.Umsebenzi wakhe onzima kwiipolyamides wakhokelela ekuthengisweni kwenayiloni, njengoko ukunqongophala kwesilika ngexesha lemfazwe kwanyanzela abafazi ukuba bajonge iikawusi kwenye indawo.
Xa ezinye izinto zazinqongophele ngexesha leMfazwe Yehlabathi II, abaphandi bajonga kwiipolymers ezenziweyo ukuze bazalise izithuba.Ngokomzekelo, ukunikezelwa kwerabha yendalo yamatayara ezithuthi kwanqunyulwa yi-Japanese ukunqoba kwe-Asia-mpuma ye-Asia, ekhokelela kwi-polymer synthetic elingana.
Ukuphumelela okuqhutywa kukufuna ukwazi kwikhemistri kukhokelele kuphuhliso oluqhubekayo lweepolymers zokwenziwa, kubandakanywa nepolypropylene esetyenziswa ngokubanzi ngoku kunye ne-high-density polyethylene.Ezinye iipholima, ezifana neTeflon, zakhubeka ngengozi.
Ekugqibeleni, indibaniselwano yentswelo, inkqubela phambili kwezenzululwazi, kunye nokuzola kukhokelele kuluhlu olupheleleyo lweepolymers onokuthi uziqonde ngokulula njenge "iplastiki."Ezi polima zaye zathengiswa ngokukhawuleza, ngenxa yomnqweno wokunciphisa ubunzima beemveliso kunye nokubonelela ngeendlela ezingabizi kakhulu kwizinto zendalo ezifana neselulosi okanye umqhaphu.
IINTLOBO ZEPLASTI
Ukuveliswa kweepholima zokwenziwa kwihlabathi jikelele kulawulwa yi-polyolefins-i-polyethylene kunye ne-polypropylene.
I-Polyethylene iza kwiindidi ezimbini: "uxinzelelo oluphezulu" kunye "noxinano oluphantsi."Kwinqanaba le-molecular, i-polyethylene ephezulu ibonakala njengekama kunye namazinyo ahlala ahlala, amfutshane.Uguqulelo loxinaniso oluphantsi, kwelinye icala, lukhangeleka njengekama elinamazinyo angalungelelanisiweyo angalinganiyo ubude obungacwangciswanga-ngandlel’ ithile njengomlambo kunye nemithombo yawo ukuba ibonwa phezulu phezulu.Nangona zombini ziyi-polyethylene, umahluko kwimilo yenza ukuba ezi zixhobo ziziphathe ngendlela eyahlukileyo xa zibunjwa zibe ziifilimu okanye ezinye iimveliso.
[Isicangca: Incoko]
IiPolyolefins zinamandla ngenxa yezizathu ezimbalwa.Okokuqala, zinokuveliswa kusetyenziswa igesi yendalo engabizi mali ininzi.Okwesibini, zezona iipolima zokwenziwa zikhaphukhaphu eziveliswe kumlinganiselo omkhulu;ukuxinana kwabo kuphantsi kangangokuba bayadada.Okwesithathu, iipololefins zixhathisa ukonakaliswa ngamanzi, umoya, igrisi, izinyibilikisi zokucoca-zonke izinto ezinokuthi zidibene nazo ezi polima xa zisetyenziswa.Okokugqibela, zilula ukumila zibe ziimveliso, ngelixa zomelele ngokwaneleyo ukuba ukupakishwa okwenziwe kuzo akuyi konakala kwilori yokuhambisa ehleli elangeni imini yonke.
Nangona kunjalo, ezi zixhobo zineemeko ezimbi kakhulu.Zithoba kabuhlungu kancinci, okuthetha ukuba iipololefins ziyakuphila kwindawo engqongileyo amashumi eminyaka ukuya kwiinkulungwane.Kwangaxeshanye, amaza kunye nomoya ovuthuzayo ziyazitshabalalisa, zenze amasuntswana amancinane anokufunxwa yintlanzi nezilwanyana, aze anyuke ityathanga lokutya esiza kuthi.
Ukurisayikilisha iipolyolefin akukho ngqo njengoko umntu angathanda ngenxa yokuqokelela kunye nokucoca imiba.Ioksijini kunye nobushushu kubangela umonakalo wetyathanga ngexesha lokuphinda kuhlaziywe, ngelixa ukutya kunye nezinye izinto zingcolisa i-polyolefin.Ukuqhubela phambili okuqhubekayo kwikhemistri kudale amabanga amatsha e-polyolefin amandla aphuculweyo kunye nokuqina, kodwa ezi azinakuhlala zixubana namanye amabanga ngexesha lokurisayikilishwa.Ngaphezu koko, iipololefins zihlala zidityaniswa kunye nezinye izinto kwipakethe ye-multilayer.Ngelixa ezi zakhiwo zininzi zisebenza kakuhle, akunakwenzeka ukuba zisetyenziswe kwakhona.
Iipolymers ngamanye amaxesha ziyagxekwa ngokuveliswa kwipetroleum enqongopheleyo kunye negesi yendalo.Nangona kunjalo, iqhezu legesi yendalo okanye i-petroleum esetyenziselwa ukuvelisa iipholima liphantsi kakhulu;ngaphantsi kwe-5% nokuba yi-oyile okanye irhasi yendalo eveliswayo ngonyaka ngamnye iqeshelwe ukwenza iiplastiki.Ngokubhekele phaya, i-ethylene inokuveliswa nge-ethanol yommoba, njengoko kusenziwa urhwebo yiBraskem yaseBrazil.
INDLELA IPLASTIKI ESETYENZISWA NGAYO
Ngokuxhomekeke kwingingqi, ukupakishwa kusebenzisa i-35% ukuya kwi-45% yepolymer yokwenziwa eveliswe iyonke, apho iipololefins zilawula.I-Polyethylene terephthalate, i-polyester, ilawula imarike yeebhotile zesiselo kunye nemicu yelaphu.
Ukwakha kunye nokwakhiwa kudla enye i-20% yeepolymers zizonke eziveliswayo, apho umbhobho wePVC kunye nabazala bayo bemichiza balawula.Imibhobho ye-PVC ilula, inokudityaniswa kunokuba ithengiswe okanye idityaniswe, kwaye ixhathise kakhulu imiphumo eyonakalisayo yeklorini emanzini.Ngelishwa, iiathom zeklorini ezinika iPVC olu ncedo zenza kube nzima kakhulu ukurisayikilisheka kwakhona-ininzi ilahlwa ekupheleni kobomi.
I-Polyurethanes, intsapho yonke yeepolymers ezinxulumene nazo, zisetyenziswa ngokubanzi kwi-foam insulation yezindlu kunye nezixhobo zombane, kunye neengubo zokwakha.
Icandelo leemoto lisebenzisa izixa ezonyukayo ze-thermoplastics, ngokuyintloko ukunciphisa ubunzima kwaye kungoko kufezekiswa imigangatho ephezulu yokusebenza kwamafutha.I-European Union iqikelela ukuba i-16% yobunzima bemoto ephakathi ngamalungu eplastiki, ingakumbi kumalungu angaphakathi kunye namalungu.
Ngaphezu kwe-70 yezigidi zeetoni ze-thermoplastics ngonyaka zisetyenziswa kwilaphu, uninzi lwempahla kunye nekhaphethi.Ngaphezu kwe-90% yeefayili zokwenziwa, ubukhulu becala i-polyethylene terephthalate, iveliswa e-Asia.Ukukhula kokusetyenziswa kwefayibha zokwenziwa ezimpahleni kufike ngeendleko zeentsinga zendalo ezifana nomqhaphu kunye noboya, obufuna izixa ezibalulekileyo zomhlaba wokufama ukuba ziveliswe.Umzi-mveliso wefayibha zokwenziwa ubone ukukhula okumangalisayo kwempahla kunye nekhaphethi, enkosi kumdla kwiipropathi ezikhethekileyo ezinje ngokuzolula, ukuthambisa, kunye nokuphefumla.
Njengakwimeko yokupakishwa, amalaphu awaqhelekanga ukurisayikilishwa.Ummi oqhelekileyo wase-US uvelisa ngaphezulu kweekhilogram ezingama-90 zenkunkuma yelaphu ngonyaka.Ngokutsho kweGreenpeace, umntu oqhelekileyo ngo-2016 uthenge i-60% yezinto ezininzi zempahla minyaka le kunokuba umntu oqhelekileyo wenza iminyaka eyi-15 ngaphambili, kwaye ugcina iimpahla ixesha elifutshane.
Ixesha lokuposa: Jul-03-2023