Maganin gauraye na poly-L-lactic acid da ethyl cellulose a cikin chloroform da cakudaccen bayani na PLLA da methyl cellulose a cikin trifluoroacetic acid an shirya, kuma an shirya cakuda PLLA / cellulose ether ta hanyar jefawa; Abubuwan haɗin gwiwar da aka samu sun haɗa da canza launin ganye ta hanyar infrared spectroscopy (FT-IR), calorimetry bambance-bambance (DSC) da diffraction X-ray (XRD). Akwai haɗin hydrogen tsakanin PLLA da cellulose ether, kuma sassan biyu sun dace da wani bangare. Tare da haɓaka abun ciki na ether cellulose a cikin haɗakarwa, wurin narkewa, crystallinity da mutuncin kristal na haɗuwa za su ragu. Lokacin da abun ciki na MC ya fi sama da 30%, ana iya samun kusan gaurayawan amorphous. Sabili da haka, ana iya amfani da ether cellulose don canza poly-L-lactic acid don shirya kayan polymer mai lalacewa tare da kaddarorin daban-daban.
Mahimman kalmomi: poly-L-lactic acid, ethyl cellulose,methyl cellulose, hadawa, cellulose ether
Haɓakawa da aikace-aikacen polymers na halitta da kayan aikin polymer roba masu lalacewa zasu taimaka wajen magance rikicin muhalli da rikicin albarkatun da ɗan adam ke fuskanta. A cikin 'yan shekarun nan, binciken da aka yi game da haɗakar da kayan polymer mai lalacewa ta amfani da albarkatu masu sabuntawa kamar yadda albarkatun polymer ya jawo hankalin jama'a. Polylactic acid yana daya daga cikin manyan polyester aliphatic da ke lalatar da su. Ana iya samar da Lactic acid ta hanyar fermentation na amfanin gona (kamar masara, dankali, sucrose, da sauransu), kuma ana iya lalata su ta hanyar ƙwayoyin cuta. Hanya ce mai sabuntawa. Ana shirya polylactic acid daga lactic acid ta hanyar polycondensation kai tsaye ko polymerization na buɗewa. Samfurin ƙarshe na lalata shi shine lactic acid, wanda ba zai gurɓata muhalli ba. PIA tana da ingantattun kaddarorin inji, iya aiki, biodegradability da biocompatibility. Saboda haka, PLA ba wai kawai yana da aikace-aikace iri-iri a fannin injiniyan halittu ba, har ma yana da manyan kasuwanni masu yuwuwa a fannonin sutura, robobi, da masaku.
Babban farashin poly-L-lactic acid da lahani na aikin sa kamar hydrophobicity da brittleness yana iyakance kewayon aikace-aikacen sa. Don rage farashinsa da inganta aikin PLLA, shirye-shiryen, dacewa, ilimin halittar jiki, biodegradability, kayan aikin injiniya, ma'auni na hydrophilic / hydrophobic da filayen aikace-aikace na polylactic acid copolymers da blends an yi nazari sosai. Daga cikin su, PLLA yana samar da haɗin haɗin gwiwa tare da poly DL-lactic acid, polyethylene oxide, polyvinyl acetate, polyethylene glycol, da dai sauransu. cikin yanayi. Abubuwan da aka samo asali na Cellulose sune farkon kayan polymer na halitta wanda ɗan adam ya haɓaka, mafi mahimmancin su shine ethers cellulose da esters cellulose. M. Nagata et al. yayi nazarin tsarin gauraya na PLLA/cellulose kuma ya gano cewa abubuwan biyu ba su dace ba, amma kristal da lalata kaddarorin PLLA sun sami tasiri sosai daga bangaren cellulose. N. Ogata et al yayi nazarin aikin da tsarin tsarin PLLA da cellulose acetate mix. Har ila yau, alamar tambarin Jafananci ta yi nazarin yanayin halittu na PLLA da haɗin gwiwar nitrocellulose. Y. Teramoto et al yayi nazarin shirye-shiryen, thermal da kayan aikin injiniya na PLLA da cellulose diacetate graft copolymers. Ya zuwa yanzu, akwai ƙananan binciken akan tsarin haɗakar da polylactic acid da ether cellulose.
A cikin 'yan shekarun nan, ƙungiyarmu ta tsunduma cikin bincike na copolymerization kai tsaye da haɓaka gyare-gyare na polylactic acid da sauran polymers. Domin hada kyawawan kaddarorin polylactic acid tare da ƙananan farashin cellulose da abubuwan da suka samo asali don shirya cikakkun kayan aikin polymer na biodegradable, mun zaɓi cellulose (ether) azaman abin da aka gyara don gyare-gyaren haɗuwa. Ethyl cellulose da methyl cellulose ne biyu muhimmanci cellulose ethers. Ethyl cellulose wani ruwa ne wanda ba shi da ruwa wanda ba shi da ionic cellulose alkyl ether, wanda za'a iya amfani dashi azaman kayan aikin likita, robobi, adhesives da kayan aikin gamawa. Methyl cellulose yana da ruwa mai narkewa, yana da kyakkyawan ruwa mai laushi, haɗin kai, riƙewar ruwa da kaddarorin fim, kuma ana amfani dashi sosai a fagen kayan gini, sutura, kayan kwalliya, magunguna da takarda. Anan, an shirya haɗin PLLA/EC da PLLA/MC ta hanyar hanyar simintin simintin, kuma an tattauna dacewa, kaddarorin thermal da kaddarorin crystallization na PLLA/cellulose ether blends.
1. Bangaren gwaji
1.1 Kayan danye
Ethyl cellulose (AR, Tianjin Huazhen Special Chemical Reagent Factory); methyl cellulose (MC450), sodium dihydrogen phosphate, disodium hydrogen phosphate, ethyl acetate, stannous isooctanoate, chloroform (a sama duk samfurori na Shanghai Chemical Reagent Co., Ltd., da kuma tsarki ne AR sa); L-lactic acid (maganin magunguna, kamfanin PURAC).
1.2 Shiri na haɗuwa
1.2.1 Shiri na polylactic acid
Poly-L-lactic acid an shirya shi ta hanyar polycondensation kai tsaye. Auna maganin ruwa na L-lactic acid tare da juzu'i na 90% kuma ƙara shi a cikin filasta mai wuya uku, cire ruwa a 150 ° C na tsawon sa'o'i 2 a ƙarƙashin matsi na al'ada, sannan ku amsa na tsawon sa'o'i 2 a ƙarƙashin matsa lamba na 13300Pa, kuma a ƙarshe. amsa na tsawon sa'o'i 4 a ƙarƙashin injin 3900Pa don samun abubuwan prepolymer da ba su da ruwa. Jimlar adadin maganin ruwa na lactic acid ban da fitowar ruwa shine jimlar adadin prepolymer. Add stannous chloride (jama'a juzu'i ne 0.4%) da p-toluenesulfonic acid (rabo na stannous chloride da p-toluenesulfonic acid ne 1/1 molar rabo) mai kara kuzari tsarin a cikin samu prepolymer, kuma a cikin condensation Molecular sieves aka shigar a cikin bututu. don sha ɗan ƙaramin ruwa, kuma an kiyaye motsi na inji. An mayar da tsarin gaba ɗaya a wani wuri na 1300 Pa da zafin jiki na 150 ° C. na 16 hours don samun polymer. Narkar da polymer ɗin da aka samu a cikin chloroform don shirya bayani na 5%, tace da hado tare da ether mai anhydrous na tsawon awanni 24, tace hazo, sa'annan a sanya shi a cikin tanda -0.1MPa a 60 ° C na sa'o'i 10 zuwa 20 don samun Pure bushe. Farashin PLLA. An ƙaddara nauyin ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar ƙwayar cuta (GPC) 45000-58000 Daltons. An adana samfurori a cikin na'urar bushewa mai dauke da phosphorus pentoxide.
1.2.2 Shiri na polylactic acid-ethyl cellulose blend (PLLA-EC)
Auna adadin da ake buƙata na poly-L-lactic acid da ethyl cellulose don yin maganin chloroform na 1% bi da bi, sannan shirya maganin gauraye na PLLA-EC. Matsakaicin PLLA-EC gauraye bayani shine: 100/0, 80/20, 60/40, 40/60, 20/80, 0/l00, lambar farko tana wakiltar babban juzu'in PLLA, kuma lambar ƙarshe tana wakiltar yawan EC Fraction. Abubuwan da aka shirya an zuga su tare da injin maganadisu na tsawon sa'o'i 1-2, sannan a zuba a cikin gilashin gilashi don ba da damar chloroform ya ƙafe ta halitta don samar da fim. Bayan da aka kafa fim din, an sanya shi a cikin tanda don bushewa a ƙananan zafin jiki na tsawon sa'o'i 10 don cire chloroform gaba daya a cikin fim din. . Maganin gauraya ba shi da launi kuma a bayyane, kuma fim ɗin gauraya kuma ba shi da launi da bayyananne. An bushe cakuda kuma an adana shi a cikin injin bushewa don amfani daga baya.
1.2.3 Shiri na polylactic acid-methylcellulose blend (PLLA-MC)
Auna adadin da ake buƙata na poly-L-lactic acid da methyl cellulose don yin maganin trifluoroacetic acid 1% bi da bi. An shirya fim ɗin haɗaɗɗen PLLA-MC ta hanya ɗaya da fim ɗin gauraya na PLLA-EC. An bushe cakuda kuma an adana shi a cikin injin bushewa don amfani daga baya.
1.3 Gwajin aiki
MANMNA IR-550 infrared spectrometer (Nicolet.Corp) ya auna bakan infrared na polymer (KBr kwamfutar hannu). DSC2901 bambanta calorimeter scanning (TA kamfanin) da aka yi amfani da su auna DSC kwana na samfurin, da dumama kudi ne 5 ° C / min, da gilashin miƙa mulki zafin jiki, narkewa batu da crystallinity na polymer aka auna. Yi amfani da Rigaku. An yi amfani da diffractometer D-MAX/Rb don gwada tsarin rarrabawar X-ray na polymer don nazarin kaddarorin crystallization na samfurin.
2. Sakamako da tattaunawa
2.1 Binciken infrared spectroscopy
Fourier canza infrared spectroscopy (FT-IR) zai iya yin nazarin hulɗar tsakanin abubuwan haɗin gwiwar ta fuskar matakin kwayoyin halitta. Idan nau'ikan homopolymer guda biyu sun dace, canzawa a cikin mita, canje-canje a cikin ƙarfi, har ma da bayyanar ko bacewar kololuwar halayen abubuwan haɗin za a iya gani. Idan nau'ikan homopolymer guda biyu ba su dace ba, bakan na gauraya shine kawai babban matsayi na homopolymers biyu. A cikin bakan PLLA, akwai ƙwanƙarar rawar jiki na C = 0 a 1755cm-1, ƙarancin rauni a 2880cm-1 wanda ke haifar da girgizawar C-H na rukunin methine, kuma babban band a 3500 cm-1 shine. lalacewa ta hanyar ƙungiyoyin hydroxyl na ƙarshe. A cikin bakan EC, ƙimar halayyar a 3483 cm-1 ita ce mafi girman girgizar girgiza OH, yana nuna cewa akwai ƙungiyoyin O-H da suka rage akan sarkar kwayoyin, yayin da 2876-2978 cm-1 shine C2H5 mai tsayin girgizar girgiza, da 1637. cm-1 shine HOH Lankwasawa kololuwar girgiza (wanda ya haifar da ruwan sha). Lokacin da aka haɗe PLLA da EC, a cikin nau'in IR na yankin hydroxyl na PLLA-EC blend, O-H kololuwa yana canzawa zuwa ƙananan lambobi tare da haɓaka abun ciki na EC, kuma ya kai mafi ƙanƙanta lokacin da PLLA/Ec ke da lamba 40/60, sa'an nan kuma aka matsa zuwa manyan lambobi, yana nuna cewa hulɗar tsakanin PUA da 0-H na EC yana da rikitarwa. A cikin yankin C = O vibration na 1758cm-1, C = 0 kololuwar PLLA-EC dan kadan ya canza zuwa ƙananan lambobi tare da karuwar EC, wanda ya nuna cewa hulɗar tsakanin C = O da OH na EC ya kasance mai rauni.
A cikin sifa na methylcellulose, ƙimar halayyar a 3480cm-1 ita ce O-H shimfidawa kololuwa, wato, akwai ragowar ƙungiyoyin O-H akan sarkar kwayoyin MC, kuma HOH na lankwasawa kololuwa yana a 1637cm-1, kuma rabon MC EC ya fi hygroscopic. Hakazalika da tsarin haɗin PLLA-EC, a cikin infrared spectra na yankin hydroxyl na PLLA-EC gauraya, O-H mafi girma yana canzawa tare da karuwar abun ciki na MC, kuma yana da mafi ƙarancin lambar igiyar ruwa lokacin da PLLA/MC yake. 70/30. A cikin yankin C = O vibration (1758 cm-1), C = O kololuwa kadan yana motsawa zuwa ƙananan lambobi tare da ƙari na MC. Kamar yadda muka ambata a baya, akwai ƙungiyoyi da yawa a cikin PLLA waɗanda za su iya yin hulɗa ta musamman tare da wasu polymers, kuma sakamakon infrared bakan na iya zama tasirin haɗuwa da yawa mai yiwuwa hulɗar musamman. A cikin tsarin haɗakarwa na PLLA da ether cellulose, za a iya samun nau'o'in haɗin gwiwar hydrogen daban-daban tsakanin ƙungiyar ester na PLLA, ƙungiyar hydroxyl ta ƙarshe da ƙungiyar ether na cellulose ether (EC ko MG), da sauran ƙungiyoyin hydroxyl. PLLA da EC ko MCs na iya dacewa da ɗan lokaci. Yana iya zama saboda wanzuwa da ƙarfin haɗin haɗin hydrogen da yawa, don haka canje-canje a yankin O-H sun fi mahimmanci. Duk da haka, saboda tsangwama na ƙungiyar cellulose, haɗin hydrogen tsakanin ƙungiyar C = O na PLLA da ƙungiyar O-H na cellulose ether yana da rauni.
2.2 Binciken DSC
DSC masu lankwasa na PLLA, EC da PLLA-EC gauraye. Matsakaicin zafin jiki na gilashin Tg na PLLA shine 56.2 ° C, zazzabi mai narkewar crystal Tm shine 174.3 ° C, kuma crystallinity shine 55.7%. EC polymer amorphous ne tare da Tg na 43°C kuma babu zafin narkewa. Tg na sassan biyu na PLLA da EC suna da kusanci sosai, kuma yankuna biyu na mika mulki sun mamaye kuma ba za a iya bambanta su ba, don haka yana da wahala a yi amfani da shi azaman ma'auni don daidaita tsarin tsarin. Tare da karuwa na EC, Tm na PLLA-EC blends ya ragu kadan, kuma crystallinity ya ragu (kristal na samfurin tare da PLLA/EC 20/80 shine 21.3%). Tm na gaurayawan sun ragu tare da haɓaka abun ciki na MC. Lokacin da PLLA/MC ya yi ƙasa da 70/30, Tm na gauraya yana da wuyar aunawa, wato, ana iya samun kusan gauraya amorphous. Ragewar ma'anar narkewa na haɗuwa na polymers crystalline tare da polymers amorphous yawanci saboda dalilai guda biyu, ɗaya shine tasirin dilution na ɓangaren amorphous; ɗayan na iya zama tasirin tsarin kamar raguwar kamala na crystallization ko girman crystal na polymer crystalline. Sakamakon DSC ya nuna cewa a cikin tsarin haɗakarwa na PLLA da cellulose ether, sassan biyu sun dace da juna, kuma an hana tsarin crystallization na PLLA a cikin cakuda, wanda ya haifar da raguwar Tm, crystallinity da crystal size of PLLA. Wannan yana nuna cewa daidaituwar sassa biyu na tsarin PLLA-MC na iya zama mafi kyau fiye da na tsarin PLLA-EC.
2.3 X-ray diffraction
Ƙwararren XRD na PLLA yana da mafi girma a 2θ na 16.64 °, wanda ya dace da 020 crystal jirgin sama, yayin da kololuwa a 2θ na 14.90 °, 19.21 ° da 22.45 ° sun dace da 101, 023, da 121. Surface, wato, PLLA shine tsarin α-crystalline. Duk da haka, babu wani kololuwar tsarin kristal a cikin madaidaicin karkatarwar EC, wanda ke nuna cewa tsari ne na amorphous. Lokacin da aka haɗe PLLA tare da EC, kololuwar a 16.64° a hankali ya faɗaɗa, ƙarfinta ya yi rauni, kuma ya ɗan motsa kaɗan zuwa ƙaramin kusurwa. Lokacin da abun ciki na EC ya kasance 60%, kololuwar crystallization ya watse. Ƙunƙarar kololuwar ɓarna na x-ray suna nuna babban crystallinity da girman girman hatsi. Faɗin kololuwar ɓarna, ƙaramar girman hatsi. Juya kololuwar diffraction zuwa ƙaramin kusurwa yana nuna cewa tazarar hatsi yana ƙaruwa, wato, amincin kristal yana raguwa. Akwai haɗin hydrogen tsakanin PLLA da Ec, da girman hatsi da crystallinity na PLLA suna raguwa, wanda zai iya zama saboda EC yana da alaƙa da PLLA don samar da tsarin amorphous, don haka rage amincin tsarin crystal na gauraya. Sakamakon rarrabawar X-ray na PLLA-MC shima yana nuna irin wannan sakamako. Ƙwararren ƙwanƙwasa na X-ray yana nuna tasirin rabo na PLLA / cellulose ether akan tsarin haɗuwa, kuma sakamakon ya dace da sakamakon FT-IR da DSC.
3. Kammalawa
An yi nazarin tsarin haɗin poly-L-lactic acid da cellulose ether (ethyl cellulose da methyl cellulose) a nan. An yi nazarin daidaitawar abubuwan haɗin biyu a cikin tsarin haɗakarwa ta hanyar FT-IR, XRD da DSC. Sakamakon ya nuna cewa haɗin gwiwar hydrogen ya kasance tsakanin PLLA da cellulose ether, kuma sassan biyu a cikin tsarin sun dace da wani bangare. Ragewar PLLA/cellulose ether rabo yana haifar da raguwa a cikin ma'anar narkewa, crystallinity, da mutuncin kristal na PLLA a cikin haɗakarwa, wanda ya haifar da shirye-shiryen haɗuwa na nau'in crystallinity daban-daban. Sabili da haka, ana iya amfani da ether cellulose don gyara poly-L-lactic acid, wanda zai haɗu da kyakkyawan aiki na polylactic acid da ƙananan farashin ether cellulose, wanda zai dace da shirye-shiryen cikakkun kayan aikin polymer na biodegradable.
Lokacin aikawa: Janairu-13-2023