Hydroxypropyl methylcellulose (HPMC)ndi ether yofunika kwambiri ya cellulose yomwe siionic yomwe imagwiritsidwa ntchito kwambiri popanga zinthu, mankhwala, chakudya, ndi mankhwala a tsiku ndi tsiku. Kukhuthala ndi chizindikiro chofunikira chowunikira ubwino ndi kugwiritsa ntchito kwa HPMC. Sikuti imangowonetsa mphamvu za rheological za yankho lake komanso imagwirizana mwachindunji ndi kukhuthala kwake, kusunga madzi, ndi mphamvu zopangira filimu. Kuti zitsimikizire kuti zinthuzo zimakhala bwino nthawi zonse, kuyeza kukhuthala kuyenera kuchitidwa pogwiritsa ntchito njira yoyesera kukhuthala yasayansi komanso yokhazikika.
1. Mfundo Yoyesera
HPMC imasungunuka m'madzi kuti ipange yankho lowonekera kapena lowala. Kukhuthala kwake kumadalira makamaka kuchuluka kwa polymerization, kuchuluka kwa kusintha, ndi kuchuluka kwa yankho. Kuyesa kwa kukhuthala kumasonyeza momwe yankho la HPMC limayendera poyesa kukangana kwamkati kwa yankho panthawi yoyenda pa kutentha kwina. Kuyeza nthawi zambiri kumachitika pogwiritsa ntchito viscometer yozungulira (mtundu wa Brookfield) kapena capillary viscometer. Njira yozungulira imagwiritsidwa ntchito kwambiri, chifukwa imapereka kumvetsetsa kwabwino kwa momwe yankho limachepetsera kudulidwa kwa liwiro lozungulira.
2. Miyezo Yofanana ndi Mikhalidwe Yoyesera
Pakadali pano, mayeso a kukhuthala kwa HPMC amachitika makamaka pa izi:
Muyezo Wachi China: GB/T 12000 “Njira Zoyesera Zonse za Cellulose Ethers”
Muyezo wa US: ASTM D1347 "Njira Zoyesera Zokhazikika za Mayankho a Cellulose Ether"
Machitidwe a mafakitale: Kukhuthala kumayesedwa pogwiritsa ntchito yankho la madzi la 2% pa 20°C pogwiritsa ntchito Brookfield rotational viscometer.
Kuchuluka kwa yankho loyesera nthawi zambiri kumakhala 2% (gawo lalikulu), koma magiredi osiyanasiyana a HPMC angafunikenso kuyesedwa pa 1%, 2%, kapena kupitirira apo. Kutentha kwa mayeso kuyenera kulamulidwa mosamala pa 20±0.1°C, chifukwa kusinthasintha kwa kutentha kungakhudze kwambiri kuwerenga kwa viscosity.
3. Njira Yoyesera
3.1. Kukonzekera kwa Reagent ndi Chida
Kulinganiza kolondola kwa kusanthula (kulondola kwa 0.1 mg)
Viscometer yozungulira ya Brookfield (yomwe imapezeka kwambiri mu LV)
3.2. Madzi osambira okhala ndi kutentha kosalekeza kapena malo olamulidwa ndi kutentha
Madzi oyera (akukwaniritsa zofunikira za madzi a GB/T 6682 Giredi III)
Chotsani beaker ndi stirrer
3.3. Kukonzekera Mayankho
Yesani molondola 2.00 g (± 0.01 g) ya chitsanzo cha HPMC.
Ikani pafupifupi 80% ya madzi oyera (pafupifupi 80 mL) mu beaker ndipo mutenthe mpaka pafupifupi 80°C. Pang'onopang'ono komanso mofanana thirani HPMC mu beaker pamene mukusakaniza kuti musamamatire.
Pitirizani kusakaniza mpaka HPMC itanyowa bwino ndikubalalika. Kenako, onjezerani madzi ozizira otsalawo ndikuziziritsa kutentha kwa chipinda, zomwe zimapangitsa kuti kuchuluka konse kufikire 100 mL.
Ikani yankho mufiriji pa 4°C usiku wonse kuti litulutse kutupa kwathunthu ndikuchotsa thovu la mpweya.
3.4. Kuyeza Kukhuthala
Samutsani yankholo ku bafa la madzi lotentha nthawi zonse, kusunga kutentha kwa 20 ± 0.1°C. Sankhani spindle yoyenera (nthawi zambiri Nambala 2 kapena Nambala 3) ndi liwiro (nthawi zambiri 30 rpm).
Yambani viscometer ndikulemba kuwerenga kwa singano ikakhazikika. Bwerezani muyeso uliwonse katatu, ndipo tengani avareji ngati zotsatira zomaliza.
Ngati kuwerenga kwapitirira malire a chipangizocho, sinthani spindle kapena sinthani kuchuluka kwake ndikuyesanso.
4. Zodzitetezera
Kulamulira kutentha n'kofunika kwambiri. Pa kutentha kulikonse kwa 1°C, kukhuthala kwa kutentha kumachepa ndi pafupifupi 2% mpaka 3%.
Yankho liyenera kusungunuka kwathunthu komanso lopanda thovu, apo ayi kuwerenga kudzakhala kochepa kapena kusinthasintha.
HPMC ili ndi mphamvu zochepetsera kudulidwa kwa tsitsi, kotero liwiro ndi nthawi yoyezera ziyenera kusungidwa nthawi zonse.
Madzi ogwiritsidwa ntchito ayenera kukhala opanda zodetsa ndi ma ayoni kuti asakhudze kusungunuka ndi kuwerengedwa.
Chidacho chiyenera kuyesedwa nthawi zonse, ndipo chopondera ndi chidebe cha chitsanzo ziyenera kukhala zoyera.
5. Kusanthula kwa Zinthu Zokhudza Chikhalidwe
Mlingo wa Polymerization ndi Mlingo wa M'malo: Mlingo wa polymerization wa HPMC ukakhala wapamwamba, unyolo wa mamolekyu umakhala wautali komanso kukhuthala kwa yankho kumakhala kwakukulu. Mlingo wa methoxy ndi hydroxypropoxy substitution umakhudzanso hydrophilicity yake ndi kapangidwe ka yankho.
Kuchuluka kwa madzi: Kuchuluka kwa madzi ndi kukhuthala kwa madzi zimayenderana kwambiri, ndipo ngakhale kusintha pang'ono kwa madzi kungakhudze kwambiri zotsatira za mayeso. Kutentha ndi pH: Kutentha kowonjezereka kumachepetsa kukhuthala kwa madzi, pomwe kusintha kwa pH nthawi zambiri sikukhudza kwambiri kukhuthala kwa madzi kwa HPMC chifukwa ndi ether ya cellulose yosakhala ionic.
Yankho la Kukalamba: Kukhuthala kungachepe pang'onopang'ono mutasunga nthawi yayitali. Ndikofunikira kuti mayeso achitike mkati mwa maola 24 kuchokera pamene mwakonzekera.
6. Kupereka Zotsatira ndi Kugwiritsa Ntchito
Zotsatira za mayeso zimafotokozedwa mu mPa·s (milliPascals·masekondi), mwachitsanzo, “2% yankho, 20°C, 20,000 mPa·s.” Mu ntchito zamafakitale,HPMCMagiredi a kukhuthala nthawi zambiri amafotokozedwa m'magawo chikwi, monga 400 cps ndi 20,000 cps. Ogwiritsa ntchito amatha kusankha magiredi osiyanasiyana kutengera zomwe akufuna kugwiritsa ntchito komanso kapangidwe kake.
Nthawi yotumizira: Julayi-30-2025