Inqubo yokwenza ipulasitiki ye-bio-polyester kanye nokusetshenziswa kwayo emaphaketheni anobungani nemvelo
Isidingo sokupakisha siyaqhubeka nokukhula kwezimboni zokudla, iziphuzo, izimonyo, kanye nezokuthutha. Ngakolunye uhlangothi, amapulasitiki asekelwe kuphethiloli abonakala kakhulu ngenxa yezinga eliphezulu lekhabhoni kanye nobunzima bokuphatha ngemva kokusetshenziswa. Enye indlela ethuthukiswayo yi-biopolyester plastic, umndeni wama-polyester polymers anezinto zawo zokusetshenziswa ezithathwe ngokuphelele noma ngokwengxenye emithonjeni yezinto eziphilayo (i-biomass), futhi kwezinye izinhlobo nawo abola/anokubola. I-Biopolyester inikeza indawo ephakathi phakathi kokusebenza kwamapulasitiki avamile kanye nezidingo zokusimama, ikakhulukazi ekusetshenzisweni kokupakisha.
Kuyini i-bio-polyester?
Ngokwekhemikhali, i-polyester iyi-polymer enezibopho ze-ester eziphindaphindayo eketangeni layo eliyinhloko. Igama elithi i-bio-polyester lingabhekisela ezintweni ezimbili: (1) ama-polyester asekelwe ku-bio, lapho ama-monomer etholakala ku-biomass njengomoba, ummbila, i-cassava, noma uwoyela wemifino; kanye/noma (2) ama-polyester abola, njenge-PLA (polylactic acid) kanye ne-PHA (polyhydroxyalkanoates). Akuwona wonke amapulasitiki asekelwe ku-bio abola ngokuzenzakalelayo, futhi akuwona wonke abola asuselwa ku-bio. Isibonelo, i-bio-PET (i-bio-based polyethylene terephthalate) ingenziwa ngezinto zokusetshenziswa ezivuselelekayo kodwa ifana ne-PET evamile futhi ngokuvamile ayiboli ngokushesha; kanti i-PLA isekelwe ku-bio futhi ibola kalula ezindaweni zokwenza umquba ezimbonini.
Uma kukhulunywa ngokupakishwa okuhambisana nemvelo, okuxoxwa kakhulu ngakho yi-PLA, i-PHA, i-PBS (i-polybutylene succinate), i-PBAT (evame ukusetshenziswa njengenhlanganisela yokwandisa ukuguquguquka, nakuba ngokuvamile ingasetshenziswa ngokuphelele nge-bio), kanye ne-bio-PET yokupakisha amabhodlela uma ingqalasizinda yokuvuselela i-PET iqinile.
Izinto zokusetshenziswa: kusukela ku-biomass kuya ku-monomer
Isigaba sokuqala ekukhiqizweni kwe-biopolyester ukulungiselela izinto zokusetshenziswa ezivuselelekayo ukuze ziguqulwe zibe ama-monomers noma ama-polymer precursors. Imithombo evamile ye-biomass ihlanganisa:
1. Ushukela kanye nesitashi (umoba, ummbila, umdumbula): kucutshungulwa kube yi-glucose ngokusebenzisa i-hydrolysis (yesitashi) bese kubila.
2. Amafutha emifino (isundu, isoya, i-castor): angaguqulwa ngokusebenzisa ukusabela kwamakhemikhali abe ama-diol/ama-acid.
3. Imfucuza ye-Lignocellulosic (i-bagasse, utshani, uthuli lwesawdust): inzima kakhulu ngoba idinga ukwelashwa kwangaphambili ukuze i-cellulose/hemicellulose ihlukaniswe ibe ushukela ovundiswayo.
Kusukela kushukela okhiqizwa yile nqubo, imboni ingakhiqiza ama-monomer abalulekile:
– I-lactic acid (i-PLA precursor) ngokubiliswa ngamagciwane athile.
– I-Succinic acid kanye ne-1,4‑butanediol (i-PBS precursor) ngokusebenzisa ukubilisa noma izindlela ze-biochemical.
– Ama-hydroxybutyrate angu-3 kanye nama-monomers afanayo ahlanganiswa abe yi-PHA ngqo ngaphakathi kwamaseli ezinto ezincane.
Inqubo yokukhiqiza ye-PLA (polylactic acid)
I-PLA ingenye yama-biopolyester athandwa kakhulu ekupakisheni ngoba icacile, ingacutshungulwa ngemishini yepulasitiki efana nepulasitiki evamile, futhi itholakala emithonjeni evuselelekayo. Uchungechunge lwayo lwenqubo luvame ukufaka:
1. Ukubiliswa koshukela ube yi-lactic acid
I-glucose ibiliswa yizinto ezincane (isb., i-Lactobacillus) ukuze ikhiqize i-lactic acid. Lesi sigaba sidinga ukulawulwa kwe-pH, izinga lokushisa, izakhamzimba, kanye nokuhlanzwa komkhiqizo.
2. Ukuhlanzwa kwe-lactic acid
Ukuze kukhiqizwe ama-polymer asezingeni eliphezulu, i-lactic acid kumele ihlanzwe kusuka kusawoti, i-biomass esele, kanye nokunye ukungcola. Ukuhlanza ngokuvamile kuhilela ukuhlunga, ukushintshaniswa kwama-ion, ukuhluzwa, noma ukwakheka kwamakristalu.
3. Ukwakheka kwe-lactide
I-lactic acid ihlanganiswa ibe yi-oligomers, bese ifakwa ku-depolymerization elawulwayo ukuze yakhe i-lactide (i-cyclic dimer). Kunezinhlobo eziningana ze-isomers (i-L-lactide, i-D-lactide) ezithinta i-crystallinity kanye nezakhiwo ze-mechanical ze-PLA.
4. Ukwenziwa kwe-polymerization yokuvula indandatho (ROP)
I-Lactide ipholishwa kusetshenziswa i-catalyst (evame ukuba ngensimbi, njenge-stannous octoate ezinqubweni ezithile zezimboni), ikhiqiza i-PLA enesisindo sama-molecule aphezulu. Isisindo sama-molecule aphezulu sibalulekile ukuze kube namandla futhi kube lula ukucutshungulwa.
5. Ukuxuba nokuhlanganisa ama-pellets
I-PLA eqediwe ifakwa i-pellet. Kulesi sigaba, izithasiselo zivame ukungezwa: ama-plasticizer ukuvimbela ukuqhekeka, ama-nucleating agents ukulawula ukwakheka kwekristalu, noma ukuxubana namanye ama-polymer ukuthuthukisa ukumelana nokushisa nokuqina.
Inqubo yokukhiqiza ye-PHA (polyhydroxyalkanoates)
Ngokungafani ne-PLA, eyenziwa ngokusabela kwamakhemikhali kwama-monomers, i-PHA "ikhiqizwa" yizilokazane ezincane njengenqolobane yamandla ngaphakathi kwamaseli azo. Inqubo imi kanje:
1. Ukubilisa
Amabhaktheriya akhuliswa ngemithombo yekhabhoni (ushukela, uwoyela, ngisho nemfucuza ethile yezinto eziphilayo) ngaphansi kwezimo ezilinganiselwe izakhamzimba (isb., ezilinganiselwe yi-nitrogen) ukuze amaseli agcine i-PHA.
2. Ukuvunwa nokukhishwa kwe-biomass
Amaseli ahlukaniswa nendawo yokubilisa, bese kukhishwa i-PHA (kusetshenziswa izinyibilikisi noma izindlela ezingancibilikisi imvelo), bese ihlanzwa.
3. Ukomisa nokufaka ama-pellet
I-PHA icutshungulwa ibe ama-pellets bese icutshungulwa ibe amafilimu, utshani, noma izitsha. I-PHA ngokuvamile iyabola, ngisho nasezindaweni zasolwandle ngaphansi kwezimo ezithile, yize izinga lokubola liyahlukahluka.
Inqubo yokukhiqiza ye-PBS kanye ne-bio-PET (umbono omfushane)
I-PBS (i-polybutylene succinate) yenziwa nge-polycondensation ye-succinic acid kanye ne-1,4-butanediol. Uma womabili ama-monomers etholakala ekuvuthweni kwe-biomass, i-PBS ingaba yi-biobased. I-PBS yaziwa ngokuguquguquka kwayo kanye nokumelana nokushisa okuqhathaniswa ne-PLA, okwenza ifaneleke ezikhwameni, amafilimu, kanye nokupakishwa kwezingqimba eziningi.
I-Bio-PET ivame ukwenziwa ngokufaka ezinye ze-PET feedstock (isb., i-ethylene glycol) nge-bio-sources, kuyilapho i-terephthalic acid isasetshenziswa kakhulu njenge-fossil (yize izindlela ze-bio-to terephthalate nazo ziyathuthukiswa). Inzuzo yayo: inezakhiwo ezifanayo ne-PET, okwenza ihambisane nezinhlelo zokuvuselela kabusha ze-PET ezisunguliwe.
Ukwakheka komkhiqizo wokupakisha: kusukela kuma-pellet kuya kumafilimu, amabhodlela namathileyi
Ngemva kokuba i-bio-polyester ibe ama-pellets, isigaba esilandelayo inqubo yokuguqula ibe yiphakheji, okuhlanganisa:
– Ifilimu ekhishwe (ifilimu ehlanganisiwe noma ifilimu evuvukile) yezikhwama kanye nezingxobo.
– Ukulungisa ukushisa ukuze kwenziwe izinkomishi, amathileyi okudla, kanye nama-blister.
– Ukubumba ngomjovo wezivalo, izipuni, amafoloko, noma izingxenye ezithile.
– Ukubumba amabhodlela (ngokuvamile ku-bio-PET noma ezixubeni ezithile).
Inselele enkulu ngama-biopolyester ukuzinza kokushisa kanye nokulawula umswakama. I-PLA, isibonelo, iyazwela ekufakweni kwe-hydrolysis ngesikhathi sokucubungula, ngakho-ke ama-pellets adinga ukomiswa ngaphambi kokukhipha noma ukubumba ngomjovo.
Izicelo ekupakisheni okunobungani nemvelo
I-bio-polyester isetshenziswa kabanzi ekupakisheni ngenhloso yokunciphisa ukukhishwa kwegesi kanye/noma ukuthuthukisa ukuphathwa ngemva kokusetshenziswa.
1. Ukupakishwa kokudla neziphuzo
I-PLA ivame ukusetshenziselwa izinkomishi zeziphuzo ezibandayo, izivalo, amathileyi ezithelo, kanye nokupakishwa kwesaladi ngenxa yokubukeka kwayo okucacile nokuqinile. Ngokudla okushisayo, i-PLA idinga ukuguqulwa (isb., ukwakheka kwekristalu okuphezulu/i-CPET) ukuze imelane namazinga okushisa aphezulu.
2. Amafilimu nezikhwama ezivundiswayo
Izingxube ze-bio‑polyester ezibolayo (isib. i-PLA ene-PBAT noma i-PBS) zisetshenziswa kabanzi ezikhwameni zemfucuza eziphilayo kanye namafilimu e-mulch yezolimo, njengoba zihlose ikhono lokubola ezindaweni zomquba noma enhlabathini (kuye ngezindinganiso kanye nokwakheka).
3. Ukupakisha ubuhle kanye nemikhiqizo yokuthengisa
I-Bio‑PET noma i-PLA zikhethwa emabhodleleni, emabhodleleni, noma emabhulashini njengengxenye yesu lomkhiqizo lokuthola izinto zokusetshenziswa ezivuselelekayo. Ubuhle nokuqina kuyizinto ezibalulekile okufanele uzicabangele lapha.
4. Ukupakisha okuxubile kwefayibha (i-hybrid yephepha nepulasitiki)
I-Biopolyester ingasetshenziswa njengesembozo ephepheni ukuthuthukisa ukumelana namanzi/amafutha. Kodwa-ke, umklamo kumele ucabangele ukuphindeka kabusha noma ukukwazi ukuhlanganisa umquba ukuze ugweme ukudala ingxube eyinkimbinkimbi yezinto okunzima ukuzihlukanisa.
Izici zemvelo kanye nezinselele zokusetshenziswa
Nakuba kuthembisa, i-biopolyester ayilona ikhambi elilodwa. Kunezici eziningana ezibalulekile:
– Ingqalasizinda yokuphela kwesikhathi: I-PLA ngokuvamile idinga ukwenziwa komquba wezimboni ngokushisa okulawulwayo kanye nomswakama. Uma ingelashwa emvelweni, ukuwohloka kwayo kungaba kancane.
– Ukuvuselela: I-Bio‑PET ingavuselelwa nge-PET, kuyilapho i-PLA idinga umfudlana ohlukile wokuvuselela ukuze kugwenywe ukwehlisa ikhwalithi ye-PET uma ixutshwe.
– Imithombo ye-biomass kanye nokusetshenziswa komhlaba: Ukukhethwa kwezinto ezingavuthiwe kumele kucabangele ukuncintisana nokudla, ukusetshenziswa kwamanzi, kanye nemiphumela yezolimo. Ukusebenzisa imfucuza ye-lignocellulosic kuyisiqondiso esibalulekile sokuzinza okukhulu.
– Izakhiwo zezinto: amanye ama-polyester e-bio avame ukuba buthakathaka kakhulu noma angamelani nokushisa kakhulu kunezinye izinto ezisetshenzisiwe, ngokuvamile ezidinga ukuhlanganiswa/izithasiselo noma ukuhlelwa kabusha kokupakisha.
I-Penutup
Inqubo yokukhiqiza ipulasitiki ye-biopolyester ixhumanisa ngokuyisisekelo imihlaba emithathu: ukukhiqizwa kwe-biomass, i-biotechnology (ukuvutshelwa), kanye nobunjiniyela be-polymer (i-polymerization kanye nokwakhiwa komkhiqizo). I-PLA ne-PHA zibonisa ukuthi izinto zokusetshenziswa ezivuselelekayo zingaguqulwa kanjani zibe yipulasitiki esebenzayo, kuyilapho i-PBS kanye ne-bio-PET zinikeza izinketho zokusebenza eziseduze nepulasitiki evamile ngamasu okunciphisa ukunyathela kwekhabhoni noma ukuhambisana kokusebenzisa kabusha. Ukuze kufezwe ukupakisha okusimeme ngempela, ukukhethwa kwe-bio-polyester kumele kuhambisane nomklamo wokupakisha ofanele, uhlelo lokuqoqa, kanye nezinketho ezicacile zokuphela kokuphila—kungaba ukuphinda kusetshenziswe, ukwenza umquba, noma ezinye izindlela zokucubungula. Ngendlela ephelele, i-bio-polyester ingaba yingxenye ebalulekile yokushintshela emnothweni ojikelezayo embonini yokupakisha.
