Cov khoom siv tshuaj ntawm HPMC

Hydroxypropyl Methylcellulose (HPMC)yog ib qho non-ionic cellulose ether, uas yog ib yam khoom hloov kho tshuaj uas tsim los ntawm kev sib xyaw ntawm cov cellulose ntuj nrog propylene oxide thiab methyl chloride tom qab alkalization. HPMC muaj kev ruaj khov zoo ntawm lub cev thiab tshuaj lom neeg thiab siv dav hauv tshuaj, cov ntaub ntawv tsim kho, khoom noj, tshuaj pleev ib ce thiab lwm yam teb. Nws cov khoom siv tshuaj lom neeg yog raws li nram no:

1. Cov yam ntxwv ntawm cov qauv molecular

Lub pob txha yooj yim ntawm HPMC yog los ntawm cov cellulose ntuj, uas yog tsim los ntawm cov glucose units txuas nrog β-1,4-glycosidic bonds los tsim cov saw hlau macromolecular linear. Kev qhia txog hydroxypropyl thiab methoxy pawg ib feem hloov cov hydroxyl (-OH) pawg ntawm cov saw hlau cellulose molecular, yog li muab nws cov khoom tshwj xeeb. Qhov kev hloov pauv no (piv txwv li, qhov kev hloov pauv ntawm methoxy thiab hydroxypropyl pawg) muaj kev cuam tshuam tseem ceeb rau kev yaj, cov khoom gel thiab kev ruaj khov ntawm HPMC.

2. Kev yaj tau

HPMC yog ib hom polymer uas yaj tau hauv dej uas tsis yog ionic uas tuaj yeem o sai sai hauv dej txias thiab tsim cov kua colloidal pob tshab lossis pob tshab. Txawm li cas los xij, hauv dej kub, HPMC tsis yooj yim yaj thiab yuav tsim cov gel ntawm qhov kub siab. Cov khoom siv thermoreversible gel no yog ib qho ntawm cov khoom siv lub cev thiab tshuaj tseem ceeb ntawm HPMC. Ntxiv rau dej, HPMC kuj tseem tuaj yeem yaj rau hauv qee cov kuab tshuaj polar organic, xws li cov kuab tshuaj sib xyaw ntawm ethanol thiab dej, dimethylformamide, thiab lwm yam.

3. Kev ruaj khov ntawm thermal thiab gelation

HPMC muaj kev ruaj khov zoo heev. Thaum qhov kub nce siab, HPMC cov saw hlau hauv cov kua dej yuav dhau los ua kev sib koom ua ke kom qhuav los tsim cov qauv network peb-seem, thiab kev hloov pauv ntawm cov tshuaj mus rau gel yuav tshwm sim. Qhov kub ntawm gelation nyob ntawm cov ntsiab lus thiab qhov hnyav molecular ntawm cov substituents. Feem ntau hais lus, HPMC nrog cov ntsiab lus hydroxypropyl siab muaj qhov kub ntawm gelation siab dua, thaum HPMC nrog cov ntsiab lus methoxy siab muaj qhov kub ntawm gelation qis dua.

Kev ua kom cov gelation rov qab tau, thiab cov gel yuav yaj rov qab mus rau hauv cov kua tom qab txias. Cov khoom siv thermogel tshwj xeeb no ua rau HPMC feem ntau siv ua cov khoom siv tso tawm tas mus li hauv kev lag luam tshuaj thiab siv hauv kev lag luam cov ntaub ntawv tsim kho kom txhim kho kev ua haujlwm ntawm cov mortar.

4. Kev ruaj khov ntawm pH

HPMC tswj tau qhov ruaj khov zoo hauv pH ntau ntawm 3 ~ 11. Qhov pH ruaj khov dav dav no tso cai rau nws siv rau ntau qhov chaw tsis muaj kev puas tsuaj lossis nag lossis daus. Thaum tus nqi pH qis dua 3 lossis siab dua 11, cov tshuaj yuav raug puas tsuaj lossis nag lossis daus vim muaj cov hydrogen ions lossis hydroxide ions ntau, ua rau kev ua haujlwm txo qis.

5. Kev Ua Haujlwm Tshuaj Lom Zem

Vim muaj qee pawg hydroxyl tsis tau hloov pauv hauv HPMC molecule, nws tseem khaws cia qee yam kev ua haujlwm tshuaj lom neeg thiab tuaj yeem ua rau muaj cov tshuaj tiv thaiv hauv qab no:

Cov tshuaj tiv thaiv esterification: Nyob rau hauv cov xwm txheej tsim nyog, HPMC tuaj yeem cuam tshuam nrog acyl chlorides, anhydrides, thiab lwm yam los tsim cov esters;

Cov tshuaj tiv thaiv etherification: Cov pab pawg hydroxyl seem tuaj yeem txuas ntxiv mus rau kev cuam tshuam nrog cov neeg sawv cev etherifying (xws li epoxides) kom hloov pauv qib ntawm kev hloov pauv thiab kev ua tau zoo ntawm HPMC;

Cov tshuaj tiv thaiv oxidation: Nyob rau hauv qhov muaj cov tshuaj oxidants muaj zog (xws li potassium permanganate, sodium hypochlorite), cov saw hlau molecular ntawm HPMC yuav tawg, ua rau viscosity txo qis;

Cov tshuaj tiv thaiv hydrolysis: Nyob rau hauv qhov kev ua ntawm cov kua qaub muaj zog lossis cov hauv paus muaj zog, hydroxypropyl thiab methoxy sab saw hlau yuav raug hydrolyzed, ua rau muaj kev hloov pauv hauv cov qauv molecular thiab kev ua haujlwm poob qis.

Feem ntau, nyob rau hauv cov xwm txheej ib txwm muaj, cov khoom siv tshuaj ntawm HPMC yog qhov ruaj khov.

6. Kev puas tsuaj ntawm cov khoom noj

HPMC yog los ntawm cov cellulose ntuj, yog li nws tuaj yeem raug rhuav tshem mus rau hauv cov suab thaj me me hauv ib puag ncig tshwj xeeb (xws li nyob rau hauv kev ua ntawm cov kab mob me me), thiab thaum kawg decomposed rau hauv carbon dioxide thiab dej. Qhov kev puas tsuaj zoo no ua rau HPMC ua tau raws li qhov xav tau ntawm cov khoom siv ib puag ncig.

7. Kev sib raug zoo nrog lwm yam tshuaj

Ua ib qho polymer uas tsis yog ionic, HPMC muaj kev sib raug zoo nrog ntau yam ionic lossis non-ionic additives (xws li lwm cov polymers, surfactants, thickeners, thiab lwm yam). Tshwj xeeb tshaj yog nyob rau hauv lub formulation system, nws tuaj yeem ua haujlwm nrog ntau yam tshuaj xyaw, cov as-ham, pigments, thiab lwm yam yam tsis muaj nag lossis stratification.

qhov kev ruaj khov ntawm HPMC nyob rau hauv qhov chaw muaj electrolyte concentration siab yuav raug cuam tshuam, thiab ntau dhau inorganic ntsev yuav ua rau cov kua viscosity txo qis lossis txawm tias precipitate.

8. Kev tiv thaiv enzyme

Piv nrog cov cellulose ntuj,HPMCmuaj kev tiv thaiv zoo dua rau cellulase vim yog kev hloov pauv ntawm qee pawg hydroxyl, thiab tsis yooj yim decomposed los ntawm cov enzymes ib txwm muaj. Qhov no ua rau nws muaj qhov zoo ntawm kev tso tawm cov tshuaj qeeb hauv ib puag ncig plab hnyuv.

Hydroxypropyl methylcellulose (HPMC) yog cov khoom siv polymer ntuj uas tau hloov kho los ntawm tshuaj lom neeg nrog kev yaj dej zoo, thermal gelation, pH stability, tshuaj lom neeg ruaj khov thiab biodegradability. Vim nws cov qauv tshwj xeeb thiab cov khoom siv tshuaj lom neeg, HPMC yog siv dav hauv kev kho mob, cov ntaub ntawv tsim kho, coatings, khoom noj, tshuaj pleev ib ce, thiab lwm yam, tshwj xeeb tshaj yog hauv cov qauv uas xav tau thickening, tswj kev tso tawm, tsim zaj duab xis, ncua, emulsification thiab lwm yam haujlwm.