Hydroxyethyl cellulose (HEC) yog ib qho polymer uas tsis yog ionic, yaj tau hauv dej los ntawm cellulose. Nws siv dav hauv ntau yam lag luam, suav nrog cov nplaum, qhov twg nws ua haujlwm ua tus neeg sawv cev thickening, rheology modifier, thiab stabilizer. HEC lub peev xwm los txhim kho qhov viscosity ntawm cov nplaum yog qhov tseem ceeb rau ntau daim ntawv thov, xyuas kom meej tias daim ntawv thov raug, kev ua tau zoo, thiab lub neej ntev ntawm cov khoom nplaum.
Cov Khoom ntawm Hydroxyethyl Cellulose
HEC yog tsim los ntawm kev sib xyaw cellulose nrog ethylene oxide nyob rau hauv alkaline tej yam kev mob, ua rau muaj ib tug polymer nrog hydroxyethyl pawg txuas rau lub cellulose backbone. Lub degree ntawm kev hloov (DS) thiab molar hloov (MS) yog cov tseem ceeb parameters uas cuam tshuam rau cov khoom ntawm HEC. Lub DS hais txog qhov nruab nrab ntawm cov hydroxyl pawg ntawm lub cellulose molecule uas tau hloov nrog hydroxyethyl pawg, thaum lub MS qhia txog qhov nruab nrab ntawm moles ntawm ethylene oxide uas tau sib xyaw nrog ib mole ntawm anhydroglucose units hauv cellulose.
HEC yog tus cwj pwm los ntawm nws cov solubility hauv dej, tsim cov tshuaj ntshiab thiab pob tshab nrog viscosity siab. Nws cov viscosity yog cuam tshuam los ntawm ntau yam, suav nrog qhov hnyav molecular, concentration, kub, thiab pH ntawm cov tshuaj. Qhov hnyav molecular ntawm HEC tuaj yeem sib txawv ntawm qis mus rau siab heev, tso cai rau kev tsim cov nplaum nrog ntau yam viscosity xav tau.
Cov txheej txheem ntawm kev txhim kho viscosity
Kev ntub dej thiab o:
HEC ua rau cov nplaum nplaum nplaum zoo dua vim nws muaj peev xwm ua kom dej noo thiab o tuaj hauv dej. Thaum ntxiv HEC rau hauv cov kua nplaum uas muaj dej, cov pab pawg hydroxyethyl nyiam cov dej molecules, ua rau cov polymer saw o tuaj. Qhov o tuaj no ua rau cov tshuaj tsis kam ntws, yog li ua rau nws cov viscosity nce ntxiv. Qhov ntau thiab tsawg ntawm o tuaj thiab qhov viscosity tshwm sim yog cuam tshuam los ntawm qhov concentration ntawm polymer thiab qhov hnyav molecular ntawm HEC.
Kev Sib Txuas Molecular:
Hauv kev daws teeb meem, HEC polymers raug kev sib txuas vim lawv cov qauv ntev. Qhov kev sib txuas no tsim ib lub network uas cuam tshuam kev txav mus los ntawm cov molecules hauv cov nplaum, yog li ua rau cov viscosity nce ntxiv. Qhov hnyav molecular siab dua HEC ua rau muaj kev sib txuas ntau dua thiab viscosity siab dua. Qhov degree ntawm kev sib txuas tuaj yeem tswj tau los ntawm kev kho qhov concentration ntawm polymer thiab qhov hnyav molecular ntawm HEC siv.
Kev sib txuas hydrogen:
HEC tuaj yeem tsim cov hydrogen bonds nrog cov dej molecules thiab lwm yam khoom hauv cov nplaum formulation. Cov hydrogen bonds no pab txhawb rau qhov viscosity los ntawm kev tsim kom muaj lub network ntau dua hauv cov tshuaj. Cov hydroxyethyl pawg ntawm cellulose backbone txhim kho lub peev xwm los tsim cov hydrogen bonds, ntxiv rau qhov viscosity.
Kev coj cwj pwm txiav-thinning:
HEC ua rau nws txoj kev shear-thinning zoo li qub, uas txhais tau tias nws cov viscosity yuav txo qis thaum muaj kev ntxhov siab shear. Cov yam ntxwv no zoo rau kev siv cov nplaum vim nws ua rau nws yooj yim siv thaum muaj kev shear (xws li kev nthuav dav lossis txhuam) thaum tseem muaj viscosity siab thaum so, ua kom cov nplaum ua haujlwm tau zoo thiab ruaj khov. HEC txoj kev shear-thinning zoo li qub yog vim muaj kev sib dhos ntawm cov saw polymer hauv qhov kev taw qhia ntawm lub zog siv, txo qhov kev tiv thaiv sab hauv ib ntus.
Cov ntawv thov hauv cov qauv nplaum
Cov nplaum uas siv dej ua ke:
HEC siv dav hauv cov nplaum uas muaj dej, xws li cov rau ntawv, ntaub, thiab ntoo. Nws lub peev xwm los ua kom cov nplaum tuab thiab ruaj khov ua kom nws sib xyaw ua ke thiab yooj yim siv. Hauv cov nplaum ntawv thiab ntim khoom, HEC muab cov viscosity tsim nyog rau kev siv thiab lub zog sib txuas.
Cov nplaum rau kev tsim kho:
Hauv cov nplaum rau kev tsim kho, xws li cov uas siv rau kev teeb tsa pobzeb lossis phab ntsa, HEC ua rau kom cov nplaum nplaum nplaum zoo dua, ua rau cov nplaum nplaum ua haujlwm tau zoo thiab tiv taus kev sag. Qhov kev ua kom tuab ntawm HEC ua kom cov nplaum nplaum nyob hauv qhov chaw thaum lub sijhawm thov thiab teeb tsa kom raug, muab kev sib txuas ruaj khov thiab ruaj khov.
Cov nplaum rau kev kho kom zoo nkauj thiab kev saib xyuas tus kheej:
HEC kuj tseem siv rau hauv cov khoom siv pleev kom zoo nkauj thiab cov khoom siv tu tus kheej uas xav tau cov khoom nplaum, xws li hauv cov tshuaj pleev plaub hau thiab cov ntaub npog ntsej muag. Hauv cov ntawv thov no, HEC muab kev sib xws thiab sib xws, txhim kho cov khoom ua tau zoo thiab kev paub ntawm tus neeg siv.
Cov Tshuaj Nplaum:
Hauv kev lag luam tshuaj, HEC siv rau hauv cov thaj ua rau daim tawv nqaij thiab lwm yam kev xa tshuaj uas qhov kev tswj hwm viscosity yog qhov tseem ceeb rau kev ua haujlwm ntawm cov nplaum. HEC ua kom ntseeg tau tias cov txheej nplaum yog sib xws, muab kev xa tshuaj tas mus li thiab kev ua raws li daim tawv nqaij.
Cov Yam Cuam Tshuam Rau Kev Txhim Kho Viscosity
Kev Ntsuas:
Qhov concentration ntawm HEC hauv cov kua nplaum yog sib npaug ncaj qha rau qhov viscosity. Cov concentration siab dua ntawm HEC ua rau muaj viscosity ntau dua vim muaj kev sib cuam tshuam ntawm cov saw polymer thiab kev sib koom ua ke. Txawm li cas los xij, cov concentration siab dhau heev tuaj yeem ua rau gelation thiab nyuaj rau kev ua.
Qhov Hnyav Molecular:
Qhov hnyav molecular ntawm HEC yog ib qho tseem ceeb hauv kev txiav txim siab qhov viscosity ntawm cov nplaum. Qhov hnyav molecular siab dua HEC muab viscosity siab dua ntawm cov concentration qis dua piv rau qhov hnyav molecular qis dua. Kev xaiv ntawm qhov hnyav molecular nyob ntawm qhov xav tau viscosity thiab daim ntawv thov xav tau.
Kub:
Kub cuam tshuam rau qhov viscosity ntawm HEC cov kua. Thaum kub nce, qhov viscosity feem ntau txo qis vim yog qhov txo qis hauv hydrogen bonding thiab nce molecular mobility. Kev nkag siab txog qhov kub thiab viscosity kev sib raug zoo yog qhov tseem ceeb rau cov ntawv thov uas raug rau ntau yam kub.
pH:
Qhov pH ntawm cov kua nplaum tuaj yeem cuam tshuam rau qhov viscosity ntawm HEC. HEC ruaj khov rau ntau qhov pH, tab sis cov xwm txheej pH siab heev tuaj yeem ua rau muaj kev hloov pauv hauv cov qauv polymer thiab viscosity. Kev tsim cov kua nplaum hauv qhov pH zoo tshaj plaws ua kom muaj kev ua haujlwm zoo sib xws.
Cov txiaj ntsig ntawm kev siv Hydroxyethyl Cellulose
Xwm txheej tsis yog Ionic:
Qhov xwm txheej tsis yog-ionic ntawm HEC ua rau nws sib xws nrog ntau yam ntawm lwm cov khoom sib xyaw, suav nrog lwm cov polymers, surfactants, thiab electrolytes. Qhov kev sib xws no tso cai rau ntau yam nplaum formulations.
Kev puas tsuaj ntawm cov tsiaj txhu:
HEC yog los ntawm cellulose, ib yam khoom siv ntuj tsim thiab rov ua dua tshiab. Nws yog biodegradable, ua rau nws yog ib qho kev xaiv zoo rau ib puag ncig rau cov khoom siv nplaum. Nws siv raws li qhov kev thov loj hlob rau cov khoom lag luam ruaj khov thiab zoo rau ib puag ncig.
Kev Ruaj Ntseg:
HEC muab kev ruaj khov zoo heev rau cov qauv nplaum, tiv thaiv kev sib cais theem thiab kev sib sau ua ke ntawm cov khoom khov. Qhov kev ruaj khov no ua kom cov nplaum tseem siv tau zoo thoob plaws nws lub neej txee thiab thaum lub sijhawm thov.
Cov Khoom Siv Ua Yeeb Yaj Kiab:
HEC tsim cov yeeb yaj kiab uas yooj ywm thiab pob tshab thaum ziab, uas yog qhov zoo rau cov ntawv thov nplaum uas xav tau cov kab sib txuas meej thiab yooj ywm. Cov cuab yeej no yog qhov tshwj xeeb tshaj yog rau cov ntawv thov xws li cov ntawv lo thiab cov kab xev.
Hydroxyethyl cellulose ua lub luag haujlwm tseem ceeb hauv kev txhim kho qhov viscosity ntawm cov nplaum los ntawm cov txheej txheem xws li hydration thiab o, molecular entanglement, hydrogen bonding, thiab shear-thinning behavior. Nws cov khoom, suav nrog solubility, non-ionic xwm, biodegradability, thiab zaj duab xis-tsim peev xwm, ua rau nws yog qhov kev xaiv zoo tshaj plaws rau ntau yam kev siv nplaum. Kev nkag siab txog cov yam ntxwv uas cuam tshuam rau HEC qhov viscosity txhim kho, xws li concentration, molecular hnyav, kub, thiab pH, tso cai rau cov formulators los kho cov khoom nplaum kom ua tau raws li cov kev xav tau kev ua tau zoo tshwj xeeb. Raws li kev lag luam txuas ntxiv nrhiav cov ntaub ntawv ruaj khov thiab ua tau zoo, HEC tseem yog ib qho tseem ceeb hauv kev tsim cov khoom nplaum siab heev.
Lub sijhawm tshaj tawm: Tsib Hlis-29-2024