Izici ezithinta i-hydrolysis ye-polylactic acid (PLA)
November 20, 2023
Njengamanje, ukukhiqizwa kweminyaka yonke yamapulasitiki amathani acishe abe yizigidi eziyi-140, ngemuva kokusetshenziswa kwemfucuza kube ngu-60% kuya ku-60% wokukhiqizwa, imiphumela eminingi yezinto ezibonakalayo kunzima ukubola, okuholela ekungcoleni komhlaba kanye nasezindlini zokungcola, ukubeka engcupheni Ukukhula kwezitshalo nezilwane, ukusongela ukusinda kwabantu kanye nempilo yabantu kanye nempilo, kanye nokuba yimikhawulo eyinhloko yezwe elimhlophe. Njengoba abantu benaka ngokwengeziwe kanye nokuningi kwezingqinamba zezemvelo, amapulasitiki angenakuqhathaniswa athandwa kancane kancane. Njenge-Aliphatic Polyester yemvelo enobungani, i-polylactic acid (PLA) nayo ingenye yezinhlobo ezisetshenziswa kakhulu zezinto zokwenziwa ezenziwa nge-bio . Ngokuqina okuhle, ukulimazeka kanye nezakhiwo ezinhle kakhulu zokucubungula, i-PLA ithole ukunakwa okubanzi futhi kubhekwa njengenye yezinto ezintsha ezithembisayo "ze-eco-woments" ukufaka esikhundleni sepulasitiki ekhona. I-1.Dadation Mechanism of Polylactic acid (PLA) Njenge-polyester impahla, ukucekelwa phansi kwe -polylactic acid kuhlukaniswe ukuwohloka okulula kwe-hydrolytic kanye nokuwohloka kwe-enzyme-catalyzed. Ukuwohloka okulula kwe-hydrolytic ukusabela okungapheli kokuchazwa, okuqala ukumuncwa kwamanzi, ama-molecule amancane amanzi athuthelwa ebusweni besampula, i-aldwali ezungeze iqhaza le-acid ne-alkali ku-medium, i-ester I-Bond Free Hydrolysis Fracture, isampula ye-molecule, inani lokuncipha kancane kwesisindo se-molecular lapho isisindo se-molefanelar sincishiswe ngezinga elithile, isampula yaqala ukuncibilikisa, kwakha imikhiqizo yokuncibilikisa. Ukuwohloka kwe-enzymatic of polylactide akuqondile, i-polylactic acid kuqala i-hydrolysis yenzeka, i-hydrolysis ngezinga elithile, kanye ne-metabolism ethile ngaphansi kwesenzo sama-enzyme, ukuze inqubo yokucekelwa phansi igcwaliswe.
2.I-Offactor ethinta i-hydrolysis kanye nokonakaliswa kwe -polylactic acid Izici ezithinta i-hydrolysis ye-PLA zingahlukaniswa ngezigaba ezimbili: Izinsiza ezibonakalayo kanye nezimo ze-hydrolysis. Izakhiwo ezibonakalayo zifaka isakhiwo samangqamuzana, i-crystaltaltity, usayizi wesisindo we-molecular kanye nokusatshalaliswa, isimo sesakhiwo, ukwakheka kwesampula, inqubo yokubumba, izengezo kanye nokungcola, njll; Izimo zeHydrolysis zifaka i-PH, izinga lokushisa kanye nomswakama, i-dielectric njalo, ukwelashwa ngemisebe, njll. 3. Ithonya lesakhiwo samangqamuzana Isakhiwo samangqamuzana siyisici esibalulekile esithinta izakhiwo zezinto zokwakha ezisekelwe kwi-PLA. Abanye abacwaningi balungiselela ama-3 - - ama-Pla ahlomile ama-3, amanye ama-Pla ahlomile ahlukahlukene asebenzisa izinto ezahlukene zokufunda izakhiwo zawo ze-hydrolysis, futhi athole ukuthi nge-pla isisindo esifanayo, isilinganiso samaketanga anamaketanga, ngokushesha inani lokuwohloka. Ukuhlaziywa kungahle kube khona ngenxa yokuthi ama-polmers aqukethe izakhiwo ezinamagatsha anezinhlaka eziphansi namaqembu esibulalayo, futhi ngenxa yalokho anciphise ngokushesha kunalawo anezinto ezinezinto ezinomugqa. Abantu bashintsha ukwakheka kwamangqamuzana kwe-PLA ngokuguqulwa kweCopolemerization futhi bahlanganisa izinhlobo ezahlukahlukene zama-copolymers nge-PLA njenge-matrix ukulawula isilinganiso sayo se-hydrolysis. Isibonelo, i-CLGA Copolymer, ukwethulwa kwe-PEG akugcini nje ngokuthuthukisa i-hydrophicility ye-pla futhi kunciphisa i-crystaltaltity yayo, kepha kusheshisa ukonakala kwe-polymer, kepha futhi kunikeza izakhiwo ezintsha nemisebenzi. The hydrophilicity of the introduced group plays a decisive role in the hydrolysis process of the Polymers in the blend modification, the better the hydrophilicity, the more significant the hydrolytic degradation.
4. Ithonya le-Crystallity I-PLA ingeyokulwa ne-Crystalline Polyester okuqukethwe, kepha noma ngabe i-PLA ingeyokubhalwa kwe-Crystalline Polyester, i-Crystallity yayo ayikwazi ukufinyelela ku-100%, futhi i-Particle noma i-Amorphous Aronsided (indawo ye-amorphoous). Enqubweni ye-hydrolysis ye-pla, i-hydrolysis njalo kwenzeka okokuqala endaweni ye-amorphous. Amanzi aqala ukungena endaweni ye-amorphoous, ukuze isibopho se-Ester endaweni ye-amorphous sephukile, lapho iningi le-amorphoous zone lihlelwe yi-hydrolyzed, kuphela ukusuka emaphethelweni isikhungo se-crystalline zone kuqala ku-hydrolyze. Kumele kwaziwe ukuthi, enqubweni yePla hydrolysis, imvamisa ehambisana ne-crystallon ye-crystallity, engabangelwa yi-hydrolysis yendawo ye-amorphoous, isizukulwane sobuningi bokuvalelwa kwesakhiwo kwezinto eziphansi zamangqamuzana, okwenza i-pla I-Crystallity inyuke. Abanye abacwaningi bakholelwa ukuthi ukukhuphuka kwe-crystaltaltity kungenxa ye-hydrolysis yendawo ye-amorphous, okukhulisa ingxenye ye-crystalline zone kusampula esele. 5. Ithonya lokuvama kwesakhiwo se-cubic Ngenxa ye-isomerism ye-optical ye-lactic acid, i-PLA nayo inama-cubes ahlukene, i-PLLA, eyenziwe nge-polymerization ye-L-lactic acid; I-PDLA, eyenziwe nge-polymerization ye-acid emsulwa ye-D-lactic; I-PDLLA, eyenziwe nge-polymerization ye-pla ephansi ekhanyayo ephansi emsulwa esilinganisweni esithile se-l-lactic acid ne-D-lactic acid; kanye ne-P (l / d) la, eyenziwe ngokuxubana kwe-PLLA nePDLA ngesilinganiso esithile. Umcwaningi waqhathanisa izakhiwo ze-hydrolysis ze-PLLA, PDLLA, PDLA, no-P (L / D) LA, futhi imiphumela yabonisa ukuthi i-PDLLA yayilula kakhulu uku-hydrolyze; UPbela noPdla babelula kakhulu ku-hydrolyze, ne-p (l / d) la benokuphikiswa okunamandla kwe-hydrolysis.
