Izinhlobo zepulasitiki ezisetshenziswa ekwenziweni kwemikhiqizo yabathengi kanye nendlela ezenziwa ngayo
Ipulasitiki ingenye yezinto ezivame kakhulu empilweni yanamuhla. Ikhethwa ngoba ilula, iqinile, iyaguquguquka, ayingenwa manzi, futhi ayibizi kakhulu ukuyikhiqiza ngobuningi. Ngemuva kohlu oluhlukahlukene lwemikhiqizo yepulasitiki—kusukela emabhodleleni eziphuzo kanye nokupakishwa kokudla kuya kumathoyizi kanye nezingxenye ze-elekthronikhi—kunezinhlobo ezahlukene zama-polymers anezici ezihlukile. Lesi sihloko sixoxa ngezinhlobo zepulasitiki ezisetshenziswa kakhulu emikhiqizweni yabathengi futhi sichaza ukuthi zenziwa kanjani, kokubili mayelana nokwakheka kwe-polymer kanye nenqubo yokukhiqiza umkhiqizo wokugcina.
1. I-PET (i-Polyethylene Terephthalate)
Izibonelo zokusetshenziswa: amanzi okuphuza namabhodlela e-soda, ukupakishwa kokudla, i-polyester fiber (izingubo), izitsha zesoso noma uwoyela.
Izakhiwo eziyinhloko: zicacile, ziqinile, azinawo umoya (ziyakwazi ukubamba i-CO₂), zilula futhi kulula ukuzisebenzisa kabusha.
Indlela i-polymer eyenziwa ngayo: I-PET yenziwa ngokusabela kwe-polymerization ye-condensation phakathi kwe-terephthalic acid (noma i-dimethyl terephthalate) kanye ne-ethylene glycol. Lokhu kusabela kukhiqiza amaketanga amade e-PET kanye nemikhiqizo elandelanayo (njengamanzi noma i-methanol, kuye ngokuthi itholakala kuphi). Ngemva kwalokho, iyahlanzwa futhi yenziwe ibe ama-pellet (ama-granule) ukuze kube lula ukuyithutha nokuyicubungula.
Inqubo yokukhiqiza umkhiqizo: Kumabhodlela, ama-PET pellets ayancibilikiswa bese enziwa i-preform (isimo esincane esifana ne-tube "njengomzimba webhodlela") ngenqubo yokubumba ngomjovo. I-preform bese ishiswa bese ifuthwa ibe yi-mold yebhodlela kusetshenziswa i-stretch blow molding, okuholela ebhodleleni eliqinile nelincane kodwa eliqinile.
2. I-HDPE (High-Density Polyethylene)
Izibonelo zokusetshenziswa: amathini kajeli, amabhodlela eshampu/isihlanzi, amajagi athile angamalitha, amapayipi, izitsha zamakhemikhali zasekhaya.
Izakhiwo eziyinhloko: ziqinile kune-LDPE, azinamthelela, azinamakhemikhali, aziqhekeki kalula.
Indlela i-polymer eyenziwa ngayo: I-HDPE itholakala ku-polymerization ye-ethylene (C₂H₄) kusetshenziswa i-catalyst (njenge-Ziegler-Natta noma i-metallocene) ekhiqiza isakhiwo se-polymer chain esiqondile nesinobukhulu, okuholela ekuxineni okuphezulu. Lesi sakhiwo esinobukhulu siyenza ibe namandla futhi iqine.
Indlela imikhiqizo eyenziwa ngayo: Imikhiqizo eminingi ye-HDPE yenziwa ngokubumba okuphumayo (isib. amabhodlela ensipho), lapho ipulasitiki incibilikiswa khona bese ikhishwa ibe yipayipi (i-parison), bese ishaywa ibe yisikhunta. Kumapayipi, i-HDPE yenziwa ngokubumba ibe amaphrofayili amade bese inqunywa ibe usayizi.
3. I-LDPE (I-Low-Density Polyethylene)
Izibonelo zokusetshenziswa: izikhwama zepulasitiki, ukugoqa ngepulasitiki, ulwelwesi lwangaphakathi lwephakheji, amabhodlela aguquguquka kakhulu, uqweqwe lwekhebula.
Izakhiwo eziyinhloko: ziguquguquka kakhulu, zikhanya kahle, azinamanzi, kodwa aziqinile njenge-HDPE.
Indlela i-polymer eyenziwa ngayo: I-LDPE ikhiqizwa nge-ethylene ngenqubo ye-polymerization ngaphansi kwengcindezi ephezulu, okuholela esakhiweni esinamagatsha. Lokhu kuhlanganiswa kwamagatsha kwenza i-polymer ikhululeke, ibe nobukhulu obuphansi, futhi iguquguquke kakhudlwana.
Indlela yokukhiqiza umkhiqizo: izikhwama zepulasitiki namafilimu ngokuvamile zenziwa ngokufuthwa kwefilimu: I-LDPE iyancibilikiswa, ikhishwe ngendandatho yokubumba, bese ifuthwa ibe yibhamuza elincane elibe selipholiswa bese ligoqwa libe yishidi.
4. PP (Polypropylene)
Izibonelo zokusetshenziswa: izitsha zokudla (ezinye izinto eziphephile kuma-microwave), utshani, izivalo zamabhodlela, amasaka epulasitiki, izinto zasendlini, izingxenye zezimoto ezilula.
Izakhiwo eziyinhloko: ukukhanya, ukumelana nokushisa, okuqinile ekukhathaleni okugoqekayo (isb. “ama-hinge aphilayo” emabhokisini epulasitiki), ukumelana namakhemikhali.
Indlela i-polymer eyenziwa ngayo: I-PP yenziwe nge-propylene monomer ngokusebenzisa i-polymerization kusetshenziswa i-catalyst ekhethekile ukulungisa isakhiwo (isotactic/syndiotactic). Isakhiwo se-isotactic ngokuvamile sinikeza amandla angcono kanye ne-crystallinity.
Izindlela zokukhiqiza umkhiqizo: Izitsha zokudla nezivalo zamabhodlela zivame ukwenziwa ngokubumba umjovo. Ekupakisheni okuncane njengezinkomishi zepulasitiki noma izitsha ze-margarine, kuvame ukusetshenziswa i-thermoforming: Amashidi e-PP ayashiswa bese enziwa kusetshenziswa i-vacuum/pressure ibe yi-mold.
5. I-PVC (i-Polyvinyl Chloride)
Izibonelo zokusetshenziswa: amapayipi nezinto zokufakelwa, phansi kwe-vinyl, isikhumba sokwenziwa, izintambo zikagesi, amakhadi (isb., amakhadi athile obulungu).
Izakhiwo eziyinhloko: zingenziwa ziqine noma ziguquguquke, zimelane nesimo sezulu (kuye ngokuthi zenziwe kanjani), zimelane namakhemikhali, kodwa zidinga izithasiselo zokuzinzisa kanye ne-plasticizer.
Indlela i-polymer eyenziwa ngayo: I-PVC yenziwe nge-vinyl chloride monomer ngokusebenzisa i-polymerization eyengeziwe (ngokuvamile ukumiswa noma i-emulsion-based). Ngenxa yokuthi i-PVC iyazwela ekushiseni, amafomula ngokuvamile afaka isiqinisi sokushisa ukuze siyivimbele ekuwohlokeni ngesikhathi sokucubungula.
Indlela yokukhiqiza umkhiqizo: Amapayipi e-PVC enziwa nge-extrusion. Ngophahla lwe-vinyl noma isikhumba sokwenziwa, i-PVC ivame ukucutshungulwa ibe amashidi ngokuwagoqa noma ukuwafaka ku-substrate.
6. I-PS (i-Polystyrene) kanye ne-EPS (i-Expanded Polystyrene)
Izibonelo zokusetshenziswa kwe-PS: izitsha ezilahlwayo, izitsha ezithile, amabhokisi alula, amakesi e-CD (ngaphambilini).
Izibonelo zokusetshenziswa kwe-EPS: i-styrofoam yokuvikela izimpahla zikagesi, izitsha zokudla, ukuvikela isakhiwo.
Izakhiwo eziyinhloko: I-PS iqinile futhi icacile kodwa ivame ukuphuka kalula. I-EPS ilula kakhulu ngoba inesakhiwo se-foam esigcwele umoya.
Indlela i-polymer eyenziwa ngayo: I-PS itholakala ekupholiseni kwama-monomers e-styrene. Ku-EPS, ama-granule e-PS aqukethe i-ejenti yokuvunguza evumela ukuthi izinto zande uma zishiswa.
Izindlela zokukhiqiza umkhiqizo: I-PS ingacutshungulwa ngokufaka umjovo noma nge-thermoforming (isb., izinkomishi/izitsha). I-EPS yenziwa ngokushisa ubuhlalu ukuze ibunwebe, bese ishisisa ubuhlalu obunwetshiwe esikhumbeni bube yisimo sabo sokugcina.
7. I-PC (I-Polycarbonate)
Izibonelo zokusetshenziswa: amagalani athile amanzi, amalensi ezibuko zamehlo, izigqoko zokuvikela, izingxenye ze-elekthronikhi, izihlangu ezisobala.
Izakhiwo eziyinhloko: ziqinile kakhulu, azinamthelela, zicacile, azinawo umswakama kangcono kunepulasitiki eziningi ezivamile.
Indlela i-polymer eyenziwa ngayo: I-PC ivame ukwenziwa ngokusabela kwe-polymerization phakathi kwe-bisphenol A kanye ne-carbonate compound (izindlela zingahluka kuye ngobuchwepheshe bokukhiqiza). Umphumela uba i-polymer enezakhiwo eziphezulu zemishini kanye nokucaca okuhle.
Izindlela zokukhiqiza umkhiqizo: Izingxenye eziningi ze-PC zakhiwa ngokufaka umjovo ngenxa yokunemba okuphezulu kanye nemininingwane edingekayo. Amashidi e-PC nawo angakhishwa bese enqunywa noma afakwe umumo.
8. I-ABS (Acrylonitrile Butadiene Styrene)
Izibonelo zokusetshenziswa: amathoyizi (isb., amabhlogo okwakha), amabhokisi kagesi, amakhibhodi, izingxenye zangaphakathi zezimoto.
Izakhiwo eziyinhloko: eqinile, emelana nokushayisana, indawo enhle yokuqedela, kulula ukuyicubungula.
Indlela i-polymer eyenziwa ngayo: I-ABS iyi-copolymer ehlanganisa izingxenye ezintathu: i-acrylonitrile (ukumelana namakhemikhali), i-butadiene (ukuqina/ukumelana nomthelela), kanye ne-styrene (ukuqina nokuqina kwendawo). Ukwakheka kungalungiswa ngokuya ngezidingo zomkhiqizo.
Indlela yokukhiqiza umkhiqizo: I-ABS ivame ukucutshungulwa ngokubumba ngomjovo. Uma seyakhiwe, i-ABS ingapendwa, igqunywe, noma iphathwe ubuso bube mhlophe.
Inqubo ejwayelekile yokukhiqiza imikhiqizo yepulasitiki
Nakuba izinhlobo zama-polymer zihlukile, ukugeleza okuvamile kuyafana:
1. Ukukhiqizwa kwe-resin/pellet: ama-polymer enziwa ezitshalweni ze-petrochemical, bese enziwa ama-pellet.
2. Ukuhlanganisa: ama-pellet axutshwa nezithasiselo ezifana nodayi, iziqinisi ze-UV, izithibi zomlilo, ama-plasticizer, noma ama-filler ukushintsha izakhiwo.
3. Ukwakha: kusetshenziswa amasu anjengalawa:
– Ukubumba ngomjovo: ipulasitiki encibilikisiwe ifakwe esikhumbeni (esifanele izimo eziyinkimbinkimbi).
– Ukukhipha: ipulasitiki icindezelwa ngesikhunta esimise okwephrofayili (ipayipi, ishidi, ikhebula).
– Ukubumba okuvunguzayo: kwamabhodlela nezitsha ezingenalutho.
– Ukulungisa ukushisa: ishidi liyashiswa bese kwakheka i-vacuum/ingcindezi.
– Ukubumba okujikelezayo: kwamatangi amakhulu angenalutho (ezinye izinhlobo ze-PE).
4. Ukuqeda nokuhlanganisa: ukusika okungaphezulu, ukubhoboza, ukunamathisela amalebula, kanye nokupakisha.
I-Penutup
Izinhlobo zepulasitiki ezisetshenziswa emikhiqizweni yabathengi zikhethwa ngokusekelwe ezidingweni zazo zokusebenza: I-PET ingcono kakhulu ekupakisheni iziphuzo, i-HDPE ne-PP ziqinile ezitsheni nasemikhiqizo yasekhaya, i-PVC ifanelekela amapayipi nezinto zokwakha, i-PS/EPS ilula ekupakisheni, kuyilapho i-PC ne-ABS zisetshenziselwa izinhlelo zokusebenza ezidinga amandla nokunemba. Ukuqonda izici zazo kanye nezindlela zokukhiqiza kusiza abathengi nabakhiqizi ukuthi benze izinqumo ezinolwazi oluthe xaxa—kokubili maqondana nekhwalithi yomkhiqizo, ukuphepha, kanye namathuba okusebenzisa kabusha kanye nokuphathwa okunesibopho kwemfucuza yepulasitiki.
