Thickener yog ib qho khoom siv thiab feem ntau siv dej-raws li additives hauv dej-raws li txheej. Tom qab ntxiv cov thickener, nws tuaj yeem ua kom cov viscosity ntawm txheej txheej txheej, yog li tiv thaiv cov khoom ntom ntom hauv txheej los ntawm kev teeb tsa. Yuav tsis muaj qhov tshwm sim sagging vim qhov viscosity ntawm cov xim yog nyias dhau. Muaj ntau ntau hom khoom thickener, thiab cov khoom sib txawv muaj cov txheej txheem sib txawv ntawm cov txheej txheem sib txawv ntawm cov txheej txheem. Muaj kwv yees li plaub yam ntawm cov thickeners: polyurethane thickeners, acrylic thickeners, inorganic thickeners thiab thickeners rau cellulose thickeners.
1. Thickening mechanism ntawm associative polyurethane thickener
Cov yam ntxwv ntawm polyurethane associative thickeners yog lipophilic, hydrophilic thiab lipophilic tri-block polymers, nrog lipophilic kawg pawg ntawm ob hnub, feem ntau aliphatic hydrocarbon pawg, thiab cov dej-soluble polyethylene glycol ntu nyob nruab nrab. Tsuav yog muaj ib tug txaus npaum li cas ntawm thickener nyob rau hauv lub system, lub system yuav tsim ib tug tag nrho network qauv.
Nyob rau hauv cov dej system, thaum lub concentration ntawm cov thickener yog ntau tshaj qhov tseem ceeb micelle concentration, lipophilic kawg pab pawg neeg koom ua ke los tsim micelles, thiab cov thickener tsim ib tug network qauv los ntawm lub koom haum ntawm micelles kom lub viscosity ntawm lub system.
Nyob rau hauv cov txheej txheem latex, lub thickener tuaj yeem tsis tsuas yog tsim kev koom tes los ntawm lipophilic davhlau ya nyob twg pab pawg micelles, tab sis qhov tseem ceeb tshaj, pawg lipophilic davhlau ya nyob twg ntawm cov thickener yog adsorbed rau saum npoo ntawm cov latex particle. Thaum ob pawg lipophilic kawg yog adsorbed ntawm cov khoom sib txawv latex, cov thickener molecules tsim txuas ntawm cov khoom.
2. Thickening mechanism ntawm polyacrylic acid alkali o thickener
Polyacrylic acid alkali swelling thickener yog ib qho kev sib txuas ntawm cov copolymer emulsion, cov copolymer muaj nyob rau hauv daim ntawv ntawm cov kua qaub thiab me me, cov tsos yog milky dawb, lub viscosity kuj tsis tshua muaj, thiab nws muaj kev ruaj ntseg zoo ntawm pH pw ua ke, thiab insoluble. hauv dej. Thaum ntxiv alkaline tus neeg sawv cev, nws hloov mus rau hauv ib qho meej thiab swellable dispersion.
Cov nyhuv thickening ntawm polyacrylic acid alkali swelling thickener yog tsim los ntawm neutralizing pawg carboxylic acid nrog hydroxide; Thaum tus neeg sawv cev alkali ntxiv, pawg carboxylic acid uas tsis yooj yim ionized yog tam sim ntawd hloov mus rau ionized ammonium carboxylate los yog hlau Nyob rau hauv daim ntawv ntsev, ib tug electrostatic repulsion nyhuv yog generated raws lub anion chaw ntawm lub copolymer macromolecular saw, kom tus ntoo khaub lig. -linked copolymer macromolecular saw expands thiab stretches sai heev. Raws li qhov tshwm sim ntawm kev sib cais hauv zos thiab o, cov khoom qub yog sib npaug ntau zaus thiab cov viscosity tau nce ntau. Txij li cov crosslinks tsis tuaj yeem yaj, cov copolymer nyob rau hauv daim ntawv ntsev tuaj yeem suav tias yog copolymer dispersion uas nws cov khoom loj heev.
Polyacrylic acid thickeners muaj cov nyhuv thickening zoo, ceev ceev ceev, thiab zoo lom neeg ruaj ntseg, tab sis lawv rhiab heev rau pH, dej tsis kam, thiab gloss.
3. Thickening mechanism ntawm inorganic thickeners
Inorganic thickeners feem ntau suav nrog hloov kho bentonite, attapulgite, thiab lwm yam. Inorganic thickeners muaj qhov zoo ntawm cov thickening, zoo thixotropy, dav pH ntau, thiab zoo stability. Txawm li cas los xij, txij li bentonite yog cov hmoov tsis zoo nrog lub teeb pom kev zoo, nws tuaj yeem txo qhov gloss ntawm txheej zaj duab xis thiab ua zoo li tus neeg sawv cev matting. Yog li ntawd, thaum siv bentonite nyob rau hauv glossy latex xim, yuav tsum tau them nyiaj mloog mus rau kev tswj cov tshuaj. Nanotechnology tau paub txog nanoscale ntawm inorganic hais, thiab kuj endowed inorganic thickeners nrog ib co tshiab zog.
Lub thickening mechanism ntawm inorganic thickeners yog qhov nyuaj. Nws yog feem ntau ntseeg hais tias lub repulsion ntawm sab hauv tsub kom lub viscosity ntawm cov xim. Vim nws cov qib tsis zoo, nws cuam tshuam rau gloss thiab pob tshab ntawm cov xim zaj duab xis. Nws feem ntau yog siv rau primer los yog siab tsim xim.
4. Thickening mechanism ntawm cellulose thickener
Cellulose thickeners muaj keeb kwm ntev ntawm kev loj hlob thiab kuj tau siv dav siv cov thickeners. Raws li lawv cov qauv molecular, lawv tau muab faib ua hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethyl cellulose, carboxymethyl cellulose, thiab lwm yam, uas yog siv ntau dua hydroxyethyl cellulose (HEC).
Lub thickening mechanism ntawm cellulose thickener yog tsuas yog siv cov hydrophobic lub ntsiab saw ntawm nws cov qauv los tsim hydrogen bonds nrog dej, thiab nyob rau tib lub sij hawm cuam tshuam nrog lwm pawg polar nyob rau hauv nws cov qauv los tsim ib tug peb-dimensional network qauv thiab ua kom lub rheological ntim. ntawm polymer. , txwv qhov chaw dawb txav ntawm cov polymer, yog li ua kom cov viscosity ntawm txheej. Thaum siv cov shear quab yuam, peb-seem lub network qauv raug rhuav tshem, hydrogen bonds ntawm cov molecules ploj, thiab viscosity txo. Thaum lub zog shear raug tshem tawm, cov ntawv cog lus hydrogen tau rov tsim dua, thiab cov qauv peb-dimensional network tau rov tsim dua, yog li ua kom cov txheej txheej tuaj yeem muaj cov khoom zoo. rheological zog.
Cellulosic thickeners yog nplua nuj nyob rau hauv hydroxyl pawg thiab hydrophobic ntu hauv lawv cov qauv. Lawv muaj cov thickening efficiency thiab tsis rhiab rau pH. Txawm li cas los xij, vim lawv cov dej tsis zoo thiab cuam tshuam rau qib ntawm cov xim zaj duab xis, lawv yooj yim cuam tshuam los ntawm microbial degradation thiab lwm yam tsis zoo, cellulose thickeners yog siv los ua cov xim latex.
Nyob rau hauv cov txheej txheem ntawm txheej txheej, kev xaiv ntawm cov thickener yuav tsum ua tib zoo xav txog ntau yam, xws li kev sib raug zoo nrog lub cev, viscosity, cia ruaj khov, kev tsim kho, nqi thiab lwm yam. Ntau cov thickeners tuaj yeem sib xyaw thiab siv los muab kev ua si tag nrho rau qhov zoo ntawm txhua lub thickener, thiab tsim nyog tswj tus nqi raws li qhov ua tau zoo txaus siab.
Post lub sij hawm: Mar-02-2023