Sodium carboxymethyl cellulose, hu ua carboxymethyl cellulose (CMC) yog ib hom high-polymer fiber ether npaj los ntawm kev hloov tshuaj ntawm ntuj cellulose. Nws cov qauv yog feem ntau D-glucose chav tsev los ntawm β (1 → 4) Cov yuam sij txuas ua ke.
CMC yog dawb los yog milky dawb fibrous hmoov los yog granules, nrog ib tug ceev ntawm 0.5-0.7 g / cm3, yuav luag odorless, tasteless, thiab hygroscopic. Yooj yim dispersed nyob rau hauv dej los tsim cov pob tshab colloidal tov, insoluble nyob rau hauv cov organic solvents xws li ethanol. pH ntawm 1% aqueous tov yog 6.5-8.5, thaum pH> 10 los yog <5, viscosity ntawm cov mucilage txo qis, thiab kev ua tau zoo yog qhov zoo tshaj plaws thaum pH = 7. Nyob ruaj khov rau cua sov, viscosity nce sai dua 20 ° C, thiab hloov maj mam ntawm 45 ° C. Lub sijhawm ntev cua sov siab tshaj 80 ° C tuaj yeem ua rau cov colloid thiab txo cov viscosity thiab kev ua haujlwm zoo. Nws yog yooj yim soluble nyob rau hauv dej thiab cov kua yog pob tshab; Nws yog qhov ruaj khov heev hauv cov tshuaj alkaline, tab sis nws yog yooj yim hydrolyzed thaum nws ntsib acid, thiab nws yuav precipitate thaum pH tus nqi yog 2-3, thiab nws kuj yuav hnov mob nrog multivalent hlau ntsev.
Cov qauv formula: C6H7(OH)2OCH2COONa Molecular formula: C8H11O5Na
Cov tshuaj tiv thaiv tseem ceeb yog: lub ntuj cellulose ua ntej dhau alkalinization cov tshuaj tiv thaiv nrog NaOH, thiab nrog ntxiv ntawm chloroacetic acid, cov hydrogen ntawm hydroxyl pawg ntawm cov piam thaj hauv cov ntshav tau hloov pauv cov tshuaj tiv thaiv nrog pawg carboxymethyl hauv chloroacetic acid. Nws tuaj yeem pom los ntawm cov qauv qauv uas muaj peb pawg hydroxyl ntawm txhua pawg piam thaj, uas yog, C2, C3, thiab C6 hydroxyl pawg. Cov hydrogen ntawm txhua pawg hydroxyl yog hloov los ntawm carboxymethyl, uas txhais tau tias yog ib qho kev hloov pauv ntawm 3. Lub degree ntawm kev hloov ntawm CMC ncaj qha cuam tshuam rau solubility, emulsification, thickening, stability, acid kuj thiab ntsev tsis kam ntawmCMC .
Nws yog feem ntau ntseeg tias thaum lub degree ntawm kev hloov yog nyob ib ncig ntawm 0.6-0.7, lub emulsifying kev ua tau zoo yog zoo dua, thiab nrog rau kev nce qib ntawm kev hloov, lwm yam khoom yog txhim kho raws li. Thaum qhov kev hloov pauv ntau dua 0.8, nws cov tshuaj tiv thaiv acid thiab ntsev kuj tau txhim kho. .
Tsis tas li ntawd, nws kuj tau hais los saum toj no tias muaj peb pawg hydroxyl ntawm txhua chav, uas yog, pawg hydroxyl theem nrab ntawm C2 thiab C3 thiab thawj pawg hydroxyl ntawm C6. Hauv txoj kev xav, kev ua ntawm thawj pawg hydroxyl yog ntau dua li ntawm pawg hydroxyl thib ob, tab sis raws li cov nyhuv isotopic ntawm C, pawg -OH ntawm C2 Nws yog acidic ntau dua, tshwj xeeb tshaj yog nyob rau hauv ib puag ncig ntawm alkali muaj zog, nws cov haujlwm. muaj zog dua C3 thiab C6, yog li nws yog qhov yooj yim rau kev hloov pauv, ua raws li C6, thiab C3 tsis muaj zog tshaj.
Qhov tseeb, kev ua tau zoo ntawm CMC tsis yog tsuas yog cuam tshuam rau qib ntawm kev hloov pauv, tab sis kuj yog qhov sib xws ntawm kev faib cov carboxymethyl pawg hauv tag nrho cov cellulose molecule thiab kev hloov ntawm hydroxymethyl pawg hauv txhua chav nrog C2, C3, thiab C6 hauv txhua molecule. muaj feem xyuam rau uniformity. Txij li thaum CMC yog ib tug heev polymerized linear compound, thiab nws cov carboxymethyl pawg muaj inhomogeneous hloov nyob rau hauv lub molecule, cov molecules muaj txawv orientations thaum cov tshuaj yog sawv ntsug, thiab qhov ntev ntawm cov linear molecule txawv thaum muaj ib tug shear quab yuam nyob rau hauv cov tshuaj. . Lub axis muaj lub siab xav tig mus rau qhov kev taw qhia ntws, thiab qhov kev nyiam no yuav muaj zog dua nrog qhov nce ntawm cov shear tus nqi kom txog rau thaum qhov kev taw qhia zaum kawg yog tag nrho. Cov yam ntxwv ntawm CMC no hu ua pseudoplasticity. Lub pseudoplasticity ntawm CMC yog qhov tsim nyog rau homogenization thiab kev thauj mus los hauv cov kav dej, thiab nws yuav tsis hnov tsw greasy hauv kua mis, uas yog qhov tsim nyog rau kev tso tawm cov mis nyuj aroma. .
Txhawm rau siv CMC cov khoom, peb yuav tsum muaj kev nkag siab zoo ntawm cov ntsiab lus tseem ceeb xws li kev ruaj ntseg, viscosity, acid tsis kam, thiab viscosity. Paub seb peb xaiv cov khoom zoo li cas.
Tsawg-viscosity CMC cov khoom lag luam muaj qhov ua kom zoo dua qub, tsis muaj viscosity, thiab yuav luag tsis muaj qhov tuab. Lawv tsuas yog siv rau hauv cov kua ntses tshwj xeeb thiab dej haus. Kev noj qab haus huv qhov ncauj kua kuj yog ib qho kev xaiv zoo.
Medium-viscosity CMC cov khoom lag luam feem ntau yog siv hauv cov dej haus, cov dej haus muaj protein ntau thiab cov kua txiv hmab txiv ntoo. Yuav xaiv li cas nyob ntawm tus kheej tus cwj pwm ntawm engineers. Hauv kev ruaj ntseg ntawm cov khoom noj siv mis, CMC tau pab ntau heev.
High-viscosity CMC cov khoom muaj qhov chaw thov loj. Piv nrog cov hmoov txhuv nplej siab, guar cov pos hniav, xanthan cov pos hniav thiab lwm yam khoom, kev ruaj ntseg ntawm CMC tseem pom tseeb, tshwj xeeb tshaj yog nyob rau hauv cov khoom nqaij, cov dej tuav kom zoo ntawm CMC yog qhov pom tseeb dua! Ntawm cov stabilizers xws li ice cream, CMC kuj yog ib qho kev xaiv zoo.
Cov cim tseem ceeb los ntsuas qhov zoo ntawm CMC yog qib kev hloov pauv (DS) thiab purity. Feem ntau, cov khoom ntawm CMC txawv yog tias DS txawv; qhov siab dua qhov kev hloov pauv, qhov muaj zog dua qhov solubility, thiab qhov zoo dua qhov pom thiab ruaj khov ntawm cov tshuaj. Raws li cov lus ceeb toom, lub pob tshab ntawm CMC yog qhov zoo dua thaum qhov kev hloov pauv yog 0.7-1.2, thiab viscosity ntawm nws cov kua dej yog qhov loj tshaj plaws thaum pH tus nqi yog 6-9.
Txhawm rau kom ntseeg tau tias nws qhov zoo, ntxiv rau kev xaiv tus neeg sawv cev etherification, qee yam cuam tshuam rau qib kev hloov pauv thiab purity yuav tsum tau txiav txim siab, xws li kev sib raug zoo ntawm tus nqi ntawm alkali thiab etherification tus neeg sawv cev, lub sijhawm etherification, cov ntsiab lus dej hauv qhov system, qhov kub thiab txias, DH tus nqi, kev daws Concentration thiab ntsev thiab lwm yam.
Qhov zoo ntawm CMC cov khoom tiav feem ntau yog nyob ntawm qhov kev daws teeb meem ntawm cov khoom. Yog hais tias qhov kev daws teeb meem ntawm cov khoom yog qhov tseeb, muaj ob peb gel hais, dawb fibers, thiab dub me ntsis ntawm impurities, nws yeej paub tseeb tias qhov zoo ntawm CMC yog zoo. Yog tias cov tshuaj tau tso tseg rau ob peb hnub, cov tshuaj tsis tshwm sim. Dawb los yog turbid, tab sis tseem meej heev, uas yog ib yam khoom zoo dua!
Post lub sij hawm: Dec-14-2022