Hydroxypropyl methylcellulose (HPMC) yog cov khoom siv polymer uas yaj tau hauv dej uas siv dav hauv tshuaj, khoom noj, kev tsim kho thiab lwm yam teb. Nws muaj kev ruaj khov zoo thermal, tab sis nws tseem tuaj yeem lwj hauv qab qhov kub siab. Qhov kub lwj ntawm HPMC feem ntau cuam tshuam los ntawm nws cov qauv molecular, cov xwm txheej ib puag ncig (xws li av noo, pH tus nqi) thiab lub sijhawm ua kom sov.
Qhov kub ntawm HPMC
Qhov kev puas tsuaj ntawm HPMC feem ntau pib tshwm sim saum toj no 200℃, thiab qhov kev rhuav tshem pom tseeb yuav tshwm sim ntawm 250℃-300℃. Tshwj xeeb:
Qis dua 100℃: HPMC feem ntau qhia txog kev ua pa dej thiab kev hloov pauv ntawm cov khoom siv lub cev, thiab tsis muaj kev puas tsuaj tshwm sim.
100℃-200℃: HPMC tej zaum yuav ua rau muaj kev oxidation ib nrab vim yog qhov kub hauv zos nce ntxiv, tab sis nws ruaj khov tag nrho.
200℃-250℃: HPMC maj mam qhia txog kev puas tsuaj ntawm thermal, uas feem ntau yog tshwm sim los ntawm kev tawg ntawm cov qauv thiab tso tawm cov khoom me me uas tsis muaj zog.
250℃-300℃: HPMC dhau los ua qhov pom tseeb decomposition, xim yuav tsaus dua, cov molecule me me xws li dej, methanol, acetic acid raug tso tawm, thiab carbonization tshwm sim.
Saum toj no 300℃: HPMC degrades sai sai thiab carbonizes, thiab qee cov inorganic tshuaj tseem nyob rau hauv qhov kawg.
Cov yam tseem ceeb uas cuam tshuam rau HPMC kev puas tsuaj
Qhov hnyav molecular thiab qib ntawm kev hloov pauv
Thaum qhov hnyav molecular ntawm HPMC loj, nws qhov kev tiv thaiv cua sov feem ntau siab.
Qhov kev hloov pauv ntawm methoxy thiab hydroxypropoxy pawg yuav cuam tshuam rau nws qhov kev ruaj khov thermal. HPMC nrog qib siab dua ntawm kev hloov pauv yooj yim dua rau kev puas tsuaj ntawm qhov kub siab.
Tej yam ib puag ncig
Av noo: HPMC muaj zog hygroscopicity, thiab av noo tuaj yeem ua rau nws puas tsuaj sai dua ntawm qhov kub siab.
Tus nqi pH: HPMC muaj kev cuam tshuam ntau dua rau hydrolysis thiab kev puas tsuaj nyob rau hauv cov kua qaub lossis alkali muaj zog.
Lub sijhawm cua sov
Cua sov rau 250℃rau lub sijhawm luv luv yuav tsis lwj tag, thaum tswj qhov kub siab rau lub sijhawm ntev yuav ua rau cov txheej txheem lwj sai dua.
Cov khoom puas tsuaj ntawm HPMC
HPMC feem ntau yog los ntawm cellulose, thiab nws cov khoom puas tsuaj zoo ib yam li cellulose. Thaum lub sijhawm ua kom sov, cov hauv qab no yuav raug tso tawm:
Cov pa dej (los ntawm cov pab pawg hydroxyl)
Methanol, ethanol (los ntawm methoxy thiab hydroxypropoxy pawg)
Acetic acid (los ntawm cov khoom lwj)
Cov pa roj carbon oxides (CO, CO₂, tsim los ntawm kev hlawv cov organic teeb meem)
Ib qho me me ntawm cov coke residue
Daim ntawv thov kub tsis kam ntawm HPMC
Txawm hais tias HPMC yuav maj mam poob qis dua 200℃, feem ntau nws tsis raug rau qhov kub thiab txias siab heev hauv kev siv tiag tiag. Piv txwv li:
Kev lag luam tshuaj: HPMC feem ntau yog siv rau cov tshuaj pleev xim thiab cov neeg sawv cev tso tawm tas mus li, feem ntau ua haujlwm ntawm 60℃-80℃, uas qis dua nws qhov kub thiab txias.
Kev lag luam zaub mov: HPMC tuaj yeem siv ua cov khoom siv tuab lossis emulsifier, thiab qhov kub thiab txias siv ib txwm muaj feem ntau tsis pub ntau tshaj 100℃.
Kev lag luam kev tsim kho: HPMC yog siv los ua cov cement thiab mortar thickener, thiab qhov kub ntawm kev tsim kho feem ntau tsis tshaj 80℃, thiab yuav tsis muaj kev puas tsuaj.
HPMC pib lwj mus rau qhov kub siab tshaj 200℃, decomposes tseem ceeb ntawm 250℃-300℃, thiab carbonizes sai sai saum 300℃Hauv kev siv ua haujlwm, yuav tsum tsis txhob raug rau qhov kub thiab txias ntev ntev kom nws ua haujlwm tau ruaj khov.
Lub sijhawm tshaj tawm: Plaub Hlis-03-2025