Qhov no yog li cas emulsifiers ua haujlwm

Nrog kev txhim kho ntawm tib neeg txoj kev ua neej, cov neeg siv khoom xav tau zaub mov tsis txwv rau cov khoom noj muaj txiaj ntsig zoo lawm. Lawv kuj xav tau cov khoom noj zoo, suav nrog qhov tsos, xim, tsw qab, saj, sib xws thiab tshiab.

Raws li cov khoom noj khoom haus hloov kho cov qauv, cov emulsifiers ua lub luag haujlwm tseem ceeb hauv kev lag luam khoom noj. Cia peb saib cov txheej txheem ntawm kev ua haujlwm ntawmcov tshuaj emulsifiers!

Cov tshuaj emulsion

Cov emulsions muaj ntau nyob rau hauv cov khoom noj. Ib theem muaj dej lossis cov kua dej, hu ua theem hydrophilic; lwm theem yog theem organic uas tsis sib tov nrog dej, tseem hu ua theem lipophilic. Thaum ob hom kua tsis sib tov xws li dej thiab roj sib xyaw, ob hom emulsions tuaj yeem tsim tau, uas yog roj-hauv-dej (O/W) emulsions thiab dej-hauv-roj (W/O) emulsions. Hauv cov roj-hauv-dej emulsions, roj raug faib ua cov tee me me hauv dej, nrog rau cov tee roj ua lub theem faib thiab dej ua cov khoom nruab nrab. Mis nyuj yog ib qho piv txwv ntawm O/W emulsion. Ntawm qhov tod tes, hauv cov dej-hauv-roj emulsions, dej raug faib ua cov tee me me hauv roj, qhov twg dej ua lub theem faib thiab roj ua cov khoom nruab nrab, nrog margarine yog tus sawv cev W/O emulsion.

Txoj Haujlwm ntawm Cov Emulsifiers

Cov khoom noj emulsifiers, tseem hu uacov tshuaj surfactants, yog cov tshuaj uas hloov cov kua dej uas tsis sib xyaw ua ke mus ua cov emulsions uas sib xyaw ua ke. Raws li cov khoom noj khoom haus ntxiv, lawv tuaj yeem txo qhov kev sib txhuam ntawm cov roj thiab cov dej tom qab muab tso rau hauv cov khoom noj, yog li tsim cov emulsions ruaj khov los ntawm cov roj uas tsis sib xyaw (cov khoom hydrophobic) thiab dej (cov khoom hydrophilic).

Ntawm ib sab tes, cov emulsifiers tsim cov zaj duab xis nyias nyias ntawm qhov sib txuas ntawm ob theem kom txo qhov zog dawb ntawm tag nrho lub cev thiab tsim cov interfaces tshiab. Cov molecules emulsifier muaj ob pawg hydrophilic thiab lipophilic, uas tuaj yeem nqus mus rau qhov chaw sib txuas ntawm cov roj thiab dej kom tsim cov txheej nyias nyias thiab txo qhov kev sib txhuam ntawm ob theem. Yuav kom meej meej, cov roj molecules cuam tshuam nrog cov ntu lipophilic ntawm emulsifiers thaum cov dej molecules cuam tshuam nrog cov ntu hydrophilic ntawm emulsifiers, thiab kev cuam tshuam ntawm ob sab no hloov qhov kev sib txhuam ntawm qhov sib txhuam. Ntawm qhov tod tes, emulsifiers tsim cov khaubncaws sab nraud povtseg tiv thaiv ntawm qhov chaw ntawm cov tee dej me me, ua rau cov tee dej muaj kev ruaj khov steric. Feem ntau, kev siv ntau dua ntawm emulsifiers ua rau muaj kev txo qis ntawm kev sib txhuam ntawm qhov sib txhuam. Qhov no tso cai rau cov tshuaj tsis sib xyaw ua ke kom sib xyaw ua ke thiab tsim cov txheej txheem dispersion homogeneous, uas hloov lub xeev qub, ua kom zoo dua cov qauv sab hauv ntawm cov khoom noj, thiab txhim kho cov khoom noj zoo.

Tus nqi sib npaug ntawm Hydrophilic-Lipophilic

Qhov sib npaug ntawm hydrophilic-lipophilic (HLB) tus nqi: Cov emulsifiers uas muaj hydrophilicity muaj zog feem ntau tsim cov roj-hauv-dej emulsions, thaum cov uas muaj lipophilicity muaj zog tsim cov dej-hauv-roj emulsions. Tus nqi HLB feem ntau yog siv los piav qhia txog qhov sib npaug ntawm hydrophilic-lipophilic ntawm cov emulsifiers thiab ntsuas lawv cov hydrophilicity. Muaj ntau txoj kev xam rau cov nqi HLB:

Cov mis sib txawv: HLB = Hydrophilicity ntawm cov pab pawg hydrophilic−Lipophobicity ntawm cov pab pawg lipophilic

Tus qauv piv: HLB = Hydrophilicity ntawm cov pab pawg hydrophilic / Lipophobicity ntawm cov pab pawg lipophilic

Tus nqi HLB ntawm txhua yam emulsifier tuaj yeem txiav txim siab los ntawm kev sim. Nws tau teev tseg tias emulsifiers nrog 100% lipophilicity (sawv cev los ntawm paraffin wax) muaj tus nqi HLB ntawm 0, thiab cov uas muaj 100% hydrophilicity (sawv cev los ntawm potassium oleate) muaj tus nqi HLB ntawm 20. Qhov ntau ntawm 0 thiab 20 yog muab faib ua 20 qhov sib npaug los qhia lub zog ntawm hydrophilicity thiab lipophilicity. Tus nqi HLB siab dua sib raug rau hydrophilicity muaj zog dua, thaum tus nqi HLB qis dua txhais tau tias muaj lipophilicity muaj zog dua.

Feem ntau cov emulsifiers qib zaub mov yog cov surfactants nonionic nrog HLB tus nqi txij li 0 txog 20; cov yam ntxwv sib xws ntawm cov emulsifiers nonionic nrog HLB tus nqi sib txawv tau teev nyob rau hauv lub rooj. Los ntawm qhov sib piv, ionic surfactants muaj HLB tus nqi txij li 0 txog 40. Yog li ntawd, emulsifiers nrog HLB tus nqi qis dua 10 feem ntau yog lipophilic, thaum cov uas muaj HLB tus nqi sib npaug lossis siab dua 10 qhia txog cov yam ntxwv hydrophilic.

Rau cov emulsifiers sib xyaw, lawv cov nqi HLB yog cov khoom ntxiv. Yog li ntawd, thaum ob lossis ntau dua emulsifiers siv ua ke, tus nqi HLB ntawm cov emulsifier sib xyaw tuaj yeem suav raws li cov feem pua ​​​​​​ntawm txhua cov khoom sib xyaw emulsifier: HLBa,b = HLBa·A% + HLBb·B%

Qhov twg HLBa,b qhia txog tus nqi HLB ntawm cov khoom sib xyaw ntawm emulsifier a thiab emulsifier b; HLBa thiab HLBb sawv cev rau cov nqi HLB ntawm emulsifier a thiab emulsifier b; A% thiab B% sawv cev rau feem pua ​​​​​​ntawm cov emulsifier a thiab emulsifier b hauv cov emulsifier sib xyaw (Cov mis no tsuas yog siv rau cov emulsifiers nonionic).

Cov Txheej Txheem Npaj thiab Cov Yam Cuam Tshuam rau Cov Emulsifiers

Muaj plaub txoj kev npaj rau cov emulsifiers, uas yog txoj kev qhuav gum, txoj kev ntub gum, txoj kev sib tov roj-dej thiab txoj kev kho tshuab.

Txoj kev ua cov roj nplaum qhuav yog ntxiv cov dej rau hauv cov roj uas muaj cov tshuaj emulsifiers. Thaum lub sijhawm npaj, hmoov roj nplaum (emulsifier) ​​yuav tsum sib tov nrog roj ua ntej, ntxiv ib qho dej, thiab cov khoom sib tov yuav tsum tau zom thiab emulsified ua cov emulsion thawj zaug, tom qab ntawd ntxiv dej kom yaj tag nrho. Txoj kev ua cov roj nplaum txhais tau tias ntxiv cov roj nplaum rau hauv cov dej uas muaj cov tshuaj emulsifiers. Thaum npaj, cov roj nplaum (emulsifier) ​​yuav tsum tau yaj rau hauv dej ua cov kua nplaum ua cov kua nplaum; tom qab ntawd ntxiv cov roj nplaum rau hauv cov dej ua pawg thiab zom ua cov emulsion thawj zaug, tom qab ntawd ntxiv dej kom tag nrho. Txoj kev sib tov roj-dej txhais tau tias sib tov roj thiab dej ib qho, sib tsoo cov roj nplaum acacia kom zoo hauv lub mortar, ntxiv cov roj-dej sib tov rau hauv kom zom sai sai ua cov emulsion thawj zaug, thiab tom qab ntawd ntxiv dej kom yaj.

Kev npaj cov emulsifiers feem ntau yog lub hom phiaj emulsify ob hom kua, thiab cov nyhuv emulsification muaj kev cuam tshuam loj rau qhov zoo ntawm emulsions. Cov yam tseem ceeb uas cuam tshuam rau emulsification suav nrog kev sib zog interfacial, viscosity thiab kub, emulsification lub sijhawm, thiab koob tshuaj ntawm emulsifiers. Feem ntau, emulsifiers uas tuaj yeem txo qhov kev sib zog interfacial raug xaiv. Qhov kub emulsification zoo tshaj plaws rau emulsifiers yog li 70°C; yog tias cov tshuaj surfactants uas tsis yog ionic siv los ua cov emulsifiers, qhov kub ntawm emulsification yuav tsum tsis pub tshaj lawv cov huab. Feem ntau hais lus, qhov ntau dua ntawm cov tshuaj emulsifiers, qhov ruaj khov dua cov emulsions uas tsim yuav.