Cellulose ndi polysaccharide yovuta kwambiri yopangidwa ndi mayunitsi ambiri a shuga olumikizidwa ndi ma bond a β-1,4-glycosidic. Ndi gawo lalikulu la makoma a maselo a zomera ndipo limapatsa makoma a maselo a zomera chithandizo champhamvu komanso kulimba. Chifukwa cha unyolo wautali wa maselo a cellulose ndi crystallinity yayikulu, imakhala yolimba komanso yosasungunuka.
(1) Kakhalidwe ka cellulose ndi kuvutika kusungunuka
Cellulose ili ndi zinthu zotsatirazi zomwe zimapangitsa kuti zikhale zovuta kusungunuka:
Kuchuluka kwa kristalo: Ma unyolo a ma cellulose amapanga kapangidwe kolimba ka lattice kudzera mu ma hydrogen bonds ndi mphamvu za van der Waals.
Mlingo wapamwamba wa polymerization: Mlingo wa polymerization (monga kutalika kwa unyolo wa molekyulu) wa cellulose ndi wokwera, nthawi zambiri umakhala kuyambira mazana ambiri mpaka zikwizikwi za mayunitsi a shuga, zomwe zimawonjezera kukhazikika kwa molekyulu.
Netiweki ya ma hydrogen bond: Ma hydrogen bond amapezeka kwambiri pakati ndi mkati mwa ma cellulose molecular chains, zomwe zimapangitsa kuti zikhale zovuta kuwononga ndi kusungunula ndi ma solvents wamba.
(2) Zinthu zoyeretsera zomwe zimasungunula cellulose
Pakadali pano, ma reagents odziwika bwino omwe amatha kusungunula bwino cellulose makamaka akuphatikizapo magulu awa:
1. Zakumwa za Ionic
Madzi a Ionic ndi madzi opangidwa ndi ma organic cations ndi ma anion achilengedwe kapena osapangidwa, nthawi zambiri amakhala ndi kusinthasintha kochepa, kutentha kwambiri komanso kusinthasintha kwakukulu. Madzi ena a Ionic amatha kusungunula cellulose, ndipo njira yayikulu ndikuswa ma hydrogen bonds pakati pa ma cellulose molecular chains. Madzi wamba a Ionic omwe amasungunula cellulose ndi awa:
1-Butyl-3-methylimidazolium chloride ([BMIM]Cl): Madzi a ionic awa amasungunula cellulose mwa kuyanjana ndi ma hydrogen bonds mu cellulose kudzera mu ma hydrogen bond acceptors.
1-Ethyl-3-methylimidazolium acetate ([EMIM][Ac]): Madzi a ionic awa amatha kusungunula kuchuluka kwa cellulose m'malo ofatsa.
2. Yankho la okosijeni la amine
Njira yothetsera oxidant ya amine monga njira yosakanikirana ya diethylamine (DEA) ndi copper chloride imatchedwa [Cu(II)-ammonium solution], yomwe ndi njira yolimba yosungunulira yomwe imatha kusungunula cellulose. Imawononga kapangidwe ka kristalo ka cellulose kudzera mu okosijeni ndi hydrogen bonding, zomwe zimapangitsa kuti cellulose molecular chain ikhale yofewa komanso yosungunuka kwambiri.
3. Dongosolo la Lithium chloride-dimethylacetamide (LiCl-DMac)
Dongosolo la LiCl-DMAc (lithium chloride-dimethylacetamide) ndi njira imodzi yakale yosungunula cellulose. LiCl imatha kupanga mpikisano wa ma hydrogen bond, motero kuwononga netiweki ya hydrogen bond pakati pa mamolekyulu a cellulose, pomwe DMac ngati solvent imatha kuyanjana bwino ndi cellulose molecular chain.
4. Hydrochloric acid/zinc chloride yankho
Mankhwala a hydrochloric acid/zinc chloride ndi mankhwala opangidwa kale omwe amatha kusungunula cellulose. Amatha kusungunula cellulose mwa kupanga mgwirizano pakati pa zinc chloride ndi cellulose molecular chains, ndipo hydrochloric acid imawononga ma hydrogen bonds pakati pa ma cellulose molecules. Komabe, mankhwalawa ndi owononga kwambiri zida ndipo amagwiritsidwa ntchito mochepa.
5. Ma enzyme a Fibrinolytic
Ma enzyme a Fibrinolytic (monga ma cellulase) amasungunula cellulose mwa kuyambitsa kugawikana kwa cellulose kukhala ma oligosaccharide ang'onoang'ono ndi ma monosaccharide. Njirayi imagwiritsidwa ntchito kwambiri m'magawo a biodegradation ndi biomass conversion, ngakhale kuti njira yake yosungunula si yosungunula kwathunthu mankhwala, koma imachitika kudzera mu biocatalysis.
(3) Njira yosungunula maselo a cellulose
Ma reagents osiyanasiyana ali ndi njira zosiyanasiyana zosungunulira cellulose, koma kawirikawiri amatha kufotokozedwa ndi njira ziwiri zazikulu:
Kuwonongeka kwa ma bond a haidrojeni: Kuwononga ma bond a haidrojeni pakati pa ma cellulose molecular chains kudzera mu mpikisano wa hydrogen bond kapena ionic interaction, zomwe zimapangitsa kuti zisasungunuke.
Kupumula kwa unyolo wa mamolekyu: Kuonjezera kufewa kwa unyolo wa mamolekyu wa cellulose ndikuchepetsa kunyezimira kwa unyolo wa mamolekyu kudzera munjira zakuthupi kapena zamankhwala, kuti athe kusungunuka mu zosungunulira.
(4) Kugwiritsa ntchito bwino kwa kusungunuka kwa cellulose
Kusungunuka kwa cellulose kumagwiritsidwa ntchito kwambiri m'magawo ambiri:
Kukonzekera zinthu zochokera ku cellulose: Pambuyo posungunuka cellulose, ikhoza kusinthidwanso ndi mankhwala kuti ikonze ma ether a cellulose, ma ester a cellulose ndi zinthu zina zochokera ku cellulose, zomwe zimagwiritsidwa ntchito kwambiri mu chakudya, mankhwala, zokutira ndi zina.
Zipangizo zopangidwa ndi cellulose: Pogwiritsa ntchito cellulose yosungunuka, ma cellulose nanofibers, cellulose membranes ndi zinthu zina zitha kukonzedwa. Zipangizozi zili ndi mphamvu zabwino zamakaniko komanso zimagwirizana ndi zinthu zina.
Mphamvu ya biomass: Mwa kusungunula ndi kuwononga cellulose, imatha kusinthidwa kukhala shuga wokhuthala popanga biofuels monga bioethanol, zomwe zimathandiza kupanga ndi kugwiritsa ntchito mphamvu zongowonjezwdwanso.
Kusungunuka kwa cellulose ndi njira yovuta yokhudzana ndi njira zosiyanasiyana zamakemikolo ndi zakuthupi. Madzi a Ionic, mayankho a amino oxidant, machitidwe a LiCl-DMAc, mayankho a hydrochloric acid/zinc chloride ndi ma enzyme a cellolytic pakadali pano amadziwika kuti ndi othandiza pakusungunula cellulose. Chothandizira chilichonse chili ndi njira yakeyake yosungunula komanso malo ogwiritsira ntchito. Ndi kafukufuku wozama wa njira yosungunula cellulose, akukhulupirira kuti njira zosungunula zogwira mtima komanso zosawononga chilengedwe zidzapangidwa, zomwe zipereka mwayi wochulukirapo wogwiritsira ntchito ndikukula kwa cellulose.
Nthawi yotumizira: Julayi-09-2024