IHydroxypropyl methylcellulose (HPMC) iyinhlanganisela ebalulekile ye-semi-synthetic cellulose ether, esetshenziswa kakhulu kwezokwelapha, izinto zokwakha, ukudla, okokugqoka kanye nezinye izimboni. I-HPMC inokuqina okuhle, i-emulsification, ukwenza ifilimu, ukuthambisa, ukuqiniswa kanye nezinye izakhiwo, ngakho-ke inenani elibalulekile lesicelo emikhakheni eminingi. Izinto zokusetshenziswa eziyinhloko zokukhiqiza i-HPMC zihlanganisa i-cellulose, i-sodium hydroxide, i-propylene oxide, i-methyl chloride namanzi.
1. I-Cellulose
I-Cellulose iyimpahla eyisisekelo eyinhloko ye-HPMC, ngokuvamile etholakala emicu yezitshalo yemvelo efana ukotini nokhuni. I-Cellulose iyi-polymer yemvelo etholakala kakhulu emhlabeni. Ukwakheka kwayo kwamangqamuzana kuyi-polysaccharide enochungechunge olude eyakhiwe amayunithi eglucose axhunywe ngamabhondi e-β-1,4-glycosidic. I-Cellulose ngokwayo ayincibiliki emanzini futhi ayinakho ukusebenza kahle kwamakhemikhali. Ngakho-ke, uchungechunge lwezinqubo zokuguqulwa kwamakhemikhali luyadingeka ukuze kuthuthukiswe ukunyibilika nokusebenza kwalo ukuze kulungiswe imikhiqizo ehlukahlukene ye-cellulose ether.
2. I-sodium hydroxide (NaOH)
I-sodium hydroxide, eyaziwa nangokuthi i-caustic soda, iyinhlanganisela ye-alkaline eqinile edlala indima ebalulekile njenge-alkalizer enqubweni yokukhiqiza ye-HPMC. Esigabeni sokuqala sokukhiqiza, i-cellulose ihlangana nesisombululo se-sodium hydroxide ukuze ivule amaqembu e-hydroxyl ochungechungeni lwengqamuzana ye-cellulose, ngaleyo ndlela inikeze amasayithi okusabela kokusabela kwe-etherification okulandelayo. Lesi sinyathelo sibizwa nangokuthi "ukusabela kwe-alkalization". I-alkalized cellulose ibhekana nezinguquko ezithile zesakhiwo, okwenza kube lula ukusabela ngama-reagents amakhemikhali alandelayo (afana ne-propylene oxide ne-methyl chloride).
3. I-Propylene oxide (C3H6O)
I-Propylene oxide ingenye yezinto ezibalulekile etherifying ekukhiqizweni kwe-HPMC, esetshenziswa kakhulu ukuguqula amaqembu e-hydroxyl ku-cellulose abe amaqembu e-hydroxypropyl. Ngokukhethekile, i-alkalized cellulose ihlangana ne-propylene oxide ngaphansi kwezimo ezithile zokushisa nengcindezi, futhi amaqembu e-epoxy asebenzayo ku-propylene oxide axhunywe ochungechungeni lwamangqamuzana e-cellulose ngokusabela okungeziwe okuvula indandatho ukuze akhe into ebambele i-hydroxypropyl. Le nqubo inika i-HPMC ukuncibilika okuhle kwamanzi kanye nekhono lokujiya.
4. I-Methyl chloride (CH3Cl)
I-Methyl chloride ingenye i-etherifying agent ebalulekile esetshenziselwa ukuguqula amaqembu e-hydroxyl we-cellulose abe amaqembu e-methoxyl. I-Methyl chloride ihlangana namaqembu e-hydroxyl kuketango lamangqamuzana e-cellulose ngokusabela kwe-nucleophilic esikhundleni sokukhiqiza i-methyl cellulose. Ngalokhu kusabela kwe-methylation, i-HPMC ithola i-hydrophobicity enhle, ikakhulukazi ekhombisa ukuncibilika okuhle kakhulu kwezinye izinyibilikisi zemvelo. Ukwengeza, ukwethulwa kwamaqembu e-methoxy kuthuthukisa ngokwengeziwe indawo yokwenza ifilimu nokuzinza kwamakhemikhali e-HPMC.
5. Amanzi
Amanzi, njengesixazululi nesisabela, asebenza kuyo yonke inqubo yokukhiqiza ye-HPMC. Ekuphenduleni kwe-alkalization kanye ne-etherification, amanzi awasizi nje kuphela ukuncibilikisa i-sodium hydroxide futhi alungise isimo se-hydration se-cellulose, kodwa futhi abambe iqhaza ekulawuleni ukushisa okusabelayo ukuze kuqinisekiswe ukulawulwa kwezinga lokushisa kuyo yonke inqubo yokusabela. Ukuhlanzeka kwamanzi kunethonya elibalulekile kwikhwalithi ye-HPMC, futhi amanzi ahlanzekile aphezulu noma amanzi ahlutshiwe ngokuvamile ayadingeka.
6. Izinyibilikisi zemvelo
Enqubweni yokukhiqiza ye-HPMC, ezinye izinyathelo zenqubo zingase futhi zidinge ukusetshenziswa kwezinye izincibilikisi eziphilayo, njenge-methanol noma i-ethanol. Lezi zincibilikisi ngezinye izikhathi zisetshenziselwa ukulungisa i-viscosity yesistimu yokusabela, ukunciphisa ukwakheka kokusabela ngemikhiqizo, noma ukukhuthaza ukusabela kwamakhemikhali okuthile. Ukukhethwa kwe-solvent ephilayo kudinga ukunqunywa ngokuya ngezidingo zenqubo yokukhiqiza kanye nokusetshenziswa komkhiqizo wokugcina.
7. Ezinye izinto ezisizayo
Ngaphezu kwalezi zinto zokusetshenziswa ezingenhla eziyinhloko, enqubweni yangempela yokukhiqiza, ezinye izinto ezisizayo nezithasiselo, njengama-catalysts, ama-stabilizer, njll., zingasetshenziswa ukuthuthukisa ukusabela kahle, ukulawula izinga lokuphendula noma ukuthuthukisa izakhiwo zomzimba namakhemikhali. yomkhiqizo wokugcina.
8. Izinyathelo eziyinhloko zenqubo yokukhiqiza
Izinyathelo eziyinhloko zenqubo yokukhiqiza i-HPMC zingahlukaniswa zibe izingxenye ezintathu: i-alkalization, i-etherification kanye nokwelashwa kokungathathi hlangothi. Okokuqala, i-cellulose ihlangana ne-sodium hydroxide ukuze i-alkalize yakhe i-alkali cellulose. Bese, i-etherification yenzeka ekuphenduleni kwe-alkali cellulose nge-propylene oxide ne-methyl chloride ukwenza i-hydroxypropyl kanye ne-methoxy esikhundleni se-cellulose ethers. Ekugcineni, ngokwelashwa kwe-neutralization, ukugeza, ukomisa nezinye izinqubo, imikhiqizo ye-HPMC ene-solubility ethize, i-viscosity nezinye izici zitholakala.
9. Umthelela wekhwalithi yezinto ezingavuthiwe ekusebenzeni kwemikhiqizo ye-HPMC
Imithombo ehlukene yezinto ezingavuthiwe nobumsulwa kunomthelela omkhulu kukhwalithi nokusebenza kwe-HPMC yokugcina. Isibonelo, ukuhlanzeka kanye nokusatshalaliswa kwesisindo samangqamuzana wezinto zokusetshenziswa kwe-cellulose kuzothinta i-viscosity kanye ne-solubility ye-HPMC; Izimo zokulinganisa nezimo zokusabela ze-propylene oxide ne-methyl chloride zizonquma izinga le-hydroxypropyl ne-methoxy substitution, ngaleyo ndlela kuthinte umphumela wokujiya kanye nezakhiwo zokwakha ifilimu zomkhiqizo. Ngakho-ke, ukukhethwa nokulawulwa kwekhwalithi yezinto ezingavuthiwe kubalulekile ngesikhathi senqubo yokukhiqiza.
Izinto zokusetshenziswa eziyinhloko ze-hydroxypropyl methylcellulose (HPMC) zihlanganisa i-cellulose, i-sodium hydroxide, i-propylene oxide, i-methyl chloride namanzi. Ngochungechunge lokusabela kwamakhemikhali okuyinkimbinkimbi, lezi zinto zokusetshenziswa ziguqulwa zibe izinto ezisebenzayo ezinenani elibanzi lokusetshenziswa. Uhla lwezicelo lwe-HPMC luhlanganisa imikhakha eminingi efana nemithi, izinto zokwakha, nokudla. Izakhiwo zayo ezinhle zomzimba namakhemikhali ziyenza ibaluleke kakhulu ezimbonini eziningi.
Isikhathi sokuthumela: Sep-30-2024