HPMC (HydroxyPropyyl methylcellulose) Yog dej-soluble polymer compound dav siv hauv cov tshuaj, kev tsim kho, kev siv tshuaj pleev thiab lwm yam kev lag luam. HPMC yog cov khoom siv hluavtaws ib nrab ntawm cov tshuaj lom neeg uas tau txais los ntawm cov cellulose kev hloov kho ntawm ntuj, thiab feem ntau yog siv los ua cov thickener, stabilizer, emulsifier thiab adhesive.
Lub cev lub cev ntawm HPMC
Lub ntsiab lus melting ntawm HPMC yog qhov nyuaj dua vim tias nws lub ntsiab lus melting tsis yog qhov pom tseeb raws li ntawm cov ntaub ntawv crystalline uas yog cov ntaub ntawv crystalline raug. Nws lub ntsiab lus melting yog cuam tshuam los ntawm cov qauv molecular, hnyav hnyav thiab qib hloov ntawm cov khoom siv hydroxypropyl, yog li nws tuaj yeem sib txawv raws li cov khoom hauv HPMC tshwj xeeb. Feem ntau, raws li dej-soluble polymer, HPMC tsis muaj qhov tseeb thiab tsis zoo me ntsis taw tes, tab sis softens thiab decompose thiab decompose tsis pub dhau qhov ntsuas kub.
Melting taw tes ntau
Lub thermal tus cwj pwm ntawm kev txhawj xeeb ® Los ntawm cov ntaub ntawv, nws tuaj yeem pom tias cov ntsiab lus melting ntau ntawm HPMC yog kwv yees li ntawm 200°C thiab 300°C, tab sis qhov no ntau tsis sawv cev cov lus qhia tiag tiag ntawm txhua HPMC cov khoom lag luam. Ntau hom HPMC cov khoom lag luam yuav muaj cov ntsiab lus melting sib txawv thiab thermal stability vim muaj ntau yam xws li molecular hnyav, qib ntawm hydroxyprropation (qib hloov chaw).
Tsawg molecular hnyav HPMC: Feem ntau melts lossis softens ntawm qis kub, thiab tej zaum yuav pib pyrolyze lossis yaj ntawm ib ncig 200°C.
High molecular hnyav HPMC: HPMC polymers nrog qhov hnyav dua molecular hnyav yuav xav tau qhov kub siab dua los ua kom lawv ntev dua molecular, thiab feem ntau pib pyrolyze thiab melt ntawm 250°C thiab 300°C.
Yam cuam tshuam rau qhov melting point ntawm HPMC
Molecular qhov hnyav: qhov hnyav molecular hnyav ntawm HPMC muaj ntau dua rau nws lub po melting. Qis dua molecular hnyav feem ntau txhais tau tias qis melting kub, thaum lub siab molecular phaus yuav ua rau muaj ntau dua melting pot.
Degree ntawm hloov chaw: Cov qib ntawm hydroxyprore (piv txwv li cov hloov chaw ntawm molecule) thiab qib hloov methylropyl hauv lub molecule) ntawm HPMC tseem cuam tshuam nws lub ntsiab lus melting. Feem ntau, qib siab dua ntawm kev hloov pauv ua solubility ntawm HPMC thiab txo nws lub taw tes melting.
Cov ntsiab lus noo: Raws li cov khoom siv dej-soluble, lub suab nrov ntawm HPMC kuj tseem cuam tshuam los ntawm nws cov ntsiab lus ya raws. HPMC nrog cov ntsiab lus noo noo yuav yauv los yog kev sib cais ib nrab, ua rau muaj kev hloov pauv ntawm lub thermal decomposition kub.
Thermal ruaj khov thiab decomposition kub ntawm HPMC
Txawm hais tias HPMC tsis muaj qhov nruj melting potinting, nws thermal ruaj khov yog qhov taw qhia tseem ceeb. Raws li Thermogravetric tsom xam (TGA) cov ntaub ntawv, HPMC feem ntau pib decompose hauv qhov ntsuas kub hauv 250°C rau 300°C. Qhov ntsuas kub tshwj xeeb yog nyob ntawm qhov hnyav molecular, degree ntawm hloov chaw thiab lwm yam tshuaj thiab tshuaj lom neeg ntawm HPMC.
Kev Kho Mob Thermal hauv HPMC cov ntawv thov
Hauv cov ntawv thov, lub ntsiab lus melting thiab thermal ruaj khov ntawm HPMC yog qhov tseem ceeb heev. Piv txwv li, hauv kev lag luam hauv lub tsev tshuaj, HPMC feem ntau siv los ua cov khoom siv rau cov ntsiav tshuaj, yeeb yaj kiab ua yeeb yaj kiab, thiab cov nqa khoom rau cov tshuaj muaj kev tiv thaiv. Hauv cov ntawv thov no, cov thermal stability ntawm HPMC xav tau raws li kev ua qhov kub thiab kub ntxhov ntau yam ntawm HPMC yog qhov tseem ceeb los tswj cov txheej txheem ntau lawm.
Nyob rau hauv lub teb tsim teb, txhawj xeeb ® feem ntau siv los ua cov tuab tuab hauv cug qhuav, txheej thiab cov nplaum. Hauv cov ntawv thov no, lub thermal stability ntawm HPMC kuj yuav tsum tau nyob hauv qee qhov ntau los xyuas kom meej tias nws tsis decompose thaum tsim kho.
HPMC, raws li cov khoom siv polymer, tsis muaj ib qho kev ua kom ruaj khov, tab sis cov khoom ua kom pom kev muag khoom thiab cov yam ntxwv pyrolysis nyob hauv qhov ntsuas kub thiab txias. Nws cov taw tes melting ntau yog feem ntau ntawm 200°C thiab 300°C, thiab cov lus meej melting taw tes yog nyob ntawm yam xws li cov molecular hnyav, degree ntawm hydroxypropation, thiab noo noo cov ntsiab lus ntawm HPMC. Hauv kev thov sib txawv, kev nkag siab cov thermal cov khoom yog qhov tseem ceeb rau nws cov kev npaj thiab siv.
Lub Sijhawm Post: Jan-04-2025