Cellulose inonzi polysaccharide yakaoma inoumbwa nezvikamu zvakawanda zveglucose zvakabatanidzwa ne β-1,4-glycosidic bonds. Ndicho chikamu chikuru chechirimwa masero madziro uye inopa chirimwa masero madziro akasimba erutsigiro uye kuoma. Nekuda kweiyo refu cellulose molecular chain uye yakakwirira crystallinity, ine yakasimba kugadzikana uye insolubleness.
(1) Zvimiro zve cellulose uye kuoma mukunyungudika
Cellulose ine zvinotevera zvivakwa zvinoita kuti zviome kunyungudika:
High crystallinity: Iyo cellulose molecular cheni inogadzira yakaomeswa retisi chimiro kuburikidza nehydrogen bond uye van der Waals masimba.
High degree yepolymerization: Chiyero chepolymerization (kureva kureba kwema molecular chain) ye cellulose yakakwirira, kazhinji kubva kumazana kusvika kuzviuru zvemayuniti eglucose, izvo zvinowedzera kugadzikana kwemorekuru.
Hydrogen bond network: Hydrogen bond dziripo zvakanyanya pakati uye mukati me cellulose molecular cheni, zvichiita kuti zviome kuparadzwa nekunyungudutswa nezvinonyungudutsa.
(2) Zvigadzirwa zvinonyungudutsa cellulose
Parizvino, mareagents anozivikanwa anogona kunyatso kunyungudutsa cellulose anosanganisira anotevera mapoka:
1. Ionic Liquids
Ionic zvinwiwa zvinwiwa zvinoumbwa neorganic cations uye organic kana inorganic anions, kazhinji ine kuderera kuderera, kusimba kwekushisa kwakanyanya uye kurongeka kwakanyanya. Zvimwe zvinwiwa zveionic zvinogona kunyungudutsa cellulose, uye nzira huru ndeyekutyora zvisungo zvehydrogen pakati pe cellulose molecular cheni. Yakajairika ionic zvinwiwa zvinonyungudutsa cellulose zvinosanganisira:
1-Butyl-3-methylimidazolium chloride ([BMIM]Cl): Iyi ionic liquid inonyungudutsa cellulose nekubatana nehydrogen bond mu cellulose kuburikidza nehydrogen bond vanogamuchira.
1-Ethyl-3-methylimidazolium acetate ([EMIM][Ac]): Iyi ionic fluid inogona kunyungudutsa huwandu hweselulosi pasi pemamiriro akapfava.
2. Amine oxidant solution
Amine oxidant solution yakadai semusanganiswa wemhinduro ye diethylamine (DEA) uye copper chloride inonzi [Cu(II)-ammonium solution], inova yakasimba solvent system inogona kunyungudutsa cellulose. Inoparadza chimiro chekristaro che cellulose kuburikidza neoxidation uye hydrogen bonding, zvichiita kuti cellulose molecular cheni ipfave uye inyungudika.
3. Lithium chloride-dimethylacetamide (LiCl-DMAC) system
Iyo LiCl-DMAc (lithium chloride-dimethylacetamide) system ndiyo imwe yenzira dzekare dzekunyungudutsa cellulose. LiCl inogona kuumba makwikwi ehydrogen bond, nekudaro ichiparadza iyo hydrogen bond network pakati pe cellulose mamorekuru, nepo DMAc sechinhu chinonyungudutsa chinogona kudyidzana zvakanaka ne cellulose molecular chain.
4. Hydrochloric acid / zinc chloride solution
Iyo hydrochloric acid/zinc chloride mhinduro ndiyo yekutanga kuwanikwa reagent inogona kunyungudutsa cellulose. Inogona kunyungudutsa cellulose nekugadzira kubatanidza mhedzisiro pakati pezinc chloride uye cellulose molecular cheni, uye hydrochloric acid ichiparadza iyo hydrogen zvisungo pakati pe cellulose mamorekuru. Nekudaro, iyi mhinduro inoshatisa zvakanyanya kumidziyo uye inogumira mumashandisirwo anoshanda.
5. Fibrinolytic enzymes
Fibrinolytic enzymes (senge cellulases) inonyungudutsa cellulose nekugadzirisa kuparara kwe cellulose kuita madiki oligosaccharides uye monosaccharides. Iyi nzira ine huwandu hwakawanda hwemashandisirwo muminda ye biodegradation uye biomass kutendeuka, kunyangwe iyo nzira yekuparara isiri zvachose kuparara kwemakemikari, asi inowanikwa kuburikidza ne biocatalysis.
(3) Mechanism yekuparara kwe cellulose
Mareagents akasiyana ane nzira dzakasiyana dzekunyungudutsa cellulose, asi kazhinji anogona kuverengerwa kune maviri makuru masisitimu:
Kuparadza kwehydrogen bond: Kuparadza ma hydrogen bond pakati pe cellulose molecular cheni kuburikidza nemakwikwi ehydrogen bond kuumbwa kana ionic kupindirana, zvichiita kuti inyungudika.
Molecular chain relaxation: Kuwedzera kupfava kwe cellulose molecular cheni uye kuderedza crystallinity yemamorekuru cheni kuburikidza nemuviri kana makemikari nzira, kuitira kuti igone kunyungudutswa mune zvinonyungudutsa.
(4) Kushanda kwekushandisa kwe cellulose kupera
Cellulose dissolution ine yakakosha maapplication mundima dzakawanda:
Kugadzirira kwe cellulose derivatives: Mushure mekunyungudutsa cellulose, inogona kuwedzeredzwa kemikari kugadzirira cellulose ethers, cellulose esters uye zvimwe zvinobva, izvo zvinoshandiswa zvakanyanya mukudya, mushonga, machira uye mamwe minda.
Cellulose-based materials: Kushandisa yakanyungudutswa cellulose, cellulose nanofibers, cellulose membranes uye zvimwe zvinhu zvinogona kugadzirwa. Zvishandiso izvi zvine hunhu hwakanaka hwemagetsi uye biocompatibility.
Biomass simba: Nekunyungudutsa uye kushatisa cellulose, inogona kushandurwa kuita shuga inoviriswa yekugadzirwa kwebiofuels senge bioethanol, iyo inobatsira kuzadzisa kusimudzira uye kushandiswa kwesimba rinogoneka.
Cellulose dissolution inzira yakaoma inosanganisira akawanda makemikari uye emuviri maitiro. Ionic zvinwiwa, amino oxidant mhinduro, LiCl-DMAc masisitimu, hydrochloric acid/zinc chloride mhinduro uye cellolytic enzymes parizvino inozivikanwa seanoshanda amiririri ekunyungudutsa cellulose. Mumwe nemumwe mumiriri ane yake yakasarudzika yekumisa meshini uye nzvimbo yekushandisa. Nekudzidza kwakadzama kweiyo cellulose dissolution mechanism, zvinotendwa kuti nzira dzakanyanya kushanda uye dzine hushamwari dzekuparadza dzichagadzirwa, zvichipa mikana yakawanda yekushandiswa nekuvandudza cellulose.
Nguva yekutumira: Jul-09-2024