Hydroxypropyl methylcellulose (HPMC) yog ib qho tseem ceeb semi-synthetic cellulose ether compound, uas yog dav siv nyob rau hauv cov tshuaj, tsev cov ntaub ntawv, zaub mov, txheej thiab lwm yam lag luam. HPMC muaj cov thickening zoo, emulsification, film-forming, moisturizing, stabilization thiab lwm yam khoom, yog li nws muaj ib qho tseem ceeb daim ntawv thov nqi nyob rau hauv ntau yam teb. Cov khoom siv tseem ceeb rau kev tsim HPMC suav nrog cellulose, sodium hydroxide, propylene oxide, methyl chloride thiab dej.
1. Cellulose
Cellulose yog cov khoom siv tseem ceeb ntawm HPMC, feem ntau yog muab los ntawm cov nroj tsuag ntuj fibers xws li paj rwb thiab ntoo. Cellulose yog cov organic polymer ntau tshaj plaws hauv ntiaj teb. Nws cov qauv molecular yog cov saw ntev polysaccharide uas muaj cov piam thaj txuas nrog β-1,4-glycosidic bonds. Cellulose nws tus kheej yog insoluble hauv dej thiab tsis muaj tshuaj zoo reactivity. Yog li, cov txheej txheem ntawm kev hloov kho tshuaj yuav tsum tau txhim kho nws cov solubility thiab kev ua haujlwm los npaj ntau yam khoom siv cellulose ether.
2. Sodium hydroxide (NaOH)
Sodium hydroxide, tseem hu ua caustic soda, yog ib qho muaj zog alkaline compound uas ua lub luag haujlwm tseem ceeb ua alkalizer hauv cov txheej txheem tsim khoom ntawm HPMC. Nyob rau theem pib ntawm kev tsim khoom, cellulose reacts nrog sodium hydroxide tov kom qhib cov hydroxyl pawg ntawm cellulose molecular saw, yog li muab qhov chaw tshuaj tiv thaiv rau cov tshuaj tiv thaiv etherification tom ntej. Cov kauj ruam no tseem hu ua "alkalization reaction". Cov alkalized cellulose tau dhau los ua qee yam kev hloov pauv, ua rau nws yooj yim dua rau cov tshuaj reagents tom ntej (xws li propylene oxide thiab methyl chloride).
3. Propylene oxide (C3H6O)
Propylene oxide yog ib qho tseem ceeb etherifying tus neeg sawv cev hauv HPMC ntau lawm, feem ntau yog siv los hloov cov hydroxyl pawg hauv cellulose rau hauv pawg hydroxypropyl. Tshwj xeeb, cov alkalized cellulose reacts nrog propylene oxide nyob rau hauv tej yam kub thiab siab tej yam kev mob, thiab active epoxy pawg nyob rau hauv propylene oxide txuas mus rau lub molecular saw ntawm cellulose los ntawm ib tug nplhaib-qhib ntxiv cov tshuaj tiv thaiv los tsim ib tug hydroxypropyl substituent. Cov txheej txheem no muab HPMC dej solubility zoo thiab muaj peev xwm thickening.
4. Methyl chloride (CH3Cl)
Methyl chloride yog lwm qhov tseem ceeb etherifying tus neeg sawv cev siv los hloov cov pawg hydroxyl ntawm cellulose rau hauv pawg methoxyl. Methyl chloride reacts nrog hydroxyl pawg ntawm cov cellulose molecular saw los ntawm kev hloov pauv nucleophilic los tsim methyl cellulose. Los ntawm cov tshuaj tiv thaiv methylation no, HPMC tau txais qhov zoo hydrophobicity, tshwj xeeb tshaj yog qhia tau zoo heev solubility hauv qee cov kuab tshuaj organic. Tsis tas li ntawd, kev qhia txog cov pab pawg methoxy ntxiv txhim kho cov cuab yeej ua yeeb yaj kiab thiab tshuaj lom neeg ruaj khov ntawm HPMC.
5. Dej
Dej, raws li qhov hnyav thiab cov tshuaj tiv thaiv nruab nrab, khiav los ntawm tag nrho HPMC cov txheej txheem tsim khoom. Nyob rau hauv cov tshuaj alkalization thiab etherification, dej tsis tsuas yog pab kom yaj sodium hydroxide thiab kho lub xeev hydration ntawm cellulose, tab sis kuj koom nyob rau hauv cov kev cai ntawm cov tshuaj tiv thaiv tshav kub los xyuas kom meej qhov kub thiab txias nyob rau hauv cov txheej txheem tshuaj tiv thaiv. Lub purity ntawm cov dej muaj ib qho tseem ceeb cuam tshuam rau qhov zoo ntawm HPMC, thiab high-purity deionized dej los yog distilled dej feem ntau yuav tsum tau.
6. Cov kuab tshuaj organic
Hauv cov txheej txheem tsim khoom ntawm HPMC, qee cov txheej txheem txheej txheem kuj yuav tsum tau siv qee cov kuab tshuaj organic, xws li methanol lossis ethanol. Cov kuab tshuaj no qee zaum siv los kho cov viscosity ntawm cov tshuaj tiv thaiv kab mob, txo qhov tsim ntawm cov tshuaj tiv thaiv los ntawm cov khoom, lossis txhawb cov tshuaj tiv thaiv tshwj xeeb. Kev xaiv cov organic hnyav yuav tsum tau txiav txim siab raws li qhov xav tau ntawm cov txheej txheem tsim khoom thiab kev siv cov khoom kawg.
7. Lwm yam khoom siv pabcuam
Ntxiv rau cov ntaub ntawv tseem ceeb saum toj no, hauv cov txheej txheem tsim khoom tiag tiag, qee cov khoom siv pabcuam thiab cov khoom siv ntxiv, xws li catalysts, stabilizers, thiab lwm yam, tuaj yeem siv los txhim kho cov tshuaj tiv thaiv, tswj cov tshuaj tiv thaiv lossis txhim kho lub cev thiab tshuaj lom neeg. ntawm cov khoom kawg.
8. Cov kauj ruam tseem ceeb ntawm cov txheej txheem ntau lawm
Cov txheej txheem tseem ceeb ntawm kev tsim HPMC tuaj yeem muab faib ua peb ntu: alkalization, etherification thiab neutralization kev kho mob. Ua ntej, cellulose reacts nrog sodium hydroxide rau alkalize los tsim alkali cellulose. Tom qab ntawd, etherification tshwm sim hauv cov tshuaj tiv thaiv ntawm alkali cellulose nrog propylene oxide thiab methyl chloride los ua hydroxypropyl thiab methoxy hloov cellulose ethers. Thaum kawg, los ntawm kev kho nruab nrab, ntxuav, ziab thiab lwm yam txheej txheem, HPMC cov khoom uas muaj cov kuab tshuaj tshwj xeeb, viscosity thiab lwm yam ntxwv tau txais.
9. Cov txiaj ntsig ntawm cov khoom siv raw zoo ntawm kev ua haujlwm ntawm HPMC cov khoom
Cov khoom sib txawv ntawm cov khoom siv raw thiab purity muaj feem cuam tshuam rau qhov zoo thiab kev ua haujlwm ntawm HPMC zaum kawg. Piv txwv li, purity thiab molecular hnyav tis ntawm cellulose raw cov ntaub ntawv yuav cuam tshuam lub viscosity thiab solubility ntawm HPMC; Kev noj tshuaj thiab cov tshuaj tiv thaiv ntawm propylene oxide thiab methyl chloride yuav txiav txim siab qib ntawm hydroxypropyl thiab methoxy hloov pauv, yog li cuam tshuam rau cov nyhuv thickening thiab zaj duab xis-tsim cov khoom ntawm cov khoom. Yog li ntawd, kev xaiv thiab kev tswj kom zoo ntawm cov khoom siv raw yog qhov tseem ceeb thaum lub sijhawm tsim khoom.
Cov ntaub ntawv tseem ceeb ntawm hydroxypropyl methylcellulose (HPMC) muaj xws li cellulose, sodium hydroxide, propylene oxide, methyl chloride thiab dej. Los ntawm ntau cov tshuaj lom neeg cov tshuaj tiv thaiv, cov khoom siv raw no tau hloov mus rau hauv cov khoom siv nrog cov nqi siv dav. Daim ntawv thov ntau yam ntawm HPMC suav nrog ntau yam xws li tshuaj, khoom siv hauv tsev, thiab zaub mov. Nws cov khoom zoo ntawm lub cev thiab tshuaj lom neeg ua rau nws tseem ceeb hauv ntau qhov kev lag luam.
Post lub sij hawm: Sep-30-2024