Hydroxypropyl methylcellulose (HPMC) yog cov khoom siv polymer feem ntau siv dav hauv kev tsim kho, tshuaj, khoom noj thiab lwm yam lag luam. Raws li cov dej-soluble polymer, HPMC muaj cov dej tuav tau zoo, ua yeeb yaj kiab, thickening thiab emulsifying zog. Nws cov dej tuav yog ib qho ntawm nws cov khoom tseem ceeb hauv ntau daim ntawv thov, tshwj xeeb tshaj yog nyob rau hauv cov ntaub ntawv xws li cov cement, mortar thiab coatings nyob rau hauv kev tsim kho kev lag luam, uas tuaj yeem ncua cov evaporation ntawm cov dej thiab txhim kho kev tsim kho kev ua tau zoo thiab cov khoom kawg. Txawm li cas los xij, kev tuav dej ntawm HPMC yog ze ze rau qhov kev hloov pauv kub hauv ib puag ncig sab nraud, thiab kev nkag siab qhov kev sib raug zoo no yog qhov tseem ceeb rau nws daim ntawv thov hauv ntau qhov chaw.
1. Cov qauv thiab dej tuav ntawm HPMC
HPMC yog tsim los ntawm kev hloov kho tshuaj ntawm ntuj cellulose, feem ntau yog los ntawm kev qhia txog hydroxypropyl (-C3H7OH) thiab methyl (-CH3) pawg rau hauv cov saw cellulose, uas muab nws zoo solubility thiab kev tswj cov khoom. Cov pab pawg hydroxyl (-OH) hauv HPMC molecules tuaj yeem tsim cov hydrogen bonds nrog dej molecules. Yog li, HPMC tuaj yeem nqus dej thiab sib xyaw nrog dej, qhia txog kev khaws dej.
Kev tuav dej yog hais txog lub peev xwm ntawm cov khoom khaws cia dej. Rau HPMC, nws yog qhov tseem ceeb tshaj plaws hauv nws lub peev xwm los tswj cov dej hauv lub cev los ntawm kev siv dej, tshwj xeeb tshaj yog nyob rau hauv qhov kub thiab txias los yog cov av noo ib puag ncig, uas tuaj yeem tiv thaiv kom tsis txhob poob dej sai thiab tswj cov dej noo ntawm cov khoom. Txij li thaum lub hydration hauv HPMC molecules yog ze ze rau kev sib cuam tshuam ntawm nws cov qauv molecular, qhov kub thiab txias hloov yuav cuam tshuam ncaj qha rau lub peev xwm nqus dej thiab khaws dej ntawm HPMC.
2. Qhov kub thiab txias ntawm cov dej tuav ntawm HPMC
Kev sib raug zoo ntawm kev tuav dej ntawm HPMC thiab qhov kub thiab txias tuaj yeem sib tham los ntawm ob yam: ib qho yog qhov cuam tshuam ntawm qhov kub thiab txias ntawm HPMC solubility, thiab lwm yam yog qhov kub thiab txias ntawm nws cov qauv molecular thiab hydration.
2.1 Qhov cuam tshuam ntawm qhov kub thiab txias ntawm qhov solubility ntawm HPMC
Kev solubility ntawm HPMC hauv dej yog cuam tshuam nrog qhov kub thiab txias. Feem ntau, cov solubility ntawm HPMC nce nrog nce kub. Thaum qhov kub nce siab, cov dej molecules tau txais thermal zog ntau dua, ua rau muaj qhov tsis muaj zog ntawm kev sib cuam tshuam ntawm cov dej molecules, yog li txhawb kev tawg ntawm HPMC. Rau HPMC, qhov kub thiab txias tuaj yeem ua rau nws yooj yim dua los tsim cov tshuaj colloidal, yog li txhim kho nws cov dej tuav hauv dej.
Txawm li cas los xij, qhov kub thiab txias heev tuaj yeem ua rau cov viscosity ntawm HPMC cov tshuaj, cuam tshuam rau nws cov khoom rheological thiab dispersibility. Txawm hais tias cov nyhuv no yog qhov zoo rau kev txhim kho ntawm solubility, qhov kub thiab txias yuav hloov qhov ruaj khov ntawm nws cov qauv molecular thiab ua rau txo qis hauv dej tuav.
2.2 Qhov cuam tshuam ntawm qhov kub thiab txias ntawm cov qauv molecular ntawm HPMC
Hauv cov qauv molecular ntawm HPMC, hydrogen bonds yog tsim los ntawm cov dej molecules los ntawm hydroxyl pawg, thiab cov hydrogen daim ntawv cog lus no tseem ceeb heev rau cov dej tuav ntawm HPMC. Raws li qhov kub thiab txias, lub zog ntawm hydrogen daim ntawv cog lus tuaj yeem hloov pauv, ua rau lub zog tsis muaj zog ntawm kev sib khi ntawm HPMC molecule thiab dej molecule, yog li cuam tshuam rau nws cov dej tuav. Tshwj xeeb, qhov nce hauv qhov kub thiab txias yuav ua rau cov hydrogen bonds hauv HPMC molecule dissociate, yog li txo nws cov dej nqus thiab khaws cov dej.
Tsis tas li ntawd, qhov kub thiab txias ntawm HPMC kuj tau tshwm sim hauv theem tus cwj pwm ntawm nws cov tshuaj. HPMC nrog qhov hnyav molecular sib txawv thiab cov pab pawg sib txawv muaj qhov sib txawv thermal rhiab heev. Feem ntau hais lus, tsis tshua muaj molecular hnyav HPMC yog qhov rhiab heev rau qhov kub thiab txias, thaum siab molecular hnyav HPMC nthuav tawm kev ua haujlwm ruaj khov dua. Yog li ntawd, nyob rau hauv kev siv tswv yim, nws yog ib qho tsim nyog yuav tau xaiv hom HPMC uas tsim nyog raws li qhov ntsuas kub tshwj xeeb kom ntseeg tau tias nws cov dej tuav ntawm qhov ua haujlwm kub.
2.3 Qhov ntsuas kub ntawm cov dej evaporation
Nyob rau hauv qhov kub thiab txias ib puag ncig, cov dej tuav ntawm HPMC yuav cuam tshuam los ntawm cov dej nrawm nrawm los ntawm qhov kub thiab txias. Thaum qhov kub ntawm sab nraud siab dhau lawm, cov dej hauv HPMC feem ntau yuav evaporate. Txawm hais tias HPMC tuaj yeem khaws dej rau qee qhov los ntawm nws cov qauv molecular, qhov kub thiab txias ntau dhau yuav ua rau lub cev poob dej sai dua li cov dej khaws cia ntawm HPMC. Nyob rau hauv cov ntaub ntawv no, cov dej tuav ntawm HPMC yog inhibited, tshwj xeeb tshaj yog nyob rau hauv ib tug kub thiab qhuav ib puag ncig.
Txhawm rau daws qhov teeb meem no, qee qhov kev tshawb fawb tau pom tias ntxiv cov tshuaj humectants tsim nyog lossis kho lwm yam hauv cov qauv tuaj yeem txhim kho cov dej tuav ntawm HPMC hauv qhov chaw kub. Piv txwv li, los ntawm kev kho cov viscosity modifier nyob rau hauv lub mis los yog xaiv ib tug uas tsis muaj-volatile solvent, cov dej tuav ntawm HPMC tuaj yeem txhim kho rau qee qhov, txo qhov kub thiab txias ntawm cov dej evaporation.
3. Muaj feem cuam tshuam
Qhov cuam tshuam ntawm qhov kub thiab txias ntawm cov dej tuav ntawm HPMC tsis yog nyob ntawm qhov ntsuas kub ntawm nws tus kheej xwb, tab sis kuj nyob ntawm qhov hnyav molecular, qib ntawm kev hloov pauv, kev daws teeb meem thiab lwm yam ntawm HPMC. Piv txwv li:
Molecular Luj:HPMC nrog ntau dua molecular hnyav feem ntau muaj zog tuav dej, vim hais tias lub network qauv tsim los ntawm siab molecular hnyav chains nyob rau hauv cov tshuaj yuav nqus tau thiab khaws cov dej zoo dua.
Kev hloov pauv qib: Qib ntawm methylation thiab hydroxypropylation ntawm HPMC yuav cuam tshuam rau nws cov kev cuam tshuam nrog dej molecules, yog li cuam tshuam rau cov dej tuav. Feem ntau hais lus, kev hloov pauv ntau dua tuaj yeem txhim kho hydrophilicity ntawm HPMC, yog li txhim kho nws cov dej tuav.
Kev daws teeb meem: Qhov concentration ntawm HPMC kuj cuam tshuam rau nws cov dej tuav. Qhov siab dua ntawm HPMC cov kev daws teeb meem feem ntau muaj cov dej tuav tau zoo dua, vim tias qhov siab ntawm HPMC tuaj yeem khaws cov dej los ntawm kev sib cuam tshuam ntau dua.
Muaj kev sib raug zoo ntawm cov dej tuav ntawmHPMCthiab kub. Qhov kub nce feem ntau txhawb kev solubility ntawm HPMC thiab tej zaum yuav ua rau kom cov dej tuav tau zoo dua qub, tab sis qhov kub thiab txias dhau yuav ua rau cov qauv molecular ntawm HPMC txo qis nws lub peev xwm los khi rau dej, thiab yog li cuam tshuam rau nws cov dej tuav. Txhawm rau kom ua tiav cov dej tuav tau zoo tshaj plaws nyob rau hauv qhov sib txawv ntawm qhov kub thiab txias, nws yog ib qho tsim nyog yuav tsum xaiv HPMC yam tsim nyog raws li cov ntawv thov tshwj xeeb thiab tsim nyog kho nws cov kev siv. Tsis tas li ntawd, lwm yam khoom siv hauv cov qauv thiab cov tswv yim tswj qhov kub thiab txias tuaj yeem txhim kho cov dej tuav ntawm HPMC nyob rau hauv qhov kub thiab txias ib puag ncig.
Post lub sij hawm: Nov-11-2024