Hydroxyethyl cellulose (HEC) thiab hydroxypropyl cellulose (HPC) yog ob hom cellulose derivatives uas tau siv dav hauv ntau qhov chaw lag luam, xws li tshuaj, tshuaj pleev ib ce, zaub mov, thiab khoom siv hauv tsev. Txawm hais tias lawv cov qauv tshuaj zoo sib xws thiab tsim los ntawm kev qhia cov khoom hloov pauv ntawm cellulose molecules, lawv muaj qhov sib txawv ntawm cov khoom siv tshuaj, lub cev, thiab daim ntawv thov.
1. Qhov sib txawv ntawm cov qauv tshuaj
Hydroxyethyl cellulose (HEC) yog tsim los ntawm kev qhia ib pab pawg hydroxyethyl (-CH₂CH₂OH) mus rau hauv lub nplhaib ntawm cov cellulose molecule. Nws cov qauv tshuaj muaj ntau ntawm hydroxyethyl substituents, uas ua rau HEC muaj dej solubility zoo thiab thickening zog.
Hydroxypropyl cellulose (HPC) qhia ib pawg hydroxypropyl (-CH₂CHOHCH₃) rau hauv cov cellulose molecule. Vim muaj cov pab pawg hydroxypropyl no, HPC nthuav tawm qee cov yam ntxwv uas txawv ntawm HEC. Piv txwv li, nws muaj ib qho kev kawm ntawm hydrophobicity, uas ua rau nws soluble nyob rau hauv tej yam organic solvents, xws li ethanol, isopropyl cawv, thiab lwm yam.
2. Solubility sib txawv
Ib qho tseem ceeb ntawm HEC yog nws cov dej solubility zoo, tshwj xeeb tshaj yog nyob rau hauv dej txias. Vim yog kev qhia txog cov pab pawg hydroxyethyl, HEC tuaj yeem tsim hydrogen bonds nrog dej molecules thaum yaj, yog li sai sai dispersing thiab dissolving. Yog li ntawd, HEC muaj ntau yam kev siv hauv cov txheej txheem dej, xws li cov txheej txheem dej, cov nplaum, cov tshuaj ntxuav tes, thiab lwm yam.
Lub solubility ntawm HPC yog qhov nyuaj. Lub solubility ntawm HPC nyob rau hauv dej yog heev cuam tshuam los ntawm kub. Nws muaj qhov zoo solubility ntawm qhov kub thiab txias, tab sis gelation lossis nag lossis daus tuaj yeem tshwm sim ntawm qhov kub thiab txias. Nyob rau tib lub sijhawm, HPC kuj tseem muaj cov kuab tshuaj hauv cov kuab tshuaj organic (xws li ethanol, isopropyl cawv, thiab lwm yam), uas muab cov txiaj ntsig zoo hauv qee cov ntawv thov tshwj xeeb, xws li cov organic solvent-based formulations thiab qee cov tshuaj npaj.
3. Qhov sib txawv ntawm cov nyhuv thickening thiab rheology
HEC muaj peev xwm thickening zoo thiab muaj peev xwm ua kom cov viscosity ntawm cov tshuaj nyob rau hauv aqueous tov, yog li nws yog feem ntau siv raws li ib tug thickener, stabilizer thiab gelling neeg sawv cev. Cov nyhuv thickening ntawm HEC cuam tshuam los ntawm qhov hnyav molecular thiab qib ntawm kev hloov pauv. Qhov loj dua qhov hnyav molecular thiab siab dua qhov kev hloov pauv, qhov ntau dua qhov viscosity ntawm cov tshuaj. Nyob rau tib lub sijhawm, tus cwj pwm rheological ntawm HEC cov kev daws teeb meem yog pseudoplastic, uas yog, raws li tus nqi shear nce, cov viscosity ntawm cov tshuaj txo qis, uas yog qhov zoo heev rau cov formulations uas yuav tsum tau stability thiab zoo flowability.
Cov nyhuv thickening ntawm HPC kuj tsis muaj zog, tab sis vim nws cov qauv molecular yam ntxwv, nws cov kev daws teeb meem qhia txawv rheological zog. HPC cov kev daws teeb meem feem ntau muaj Newtonian kua zog, uas yog, cov tshuaj viscosity yog ywj siab ntawm shear npaum li cas, uas yog ib qho tseem ceeb heev nyob rau hauv tej daim ntawv thov uas yuav tsum tau uniform viscosity. Tsis tas li ntawd, HPC kuj muaj cov yeeb yaj kiab zoo, uas ua rau nws siv dav hauv kev lag luam xws li tshuaj thiab txheej txheej.
4. Kev ruaj ntseg thiab tshuaj tiv thaiv
HEC qhia tau hais tias muaj tshuaj lom neeg ruaj khov nyob rau hauv cov nqi pH sib txawv thiab feem ntau tuaj yeem ua haujlwm ruaj khov hauv pH ntau ntawm 2 txog 12. Yog li ntawd, HEC yog tsim rau siv nyob rau hauv acidic thiab alkaline tej yam kev mob thiab yog dav siv nyob rau hauv detergents, tshuaj pleev ib ce thiab lwm yam teb.
Txawm hais tias HPC muaj kev ruaj ntseg zoo, nws hloov tau rau pH tus nqi yog me ntsis nqaim, thiab nws yog feem ntau haum rau nruab nrab lossis tsis muaj zog acidic ib puag ncig. Hauv qee qhov xwm txheej uas yuav tsum tau tsim cov yeeb yaj kiab lossis hydrophobicity, HPC tuaj yeem muab kev ua tau zoo heev vim nws cov qauv tshwj xeeb, xws li cov khoom tso tawm los yog txheej txheej rau cov tshuaj.
5. Qhov txawv ntawm daim ntawv thov teb
Daim ntawv thov teb ntawm HEC feem ntau suav nrog:
Cov ntaub ntawv siv: Raws li cov thickener thiab gelling tus neeg sawv cev, HEC yog dav siv nyob rau hauv cov ntaub ntawv cement-based, coatings thiab siv mortars los pab txhim kho kev tsim kho thiab dej tsis kam.
Coatings thiab xim: HEC yog siv rau hauv cov dej-raws li txheej txheej kom thicken, suspend, disperse thiab stabilize, yog li txhim kho cov txheej txheem siv thiab zoo li.
Cov khoom siv tshuaj lom neeg txhua hnub: Hauv cov khoom siv tshuaj niaj hnub xws li tshuaj ntxuav tes thiab tshuaj zawv plaub hau, HEC ua haujlwm ua kom tuab thiab stabilizer, uas tuaj yeem txhim kho kev ntxhib los mos thiab kev siv ntawm cov khoom.
Cov cheeb tsam tseem ceeb ntawm HPC suav nrog:
Pharmaceutical teb: HPC feem ntau yog siv los ua cov khoom siv txheej thiab kev npaj tawm-tso tawm rau cov tshuaj vim nws cov yeeb yaj kiab zoo tshaj plaws thiab kev tso tawm zoo. Tsis tas li ntawd, nws kuj muaj cov ntawv thov tseem ceeb hauv cov ntsiav tshuaj binders.
Khoom noj khoom haus thiab tshuaj pleev ib ce: HPC yog siv los ua cov thickener thiab emulsifier hauv kev lag luam khoom noj khoom haus, thiab ua tus neeg ua yeeb yaj kiab hauv cov tshuaj pleev ib ce los pab txhim kho kev ntxhib los mos thiab ductility ntawm cov khoom.
Txheej thiab Inks: Vim nws solubility thiab zaj duab xis-tsim zog, HPC feem ntau yog siv nyob rau hauv txheej thiab number case formulation uas yuav tsum tau organic solvents, muab cov zaj duab xis du txheej thiab zoo flowability.
6. Kev tiv thaiv ib puag ncig thiab kev nyab xeeb
Ob leeg HEC thiab HPC yog suav tias yog cov khoom siv nyab xeeb rau tib neeg lub cev thiab ib puag ncig thiab tau siv dav hauv cov khoom uas xav tau kev sib cuag nrog tib neeg lub cev, xws li tshuaj pleev ib ce thiab tshuaj. Txawm li cas los xij, HPC yog soluble hauv qee cov kuab tshuaj organic, uas yuav ua rau muaj teeb meem rau cov ntawv thov nrog ib puag ncig siab dua, thaum HEC feem ntau yog siv hauv cov dej-soluble formulations, yog li nws yooj yim dua kom tau raws li cov kev cai ntawm ib puag ncig ntsuab.
Hydroxyethyl cellulose (HEC) thiab hydroxypropyl cellulose (HPC), raws li cellulose derivatives, muaj qhov zoo sib xws hauv cov qauv tshuaj, solubility, thickening nyhuv, rheological zog, daim ntawv thov teb thiab ib puag ncig tiv thaiv zog. Muaj qhov sib txawv tseem ceeb hauv qhov. Vim nws cov dej zoo heev solubility thiab thickening zog, HEC yog dav siv nyob rau hauv dej-raws li formulations, xws li coatings, tsev cov ntaub ntawv thiab cov khoom siv tshuaj txhua hnub. HPC muaj cov ntawv thov tshwj xeeb hauv cov tshuaj, khoom noj thiab qee cov txheej txheem tshwj xeeb vim nws cov dej solubility, kev tsim cov yeeb yaj kiab thiab cov khoom tso tawm. Kev xaiv ntawm cov cellulose derivative siv feem ntau yog nyob ntawm cov kev xav tau tshwj xeeb ntawm daim ntawv thov thiab cov qauv tsim.
Post lub sij hawm: Oct-29-2024