Hydroxypropyl methylcellulose (HPMC) ndi polima wosungunuka m'madzi wosasungunuka ndi ionic womwe umapezeka mwa kusintha kwa mankhwala a cellulose achilengedwe. Umagwiritsidwa ntchito kwambiri m'mafakitale azakudya, mankhwala, zodzoladzola ndi zomangamanga, makamaka ngati guluu, chokhuthala, chosakaniza ndi chosungunula mu mankhwala. Mu njira yogwiritsira ntchito, mawonekedwe a kukhuthala kwa yankho lamadzi la HPMC ndi ofunikira kwambiri pakugwira ntchito kwake m'magawo osiyanasiyana.
1. Kapangidwe ndi makhalidwe a hydroxypropyl methylcellulose
Kapangidwe ka mamolekyu a HPMC kali ndi magulu awiri olowa m'malo, hydroxypropyl (-CH2)₂CHOHCH₃ndi methyl (-OCH₃), zomwe zimapangitsa kuti ikhale ndi madzi abwino osungunuka komanso kuthekera kosintha. Unyolo wa mamolekyulu a HPMC uli ndi kapangidwe kolimba, koma ukhozanso kupanga kapangidwe ka netiweki ya magawo atatu mu yankho lamadzi, zomwe zimapangitsa kuti kukhuthala kwake kuchuluke. Kulemera kwake kwa mamolekyulu, mtundu wa cholowa m'malo mwake ndi digiri ya cholowa m'malo mwake (mwachitsanzo, digiri ya hydroxypropyl ndi methyl substitution ya unit iliyonse) zimakhudza kwambiri kukhuthala kwa yankho.
2. Makhalidwe a kukhuthala kwa yankho lamadzi
Makhalidwe a kukhuthala kwa yankho lamadzi la HPMC amagwirizana kwambiri ndi zinthu monga kuchuluka, kulemera kwa mamolekyulu, kutentha ndi pH ya chosungunulira. Kawirikawiri, kukhuthala kwa yankho lamadzi la HPMC kumawonjezeka ndi kuwonjezeka kwa kuchuluka kwake. Kukhuthala kwake kumasonyeza khalidwe la rheological losakhala la Newtonian, ndiko kuti, pamene kuchuluka kwa kudulidwa kwa madzi kukukwera, kukhuthala kwa yankho kumachepa pang'onopang'ono, kusonyeza kuchepetsedwa kwa kudulidwa kwa madzi.
(1) Zotsatira za kusinkhasinkha
Pali ubale wina pakati pa kukhuthala kwa yankho lamadzi la HPMC ndi kuchuluka kwake. Pamene kuchuluka kwa HPMC kukuchulukirachulukira, kuyanjana kwa mamolekyu mu yankho lamadzi kumawonjezeka, ndipo kusakanikirana ndi kulumikizidwa kwa maunyolo a mamolekyu kumawonjezeka, zomwe zimapangitsa kuti kukhuthala kwa yankho kuchuluke. Pakuchulukira pang'ono, kukhuthala kwa yankho lamadzi la HPMC kumawonjezeka motsatizana ndi kuwonjezeka kwa kuchuluka, koma pakukula kwakukulu, kukula kwa kukhuthala kwa yankho kumakhala kosalala ndipo kumafika pamtengo wokhazikika.
(2) Zotsatira za kulemera kwa mamolekyulu
Kulemera kwa mamolekyulu a HPMC kumakhudza mwachindunji kukhuthala kwa yankho lake lamadzi. HPMC yokhala ndi kulemera kwakukulu kwa mamolekyulu imakhala ndi maunyolo ataliatali a mamolekyulu ndipo imatha kupanga kapangidwe ka netiweki kovuta kwambiri ka magawo atatu mu yankho lamadzi, zomwe zimapangitsa kukhuthala kwakukulu. Mosiyana ndi zimenezi, HPMC yokhala ndi kulemera kochepa kwa mamolekyulu imakhala ndi kapangidwe ka netiweki komasuka komanso kukhuthala kochepa chifukwa cha maunyolo ake afupiafupi a mamolekyulu. Chifukwa chake, mukamagwiritsa ntchito, ndikofunikira kwambiri kusankha HPMC yokhala ndi kulemera koyenera kwa mamolekyulu kuti mukwaniritse zotsatira zabwino za kukhuthala.
(3) Zotsatira za kutentha
Kutentha ndi chinthu chofunikira chomwe chimakhudza kukhuthala kwa yankho lamadzi la HPMC. Pamene kutentha kukukwera, kuyenda kwa mamolekyulu amadzi kumawonjezeka ndipo kukhuthala kwa yankho nthawi zambiri kumachepa. Izi zili choncho chifukwa kutentha kukakwera, ufulu wa unyolo wa mamolekyulu a HPMC umawonjezeka ndipo kuyanjana pakati pa mamolekyu kumachepa, motero kuchepetsa kukhuthala kwa yankho. Komabe, momwe HPMC imayankhira kuchokera ku magulu osiyanasiyana kapena mitundu yosiyanasiyana ku kutentha kungasiyanenso, kotero mikhalidwe ya kutentha iyenera kusinthidwa malinga ndi zofunikira zinazake zogwiritsidwa ntchito.
(4) Zotsatira za pH
HPMC yokha ndi mankhwala osakhala a ayoni, ndipo kukhuthala kwa yankho lake lamadzi kumakhudzidwa ndi kusintha kwa pH. Ngakhale kuti HPMC ili ndi makhalidwe okhazikika a kukhuthala m'malo okhala ndi asidi kapena osalowerera ndale, kusungunuka ndi kukhuthala kwa HPMC kudzakhudzidwa m'malo okhala ndi asidi kapena alkaline kwambiri. Mwachitsanzo, pansi pa mkhalidwe wa asidi kapena alkaline wamphamvu, mamolekyu a HPMC akhoza kuwonongeka pang'ono, motero kuchepetsa kukhuthala kwa yankho lake lamadzi.
3. Kusanthula kwa rheological kwa makhalidwe a kukhuthala kwa yankho la madzi la HPMC
Kachitidwe ka rheological ka HPMC aqueous solution nthawi zambiri kamasonyeza makhalidwe a madzi osakhala a Newtonian fluid, zomwe zikutanthauza kuti kukhuthala kwake sikungogwirizana ndi zinthu monga kuchuluka kwa yankho ndi kulemera kwa mamolekyulu, komanso ndi kuchuluka kwa kumeta. Kawirikawiri, pamlingo wotsika wa kumeta, HPMC aqueous solution imawonetsa kukhuthala kwakukulu, pomwe pamene kuchuluka kwa kumeta kumawonjezeka, kukhuthala kumachepa. Khalidweli limatchedwa "kumeta shear" kapena "kumeta shear" ndipo ndilofunika kwambiri pa ntchito zambiri zothandiza. Mwachitsanzo, m'magawo a zokutira, kukonzekera mankhwala, kukonza chakudya, ndi zina zotero, makhalidwe a kumeta shear a HPMC amatha kutsimikizira kuti kukhuthala kwakukulu kumasungidwa panthawi yogwiritsa ntchito liwiro lochepa, ndipo imatha kuyenda mosavuta pansi pa mikhalidwe yometa mwachangu.
4. Zinthu zina zomwe zimakhudza kukhuthala kwa yankho lamadzi la HPMC
(1) Zotsatira za mchere
Kuonjezera mchere wosungunuka (monga sodium chloride) kungawonjezere kukhuthala kwa madzi a HPMC. Izi zili choncho chifukwa mchere ukhoza kuwonjezera kuyanjana pakati pa mamolekyu mwa kusintha mphamvu ya ayoni ya yankho, kotero kuti mamolekyu a HPMC amapanga kapangidwe kakang'ono ka netiweki, motero kuwonjezera kukhuthala. Komabe, mphamvu ya mtundu wa mchere ndi kuchuluka kwake pa kukhuthala kuyeneranso kusinthidwa malinga ndi zochitika zinazake.
(2) Zotsatira za zowonjezera zina
Kuwonjezera zina zowonjezera (monga ma surfactants, ma polima, ndi zina zotero) ku yankho lamadzi la HPMC kudzakhudzanso kukhuthala kwa HPMC. Mwachitsanzo, ma surfactants angachepetse kukhuthala kwa HPMC, makamaka pamene kuchuluka kwa surfactant kuli kwakukulu. Kuphatikiza apo, ma polima kapena tinthu tina tingathenso kuyanjana ndi HPMC ndikusintha mawonekedwe a rheological a yankho lake.
Makhalidwe a kukhuthala kwahydroxypropyl methylcellulose Madzi amadzi amakhudzidwa ndi zinthu zambiri, kuphatikizapo kuchuluka kwa madzi, kulemera kwa mamolekyulu, kutentha, pH, ndi zina zotero. Madzi amadzi a HPMC nthawi zambiri amakhala ndi mphamvu zosakhala za Newtonian rheological, amakhala ndi mphamvu zabwino zokhuthala komanso zochepetsera kuuma kwa madzi, ndipo amagwiritsidwa ntchito kwambiri m'magawo osiyanasiyana a mafakitale ndi mankhwala. Kumvetsetsa ndikudziwa bwino makhalidwe a kukhuthala kumeneku kungathandize kugwiritsa ntchito bwino HPMC m'magwiritsidwe osiyanasiyana. Mu ntchito zenizeni, mtundu woyenera wa HPMC ndi momwe zinthu zilili ziyenera kusankhidwa malinga ndi zosowa zenizeni kuti mupeze kukhuthala koyenera komanso mphamvu zochiritsira matenda a m'magazi.
Nthawi yotumizira: Mar-01-2025