Ipulasitiki ingenye yezinto ezisetshenziswa kakhulu abantu ukukhiqiza inani elikhulu lemikhiqizo, njengamabhodlela, amathoyizi, iziqukathi nokunye. Kodwa-ke, alukho uhlobo olulodwa lwazo, kodwa kukhona ukuhlukaniswa okubanzi kwamapulasitiki esizokubonisa wona kulesi sihloko. Sikumema ukuthi uqhubeke ufunda.
Ukuhlukaniswa Kwepulasitiki
Uma uthi nhlá, uma uvakashela zonke izindawo ezisendlini noma ehhovisi lakho, uzobona izinhlobonhlobo zemikhiqizo eyenziwe ngepulasitiki. Ngokwayo, ipulasitiki, njengoba kushiwo ngaphambili, ingenye yezinto ezisetshenziswa kakhulu emhlabeni ekwenzeni zonke izinhlobo zemikhiqizo engase icatshangwe. Kulula ukuhlukanisa yonke into ngokuthi "ipulasitiki." Kodwa-ke, ukuhlukaniswa kwamapulasitiki kuvame ukuthinta cishe izinhlobo eziyisi-7 zalezi okufanele wazi ngazo. Uhlu oluphelele lwamapulasitiki luhlanganisa:
I-Polyethylene terephthalate (PET noma i-PETE)
Ikhiqizwa nge-polymerization ye i-ethylene glycol ne-terephthalic acid. I-Ethylene glycol iwuketshezi olungenambala olutholakala ku-ethylene, futhi i-terephthalic acid iwuketshezi oluyikristale olutholakala ku-xylene. Lapho kushiswa ndawonye ngaphansi kwethonya lama-catalysts amakhemikhali, i-ethylene glycol ne-terephthalic acid ikhiqiza i-PET ngendlela yokuncibilika kwe-viscous engaphothwa ngokuqondile ibe imicu noma iqiniswe ukuze iqhubeke nokusebenza njengepulasitiki.
Uma sikhuluma ngamakhemikhali, i-ethylene glycol iyi-diol, i-alcohol enesakhiwo samangqamuzana aqukethe amaqembu amabili e-hydroxyl (OH), kanti i-terephthalic acid iyi-dicarboxylic acid enamakha, i-asidi enesakhiwo samangqamuzana equkethe ikhabhoni enkulu enezinhlangothi eziyisithupha (noma iphunga elimnandi) futhi amaqembu amabili e-carboxyl (CO 2 H). Ngaphansi kwethonya lokushisa nama-catalysts, amaqembu e-hydroxyl ne-carboxyl asabela ekwakheni ama-esters (CO-O), asebenza njengamabhondi amakhemikhali axhuma amayunithi e-PET ahlukahlukene kuma-polymer amaketango amade. Amanzi nawo ayi-byproduct.
Yipulasitiki egaywe kabusha kakhulu. Nokho, e-United States, amaphesenti angaba ngu-20 kuphela asetshenziswa kabusha. Amabhodlela e-PET neziqukathi ngokuvamile ziyancibilika futhi ziphothwe zibe imicu yokwenza upholstery noma amaragi. Uma iqoqwe esimweni esihlanzekile ngokufanelekile, i-PET ingagaywa kabusha ukuze isetshenziswe ekuqaleni, futhi kuye kwaklanywa izindlela zokuhlephula i-polymer ibe izandulela zayo zamakhemikhali ukuze iphinde ihlanganiselwe ku-PET. Inombolo yekhodi yokugaya kabusha ye-PET ngu-1.
I-polyethylene ephezulu kakhulu (i-HDPE)
Ikhiqizwa emazingeni okushisa aphansi nezingcindezi ngezigxivizo ze-Ziegler-Natta kanye ne-metallocene ecushiwe noma i-chromium oxide (eyaziwa ngokuthi i-Phillips catalyst). Ukuntuleka kwe-branching esakhiweni sawo kuvumela ukuthi amaketanga e-polymer ahlanganiswe eduze, okuholela ekutheni kube nezinto eziminyene, ezicwebezelayo ezinamandla amakhulu nokuqina okulinganiselwe. Ngephoyinti lokuncibilika elingaphezu kuka-20°C (36°F) ngaphezu kwe-LDPE, ingamelana nokuchayeka okuphindaphindiwe ku-120°C (250°F) ukuze ivalwe inzalo.
Ngakolunye uhlangothi, kungaphinde kukhulunywe ukuthi imikhiqizo ekhiqizwa yilolu hlobo lokuhlukaniswa kwepulasitiki ihlanganisa amabhodlela abunjiwe obisi kanye nabahlanza indlu; ukudubula ukuqhuma kwezikhwama zokudla ezikhishwe, amafilimu okwakha kanye ne-pulp yezolimo; namabhakede abunjwe ngomjovo, izivalo, amakesi ezinto zikagesi namathoyizi. Ngaphakathi kwesigaba sokugaywa kabusha, lolu hlobo lwepulasitiki lungachazwa ngokubala okulandelayo: 2.
I-Polyvinyl chloride (PVC)
Iwuhlobo lokuphuma kokunye okukhiqizwa yi-polymerization ye-vinyl chloride. Okwesibili kuphela ku-polyethylene phakathi kwamapulasitiki ekukhiqizeni nasekusetshenzisweni. Isetshenziswa ezinhlobonhlobo zemikhiqizo yasendlini neyezimboni, kusukela kuma-raincoats namakhethini okugeza kuya kumafreyimu amafasitela kanye namapayipi angaphakathi. Ipulasitiki eqinile, engasindi ngesimo sayo esimsulwa, nayo yenziwe ngendlela eguquguqukayo "yepulasitiki". Ngaphakathi kwegama legama elisetshenziselwa ukugaywa kabusha, lolu hlobo lokuhlukaniswa kwepulasitiki lukleliswe endaweni yesithathu.
Yalungiswa ngusokhemisi ongumFulentshi u-Henri Victor Regnault ngo-1835 kwase kuba ngusokhemisi waseJalimane u-Eugen Baumann ngo-1872, kodwa yanikezwa ilungelo lobunikazi ngo-1912, lapho omunye usokhemisi waseJalimane, uFriedrich Heinrich August Klatte, esebenzisa ukukhanya kwelanga ukuze aqalise ukupolymerization kwe-vinyl chloride. . Ukusetshenziswa kwepulasitiki kwezentengiselwano ekuqaleni kwakulinganiselwe ngenxa yokuqina kwayo okwedlulele; kodwa-ke, ngo-1926, kwenziwa imizamo yokuyikhipha ku-solvent ebilayo kakhulu ukuze kutholwe i-polymer engagcwele engahlanganisa iraba nensimbi.
Ngakolunye uhlangothi, kwakungu-Waldo Lunsbury Semon owasungula i-PVC eyenziwe ngepulasitiki, umkhiqizo wayo ongasebenzi futhi oguquguqukayo wawunesibopho sokuphumelela kwezentengiselwano kwe-polymer. Ngaphansi kwegama lebhrendi ye-Koroseal, iguqule ipulasitiki yaba izivalo ezibamba ukushaqeka, okokufaka izintambo zikagesi, kanye nemikhiqizo yendwangu eboshiwe. Enye yezindlela ezaziwa kakhulu zokusebenzisa ipulasitiki yaqala ngo-1930, lapho i-Union Carbide neCarbon Corporation ikhipha i-Vinylite, okuphuma kokunye okwaba ukwaziswa okujwayelekile kwamarekhodi egilamafoni e-United States.
I-PVC ehlanzekile ithola isicelo ekuhwebeni kwesakhiwo, lapho ukuqina kwayo, amandla, kanye nokumelana nomlilo kuyasiza kumapayipi, imigudu, i-siding, iminyango kanye namafreyimu amafasitela. Iphinde ivuthwe ibe amabhodlela acacile futhi asobala. Ngenxa yokuqina kwayo, kufanele ikhishwe noma ibunjwe ngaphezu kuka-100 °C, izinga lokushisa eliphezulu ngokwanele ukuqalisa ukubola kwamakhemikhali (ikakhulukazi, ukukhishwa kwe-hydrogen chloride). Ukubola kungancishiswa ngokungeza izinza, okuyizinhlanganisela zensimbi ngokuyinhloko njenge-cadmium, i-zinc, ithini, noma umthofu.
I-Low density polyethylene (LDPE)
Yenziwe ngegesi ye-ethylene ngezingcindezi eziphakeme kakhulu (kufika ku-350 megapascals noma amakhilogremu angu-50.000 nge-intshi yesikwele) kanye nokushisa okuphezulu (kufika cishe ku-350 ° C noma 660 ° F) phambi kwabaqalisi bokugqwala. Lezi zinqubo zikhiqiza isakhiwo se-polymer esinamagatsha amade namafushane. Ngenxa yokuthi amagatsha avimbela ama-molecule e-polyethylene ukuthi angahlangani abe ama-crystalline aqinile, amalungiselelo aqinile, i-LDPE iyinto evumelana nezimo kakhulu. Indawo yayo yokuncibilika icishe ibe ngu-110°C noma i-230°F.
Uma ukhuluma ngezinto ezisetshenziswayo eziyinhloko noma imikhiqizo engenziwa ngalolu hlobo ngaphakathi kwezigaba zamapulasitiki, kungashiwo ukuthi ukusetshenziswa okuyinhloko amafilimu okupakisha, izikhwama zikadoti nezikhwama zokuthenga, i-mulch yezolimo, ukuvala amakhebula kanye nezintambo, amabhodlela okucindezela, amathoyizi. nezinto zasendlini. Njengawo wonke amapulasitiki angaphakathi kwesigaba, uma egaywa kabusha anenombolo, kulokhu 4.
I-Polypropylene (PP)
Kuyinhlanganisela yegesi etholakala ngokuqhekeka okushisayo kwe-ethane, i-propane, i-butane kanye nengxenye ye-naphtha ye-petroleum. Njenge-ethylene, ingeyawo "ama-olefin aphansi," ikilasi lama-hydrocarbon ama-molecule awo aqukethe ipheya elilodwa lama-athomu ekhabhoni ahlanganiswe isibopho esiphindwe kabili. Isakhiwo samakhemikhali se-molecule ye-propylene yi-CH2 = CHCH3. Kodwa-ke, ngaphansi kwesenzo se-polymerization catalysts, isibopho esiphindwe kabili singaphulwa futhi izinkulungwane zama-molecule e-propylene zihlangane ukuze zakhe iketango le-polymer (i-molecule enkulu yamayunithi amaningi).
Okuningi kokukhiqizwa kwe-polypropylene kuphothwa ngokuhlangana kube imicu, esetshenziswa empahleni yasekhaya, njenge-upholstery kanye namaragi angaphakathi nangaphandle. Kukhona futhi ukusetshenziswa okuningi kokuphela kwezimboni, okuhlanganisa intambo ne-twine, ama-nonwovens alahlwayo ama-diaper kanye nezicelo zezokwelapha, kanye nama-nonwovens okusimamisa nokuqinisa inhlabathi ekwakhiweni nasekwakhiweni komgwaqo. ukugandaya. Lezi zinhlelo zokusebenza zisebenzisa ubulukhuni be-polymer, ukunwebeka, ukumelana namanzi kanye nokungangeni kwamakhemikhali. Emhlabeni wokugaywa kabusha, leli lungu lesigaba samapulasitiki singu-5.
I-Polystyrene noma i-Styrofoam (PS)
Le resin ye-thermoplastic eqinile futhi eqinile yenziwa i-polymerized kusuka ku-styrene (CH2 = CHC6H5). I-styrene, esaziwa nangokuthi yi-phenylethylene, senziwa ngokuphendula i-ethylene ne-benzene lapho kukhona i-aluminium chloride ukuze kukhiqizwe i-ethylbenzene, ebuye ikhishwe i-dehydrogen ukuze ikhiqize i-styrene yoketshezi ecacile. I-Styrene monomer yenziwe nge-polymerized kusetshenziswa ama-radical Initiators amahhala ngokuyinhloko ngobuningi kanye nezinqubo zokumiswa, nakuba i-emulsion nezindlela zesixazululo nazo zisetshenziswa.
I-polystyrene enegwebu yenziwe ibe into yokuvala, ukupakisha ukudla, neziqukathi ezifana nezinkomishi zesiphuzo, amabhokisi amaqanda, namapuleti namathileyi alahlwayo. Imikhiqizo ye-polystyrene eqinile ihlanganisa izinto zokupheka ezibunjwe ngomjovo, izibambi zamakhasethi alalelwayo namakesi okupakisha ama-compact disc. Ukudla okuningi kugcinwa kumathileyi abonisa ngale aphuma ku-vacuum, ngenxa yokungena kwegesi ephezulu kanye nokudluliswa okuhle komhwamuko wamanzi. Ikleliswe endaweni yesi-6 ohlwini lwamapulasitiki ekugayweni kabusha.
amapulasitiki ahlukahlukene
Lesi sigaba sokugcina samapulasitiki, sizothola zonke lezo zinhlobo ezingakwazanga ukuhlukaniswa phakathi kwemihlahlandlela yalokhu okukhulunywe ngakho ngenhla. Kulezi zimo singathola ezinye izibonelo ezifana Acrylonitrile Butadiene Styrene, fiberglass, inayiloni, phakathi kwezinye eziningi. Wonke lawa mapulasitiki akha leli qembu elikhulu ngokuvamile ahlonzwa ngaphakathi kwemingcele yokugaywa kabusha ngenombolo 7.
I-Polycarbonate (PC)
I-PC yethulwa ngo-1958 yi-Bayer AG eJalimane futhi ngo-1960 yiGeneral Electric Company e-United States. Njengoba ithuthukiswe yilezi zinkampani, i-PC ikhiqizwa ngokusabela kwe-polymerization phakathi kwe-bisphenol A, uketshezi olushintshashintshayo olutholakala ku-benzene, ne-phosgene, igesi esebenza kakhulu futhi enobuthi etholwe ngokuphendula i-carbon monoxide ne-chlorine. Ama-polymers avelayo (ama-molecule amade anamayunithi amaningana) ahlanganisa amayunithi aphindaphindayo aqukethe izindandatho ezimbili ezinephunga elimnandi (benzene) futhi axhunywe namaqembu e-ester (CO-O).
Ikakhulukazi ngenxa yamasongo anamakha ashumekwe ochungechungeni lwe-polymer, i-PC inokuqina okukhethekile. Iphinde ibe sobala kakhulu, ivumela cishe amaphesenti angu-90 okukhanya okubonakalayo ukuba kudlule. Kusukela maphakathi nawo-1980s, lesi sakhiwo, sihlanganiswe nezakhiwo ezinhle kakhulu zokugeleza kwe-polymer encibilikisiwe, sithole ukusetshenziswa okukhulayo ekubumbeni umjovo we-CD. Ngenxa yokumelana nomthelela ophakeme kakhulu kunoplastiki abaningi, amabhodlela amanzi amakhulu, amafasitela angashayi, izihlangu zokuphahlazeka, nezigqoko zokuphahlazeka nazo zenziwe.
I-Polylactic acid (PLA)
Yipolymer esetshenziswa kakhulu yezemvelo futhi ukubola kwayo yiphuzu elibalulekile emakethe. Njengamanje isetshenziswa kumafilimu okupakisha esikhashana, izitsha, imikhiqizo yezinsiza zokudla namabhodlela. Futhi iyi-biopolymer ethembisayo yezinhlelo zokusebenza ezahlukahlukene emkhakheni we-biomedical, esetshenziselwa ukwenza izimila namadivayisi asuselwa emithonjeni yebhayoloji, kanye nama-sutures, izikulufu nezikafula. Futhi njengomthwali wezidakamizwa. Inamandla amakhulu okushintsha i-polycarbonate (i-PC), ikakhulukazi ekwenziweni kwezivalo zikagesi, njengoba izindleko zayo ziphansi.
Ama-Acrylics
Enye yezinhlobo eziwela ngaphakathi kwezigaba zamapulasitiki yizo zonke ezitholakala kuma-acrylic compounds. Lawa noma yiliphi ikilasi lamapulasitiki okwenziwa, ama-resin, namafutha asetshenziselwa ukwenza imikhiqizo eminingi. Ngokushintsha ama-reagents okuqala kanye nenqubo yokubunjwa, impahla ingakhiqizwa eqinile futhi esobala, ethambile futhi enwebekayo, noma i-viscous liquid. Amakhompiyutha e-Acrylic asetshenziselwa ukwenza ukubunjwa kwe-optical kanye nesakhiwo, ubucwebe, izinto zokunamathisela, izinhlanganisela zokugqoka, kanye nemicu yendwangu.
I-Acrylonitrile Butadiene Styrene (ABS)
Kuwuhlobo lokuhlukaniswa kwepulasitiki okwenziwa nge-emulsion noma i-polymerization yobuningi be-acrylonitrile ne-styrene phambi kwe-polybutadiene. Izici ezibaluleke kakhulu enazo ukumelana nomthelela kanye nokuqina. Ngaphezu kwalokho, kuvame ukuchazwa yizici ezintathu eziyinhloko: uketshezi, ukumelana nokushisa, nokumelana nomthelela. I-Styrene monomer inikeza i-ABS machinability enhle, i-acrylonitrile iyinika ukuqina, ukumelana namakhemikhali nokushisa, kuyilapho i-butadiene yenza umkhiqizo ube nzima futhi unwebeka nakakhulu ngisho namazinga okushisa aphansi.
Izinguquko ezilinganisweni zezakhi ezakha lolu hlobo lwezinto zepulasitiki noma ukungezwa kwezithasiselo ezithile kuvumela amazinga ahlukene ezakhiwo ezithile ukuthi athuthukiswe. Ngakolunye uhlangothi, kungashiwo ukuthi kunokumelana okuncane nesimo sezulu futhi yingakho kunconywa ukusisebenzisa endlini kuphela. Ukwengeza, kufanele kuqashelwe ukuthi uma ufuna ukusebenza nalokhu okuphuma kokunye, udinga amazinga okushisa angasukela ku -20 °C kuya + 80 °C.
I-Fiberglass
Imicu yengilazi yayingeyona into entsha kwaze kwaba ngawo-1930, lapho izakhiwo zabo zokuvikela ezishisayo nezikagesi zaziswa futhi kwakhiwa izindlela zokukhiqiza imicu yengilazi eqhubekayo. Ukukhiqiza kwesimanje kuqala ngengilazi ewuketshezi etholakala ngqo esithandweni esincibilikisa ingilazi noma ngokucibilikisa ubuhlalu bengilazi obakhiwe ngaphambilini. Ukuze kukhiqizwe i-fiber eqhubekayo, uketshezi lufakwa embotsheni, isitsha esinezimbobo ezingamakhulukhulu lapho uketshezi luphuma ngamajethi amahle.
Imisinga yokuqinisa iqoqwa emculweni owodwa, oboshwe kukhoyili. Imicu ingase isongwe noma ihlanganiswe ibe imicu, ilukwe ibe yindwangu, noma isikwe ibe izingcezu ezincane bese iboshelwa kumata. Izintambo eziyisisekelo ngokuvamile zenziwe ngenqubo yokuzungeza, lapho imifudlana emihle yengilazi ijikijelwa ngezimbobo ku-turntable, bese ihlukaniswa futhi iphephethwe ngendiza yomoya noma isitimu. Imicu inqwabelana ku-conveyor enyakazayo bese iguqulwa ibe wuvolo, amacansi noma amashidi.
I-insulator enhle kakhulu eshisayo ne-acoustic, uboya be-fiberglass buvame ukusetshenziswa ezakhiweni, izinto zikagesi, namapayipi. Imicu yengilazi nemicu yengeza amandla kagesi kanye nokumelana nemikhiqizo yepulasitiki ebunjiwe efana nezikebhe zokungcebeleka, izingxenye zomzimba wemoto, nezindlu zezinhlobonhlobo zama-electronics abathengi. Izindwangu zengilazi zisetshenziswa njengezivikeli zikagesi nanjengamabhande okuqinisa amathayi ezimoto.
Inayiloni
Yinoma iyiphi impahla yepulasitiki yokwenziwa eyenziwe nge-polyamide yesisindo samangqamuzana futhi ngokuvamile, kodwa hhayi ngaso sonke isikhathi, yenziwa njengefayibha. Yasungulwa ngeminyaka yawo-1930 ithimba labacwaningi elaliholwa usokhemisi waseMelika u-Wallace H. Carothers, owayesebenzela i-EI du Pont de Nemours & Company. Ukwenziwa ngempumelelo kwefayibha ewusizo ngokuhlanganisa amakhemikhali ezinhlanganisela ezitholakala kalula emoyeni, emanzini, nasemalahleni noma kuwoyela kwashukumisa ukwanda kocwaningo lwe-polymer futhi kwaphumela emndenini okhula ngokushesha wamapulasitiki.
Inayiloni ingadwetshwa, ibunjwe, noma ikhishwe ngemigqa yokuncibilika noma isixazululo ukuze kwakheke imicu, imicu, amabristles, noma amashidi okwenza intambo, indwangu, nentambo; futhi ingakhiwa ibe yimikhiqizo ebunjiwe. Inokumelana okuphezulu kokugqoka, ukushisa kanye nemikhiqizo yamakhemikhali. Yelulwe amakhaza, iqinile, iyanwebeka futhi inamandla. Eyaziwa kakhulu ngesimo semicu ewugqinsi nencane ezintweni ezinjengamasokisi, amapharashuthi, namabristles, inayiloni iphinde isetshenziswe ekuhwebeni kokubumba, ikakhulukazi ukubumba umjovo.
Angalungiswa kusuka ku-dicarboxylic acid kanye ne-diamine noma i-amino acid ekwazi ukuzibamba, ebonakala ngeqembu elisebenzayo le-"CONH" eringini, njenge-ε-caprolactam. Ngokushintshanisa i-asidi ne-amine, kungenzeka ukwenza imikhiqizo efana nenjoloba. Kungakhathaliseki ukuthi zenziwe njengezintambo noma isikhunta, zibonakala ngezinga eliphakeme lokucwebezela. Ngaphansi kwe-tension, umumo wama-molecule uyaqhubeka kuze kube isampula inwetshwa cishe izikhathi ezine ubude bayo bangempela, into ebaluleke kakhulu kumafilamenti.
i-bioplastic
Kuyipulasitiki kanye nezinto ezithambileyo ezakhiwe yinhlanganisela yamakhemikhali etholakala noma ehlanganiswe amagciwane afana namagciwane noma izitshalo ezishintshwe izakhi. Ngokungafani nezinhlobo eziningi esizibalula lapho sihlukanisa amapulasitiki enziwe nge-petroleum, ama-bioplastics enziwa ngezinsiza ezivuselelekayo, kanti amanye ama-bioplastic ayabola. Kusukela ekuqaleni kwekhulu lama-XNUMX, ukuthuthukiswa nokusetshenziswa kwamapulasitiki kuye kwanda kakhulu futhi usizo nokubaluleka kwazo kuye kwakhula kangangokuthi kunzima ukucabanga impilo yesimanje ngaphandle kwazo.
Namuhla, cishe wonke amapulasitiki atholakala ku-petroleum ngokukhipha amakhemikhali kanye nokuhlanganisa. Ngenxa yokuthi amapulasitiki asekelwe ku-petroleum ngokuvamile awaboli, imfucuza yepulasitiki ihlala isikhathi eside futhi ukulahlwa kwayo sekuyinkinga enkulu. Naphezu kwemizamo yokukhuthaza nokusekela ukugaywa kabusha, izindawo zokulahla imfucumfucu zigcwele imfucumfucu yepulasitiki, nayo enqwabelana endaweni ezungezile.
Inkinga eyengeziwe ngamapulasitiki atholakala ku-petroleum ukuthi izinsiza ezitholakala ku-petroleum ziyaphela. Imithombo elondolozayo ikholelwa ukuthi, ngezinga lamanje lokusetshenziswa, yonke imithombo kawoyela eyaziwayo eMhlabeni izobe isiphelile ekupheleni kwekhulu lama-XNUMX. Njengoba ukuphila kwanamuhla kuncike kumapulasitiki, uwoyela uwumthombo ongavuseleleki, futhi imfucumfucu yepulasitiki etholakala kuwoyela ingcolisa imvelo, i-bioplastics ingase ithole ikhambi elisimeme lesikhathi eside.
I-bioplastic yokuqala eyaziwayo, i-polyhydroxybutyrate (PHB), yatholwa ngo-1926 umcwaningi waseFrance, uMaurice Lemoigne, emsebenzini wakhe we-bacterium Bacillus megaterium. Ukubaluleka kokutholakala kwe-Lemoigne kwakunganakwa amashumi amaningi eminyaka, ikakhulukazi ngenxa yokuthi uwoyela wawushibhile futhi umuningi ngaleso sikhathi. Inkinga kawoyela yaphakathi nawo-1970 yavusa isithakazelo ekutholeni ezinye izindlela esikhundleni semikhiqizo kaphethiloli.
Ukwanda kofuzo lwamangqamuzana kanye nobuchwepheshe be-DNA obuyinhlanganisela ngemva kwalesi sikhathi kwabhebhethekisa ucwaningo, kangangokuthi ekuqaleni kwekhulu lama-XNUMX kwase kusungulwe izakhiwo, izindlela zokukhiqiza kanye nokusetshenziswa kwezinhlobo eziningi ze-bioplastics. I-Bioplastics eyasetshenziswa noma esacwaningwa yayihlanganisa i-PHB kanye ne-polyhydroxyalkanoate (PHA), yomibili ehlanganiswe kumagciwane akhethekile, kanye ne-polylactic acid (PLA), ephuma ku-lactic acid monomers ekhiqizwa ukuvutshelwa kwe-microbial koshukela ophuma ezitshalweni. isitashi.
Futhi, kungashiwo ukuthi ukuwohloka kwezibopho zamakhemikhali phakathi kwama-monomers kulawa mapulasitiki kubangelwa ama-microorganisms noma amanzi, okwenza i-bioplastics izinto ezifiseleka kakhulu zokwenza amabhodlela e-biodegradable namafilimu okupakisha. Ngenxa yokuthi imikhiqizo yokucekela phansi ingama-metabolite emvelo, ama-polymers anentshisekelo kwizicelo zezokwelapha ezifana nokupakishwa kwezidakamizwa ezikhishwa okulawulwayo kanye nama-sutures okuhlinzwa amunca.
Kumele kuqashelwe ukuthi lokhu kuhlukaniswa kwamapulasitiki okwamanje kubonisa ingxenye engabalulekile yokukhiqizwa komhlaba wonke kwamapulasitiki. Izinqubo zokukhiqiza ezentengiselwano zihlotshaniswa ne-output ephansi kanye nezindleko eziphezulu. Kodwa-ke, ukuthuthukiswa kobunjiniyela bezakhi zofuzo kanye ne-metabolism kuye kwaholela ezinhlobonhlobo zamagciwane nezitshalo ezingathuthukisa kakhulu izivuno namandla okukhiqiza kuyilapho kwehlisa izindleko zizonke. Lezi zinto zingandisa imakethe ye-bioplastics ngokuzayo.
I-PDK-Plastiki
Njengamanje, cishe uzwile izibalo zokuthi cishe amaphesenti angu-9 kuphela amapulasitiki agaywa kabusha, kanti amanye agcina ezindawo zokulahla imfucumfucu kanye nolwandle. Ukuze kuliwe nenkinga yepulasitiki, abantu abaningi abaqaphela imvelo bayasuka ezintweni ezibonakalayo, kodwa iqembu lososayensi eBerkeley, eCalifornia lizama ukushintsha izinto. Ngokocwaningo, ososayensi benze uhlobo olusha lwepulasitiki oluvumela inqubo yokugaywa kabusha kwamaluphu avaliwe ngaphandle kokumosha.
Ipulasitiki ibizwa nge-polydiketoenamine noma i-PDK. Ngokuvamile, iwuhlobo lwepulasitiki oluvumela ukuthi lusetshenzwe kusuka ezingeni lamangqamuzana, luhlukanise ingxenye ngayinye yezakhi futhi luphinde luzihlanganise, ukuze lwenze izikhathi eziningi futhi ngaleyo ndlela lwenza ipulasitiki icishe isebenziseke. . Izakhiwo zayo zifana kakhulu nezinye izinhlobo zepulasitiki njengenayiloni ngakho-ke, ingasetshenziswa ukwenza iziqukathi zokugcina zonke izinhlobo zokudla. Ngamafuphi, ikhandidethi elifanele ukuba phakathi kwezigaba zamapulasitiki.
Amakhodi e-SPI okuhlelwa kwepulasitiki
Ngo-1988, i-Society for the Plastics Industry (SPI) yasungula uhlelo lokuhlukanisa ukuze lusize abantu basebenzise kabusha futhi balahle upulasitiki ngendlela efanele. Namuhla, abakhiqizi balandela lolu hlelo lokufaka amakhodi futhi babeke inombolo, noma ikhodi ye-SPI, kumkhiqizo ngamunye, ngokuvamile ngezansi. Ipulasitiki ephawulwe ngekhodi ye-SPI 1 yenziwe nge-polyethylene terephthalate. Lezi zitsha ngezinye izikhathi zimunca iphunga nama-flavour ekudleni naseziphuzweni ezigcinwe ngaphakathi. Kodwa-ke, lokhu kuseyipulasitiki evamile yezinto eziningi zasendlini kanye nempahla.
Ikhodi ye-SPI engu-2 ikhomba ipulasitiki eyenziwe nge-polyethylene enokuminyana okuphezulu. Le mikhiqizo iphephe kakhulu futhi abukho ubufakazi bamakhemikhali angena ekudleni noma eziphuzweni. Kodwa-ke, ngenxa yengozi yokungcola, akuphephile ukusebenzisa kabusha ibhodlela le-HDPE njengokudla noma isitsha sesiphuzo uma ekuqaleni belingenalo noma yiluphi uhlobo lwento edliwayo. Isibonelo, akulungile ukuphinda usebenzise i-shampoo noma iziqukathi zensipho ukugcina isoso sikatamatisi.
Ipulasitiki ebhalwe ngekhodi ye-SPI engu-3 yenziwe nge-polyvinyl chloride. Lolu hlobo lwepulasitiki akufanele luhlangane nokudla, ngoba luyikhemikhali enobuthi futhi eyingozi. I-PVC itholakala ezintweni eziningi zansuku zonke, kodwa ngokuyinhloko ihloselwe ukusetshenziswa kwezimboni emikhakheni yamapayipi kanye neyokwakha. Ngakolunye uhlangothi, leyo enekhodi ye-SPI ye-4 yenziwe nge-polyethylene ephansi. Le pulasitiki ijwayele ukuhlala isikhathi eside futhi iguquguquke. Futhi ayikhiphi amakhemikhali ayingozi ezintweni, okwenza kube ukukhetha okuphephile ekugcineni ukudla.
Uzothola ikhodi ye-SPI 5 ezintweni zepulasitiki ezenziwe nge-polypropylene. Ipulasitiki ephawulwe ngekhodi ye-SPI engu-6 yenziwe nge-polystyrene, engagaywa kabusha, kodwa ingasebenzi kahle. Ukugaywa kabusha kudinga amandla amaningi, okusho ukuthi zimbalwa izindawo ezikwamukelayo. Ekugcineni, ikhodi ye-SPI 7 isetshenziselwa ukukhombisa izinhlobo ezahlukene zepulasitiki ezingachazwanga amanye amakhodi ayisithupha. Cabanga ngalezi zinhlobonhlobo njengezipulasitiki, kodwa azihambisani nemithetho yomphakathi.
Uma uthanda lesi sihloko ngezinhlobo nokuhlukaniswa kwamapulasitiki futhi ufuna ukufunda okwengeziwe ngezinye izihloko ezithakazelisayo, ungabheka izixhumanisi ezilandelayo: