Xalka isku dhafan ee poly-L-lactic acid iyo ethyl cellulose ee chloroform iyo xalalka isku dhafan ee PLLA iyo methyl cellulose ee trifluoroacetic acid ayaa la diyaariyey, iyo isku dhafka PLLA / cellulose ether ayaa la diyaariyey iyadoo la tuurayo;Isku darka la helay waxaa lagu gartaa isbeddelka caleenta infrared spectroscopy (FT-IR), calorimetry scanning kala duwan (DSC) iyo kala-duwanaanta raajada (XRD).Waxaa jira dammaanad haydaroojiin ah oo u dhexeeya PLLA iyo ether cellulose, iyo labada qayboodba qayb ahaan way iswaafaqayaan.Marka la kordhiyo maadada ether-ka cellulose ee isku-dhafka ah, barta dhalaalka, crystallinity iyo daacadnimada crystal ee isku dhafka ayaa dhammaan hoos u dhigi doona.Marka nuxurka MC uu ka sarreeyo 30%, ku dhawaad isku darka amorphous ayaa la heli karaa.Sidaa darteed, ether cellulose waxaa loo isticmaali karaa in lagu beddelo poly-L-lactic acid si loogu diyaariyo alaabada polymer-ka-guurka ah ee leh sifooyin kala duwan.
Erayada muhiimka ah: poly-L-lactic acid, ethyl cellulose,methyl cellulose, isku dhafka, ether cellulose
Kobcinta iyo adeegsiga polymers-ka dabiiciga ah iyo agabka polymer synthetic ee la dumin karo ayaa gacan ka geysan doona xallinta dhibaatooyinka deegaanka iyo dhibaatada kheyraadka ee soo food saartay aadanaha.Sanadihii la soo dhaafay, cilmi-baarista ku saabsan isku-darka walxaha polymer-ka-biodegradable iyadoo la adeegsanayo kheyraadka dib loo cusboonaysiin karo sida alaabta ceeriin ee polymer ayaa soo jiidatay dareen baahsan.Polylactic acid waa mid ka mid ah polyester-yada aliphatic-ga ah ee muhiimka ah.Lactic acid waxaa lagu soo saari karaa halsano ee dalagyada (sida galleyda, baradhada, sukrose, iwm.), iyo sidoo kale waxaa qudhmi kara by microorganisms.Waa kheyraad dib loo cusboonaysiin karo.Polylactic acid waxaa laga soo diyaariyaa lactic acid iyadoo la isticmaalayo polycondensation toos ah ama polymerization-ka furitaanka giraanta.Wax soo saarka ugu dambeeya ee nabaad-guurintiisa waa lactic acid, taas oo aan wasakhayn doonin deegaanka.PIA waxay leedahay sifooyin farsamo oo aad u wanaagsan, habaysan, biodegradability iyo biocompatibility.Sidaa darteed, PLA kaliya ma laha codsiyo kala duwan oo xagga injineerinka noolaha, laakiin sidoo kale waxay leedahay suuqyo waaweyn oo suurtagal ah oo ku saabsan dhinacyada dahaarka, balaastikada, iyo dunta.
Qiimaha sare ee poly-L-lactic acid iyo cilladaha wax qabadkeeda sida hydrophobicity iyo jajabnaanta ayaa xaddidaya xadka codsigeeda.Si loo yareeyo kharashkeeda oo loo hagaajiyo waxqabadka PLLA, diyaarinta, iswaafajinta, qaab-dhismeedka, biodegradability, sifooyinka farsamada, dheelitirka hydrophilic / hydrophobic iyo goobaha codsiga ee copolymers acid polylactic iyo isku-dhafka ayaa si qoto dheer loo darsay.Waxaa ka mid ah, PLLA waxay samaysaa isku-dhafan la jaan qaada poly DL-lactic acid, polyethylene oxide, polyvinyl acetate, polyethylene glycol, iwm. dabeecadda.Derivatives Cellulose waa walxaha ugu horreeya ee polymer-dabiiciga ah ay sameeyeen bini'aadamka, kuwaas oo ay ugu muhiimsan yihiin ethers cellulose iyo cellulose esters.M.Nagata iyo al.dersay nidaamka isku dhafka PLLA/cellulose waxaana la ogaaday in labada qaybood aysan isqaban karin, laakiin sifooyinka crystallization iyo xaalufka PLLA waxaa si weyn u saameeyay qaybta cellulose.N.Ogata et al ayaa bartay waxqabadka iyo qaabdhismeedka PLLA iyo nidaamka isku dhafka acetate cellulose.Patent-ka Japan ayaa sidoo kale bartay biodegradability-ga PLLA iyo isku-dhafka nitrocellulose.Y.Teramoto et al waxay barteen diyaarinta, kulaylka iyo sifooyinka farsamada ee PLLA iyo cellulose diacetate copolymers.Ilaa hadda, waxaa jira daraasado aad u yar oo ku saabsan habka isku dhafka ah ee polylactic acid iyo ether cellulose.
Sanadihii la soo dhaafay, kooxdayadu waxay ku hawlanaayeen cilmi-baadhista isku-dhafka tooska ah iyo wax ka beddelka isku-dhafka polylactic acid iyo polymers kale.Si loo isku daro sifooyinka wanaagsan ee polylactic acid iyo qiimaha hooseeya ee cellulose iyo waxyaabaha ka soo baxa si loo diyaariyo alaabta polymer-ka si buuxda loo nadiifiyo, waxaan dooraneynaa cellulose (ether) oo ah qaybta wax laga beddelay ee wax ka beddelka.Ethyl cellulose iyo methyl cellulose waa laba ethers cellulose muhiim ah.Ethyl cellulose waa biyo aan milmi karin oo aan ionic cellulose alkyl ether ahayn, kaas oo loo isticmaali karo agab caafimaad, balaastiig, koollo iyo walxaha dhammays tirka ah.Methyl cellulose waa biyo-milmi leh, waxay leedahay qoyaan aad u fiican, isku-duubni, haynta biyaha iyo sameynta filimada, waxaana si ballaaran loo isticmaalaa dhinacyada qalabka dhismaha, dahaarka, qurxinta, daawooyinka iyo waraaqaha.Halkan, isku darka PLLA/EC iyo PLLA/MC waxaa lagu diyaariyay habka shubista xalalka, iyo iswaafajinta, guryaha kulaylka iyo walxaha crystallization ee isku darka PLLA/cellulose ether ayaa laga wada hadlay.
1. Qaybta tijaabada ah
1.1 Qalabka ceeriin
Ethyl cellulose (AR, Tianjin Huazhen Kiimikada Gaarka ah ee Warshadamethyl cellulose (MC450), sodium dihydrogen phosphate, disodium hydrogen phosphate, ethyl acetate, stannous isooctanoate, chloroform (kor ku xusan waa dhammaan alaabta Shanghai Chemical Reagent Co., Ltd., iyo daahirsanaanta waa AR fasalka);L-lactic acid (darajada dawooyinka, shirkadda PURAC).
1.2 Diyaarinta isku dhafka
1.2.1 Diyaarinta polylactic acid
Poly-L-lactic acid waxaa lagu diyaariyay habka kondensation-ka tooska ah.Miisaan L-lactic acid xal aqueous ah oo leh jajab ballaaran oo ah 90% kuna dar galaas saddex luqun ah, fuuqbax 150 ° C 2 saacadood oo cadaadis caadi ah, ka dibna ka jawaab 2 saacadood cadaadiska faakuumka ee 13300Pa, iyo ugu dambeyntii falcelis 4 saacadood hoos maran 3900Pa si aad u hesho walxaha prepolymer fuuqbaxay.Tirada guud ee xalalka aashitada lactic acid marka laga reebo wax soo saarka biyuhu waa wadarta cadadka prepolymer.Ku dar chloride stannous ah (jajab mass waa 0.4%) iyo p-toluenesulfonic acid (saamiga stannous chloride iyo p-toluenesulfonic acid waa 1/1 saamiga molar) nidaamka kicinta ee prepolymer ee la helay, iyo uumi shaandho molecular ayaa lagu rakibay tuubada si loo nuugo qadar yar oo biyo ah, iyo walaaqinta farsamada waa la joogteeyey.Nidaamka oo dhan waxaa lagu falceliyay meel faaruq ah 1300 Pa iyo heerkul ah 150 ° C. 16 saacadood si loo helo polymer.Kala dir polymer-ka la helay ee chloroform si aad u diyaariso xal 5% ah, shaandheeya oo ku soo daadi ether anhydrous 24 saacadood, miir da'da, oo ku rid foornada faakuumka -0.1MPa at 60°C 10 ilaa 20 saacadood si aad u hesho Pure ether polymer PLLA.Miisaanka molecular ee qaraabada ah ee PLLA-ga la helay waxaa lagu go'aamiyay inuu noqdo 45000-58000 Dalton iyadoo la adeegsanayo chromatography dareeraha waxqabadka sare leh (GPC).Tusaalooyinka waxaa lagu kaydiyay qalajiyaha ka kooban fosfooraska pentoxide.
1.2.2 Diyaarinta polylactic acid-ethyl cellulose mix (PLLA-EC)
Miisaam qaddarka loo baahan yahay ee poly-L-lactic acid iyo ethyl cellulose si aad u samayso 1% chloroform xal siday u kala horreeyaan, ka dibna u diyaari xal isku dhafan PLLA-EC.Saamiga PLLA-EC xal isku qasan waa: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, lambarka kowaad wuxuu matalaa tirada guud ee PLLA, iyo tirada dambe waxay u taagan tahay tirada guud ee Jajabka EC.Xalalka la diyaariyey ayaa lagu walaaqay kicinta magnetic 1-2 saacadood, ka dibna lagu shubay saxan galaas ah si loogu oggolaado chloroform inuu si dabiici ah uumi u baxo si uu u sameeyo filim.Ka dib markii filimka la sameeyay, waxaa la geliyay foornada faakuumka si ay u qallajiso heerkul hooseeya 10 saacadood si gebi ahaanba looga saaro chloroform-ka filimka..Xalka isku-dhafka ah waa mid aan midab lahayn oo hufan, filimka isku-dhafka ah sidoo kale waa mid aan midab lahayn oo hufan.Isku darka waa la engejiyey waxaana lagu kaydiyey qallajiye si hadhow loo isticmaalo.
1.2.3 Diyaarinta isku dhafka polylactic acid-methylcellulose (PLLA-MC)
Miisaam qaddarka loo baahan yahay ee poly-L-lactic acid iyo methyl cellulose si aad u samayso 1% xal trifluoroacetic acid siday u kala horreeyaan.Filimka isku dhafka ah ee PLLA-MC waxaa loo diyaariyay qaab la mid ah filimka isku dhafka PLLA-EC.Isku darka waa la engejiyey waxaana lagu kaydiyey qallajiye si hadhow loo isticmaalo.
1.3 Imtixaanka waxqabadka
MANMNA IR-550 spectrometer infrared (Nicolet.Corp) ayaa cabiray spectrum infrared of polymer (KBr tablet).DSC2901 calorimeterka kala duwan ee iskaanka (shirkadda TA) ayaa loo isticmaalay in lagu cabbiro qalooca DSC ee muunada, heerka kulaylku waxa uu ahaa 5°C/min, iyo heerkulka kala guurka galaas, barta dhalaalka iyo crystallinity ee polymer ayaa la qiyaasay.Isticmaal Rigaku.Diffractometer-ka D-MAX/Rb ayaa loo isticmaalay in lagu tijaabiyo qaabka kala-duwanaanshaha raajada ee polymerka si loo barto sifooyinka crystallization ee muunadda.
2. Natiijooyinka iyo doodaha
2.1 Cilmi-baarista infrared spectroscopy
Fourier transforming infrared spectroscopy (FT-IR) waxay baran kartaa isdhexgalka ka dhexeeya qaybaha isku dhafka marka loo eego heerka molecular.Haddii labada homopolymers ay iswaafaqayaan, isbeddellada soo noqnoqda, isbeddelka xoogga, iyo xitaa muuqaalka ama maqnaanshaha meelaha ugu sarreeya ee sifooyinka qaybaha ayaa la arki karaa.Haddii labada homopolymers aysan isqaban karin, xajmiga isku-dhafka ayaa si fudud u sarreeya labada homopolymers.Muuqaalka PLLA, waxaa jira gariir fidsan oo C=0 ah 1755cm-1, daciif daciif ah oo ah 2880cm-1 oo ay sababtay gariirka fiditaanka C-H ee kooxda methine, iyo qayb ballaaran oo ah 3500 cm-1 waa oo ay sababaan kooxaha terminal hydroxyl.Marka la eego EC spectrum, heerka ugu sarreeya ee 3483 cm-1 waa OH fidinta gariirka ugu sarreeya, taas oo muujinaysa inay jiraan kooxaha O-H ee ku hadhay silsiladda molecular, halka 2876-2978 cm-1 ay tahay C2H5 fidinta gariirka ugu sarreeya, iyo 1637 cm-1 waa HOH leexinta ugu sarreysa gariirka (oo ay sababto muunada biyaha nuugaya).Marka PLLA lagu daro EC, ee IR spectrum ee gobolka hydroxyl ee isku dhafka PLLA-EC, O-H ugu sarraysa waxay u beddeshaa tirada mowjadaha hoose iyadoo korodhka nuxurka EC, oo gaadho ugu yaraan marka PLLA/EC ay tahay 40/60 tirada mawjadaha, ka dibna loo wareejiyay mowjadaha sare, taas oo muujinaysa in isdhexgalka PUA iyo 0-H ee EC uu yahay mid adag.Gobolka gariir C=O ee 1758cm-1, C=0 ugu sarraysa PLLA-EC waxyar ayaa loo bedelay lambar mowjad hoose oo korodhay EC, taas oo muujinaysa in isdhexgalka C=O iyo OH ee EC uu daciif yahay.
Marka la eego spectrogram of methylcellulose, heerka ugu sarreeya ee 3480cm-1 waa O-H fidinta gariirka ugu sarreeya, taas oo ah, waxaa jira kooxo O-H ah oo ku yaal silsiladda molecular MC, iyo HOH foorarsiga gariirka ugu sarreeya waa 1637cm-1, iyo saamiga MC EC waa hygroscopic badan.Si la mid ah nidaamka isku dhafka PLLA-EC, ee spectra infrared ee gobolka hydroxyl ee isku dhafka PLLA-EC, O-H ugu sarreeya ayaa isbeddelaya kororka nuxurka MC, wuxuuna leeyahay lambarka mawjada ugu yar marka PLLA/MC uu yahay 70/30Gobolka gariirka C=O (1758 cm-1), C=O ugu sarraysa waxa ay waxyar u beddeshaa mawjado hoose oo lagu daro MC.Sida aan horay u soo sheegnay, waxaa jira kooxo badan oo PLLA ah kuwaas oo samayn kara isdhexgalka gaarka ah ee polymers kale, iyo natiijooyinka spectrum infrared waxay noqon kartaa saameynta isku dhafan ee isdhexgalka gaarka ah ee suurtogalka ah.Nidaamka isku dhafka ah ee PLLA iyo ether cellulose, waxaa jiri kara qaabab kala duwan oo hydrogen ah oo u dhexeeya kooxda ester ee PLLA, kooxda hydroxyl ee terminal iyo kooxda ether ee cellulose ether (EC ama MG), iyo kooxaha haray ee hydroxyl.PLLA iyo EC ama MCs ayaa laga yaabaa inay qayb ahaan iswaafaqayaan.Waxaa laga yaabaa inay sabab u tahay jiritaanka iyo xoogga curaarta hydrogen ee badan, markaa isbeddelada gobolka O-H ayaa aad muhiim u ah.Si kastaba ha ahaatee, caqabada adag ee kooxda cellulose awgeed, xidhiidhka hydrogen ka dhexeeya kooxda C=O ee PLLA iyo kooxda O-H ee etherka cellulose waa daciif.
2.2 cilmi baarista DSC
Qallooca DSC ee PLLA, EC iyo PLLA-EC isku darkaHeerkulka kala-guurka dhalada ee Tg ee PLLA waa 56.2 ° C, heerkulka dhalaalidda crystal Tm waa 174.3 ° C, iyo crystallinity waa 55.7%.EC waa polymer amorphous leh Tg ah 43 ° C oo aan lahayn heerkul dhalaalid.Tg labada qaybood ee PLLA iyo EC aad bay isugu dhow yihiin, labada gobol ee kala-guurka ahi way is dul saaran yihiin oo lama kala saari karo, markaa way adag tahay in loo isticmaalo halbeeg u dhiganta nidaamka waafaqsan.Kor u kaca EC, Tm ee isku dhafka PLLA-EC wax yar ayaa hoos u dhacay, iyo crystallinity-ka ayaa hoos u dhacay (kristaliinnimada muunada PLLA/EC 20/80 waxay ahayd 21.3%).Tm isku-darka ayaa hoos u dhacay kororka maadada MC.Marka PLLA/MC ay ka hooseyso 70/30, Tm ee isku darka way adag tahay in la cabbiro, taas oo ah, ku dhawaad isku darka amorphous ayaa la heli karaa.Hoos u dhigista barta dhalaalka ee isku dhafka ah ee polymers crystalline leh polymers amorphous badanaa waxaa sabab u ah laba sababood, mid ka mid ah saameynta dilution ee qaybta amorphous;Midda kale waxay noqon kartaa saameyn qaabdhismeed sida hoos u dhigista kaamilnimada crystallization ama cabbirka crystalline polymer.Natiijooyinka DSC waxay muujiyeen in nidaamka isku dhafka ah ee PLLA iyo ether cellulose, labada qaybood ay qayb ahaan iswaafajiyeen, iyo habka crystallization ee PLLA ee isku dhafka ah ayaa la joojiyay, taasoo keentay hoos u dhaca Tm, crystallinity iyo crystal size of PLLA.Tani waxay tusinaysaa in iswaafajinta labada qaybood ka kooban ee nidaamka PLLA-MC laga yaabo in uu ka fiicnaado kan nidaamka PLLA-EC.
2.3 X-ray diffraction
Qalooca XRD ee PLLA wuxuu leeyahay ugu sarreeya 2θ ee 16.64 °, taas oo u dhiganta 020 diyaaradda crystal, halka ugu sarreeya 2θ ee 14.90 °, 19.21 ° iyo 22.45 ° u dhiganta 101, 023, iyo 121 crystals, siday u kala horreeyaan.Dusha sare, taas oo ah, PLLA waa qaab-dhismeedka α-crystalline.Si kastaba ha ahaatee, ma jiro qaab-dhismeedka ugu sarreeya ee qalooca kala-duwanaanta ee EC, taas oo muujinaysa in ay tahay qaab-dhismeedka amorphous.Marka PLLA lagu qaso EC, heerka ugu sarreeya ee 16.64° tartiib tartiib ayuu u balaadhay, xooggeedii ayaa daciifay, oo wax yar bay u dhaqaaqday xagal hoose.Marka nuxurka EC uu ahaa 60%, heerka ugu sarreeya ee crystallization ayaa kala firdhiyey.Kala-duwanaanta raajada ee cidhiidhiga ah waxay tilmaamaysaa crystallinity sare iyo cabbirka badarka weyn.Baaxadda ugu sarreysa kala-duwanaanta, waa yaraanta cabbirka hadhuudhka.Isbeddelka ugu sarreeya ee kala-duwanaanshaha xagasha hoose waxay muujinaysaa in kala fogaanshiyaha hadhuudhka uu kordho, taas oo ah, daacadnimada kareemka ayaa hoos u dhacaya.Waxaa jira dammaanad haydarojiin ah oo u dhexeeya PLLA iyo Ec, iyo cabbirka hadhuudhka iyo crystallinity ee PLLA hoos u dhacay, taas oo laga yaabo inay sababto EC waxay qayb ahaan la jaan qaadaysaa PLLA si ay u samayso qaab-dhismeedka amorphous, taas oo yaraynaysa daacadnimada qaab dhismeedka crystal ee isku dhafka.Natiijooyinka kala-duwanaanta raajada ee PLLA-MC waxay sidoo kale ka tarjumaysaa natiijooyin la mid ah.Qalooca raajada kala-duwanaanshaha waxay ka tarjumaysaa saamaynta saamiga PLLA/cellulose ether ee qaabdhismeedka isku-dhafka, natiijadu waxay si buuxda ula socotaa natiijooyinka FT-IR iyo DSC.
3. Gabagabo
Nidaamka isku dhafka ah ee poly-L-lactic acid iyo ether cellulose (ethyl cellulose iyo methyl cellulose) ayaa lagu bartay halkan.Iswaafajinta labada qaybood ee nidaamka isku dhafka ah waxaa lagu bartay FT-IR, XRD iyo DSC.Natiijooyinku waxay muujiyeen in isku xidhka hydrogen uu ka dhex jiro PLLA iyo ether cellulose, iyo labada qaybood ee nidaamka ayaa qayb ahaan iswaafaqsan.Hoos u dhaca saamiga PLLA/cellulose ether wuxuu keenayaa hoos u dhaca barta dhalaalka, crystallinity, iyo daacadnimada PLLA ee isku dhafka, taasoo keentay diyaarinta isku-dhafka crystallinity kala duwan.Sidaa darteed, ether cellulose waxaa loo isticmaali karaa in lagu beddelo poly-L-lactic acid, taas oo isku dari doonta waxqabadka wanaagsan ee polylactic acid iyo qiimaha hooseeya ee ether cellulose, kaas oo ku habboon diyaarinta alaabta polymer-ka ee si buuxda loo nadiifin karo.
Waqtiga boostada: Jan-13-2023