Hydroxyethyl cellulose (HEC) yog non-ionic, dej-soluble polymer muab los ntawm cellulose. Nws yog dav siv nyob rau hauv ntau yam lag luam, nrog rau cov nplaum, qhov twg nws ua hauj lwm raws li ib tug thickening neeg sawv cev, rheology modifier, thiab stabilizer. HEC lub peev xwm los txhim kho cov viscosity ntawm cov nplaum yog qhov tseem ceeb rau ntau daim ntawv thov, ua kom cov ntawv thov kom raug, kev ua tau zoo, thiab lub neej ntev ntawm cov khoom nplaum.
Cov khoom ntawm Hydroxyethyl Cellulose
HEC yog tsim los ntawm reacting cellulose nrog ethylene oxide nyob rau hauv alkaline tej yam kev mob, ua rau ib tug polymer nrog hydroxyethyl pawg txuas mus rau lub cellulose qaum. Qhov degree ntawm kev hloov pauv (DS) thiab molar hloov pauv (MS) yog qhov tseem ceeb ntawm cov khoom ntawm HEC. DS hais txog qhov nruab nrab ntawm cov pawg hydroxyl ntawm cov cellulose molecule uas tau hloov nrog hydroxyethyl pawg, thaum MS qhia qhov nruab nrab ntawm cov moles ntawm ethylene oxide uas tau hnov mob nrog ib mole ntawm anhydroglucose units hauv cellulose.
HEC yog tus cwj pwm los ntawm nws cov solubility hauv dej, tsim cov kev daws teeb meem meej thiab pob tshab nrog cov viscosity siab. Nws viscosity yog cuam tshuam los ntawm ntau yam, nrog rau qhov hnyav molecular, concentration, kub, thiab pH ntawm cov tshuaj. Qhov hnyav molecular ntawm HEC tuaj yeem nyob ntawm qhov qis mus rau siab heev, tso cai rau kev tsim cov nplaum nrog ntau qhov kev xav tau viscosity.
Mechanisms ntawm Viscosity Enhancement
Hydration thiab o:
HEC txhim kho cov nplaum viscosity feem ntau los ntawm nws lub peev xwm los hydrate thiab o hauv dej. Thaum HEC tau ntxiv rau cov txheej txheem aqueous adhesive, pawg hydroxyethyl nyiam cov dej molecules, ua rau o ntawm cov saw hlau polymer. Qhov no o ua rau cov tshuaj tiv thaiv kom ntws, yog li ua rau nws cov viscosity nce. Qhov ntev ntawm qhov o thiab qhov tshwm sim viscosity yog cuam tshuam los ntawm polymer concentration thiab molecular hnyav ntawm HEC.
Molecular Entanglement:
Hauv kev daws teeb meem, HEC polymers raug cuam tshuam vim lawv cov qauv txuas ntev. Qhov no entanglement tsim ib lub network uas impedes lub zog ntawm molecules nyob rau hauv lub nplaum, yog li ua rau viscosity. Kev hnyav dua molecular HEC ua rau muaj kev cuam tshuam ntau dua thiab muaj viscosity ntau dua. Lub degree ntawm entanglement tuaj yeem tswj tau los ntawm kev kho cov polymer concentration thiab qhov hnyav molecular ntawm HEC siv.
Hydrogen Bonding:
HEC tuaj yeem tsim cov ntawv cog lus hydrogen nrog cov dej molecules thiab lwm yam khoom hauv daim ntawv nplaum. Cov ntawv cog lus hydrogen no ua rau muaj viscosity los ntawm kev tsim kom muaj kev sib koom ua ke hauv kev daws teeb meem. Cov pab pawg hydroxyethyl ntawm cov pob txha cellulose txhim kho lub peev xwm los tsim cov ntawv cog lus hydrogen, ntxiv rau qhov viscosity.
Shear-Thinning Behavior:
HEC nthuav tawm tus cwj pwm shear-thinning, txhais tau tias nws cov viscosity txo qis hauv kev ntxhov siab. Cov cuab yeej no muaj txiaj ntsig zoo hauv cov ntawv nplaum vim tias nws tso cai rau daim ntawv thov yooj yim hauv qab shear (xws li kev sib kis lossis txhuam) thaum tuav cov viscosity siab thaum so, ua kom cov nplaum ua haujlwm zoo thiab ruaj khov. Lub shear-thinning tus cwj pwm ntawm HEC yog ntaus nqi los ntawm kev sib raug zoo ntawm polymer chains nyob rau hauv cov kev taw qhia ntawm lub zog thov, txo nyob rau hauv tsis kam mus ib ntus.
Daim ntawv thov hauv Adhesive Formulations
Dej-raws li Adhesives:
HEC feem ntau yog siv rau hauv dej-raws li adhesives, xws li cov ntawv, textiles, thiab ntoo. Nws muaj peev xwm ua kom tuab thiab ruaj khov ntawm cov nplaum nplaum kom ntseeg tau tias nws tseem sib xyaw ua ke thiab yooj yim rau kev thov. Hauv daim ntawv thiab ntim cov nplaum, HEC muab qhov tsim nyog viscosity rau kev thov kom raug thiab kev sib txuas lub zog.
Kev tsim kho Adhesive:
Hauv kev tsim cov nplaum, xws li cov khoom siv rau kev teeb tsa pobzeb lossis phab ntsa, HEC txhim kho cov viscosity, txhim kho cov nplaum ua haujlwm thiab sag kuj. 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 ruaj khov thiab ruaj khov.
Cosmetic and Personal Care Adhesives:
HEC kuj tseem siv rau hauv cov khoom siv tshuaj pleev ib ce thiab kev tu tus kheej uas xav tau cov khoom nplaum, xws li hauv cov plaub hau styling gels thiab lub ntsej muag lub ntsej muag. Hauv cov ntawv thov no, HEC muab qhov sib luag thiab sib luag, txhim kho cov khoom lag luam kev ua tau zoo thiab cov neeg siv kev paub.
Pharmaceutical Adhesives:
Hauv kev lag luam kws kho mob, HEC yog siv rau hauv cov khoom siv kho mob thiab lwm lub tshuab xa tshuaj uas tswj cov viscosity yog qhov tseem ceeb rau cov nplaum ua haujlwm. HEC xyuas kom meej tias cov nplaum txheej yog ib yam, muab cov tshuaj zoo ib yam thiab ua raws li daim tawv nqaij.
Cov yam ntxwv cuam tshuam rau viscosity txhim kho
Concentration:
Lub concentration ntawm HEC nyob rau hauv ib tug nplaum formulation yog ncaj qha proportional rau lub viscosity. Qhov siab dua ntawm HEC ua rau muaj qhov viscosity ntau ntxiv vim muaj kev sib cuam tshuam ntawm cov saw hlau tseem ceeb thiab kev cuam tshuam. Txawm li cas los xij, kev siv ntau dhau tuaj yeem ua rau gelation thiab nyuaj rau kev ua haujlwm.
Molecular Luj:
Qhov hnyav molecular ntawm HEC yog qhov tseem ceeb hauv kev txiav txim siab viscosity ntawm cov nplaum. Qhov hnyav dua molecular HEC muab ntau dua viscosity ntawm qis concentrations piv rau qis dua molecular variants. Kev xaiv ntawm qhov hnyav molecular nyob ntawm qhov xav tau viscosity thiab daim ntawv thov yuav tsum tau ua.
Kub:
Qhov kub thiab txias cuam tshuam rau viscosity ntawm HEC cov kev daws teeb meem. Raws li qhov kub thiab txias, qhov viscosity feem ntau txo qis vim qhov txo qis hauv hydrogen bonding thiab nce molecular mus. Nkag siab txog qhov kub-viscosity kev sib raug zoo yog qhov tseem ceeb rau cov ntawv thov raug rau qhov sib txawv ntawm qhov kub thiab txias.
pH:
Cov pH ntawm cov nplaum nplaum tuaj yeem cuam tshuam qhov viscosity ntawm HEC. HEC ruaj khov tshaj pH ntau yam, tab sis huab cua pH tuaj yeem ua rau muaj kev hloov pauv hauv cov qauv polymer thiab viscosity. Formulating adhesives nyob rau hauv qhov zoo tshaj pH ntau yam ua kom zoo ib yam.
Qhov zoo ntawm kev siv Hydroxyethyl Cellulose
Tsis yog-ionic xwm:
Qhov tsis yog-ionic xwm ntawm HEC ua rau nws sib xws nrog ntau yam ntawm lwm cov khoom tsim, nrog rau lwm cov polymers, surfactants, thiab electrolytes. Qhov no compatibility tso cai rau ntau yam nplaum formulations.
Biodegradability:
HEC yog muab los ntawm cellulose, ib qho khoom siv ntuj tsim thiab txuas ntxiv mus. Nws yog biodegradable, ua rau nws xaiv ib puag ncig tus phooj ywg rau cov nplaum formulations. Nws siv raws li qhov xav tau ntawm cov khoom lag luam ruaj khov thiab eco-friendly.
Kev ruaj ntseg:
HEC muab kev ruaj ntseg zoo heev rau cov nplaum nplaum, tiv thaiv theem kev sib cais thiab kev daws teeb meem ntawm cov khoom siv. Qhov kev ruaj ntseg no ua kom cov nplaum nplaum tseem siv tau thoob plaws hauv nws lub txee lub neej thiab thaum siv.
Film-Forming Properties:
HEC tsim cov yeeb yaj kiab hloov tau yooj yim thiab pob tshab thaum ziab, uas muaj txiaj ntsig zoo rau daim ntawv thov nplaum uas yuav tsum tau ua kom pom tseeb thiab hloov tau yooj yim. Cov cuab yeej no muaj txiaj ntsig tshwj xeeb hauv cov ntawv thov xws li cov ntawv sau thiab cov kab xev.
Hydroxyethyl cellulose ua lub luag haujlwm tseem ceeb hauv kev txhim kho cov viscosity ntawm cov nplaum los ntawm cov txheej txheem xws li dej thiab o, molecular entanglement, hydrogen bonding, thiab shear-thinning tus cwj pwm. Nws cov khoom, suav nrog solubility, non-ionic xwm, biodegradability, thiab zaj duab xis-tsim peev xwm, ua rau nws yog ib qho kev xaiv zoo tagnrho rau ntau daim ntawv nplaum. Kev nkag siab txog cov xwm txheej uas cuam tshuam rau HEC qhov kev txhim kho viscosity, xws li concentration, molecular yuag, kub, thiab pH, tso cai rau cov neeg tsim khoom los txiav cov khoom nplaum kom tau raws li cov kev xav tau tshwj xeeb. Raws li kev lag luam txuas ntxiv mus nrhiav cov ntaub ntawv muaj txiaj ntsig thiab ua tau zoo, HEC tseem yog ib qho tseem ceeb hauv kev tsim cov khoom nplaum siab heev.
Post lub sij hawm: May-29-2024