HPMC cov khoom xyaw

Hydroxypropyl Methylcellulose (HPMC) yog cellulose ether muab los ntawm cov cellulose ntuj, feem ntau yog ntoo lossis paj rwb, los ntawm cov txheej txheem tshuaj lom neeg. Nov yog cov lus piav qhia ntawm cov khoom xyaw thiab cov khoom ntawm HPMC:

1. Cellulose: Cellulose yog cov khoom tseem ceeb hauv HPMC. Nws yog ib txwm tshwm sim polysaccharide uas muaj cov piam thaj rov qab txuas ua ke hauv cov saw ntev. Cellulose ua haujlwm raws li tus txha caj qaum ntawm HPMC thiab muab kev ntseeg ruaj khov.
2. Methylation: Cov pob txha cellulose yog tshuaj hloov kho los ntawm cov txheej txheem hu ua methylation, qhov twg methyl chloride reacted nrog cellulose nyob rau hauv lub xub ntiag ntawm alkali los qhia methyl (-CH3) pawg mus rau cov saw cellulose. Cov txheej txheem methylation no yog qhov tseem ceeb rau kev txhim kho cov dej solubility thiab lwm yam khoom ntawm cellulose.
3. Hydroxypropylation: Ntxiv nrog rau methylation, hydroxypropyl pawg (-CH2CHOHCH3) kuj tuaj yeem nkag mus rau cov saw cellulose los ntawm hydroxypropylation. Qhov no ntxiv hloov cov khoom ntawm cellulose, txhim kho nws cov dej tuav, kev ua yeeb yaj kiab, thiab lwm yam ntxwv.
4. Etherification: Kev taw qhia ntawm methyl thiab hydroxypropyl pawg mus rau cov saw cellulose hu ua etherification. Etherification hloov kho cov qauv tshuaj ntawm cellulose, ua rau tsim HPMC nrog cov khoom tshwj xeeb tsim nyog rau ntau yam kev siv.
5. Lub cev muaj zog: HPMC feem ntau yog xim dawb rau dawb, tsis muaj ntxhiab tsw, thiab tsw qab hmoov. Nws yog soluble nyob rau hauv dej txias thiab cov ntaub ntawv ntshiab los yog me ntsis turbid daws nyob ntawm qhov concentration thiab qib. HPMC nthuav tawm cov dej tuav tau zoo, ua kom tuab, ua yeeb yaj kiab, thiab cov khoom ua haujlwm saum npoo av, ua rau nws muaj txiaj ntsig hauv ntau qhov kev lag luam, suav nrog kev tsim kho, tshuaj, khoom noj, thiab tshuaj pleev ib ce.

Zuag qhia tag nrho, cov khoom xyaw tseem ceeb hauv HPMC yog cellulose, methyl chloride (rau methylation), thiab propylene oxide (rau hydroxypropylation), nrog rau alkali catalysts thiab lwm yam additives siv hauv kev tsim khoom. Cov khoom xyaw no dhau los ua tshuaj lom neeg los tsim HPMC nrog cov khoom tshwj xeeb tsim kom tau raws li cov kev xav tau ntawm cov ntawv thov sib txawv.