Hydroxypropyl methylcellulose (HPMC) yog ntau yam polymer nrog ntau yam kev siv hauv ntau yam lag luam xws li tshuaj, khoom noj khoom haus, kev tsim kho thiab tshuaj pleev ib ce. Lub ntsiab raw khoom siv los ua ke HPMC yog cellulose thiab propylene oxide.
1. Cellulose: lub hauv paus ntawm HPMC
1.1 Txheej txheem cej luam ntawm cellulose
Cellulose yog ib tug complex carbohydrate uas yog lub ntsiab structural tivthaiv ntawm ntsuab cog cell phab ntsa. Nws muaj cov kab sib txuas ntawm cov piam thaj molecules txuas ua ke los ntawm β-1,4-glycosidic bonds. Kev nplua nuj ntawm cov pab pawg hydroxyl hauv cellulose ua rau nws tsim cov khoom pib rau kev sib txuas ntawm ntau yam cellulose derivatives, suav nrog HPMC.
1.2 Cellulose khoom
Cellulose tuaj yeem muab tau los ntawm cov khoom siv cog ntoo sib txawv, xws li ntoo pulp, paj rwb linters, lossis lwm yam nroj tsuag fibrous. Ntoo pulp yog ib qho chaw vim nws cov nplua nuj, muaj txiaj ntsig zoo, thiab kev ruaj khov. Kev rho tawm ntawm cellulose feem ntau cuam tshuam nrog kev rhuav tshem cov nroj tsuag fibers los ntawm kev siv tshuab thiab tshuaj lom neeg.
1.3 Purity thiab yam ntxwv
Qhov zoo thiab purity ntawm cellulose yog qhov tseem ceeb hauv kev txiav txim siab cov yam ntxwv ntawm HPMC cov khoom kawg. High-purity cellulose xyuas kom meej tias HPMC yog tsim nrog cov khoom sib xws xws li viscosity, solubility thiab thermal stability.
2. Propylene oxide: kev taw qhia ntawm hydroxypropyl pawg
2.1 Taw qhia rau propylene oxide
Propylene oxide (PO) yog cov organic compound nrog cov tshuaj formula C3H6O. Nws yog ib qho epoxide, txhais tau tias nws muaj cov pa oxygen atom txuas rau ob lub atoms uas nyob ib sab. Propylene oxide yog cov khoom siv tseem ceeb rau kev sib txuas ntawm hydroxypropyl cellulose, uas yog ib qho nruab nrab rau kev tsim HPMC.
2.2 Hydroxypropylation txheej txheem
Cov txheej txheem hydroxypropylation suav nrog cov tshuaj tiv thaiv ntawm cellulose nrog propylene oxide los qhia cov pab pawg hydroxypropyl mus rau cov pob txha cellulose. Cov tshuaj tiv thaiv no feem ntau yog ua nyob rau hauv lub xub ntiag ntawm ib qho yooj yim catalyst. Hydroxypropyl pawg impart txhim kho solubility thiab lwm yam khoom tsim nyog rau cellulose, ua rau tsim hydroxypropyl cellulose.
3. Methylation: Ntxiv methyl pawg
3.1 Methylation txheej txheem
Tom qab hydroxypropylation, cov kauj ruam tom ntej hauv HPMC synthesis yog methylation. Cov txheej txheem suav nrog kev qhia txog cov pab pawg methyl mus rau cov pob txha cellulose. Methyl chloride yog ib qho tshuaj reagent siv rau cov tshuaj tiv thaiv no. Qib ntawm methylation cuam tshuam cov khoom ntawm HPMC cov khoom kawg, suav nrog nws cov viscosity thiab gel cwj pwm.
3.2 Degree ntawm kev hloov
Qhov degree ntawm kev hloov pauv (DS) yog qhov tseem ceeb rau kev ntsuas qhov nruab nrab ntawm cov neeg hloov pauv (methyl thiab hydroxypropyl) ib chav tsev anhydroglucose hauv cov saw cellulose. Cov txheej txheem tsim khoom yog ua tib zoo tswj kom ua tiav qhov kev xav tau ntawm HPMC cov khoom.
4. Purification thiab Kev Tswj Xyuas Zoo
4.1 Tshem tawm los ntawm cov khoom lag luam
Kev sib xyaw ntawm HPMC tuaj yeem ua rau tsim cov khoom lag luam xws li cov ntsev los yog cov tshuaj tsis muaj zog. Cov kauj ruam ua kom huv nrog rau kev ntxuav thiab lim yog siv los tshem tawm cov impurities thiab ua kom cov purity ntawm cov khoom kawg.
4.2 Kev tswj xyuas kev ua tau zoo
Kev tswj xyuas nruj nruj yog siv thoob plaws hauv cov txheej txheem tsim khoom kom ntseeg tau qhov sib xws thiab zoo ntawm HPMC. Cov txheej txheem tshuaj ntsuam xyuas xws li spectroscopy, chromatography thiab rheology yog siv los ntsuas qhov ntsuas xws li qhov hnyav molecular, qib kev hloov pauv thiab viscosity.
5. Yam ntxwv ntawm Hydroxypropyl Methylcellulose (HPMC)
5.1 Lub cev muaj zog
HPMC yog cov hmoov dawb mus rau dawb, tsis muaj ntxhiab tsw nrog cov yeeb yaj kiab zoo heev. Nws yog hygroscopic thiab yooj yim tsim cov pob tshab gel thaum dispersed hauv dej. Lub solubility ntawm HPMC nyob ntawm seb qhov kev hloov pauv thiab cuam tshuam los ntawm cov yam ntxwv xws li kub thiab pH.
5.2 Cov qauv tshuaj
Cov qauv tshuaj ntawm HPMC muaj cov pob txha cellulose nrog hydroxypropyl thiab methyl substituents. Qhov piv ntawm cov khoom hloov pauv no, cuam tshuam txog qib ntawm kev hloov pauv, txiav txim siab tag nrho cov qauv tshuaj thiab yog li cov khoom ntawm HPMC.
5.3 Viscosity thiab rheological zog
HPMC muaj nyob rau hauv ntau qib nrog cov viscosity sib txawv. Lub viscosity ntawm HPMC cov kev daws teeb meem yog qhov tseem ceeb hauv kev siv xws li tshuaj, qhov twg nws cuam tshuam rau kev tso tawm cov tshuaj, thiab hauv kev tsim kho, qhov twg nws cuam tshuam rau kev ua haujlwm ntawm mortars thiab pastes.
5.4 Film-forming thiab thickening zog
HPMC yog dav siv raws li ib tug zaj duab xis yav dhau los nyob rau hauv tshuaj coatings thiab raws li ib tug thickening neeg sawv cev nyob rau hauv ntau yam formulations. Nws cov yeeb yaj kiab-tsim muaj peev xwm ua rau nws muaj txiaj ntsig hauv kev txhim kho kev tswj hwm-tso tshuaj txheej txheej, thaum nws cov khoom thickening txhim khu kev ntxhib los mos thiab ruaj khov ntawm ntau yam khoom.
6. Daim ntawv thov ntawm hydroxypropyl methylcellulose
6.1 Pharmaceutical kev lag luam
Hauv kev lag luam kws tshuaj, HPMC yog siv los tsim cov ntaub ntawv ntawm qhov ncauj zoo li cov ntsiav tshuaj thiab tshuaj ntsiav. Nws yog feem ntau yog siv los ua ib tug binder, disintegrant thiab zaj duab xis txheej tus neeg sawv cev. Cov khoom tswj-tso tawm ntawm HPMC pab txhawb nws daim ntawv thov hauv cov qauv tsim tawm.
6.2 Kev tsim kho kev lag luam
Hauv kev tsim kho, HPMC yog siv los ua tus neeg saib xyuas dej, thickener thiab nplaum hauv cov khoom siv cement. Nws txhim khu kev ua haujlwm ntawm cov mortar, tiv thaiv sagging nyob rau hauv daim ntawv thov ntsug, thiab txhim kho tag nrho cov kev ua tau zoo ntawm cov khoom siv hauv tsev.
6.3 Kev lag luam zaub mov
HPMC yog siv rau hauv kev lag luam khoom noj khoom haus ua cov thickener, stabilizer thiab emulsifier. Nws lub peev xwm los tsim cov gels ntawm qhov tsis tshua muaj siab ua rau nws haum rau ntau yam kev siv, nrog rau cov kua ntses, hnav khaub ncaws thiab khoom qab zib.
6.4 Tshuaj pleev ib ce thiab khoom tu tus kheej
Hauv cov tshuaj pleev ib ce thiab cov khoom tu tus kheej, HPMC muaj nyob rau hauv ntau hom tshuaj xws li cream, tshuaj pleev thiab tshuaj zawv plaub hau. Nws pab txhim kho kev ntxhib los mos, ruaj khov thiab kev ua tau zoo tag nrho ntawm cov khoom no.
6.5 Lwm yam kev lag luam
HPMC qhov kev ua tau zoo txuas ntxiv mus rau lwm qhov kev lag luam, suav nrog textiles, xim thiab cov nplaum, qhov uas nws tuaj yeem siv los ua tus hloov kho rheology, tus neeg saib xyuas dej thiab cov thickener.
7. Cov lus xaus
Hydroxypropylmethylcellulose yog ntau yam polymer nrog ntau daim ntawv thov. Nws cov synthesis siv cellulose thiab propylene oxide ua cov ntaub ntawv tseem ceeb, thiab cov cellulose yog hloov los ntawm hydroxypropylation thiab methylation txheej txheem. Kev tswj hwm ntawm cov khoom siv raw thiab cov tshuaj tiv thaiv tuaj yeem tsim HPMC nrog cov khoom tsim kho kom tau raws li cov kev xav tau tshwj xeeb hauv kev lag luam. Yog li, HPMC ua lub luag haujlwm tseem ceeb hauv kev txhim kho kev ua haujlwm thiab kev ua haujlwm ntawm cov khoom thoob plaws kev lag luam. Kev tshawb nrhiav txuas ntxiv ntawm cov ntawv thov tshiab thiab kev txhim kho cov txheej txheem tsim khoom pab HPMC txuas ntxiv ua lub luag haujlwm tseem ceeb hauv kev ua lag luam thoob ntiaj teb.
Post lub sij hawm: Dec-28-2023