Tharollo e tsoakiloeng ea poly-L-lactic acid le ethyl cellulose ka chloroform le tharollo e tsoakiloeng ea PLLA le methyl cellulose ka trifluoroacetic acid e ile ea lokisoa, 'me motsoako oa PLLA / cellulose ether o ile oa lokisoa ka ho lahla; Metsoako e fumanoeng e ne e tšoauoa ka makhasi a fetolang infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) le X-ray diffraction (XRD). Ho na le tlamo ea hydrogen pakeng tsa PLLA le cellulose ether, 'me likarolo tsena tse peli li lumellana ka mokhoa o itseng. Ka keketseho ea cellulose ether content motsoako, ntlha e qhibilihisang, crystallinity le kristale botšepehi ba motsoako li tla fokotseha kaofela. Ha litaba tsa MC li phahame ho feta 30%, hoo e ka bang metsoako ea amorphous e ka fumanoa. Ka hona, cellulose ether e ka sebelisoa ho fetola poly-L-lactic acid ho lokisa lisebelisoa tsa polymer tse senyehang tse nang le thepa e fapaneng.
Mantsoe a bohlokoa: poly-L-lactic acid, ethyl cellulose,methyl cellulose, ho kopanya, cellulose ether
Nts'etsopele le ts'ebeliso ea li-polymer tsa tlhaho le lisebelisoa tse senyehang tsa polima tsa maiketsetso li tla thusa ho rarolla bothata ba tikoloho le bothata ba lisebelisoa boo batho ba tobaneng le bona. Lilemong tsa morao tjena, lipatlisiso mabapi le ho qaptjoa ha thepa ea polymer e ka senyehang e sebelisa lisebelisoa tse ka nchafatsoang joalo ka thepa e tala ea polymer e hohetse tlhokomelo e atileng. Polylactic acid ke e 'ngoe ea li-polyester tsa bohlokoa tse senyehang. Asiti ea lactic e ka hlahisoa ka ho belisoa ha lijalo (joalo ka poone, litapole, sucrose, joalo-joalo), hape e ka bolisoa ke likokoana-hloko. Ke mohlodi o ka ntjhafatswang. Asiti ea polylactic e lokisoa ho tloha lactic acid ka polycondensation e tobileng kapa polymerization e bulang lesale. Sehlahisoa sa ho qetela sa ho senyeha ha eona ke lactic acid, e ke keng ea silafatsa tikoloho. PIA e na le thepa e ntle haholo ea mochini, ho sebetsa hantle, ho senyeha ha bophelo le ho lumellana ha lintho. Ka hona, PLA ha e na lits'ebetso tse fapaneng feela lefapheng la boenjineri ba biomedical, empa hape e na le mebaraka e meholo e ka bang teng maemong a likobo, polasetiki le masela.
Litsenyehelo tse phahameng tsa poly-L-lactic acid le mefokolo ea eona ea ts'ebetso joalo ka hydrophobicity le brittleness li fokotsa mefuta ea ts'ebeliso ea eona. E le ho fokotsa litšenyehelo tsa eona le ho ntlafatsa ts'ebetso ea PLLA, ho itokisa, ho lumellana, morphology, biodegradability, thepa ea mechine, tekanyo ea hydrophilic / hydrophobic le masimo a kopo ea polylactic acid copolymers le metsoako e 'nile ea ithutoa ka botebo. Har'a tsona, PLLA e etsa motsoako o lumellanang le poly DL-lactic acid, polyethylene oxide, polyvinyl acetate, polyethylene glycol, joalo-joalo Cellulose ke motsoako oa tlhaho oa polymer o entsoeng ke condensation ea β-glucose, 'me ke e' ngoe ea lisebelisoa tse ngata tse ka nchafatsoang. tlhahong. Li-derivatives tsa cellulose ke lisebelisoa tsa pele tsa polima tsa tlhaho tse entsoeng ke batho, tseo tse bohlokoa ka ho fetisisa e leng li-cellulose ethers le cellulose esters. M. Nagata et al. o ithutile mokhoa oa ho kopanya PLLA / cellulose mme o fumane hore likarolo tse peli li ne li sa lumellane, empa thepa ea crystallization le ho senyeha ha PLLA e ne e amehile haholo ke karolo ea cellulose. N. Ogata et al o ithutile ts'ebetso le sebopeho sa PLLA le cellulose acetate blend system. Patent ea Majapane e boetse e ithutile ka biodegradability ea PLLA le metsoako ea nitrocellulose. Y. Teramoto et al o ile a ithuta ka boitokiso, thepa ea mocheso le mochini oa PLLA le cellulose diacetate graft copolymers. Ho fihlela joale, ho na le lithuto tse fokolang haholo mabapi le mokhoa oa ho kopanya oa acid e polylactic le cellulose ether.
Lilemong tsa morao tjena, sehlopha sa rona se 'nile sa etsa lipatlisiso tsa copolymerization e tobileng le ho kopanya phetoho ea polylactic acid le li-polymers tse ling. E le ho kopanya thepa e babatsehang ea acid e polylactic le theko e tlaase ea selulose le lihlahisoa tsa eona ho lokisetsa lisebelisoa tsa polymer ka ho feletseng, re khetha selulose (ether) e le karolo e fetotsoeng bakeng sa phetoho ea ho kopanya. Ethyl cellulose le methyl cellulose ke li-ether tse peli tsa bohlokoa tsa cellulose. Ethyl cellulose ke metsi a sa tsitsang a selulose alkyl ether e se nang ionic, e ka sebelisoang e le lisebelisoa tsa bongaka, lipolasetiki, li-adhesives le li-textile finishing agents. Methyl cellulose e na le metsi, e na le metsi a mangata haholo, a kopantsoe, a boloka metsi le thepa ea ho etsa lifilimi, 'me e sebelisoa haholo masimong a thepa ea mohaho, liaparo, litlolo, meriana le ho etsa pampiri. Mona, metsoako ea PLLA / EC le PLLA / MC e lokiselitsoe ka mokhoa oa ho lahla tharollo, 'me ho lumellana, thepa ea mocheso le thepa ea crystallization ea PLLA / cellulose ether blends e ile ea tšohloa.
1. Karolo ea teko
1.1 Lisebelisoa tse tala
Ethyl cellulose (AR, Tianjin Huazhen Special Chemical Reagent Factory); methyl cellulose (MC450), sodium dihydrogen phosphate, disodium hydrogen phosphate, ethyl acetate, stannous isooctanoate, chloroform (tse ka holimo ke lihlahisoa tsa Shanghai Chemical Reagent Co., Ltd., 'me bohloeki ke AR grade); L-lactic acid (sehlopha sa meriana, k'hamphani ea PURAC).
1.2 Tokisetso ea metsoako
1.2.1 Tokiso ea asiti ea polylactic
Poly-L-lactic acid e entsoe ka mokhoa o tobileng oa polycondensation. Leka tharollo ea metsi ea L-lactic acid ka karolo e boima ea 90% 'me u e kenye ka har'a botlolo e nang le melamo e meraro, e felise metsi ka 150 ° C bakeng sa lihora tse 2 tlas'a khatello e tloaelehileng, ebe u itšoara ka lihora tse 2 tlas'a khatello ea vacuum ea 13300Pa,' me qetellong. itšoara ka lihora tse 4 tlas'a vacuum ea 3900Pa ho fumana lintho tsa prepolymer tse omeletseng. Kakaretso ea tharollo e nang le lactic acid e nang le metsi ha e tlose phallo ea metsi ke kakaretso ea prepolymer. Eketsa stannous chloride (karolo ea boima ke 0.4%) le p-toluenesulfonic acid (karo-karolelano ea stannous chloride le p-toluenesulfonic acid ke 1/1 molar ratio) tsamaiso ea catalyst ho prepolymer e fumanoeng, 'me ka condensation li-sieve tsa molek'hule li ile tsa kenngoa ka har'a tube. ho monya metsi a seng makae, 'me ho ts'oaroa ha mochini ho bolokoa. Tsamaiso eohle e ile ea itšoara ka vacuum ea 1300 Pa le mocheso oa 150 ° C. bakeng sa lihora tsa 16 ho fumana polymer. Hlakola polymer e fumanoeng ka chloroform ho lokisa tharollo ea 5%, sefa le ho phophoma ka ether ea anhydrous bakeng sa lihora tse 24, sefa metsi, 'me ue behe ka ontong ea vacuum ea -0.1MPa e 60 ° C bakeng sa lihora tse 10 ho isa ho tse 20 ho fumana Pure dry. PLLA polymer. Boima bo lekanang ba molek'hule ea PLLA e fumanoeng e ne e ikemiselitse ho ba 45000-58000 Daltons ka chromatography ea metsi a phahameng a sebetsang hantle (GPC). Mehlala e ne e bolokoa ka har'a setlolo se nang le phosphorus pentoxide.
1.2.2 Tokisetso ea motsoako oa polylactic acid-ethyl cellulose (PLLA-EC)
Beha boima bo hlokahalang ba poly-L-lactic acid le ethyl cellulose ho etsa 1% ea tharollo ea chloroform ka ho latellana, ebe u lokisa tharollo e tsoakiloeng ea PLLA-EC. Karo-karolelano ea tharollo e tsoakiloeng ea PLLA-EC ke: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, palo ea pele e emela karoloana ea bongata ba PLLA, 'me palo ea ho qetela e emela boima ba EC Fraction. Litharollo tse lokiselitsoeng li ile tsa tsosoa ka motlakase oa magnetic bakeng sa lihora tse 1-2, ebe li tšeloa ka sejana sa khalase ho lumella chloroform hore e fetohe mouoane ka tlhaho ho etsa filimi. Ka mor'a hore filimi e thehoe, e ne e kenngoa ka ontong ea vacuum ho omisa mocheso o tlaase ka lihora tse 10 ho tlosa chloroform ka ho feletseng filiming. . Tharollo ea motsoako ha e na 'mala ebile e hlakile,' me filimi ea motsoako e boetse e se na 'mala ebile e hlakile. Motsoako o ne o omisitsoe mme oa bolokoa ka har'a setlolo hore se sebelisoe hamorao.
1.2.3 Tokisetso ea motsoako oa polylactic acid-methylcellulose (PLLA-MC)
Beha boima bo hlokahalang ba acid e poly-L-lactic le methyl cellulose ho etsa 1% ea tharollo ea trifluoroacetic acid ka ho latellana. Filimi ea motsoako oa PLLA-MC e lokiselitsoe ka mokhoa o ts'oanang le filimi ea motsoako oa PLLA-EC. Motsoako o ne o omisitsoe mme oa bolokoa ka har'a setlolo hore se sebelisoe hamorao.
1.3 Teko ea tšebetso
MANMNA IR-550 spectrometer ea infrared (Nicolet.Corp) e ile ea lekanya sekhahla sa infrared sa polymer (Letlapa la KBr). DSC2901 differential scanning calorimeter (TA khamphani) e ne e sebelisetsoa ho lekanya mokoloko oa DSC oa sampuli, tekanyo ea ho futhumatsa e ne e le 5 ° C / min, 'me mocheso oa phetoho ea khalase, ntlha e qhibilihisang le crystallinity ea polymer e ne e lekanngoa. Sebelisa Rigaku. D-MAX/Rb diffractometer e ile ea sebelisoa ho leka mohlala oa X-ray diffraction oa polymer ho ithuta thepa ea crystallization ea sampole.
2. Liphetho le lipuisano
2.1 Patlisiso ea infrared spectroscopy
Fourier transform infrared spectroscopy (FT-IR) e ka ithuta tšebelisano lipakeng tsa likarolo tsa motsoako ho latela pono ea boemo ba limolek'hule. Haeba li-homopolymers tse peli li lumellana, ho fetoha ha maqhubu, ho fetoha ho matla, esita le ponahalo kapa ho nyamela ha litlhōrō tsa likarolo tsa likarolo li ka bonoa. Haeba li-homopolymer tse peli li sa tsamaisane, sekhahla sa motsoako ke feela superposition ea li-homopolymer tse peli. Sebokeng sa PLLA, ho na le tlhōrō e otlolohileng ea ho sisinyeha ea C = 0 ho 1755cm-1, tlhōrō e fokolang ho 2880cm-1 e bakoang ke C-H e otlollang ho sisinyeha ha sehlopha sa methine, 'me sehlopha se pharaletseng ho 3500 cm-1 ke e bakoang ke lihlopha tsa terminal hydroxyl. Sebakeng sa EC spectrum, tlhōrō e ikhethang ho 3483 cm-1 ke tlhōrō ea OH e otlolohileng ea vibration, e bontšang hore ho na le lihlopha tsa O-H tse setseng holim'a ketane ea molek'hule, ha 2876-2978 cm-1 ke C2H5 e otlollang thothomelo, le 1637. cm-1 ke HOH Koba tlhōrō ea vibration (e bakoang ke sampole e monyang metsi). Ha PLLA e kopantsoe le EC, sebakeng sa IR sa hydroxyl sebakeng sa motsoako oa PLLA-EC, tlhōrō ea O-H e fetela ho palo e tlaase ea wavenumber ka keketseho ea EC content, 'me e fihla bonyane ha PLLA/Ec e le 40/60 wavenumber, ebe e fetela ho linomoro tse phahameng tsa maqhubu, e leng se bontšang hore tšebelisano pakeng tsa PUA le 0-H ea EC e rarahane. Sebakeng sa C = O vibration ea 1758cm-1, C = 0 tlhōrō ea PLLA-EC e fetotsoe hanyenyane ho palo e tlaase ea maqhubu ka keketseho ea EC, e bontšang hore tšebelisano pakeng tsa C = O le OH ea EC e ne e fokola.
Ho spectrogram ea methylcellulose, tlhoro e hlahelletseng ho 3480cm-1 ke tlhoro ea ho sisinyeha e otlollang ea O-H, ke hore, ho na le lihlopha tse setseng tsa O-H letotong la limolek'hule tsa MC, mme tlhoro ea HOH beng vibration e ho 1637cm-1, 'me MC karo-karolelano EC e feta hygroscopic. Ho tšoana le tsamaiso ea motsoako oa PLLA-EC, sebakeng sa infrared sa sebaka sa hydroxyl sa motsoako oa PLLA-EC, tlhōrō ea O-H e fetoha ka ho eketseha ha litaba tsa MC, 'me e na le palo e fokolang ea maqhubu ha PLLA / MC e le teng. 70/30. Sebakeng sa C=O vibration (1758 cm-1), tlhoro ea C=O e fetoha hanyane ho ea ho linomoro tse tlase tsa maqhubu ka kenyelletso ea MC. Joalokaha re boletse pejana, ho na le lihlopha tse ngata ho PLLA tse ka etsang litšebelisano tse khethehileng le li-polymers tse ling, 'me liphello tsa mahlaseli a infrared e ka ba phello e kopantsoeng ea litšebelisano tse ngata tse khethehileng tse ka khonehang. Tsamaisong ea motsoako oa PLLA le cellulose ether, ho ka 'na ha e-ba le mefuta e sa tšoaneng ea bond ea hydrogen pakeng tsa sehlopha sa ester sa PLLA, sehlopha sa terminal sa hydroxyl le sehlopha sa ether sa cellulose ether (EC kapa MG), le lihlopha tse setseng tsa hydroxyl. PLLA le EC kapa MCs li ka lumellana ka mokhoa o itseng. E ka 'na ea e-ba ka lebaka la boteng le matla a maqhama a mangata a hydrogen, kahoo liphetoho sebakeng sa O-H li bohlokoa haholo. Leha ho le joalo, ka lebaka la tšitiso ea steric ea sehlopha sa cellulose, tlamahano ea hydrogen pakeng tsa sehlopha sa C = O sa PLLA le sehlopha sa O-H sa cellulose ether se fokola.
2.2 Lipatlisiso tsa DSC
Li-curve tsa DSC tsa motsoako oa PLLA, EC le PLLA-EC. Mocheso oa phetoho ea khalase Tg ea PLLA ke 56.2 ° C, mocheso oa kristale o qhibilihang Tm ke 174.3 ° C, 'me crystallinity ke 55.7%. EC ke polymer ea amorphous e nang le Tg ea 43 ° C mme ha e na mocheso o qhibilihang. Tg ea likarolo tse peli tsa PLLA le EC li haufi haholo, 'me libaka tse peli tsa phetoho li kopana 'me li ke ke tsa khetholloa, kahoo ho thata ho li sebelisa e le mokhoa oa ho lumellana le tsamaiso. Ka keketseho ea EC, Tm ea metsoako ea PLLA-EC e fokotsehile hanyenyane, 'me crystallinity e fokotsehile (crystallinity ea sampuli e nang le PLLA / EC 20 / 80 e ne e le 21.3%). Tm ea metsoako e fokotsehile ka keketseho ea litaba tsa MC. Ha PLLA / MC e le tlase ho 70/30, Tm ea motsoako e thata ho lekanya, ke hore, hoo e ka bang motsoako oa amorphous o ka fumanoa. Ho theola ntlha ea ho qhibiliha ha motsoako oa li-polymers tsa crystalline tse nang le li-polymers tsa amorphous hangata li bakoa ke mabaka a mabeli, e 'ngoe ke phello ea dilution ea karolo ea amorphous; e 'ngoe e ka' na ea e-ba liphello tsa tlhophiso tse kang ho fokotsa ho phethahala ha crystallization kapa boholo ba kristale ea polymer ea crystalline. Liphello tsa DSC li bontšitse hore tsamaisong ea motsoako oa PLLA le cellulose ether, likarolo tse peli li ne li lumellana ka mokhoa o itseng, 'me mokhoa oa crystallization oa PLLA motsoako o ne o thibetsoe, o fella ka ho fokotseha ha Tm, crystallinity le boholo ba kristale ea PLLA. Sena se bontša hore ho lumellana ha likarolo tse peli tsa tsamaiso ea PLLA-MC ho ka ba molemo ho feta tsamaiso ea PLLA-EC.
2.3 Phapang ea X-ray
XRD Curve ea PLLA e na le tlhōrō e matla ka ho fetisisa ho 2θ ea 16.64 °, e lumellanang le sefofane sa kristale sa 020, ha litlhōrō tsa 2θ tsa 14.90 °, 19.21 ° le 22.45 ° li lumellana le 101, 023, le 121 ka ho latellana. Bokaholimo, ke hore, PLLA ke sebopeho sa α-crystalline. Leha ho le joalo, ha ho na tlhōrō ea sebopeho sa kristale karolong ea diffraction curve ea EC, e bontšang hore ke sebopeho sa amorphous. Ha PLLA e kopantsoe le EC, tlhōrō ea 16.64 ° e ile ea pharalla butle-butle, matla a eona a fokotseha, 'me a fallela hanyenyane ho ea tlaase. Ha litaba tsa EC li ne li le 60%, tlhoro ea crystallization e ne e qhalane. Litlhōrō tse tšesaane tsa x-ray diffraction li bontša bokhabane bo phahameng le boholo ba lijo-thollo. Ha tlhōrō ea diffraction e pharalletse, boholo ba lijo-thollo bo fokotseha. Ho fetoha ha tlhōrō ea diffraction ho ea ka lehlakoreng le tlaase ho bontša hore sebaka sa lijo-thollo sea eketseha, ke hore, botšepehi ba kristale bo fokotseha. Ho na le tlamo ea hydrogen pakeng tsa PLLA le Ec, 'me boholo ba lijo-thollo le crystallinity ea PLLA e fokotseha, e ka' nang ea e-ba hobane EC e lumellana ka mokhoa o itseng le PLLA ho theha sebopeho sa amorphous, kahoo ho fokotsa botšepehi ba sebopeho sa kristale ea motsoako. Liphetho tsa X-ray diffraction tsa PLLA-MC le tsona li bonts'a liphetho tse ts'oanang. X-ray diffraction curve e bonahatsa phello ea karo-karolelano ea PLLA / cellulose ether sebopeho sa motsoako, 'me liphello li lumellana ka ho feletseng le liphello tsa FT-IR le DSC.
3. Qetello
Sistimi ea motsoako oa acid e poly-L-lactic le cellulose ether (ethyl cellulose le methyl cellulose) e ile ea ithutoa mona. Ho lumellana ha likarolo tse peli tsamaisong ea motsoako ho ile ha ithutoa ka FT-IR, XRD le DSC. Liphello li bontšitse hore bonding ea hydrogen e ne e le teng pakeng tsa PLLA le cellulose ether, 'me likarolo tse peli tsa tsamaiso li ne li lumellana ka mokhoa o itseng. Ho fokotseha ha PLLA / cellulose ether ratio ho fella ka ho fokotseha ha ntlha ea ho qhibiliha, crystallinity, le crystal integrity ea PLLA motsoako, e leng se etsang hore ho lokisoe metsoako ea crystallinity e fapaneng. Ka hona, cellulose ether e ka sebelisoa ho fetola poly-L-lactic acid, e tla kopanya ts'ebetso e babatsehang ea acid e polylactic le theko e tlaase ea cellulose ether, e leng se loketseng ho lokisoa ha lisebelisoa tsa polymer ka botlalo.
Nako ea poso: Jan-13-2023