Hydroxypropyl methylcellulose (HPMC) ndi gawo lofunikira la semi-synthetic cellulose ether, lomwe limagwiritsidwa ntchito kwambiri muzamankhwala, zomangira, chakudya, zokutira ndi mafakitale ena. HPMC ali thickening wabwino, emulsification, filimu kupanga, moisturizing, kukhazikika ndi katundu zina, choncho ali zofunika ntchito phindu m'madera ambiri. Zida zazikulu zopangira HPMC zimaphatikizapo mapadi, sodium hydroxide, propylene oxide, methyl chloride ndi madzi.
1. Ma cellulose
Cellulose ndiye chinthu chachikulu cha HPMC, chomwe nthawi zambiri chimachokera ku ulusi wachilengedwe monga thonje ndi nkhuni. Cellulose ndiye polima wachilengedwe wochuluka kwambiri padziko lapansi. Mapangidwe ake a molekyulu ndi polysaccharide yayitali yopangidwa ndi mayunitsi a shuga olumikizidwa ndi β-1,4-glycosidic bond. Cellulose palokha sisungunuka m'madzi ndipo ilibe ma reactivity abwino a mankhwala. Chifukwa chake, njira zingapo zosinthira mankhwala zimafunikira kuti ziwonjezere kusungunuka kwake ndi magwiridwe antchito pokonzekera zinthu zosiyanasiyana zama cellulose ether.
2. Sodium hydroxide (NaOH)
Sodium hydroxide, yomwe imadziwikanso kuti caustic soda, ndi yamchere yamchere yomwe imagwira ntchito yofunika kwambiri ngati alkalizer popanga HPMC. Kumayambiriro kwa kupanga, cellulose imakhudzidwa ndi sodium hydroxide solution kuti ayambitse magulu a hydroxyl pa cellulose cell chain, potero amapereka malo ochitirapo etherification. Sitepe iyi imatchedwanso "alkalization reaction". Ma cellulose opangidwa ndi alkalized amatha kusintha kamangidwe kake, kupangitsa kuti zikhale zosavuta kuchitapo kanthu ndi ma reagents amtundu wotsatira (monga propylene oxide ndi methyl chloride).
3. Propylene oxide (C3H6O)
Propylene oxide ndi imodzi mwazinthu zopangira etherifying pakupanga kwa HPMC, zomwe zimagwiritsidwa ntchito makamaka kutembenuza magulu a hydroxyl mu cellulose kukhala magulu a hydroxypropyl. Mwachindunji, mapadi a alkalized cellulose amakhudzidwa ndi propylene oxide pansi pa kutentha ndi kupanikizika kwina, ndipo magulu a epoxy omwe amagwira ntchito mu propylene oxide amalumikizidwa ndi unyolo wa cellulose kudzera munjira yotsegulira mphete kuti apange cholowa cha hydroxypropyl. Izi zimapatsa HPMC kusungunuka kwamadzi kwabwino komanso kukulitsa luso.
4. Methyl chloride (CH3Cl)
Methyl chloride ndi chinthu china chofunikira chopangira etherifying chomwe chimagwiritsidwa ntchito kusintha magulu a hydroxyl a cellulose kukhala magulu a methoxyl. Methyl chloride imakhudzidwa ndi magulu a hydroxyl pama cellulose cellulose kudzera mu nucleophilic substitution reaction kuti apange methyl cellulose. Kudzera mukuchita kwa methylation, HPMC imapeza hydrophobicity yabwino, makamaka kuwonetsa kusungunuka kwabwino mu zosungunulira zina. Kuonjezera apo, kukhazikitsidwa kwa magulu a methoxy kumapangitsanso kuti katundu wopangira mafilimu azitha kukhazikika komanso kukhazikika kwa mankhwala a HPMC.
5. Madzi
Madzi, monga zosungunulira ndi kuchitapo kanthu, amadutsa munjira yonse yopanga HPMC. Mu alkalization ndi etherification zimachitikira, madzi osati kumathandiza kupasuka sodium hydroxide ndi kusintha hydration boma mapadi, komanso nawo lamulo la anachita kutentha kuonetsetsa kutentha kulamulira lonse ndondomeko anachita. Kuyera kwamadzi kumakhudza kwambiri khalidwe la HPMC, ndipo madzi oyeretsedwa kwambiri kapena madzi osungunuka nthawi zambiri amafunikira.
6. Organic solvents
Popanga HPMC, masitepe ena angafunikenso kugwiritsa ntchito zosungunulira za organic, monga methanol kapena Mowa. Zosungunulira izi nthawi zina ntchito kusintha mamasukidwe akayendedwe dongosolo anachita, kuchepetsa mapangidwe anachita ndi mankhwala, kapena kulimbikitsa enieni zimachitikira. Kusankhidwa kwa zosungunulira za organic kuyenera kutsimikiziridwa molingana ndi zosowa za njira yopangira komanso kugwiritsa ntchito komaliza.
7. Zida zina zothandizira
Kuwonjezera pa pamwamba zipangizo zazikulu zopangira, mu ndondomeko yeniyeni kupanga, zinthu zina wothandiza ndi zina, monga chothandizira, stabilizers, etc., angagwiritsidwe ntchito kusintha anachita dzuwa, kulamulira anachita mlingo kapena kusintha thupi ndi mankhwala katundu. wa mankhwala omaliza.
8. Njira zazikulu zopangira
Njira zazikulu zopangira HPMC zitha kugawidwa m'magawo atatu: alkalization, etherification ndi neutralization chithandizo. Choyamba, cellulose imakhudzidwa ndi sodium hydroxide kuti alkalize kupanga alkali cellulose. Kenako, etherification imachitika pakuchita kwa alkali cellulose ndi propylene oxide ndi methyl chloride kupanga hydroxypropyl ndi methoxy substituted cellulose ethers. Pomaliza, kudzera mu chithandizo cha neutralization, kutsuka, kuyanika ndi njira zina, zinthu za HPMC zokhala ndi kusungunuka kwapadera, mamasukidwe akayendedwe ndi zina zimapezedwa.
9. Zotsatira za khalidwe lazopangira pa ntchito ya mankhwala a HPMC
Zopangira zosiyanasiyana zopangira ndi kuyera zimakhudza kwambiri mtundu ndi magwiridwe antchito a HPMC yomaliza. Mwachitsanzo, chiyero ndi kugawa kwa maselo a cellulose yaiwisi kukhudza kukhuthala ndi kusungunuka kwa HPMC; Mlingo ndi machitidwe a propylene oxide ndi methyl chloride zidzatsimikizira kuchuluka kwa hydroxypropyl ndi methoxy substitution, motero zimakhudza kukhuthala ndi kupanga mafilimu a mankhwala. Choncho, kusankha ndi kuwongolera khalidwe la zipangizo ndizofunikira kwambiri panthawi yopanga.
Zida zazikulu za hydroxypropyl methylcellulose (HPMC) zimaphatikizapo mapadi, sodium hydroxide, propylene oxide, methyl chloride ndi madzi. Kupyolera m'njira zingapo zovuta zamankhwala, zopangira izi zimasinthidwa kukhala zinthu zogwirira ntchito zomwe zimakhala ndi phindu lalikulu. Mitundu yogwiritsira ntchito HPMC imakhudza magawo ambiri monga mankhwala, zomangira, ndi chakudya. Ubwino wake wakuthupi ndi mankhwala zimapangitsa kuti ikhale yofunika kwambiri m'mafakitale ambiri.
Nthawi yotumiza: Sep-30-2024