Hydroxyethylcellulose (HEC) yog ib qho uas tsis yog-ionic dej-soluble polymer dav siv nyob rau hauv coatings, tshuaj pleev ib ce, tsev cov ntaub ntawv, tshuaj thiab lwm yam lag luam. Nws lub luag haujlwm tseem ceeb yog ua cov thickener, tshem tawm tus neeg sawv cev, tus neeg sawv cev ua yeeb yaj kiab thiab stabilizer, uas tuaj yeem txhim kho cov khoom rheological ntawm cov khoom. HEC muaj zoo solubility, thickening, film-forming thiab compatibility, yog li nws yog nyiam nyob rau hauv ntau yam teb. Txawm li cas los xij, hais txog kev ruaj ntseg ntawm HEC thiab nws cov kev ua tau zoo nyob rau hauv qhov sib txawv pH ib puag ncig, nws yog ib qho tseem ceeb uas yuav tsum tau xav txog hauv kev siv tswv yim.
Nyob rau hauv cov nqe lus ntawm pH rhiab heev, hydroxyethylcellulose, raws li ib tug non-ionic polymer, yog inherently tsawg rhiab heev rau pH hloov. Qhov no txawv ntawm lwm cov ionic thickeners (xws li carboxymethylcellulose los yog qee cov acrylic polymers), uas muaj cov ionic pawg hauv lawv cov qauv molecular thiab muaj feem cuam tshuam los yog ionization hauv acidic lossis alkaline ib puag ncig. , yog li cuam tshuam cov nyhuv thickening thiab rheological zog ntawm cov tshuaj. Vim hais tias HEC tsis muaj nqi, nws cov nyhuv thickening thiab solubility nyob rau hauv qhov tseem ceeb ruaj khov tshaj pH ntau yam (feem ntau pH 3 txog pH 11). Cov yam ntxwv no ua rau HEC hloov mus rau ntau hom kev tsim qauv thiab tuaj yeem ua kom cov nyhuv thickening zoo nyob rau hauv acidic, nruab nrab lossis tsis muaj zog alkaline.
Txawm hais tias HEC muaj kev ruaj ntseg zoo nyob rau hauv feem ntau pH tej yam kev mob, nws cov kev ua tau zoo tej zaum yuav cuam tshuam rau huab pH ib puag ncig, xws li tsis tshua muaj acidic los yog alkaline ib puag ncig. Piv txwv li, nyob rau hauv acidic tej yam kev mob (pH <3), solubility ntawm HEC tej zaum yuav raug txo thiab cov thickening nyhuv yuav tsis tseem ceeb li nyob rau hauv nruab nrab los yog me ntsis acidic ib puag ncig. Qhov no yog vim tias ntau dhau ntawm hydrogen ion concentration yuav cuam tshuam rau kev sib haum xeeb ntawm HEC molecular saw, txo nws lub peev xwm rau diffuse thiab o hauv dej. Ib yam li ntawd, nyob rau hauv cov xwm txheej alkaline heev (pH> 11), HEC tuaj yeem raug kev puas tsuaj ib nrab lossis hloov tshuaj lom neeg, cuam tshuam rau nws cov nyhuv thickening.
Ntxiv nrog rau kev solubility thiab thickening teebmeem, pH kuj tseem cuam tshuam rau kev sib raug zoo ntawm HEC nrog rau lwm cov khoom tsim. Nyob rau hauv ib puag ncig pH sib txawv, qee cov khoom xyaw nquag tuaj yeem ionize lossis sib cais, yog li hloov lawv cov kev cuam tshuam nrog HEC. Piv txwv li, nyob rau hauv acidic tej yam kev mob, ib co hlau ions los yog cationic active cov khoom xyaw tej zaum yuav tsim complexes nrog HEC, ua rau nws thickening nyhuv kom tsis muaj zog los yog precipitate. Yog li ntawd, hauv kev tsim qauv, kev sib cuam tshuam ntawm HEC thiab lwm cov khoom xyaw hauv cov pH sib txawv yuav tsum tau txiav txim siab los xyuas kom meej qhov ruaj khov thiab ua haujlwm ntawm tag nrho cov kab ke.
Txawm hais tias HEC nws tus kheej tsis tshua nkag siab rau cov kev hloov pauv pH, nws qhov kev sib cais thiab cov txheej txheem tawg tuaj yeem cuam tshuam los ntawm pH. HEC feem ntau dissolves sai sai nyob rau hauv nruab nrab los yog me ntsis acidic tej yam kev mob, thaum nyob rau hauv tsis tshua muaj acidic los yog alkaline tej yam kev mob lub dissolution txheej txheem yuav ua qeeb dua. Yog li ntawd, thaum npaj cov kev daws teeb meem, nws feem ntau pom zoo kom ua ntej ntxiv HEC rau qhov nruab nrab lossis ze- nruab nrab aqueous tov kom ntseeg tau tias nws yaj sai sai thiab sib npaug.
Hydroxyethylcellulose (HEC), raws li cov polymer uas tsis yog-ionic, tsis tshua muaj siab rau pH thiab tuaj yeem tswj xyuas cov nyhuv thickening ruaj khov thiab cov khoom solubility tshaj pH ntau yam. Nws qhov kev ua tau zoo yog qhov ruaj khov nyob rau hauv thaj tsam ntawm pH 3 txog pH 11, tab sis nyob rau hauv huab cua acid thiab alkali ib puag ncig, nws cov nyhuv thickening thiab solubility yuav cuam tshuam. Yog li ntawd, thaum thov HEC, txawm hais tias feem ntau tsis tas yuav tsum tau them nyiaj ntau dhau rau cov kev hloov pauv pH, nyob rau hauv cov xwm txheej tsis zoo, kev ntsuas tsim nyog thiab kev hloov kho tseem yuav tsum tau ua kom muaj kev ruaj ntseg thiab ua haujlwm ntawm lub cev.
Post lub sij hawm: Oct-22-2024