Kev tsim cov hydroxyethyl cellulose (HEC) muaj cov tshuaj tiv thaiv kab mob los hloov cov cellulose, ib yam khoom ntuj tsim los ntawm cov nroj tsuag. HEC yog dav siv nyob rau hauv ntau yam lag luam, xws li tshuaj, tshuaj pleev ib ce, khoom noj khoom haus, thiab kev tsim kho, vim nws thickening, stabilizing, thiab dej-retaining zog.
Taw qhia rau Hydroxyethyl Cellulose (HEC)
Hydroxyethyl cellulose (HEC) yog non-ionic, dej-soluble polymer muab los ntawm cellulose los ntawm kev hloov tshuaj. Nws yog dav siv los ua thickening, gelling, thiab stabilizing tus neeg sawv cev nyob rau hauv ntau yam lag luam.
Cov khoom siv raw
Cellulose: Cov khoom siv tseem ceeb rau HEC ntau lawm. Cellulose tuaj yeem tau txais los ntawm ntau yam khoom siv cog xws li ntoo pulp, paj rwb, lossis cov khoom ua liaj ua teb.
Ethylene Oxide (EO): Cov tshuaj tseem ceeb siv los qhia cov pab pawg hydroxyethyl mus rau cov pob txha cellulose.
Alkali: Feem ntau sodium hydroxide (NaOH) lossis potassium hydroxide (KOH) yog siv los ua cov tshuaj tiv thaiv.
Kev tsim khoom
Kev tsim cov HEC suav nrog etherification ntawm cellulose nrog ethylene oxide nyob rau hauv alkaline tej yam kev mob.
Cov kauj ruam hauv qab no qhia txog tus txheej txheem:
1. Kev kho mob ua ntej ntawm Cellulose
Cellulose yog thawj purified kom tshem tawm impurities xws li lignin, hemicellulose, thiab lwm yam extractives. Lub purified cellulose yog ces qhuav mus rau ib tug tshwj xeeb noo noo ntsiab lus.
2. Etherification Reaction
Kev npaj ntawm Alkaline tov: Ib qho aqueous tov ntawm sodium hydroxide (NaOH) los yog potassium hydroxide (KOH) yog npaj. Qhov concentration ntawm cov tshuaj alkali yog qhov tseem ceeb thiab yuav tsum tau ua kom zoo raws li qhov xav tau ntawm kev hloov pauv (DS) ntawm cov khoom kawg.
Reaction Setup: Purified cellulose yog dispersed nyob rau hauv alkali tov. Cov sib tov yog rhuab mus rau ib tug tshwj xeeb kub, feem ntau nyob ib ncig ntawm 50-70 ° C, kom ntseeg tau tias cov cellulose yog kiag li o thiab nkag mus rau cov tshuaj tiv thaiv.
Ntxiv ntawm Ethylene Oxide (EO): Ethylene oxide (EO) yog ntxiv maj mam mus rau cov tshuaj tiv thaiv hlab ntsha thaum tswj qhov kub thiab txias tsis tu ncua. Cov tshuaj tiv thaiv yog exothermic, yog li kev tswj qhov kub thiab txias yog qhov tseem ceeb los tiv thaiv overheating.
Reaction Monitoring: Qhov kev nce qib ntawm cov tshuaj tiv thaiv yog saib xyuas los ntawm kev tshuaj xyuas cov qauv ntawm ib ntus. Cov txuj ci zoo li Fourier-transform infrared spectroscopy (FTIR) tuaj yeem siv los txiav txim siab qhov kev hloov pauv (DS) ntawm pawg hydroxyethyl ntawm cov pob txha cellulose.
Neutralization thiab Ntxuav: Thaum qhov xav tau DS tiav, cov tshuaj tiv thaiv yog quenched los ntawm neutralizing alkaline tov nrog ib tug acid, feem ntau acetic acid. Lub resulting HEC yog ces ntxuav kom huv si nrog dej kom tshem tawm tej yam unreacted reagents thiab impurities.
3. Purification thiab ziab
HEC ntxuav yog ntxiv purified los ntawm kev pom los yog centrifugation kom tshem tawm tej impurities seem. Lub HEC purified yog ces qhuav mus rau ib tug tshwj xeeb noo noo ntsiab lus kom tau cov khoom kawg.
Kev Tswj Xyuas Zoo
Kev tswj hwm zoo yog qhov tseem ceeb thoob plaws hauv HEC cov txheej txheem tsim khoom kom ntseeg tau qhov sib xws thiab purity ntawm cov khoom kawg. Cov tsis tseem ceeb los saib xyuas muaj xws li:
Degree ntawm kev hloov pauv (DS)
viscosity
Cov dej noo
pH
Purity (tsis muaj impurities)
Cov txheej txheem tshuaj ntsuam xyuas xws li FTIR, kev ntsuas viscosity, thiab kev tsom xam cov ntsiab lus feem ntau yog siv rau kev tswj kom zoo.
Kev siv ntawm Hydroxyethyl Cellulose (HEC)
HEC pom cov ntawv thov hauv ntau qhov kev lag luam vim nws muaj ntau yam khoom:
Pharmaceuticals: Siv los ua tus neeg sawv cev thickening hauv qhov ncauj tshem tawm, tshuaj pleev ib ce, thiab tswj-tso tshuaj xa cov tshuab.
Tshuaj pleev ib ce: Feem ntau siv nyob rau hauv cream, tshuaj pleev ib ce, thiab tshuaj zawv plaub hau raws li ib tug thickener thiab stabilizer.
Khoom noj khoom haus: Ntxiv rau cov khoom noj khoom haus ua cov thickening thiab gelling tus neeg sawv cev, emulsifier, thiab stabilizer.
Kev tsim kho: Siv hauv cov cement-based mortars thiab grouts los txhim kho kev ua haujlwm thiab khaws dej.
Environmental thiab Safety Considerations
Environmental Impact: Kev tsim HEC suav nrog kev siv tshuaj xws li ethylene oxide thiab alkalis, uas tuaj yeem cuam tshuam rau ib puag ncig. Kev tswj cov khoom pov tseg kom raug thiab ua raws li cov cai yog qhov tseem ceeb los txo qhov cuam tshuam ib puag ncig.
Kev Nyab Xeeb: Ethylene oxide yog cov pa hluav taws xob zoo heev thiab cov nplaim hluav taws kub, ua rau muaj kev nyab xeeb thaum tuav thiab khaws cia. Kev ua pa kom txaus, cov cuab yeej tiv thaiv tus kheej (PPE), thiab cov txheej txheem kev nyab xeeb yog tsim nyog los xyuas kom meej cov neeg ua haujlwm nyab xeeb.
Hydroxyethyl cellulose (HEC) yog ib qho tseem ceeb polymer nrog ntau yam kev siv hauv kev lag luam xws li tshuaj mus rau kev tsim kho. Nws cov khoom lag luam suav nrog etherification ntawm cellulose nrog ethylene oxide nyob rau hauv alkaline tej yam kev mob. Kev tswj xyuas kev ua tau zoo yog qhov tseem ceeb los xyuas kom meej qhov sib xws thiab purity ntawm cov khoom kawg. Kev xav txog ib puag ncig thiab kev nyab xeeb yuav tsum tau hais txog thoob plaws hauv cov txheej txheem tsim khoom. Los ntawm kev ua raws li cov txheej txheem thiab cov txheej txheem tsim nyog, HEC tuaj yeem tsim tau zoo thaum txo qhov cuam tshuam ib puag ncig thiab ua kom cov neeg ua haujlwm nyab xeeb.
Cov lus qhia dav dav no suav nrog cov txheej txheem tsim tawm ntawm hydroxyethyl cellulose (HEC) kom ntxaws, los ntawm cov khoom siv raw mus rau kev tswj xyuas kom zoo thiab kev siv, muab kev nkag siab zoo txog cov txheej txheem tseem ceeb ntawm cov polymer no.
Lub sij hawm xa tuaj: Plaub Hlis-10-2024