Qhov tseem ceeb tshaj plaws ntawm cov tshuaj cellulose ether yog nws cov khoom rheological. Cov khoom tshwj xeeb rheological ntawm ntau cov cellulose ethers ua rau lawv siv dav hauv ntau qhov chaw, thiab kev kawm txog cov khoom rheological yog qhov zoo rau kev txhim kho cov teb thov tshiab lossis kev txhim kho ntawm qee qhov chaw thov. Li Jing los ntawm Shanghai Jiao Tong University tau ua ib txoj kev tshawb fawb txog cov khoom rheological ntawmcarboxymethylcellulose (CMC), suav nrog kev cuam tshuam ntawm CMC cov qauv molecular parameters (molecular weight thiab degree of substitution), concentration pH, thiab ionic strength. Cov txiaj ntsig tshawb fawb qhia tau hais tias qhov xoom-shear viscosity ntawm cov tshuaj nce nrog rau qhov nce ntawm molecular weight thiab degree of substitution. Qhov nce ntawm molecular weight txhais tau tias kev loj hlob ntawm molecular saw, thiab qhov yooj yim entanglement ntawm cov molecules nce viscosity ntawm cov tshuaj; qhov loj degree ntawm substitution ua rau cov molecules ncab ntau dua hauv cov tshuaj. Lub xeev muaj, lub hydrodynamic ntim yog qhov loj heev, thiab viscosity ua loj. Lub viscosity ntawm CMC aqueous kua nce nrog rau qhov nce ntawm concentration, uas muaj viscoelasticity. Lub viscosity ntawm cov tshuaj txo qis nrog rau pH tus nqi, thiab thaum nws qis dua ib qho nqi, lub viscosity nce me ntsis, thiab thaum kawg free acid yog tsim thiab precipitated. CMC yog ib tug polyanionic polymer, thaum ntxiv monovalent ntsev ions Na +, K + shield, lub viscosity yuav txo qis raws li. Qhov ntxiv ntawm divalent cation Caz + ua rau lub viscosity ntawm cov tshuaj kom txo qis ua ntej thiab tom qab ntawd nce. Thaum qhov concentration ntawm Ca2+ siab dua qhov stoichiometric point, CMC molecules sib cuam tshuam nrog Ca2+, thiab muaj ib qho superstructure nyob rau hauv cov tshuaj. Liang Yaqin, North University of China, thiab lwm yam. siv txoj kev viscometer thiab txoj kev rotational viscometer los ua kev tshawb fawb tshwj xeeb ntawm cov khoom rheological ntawm cov tshuaj dilute thiab concentrated ntawm cov tshuaj hydroxyethyl cellulose hloov kho (CHEC). Cov txiaj ntsig tshawb fawb pom tias: (1) Cationic hydroxyethyl cellulose muaj tus cwj pwm polyelectrolyte viscosity hauv dej ntshiab, thiab qhov viscosity txo qis nce nrog qhov nce ntawm concentration. Qhov viscosity intrinsic ntawm cationic hydroxyethyl cellulose nrog qib siab ntawm kev hloov pauv yog ntau dua li ntawm cationic hydroxyethyl cellulose nrog qib qis ntawm kev hloov pauv. (2) Cov tshuaj ntawm cationic hydroxyethyl cellulose qhia txog cov yam ntxwv tsis yog Newtonian kua thiab muaj cov yam ntxwv shear thinning: raws li qhov concentration ntawm cov tshuaj nce ntxiv, nws qhov viscosity pom tseeb nce ntxiv; hauv qee qhov concentration ntawm cov tshuaj ntsev, CHEC pom tseeb viscosity Nws txo qis nrog qhov nce ntawm qhov concentration ntsev ntxiv. Nyob rau hauv tib lub shear rate, qhov pom tseeb viscosity ntawm CHEC hauv CaCl2 solution system yog siab dua li ntawm CHEC hauv NaCl solution system.
Nrog rau kev tshawb fawb txuas ntxiv mus tob zuj zus thiab kev nthuav dav ntawm cov teb thov, cov khoom ntawm cov kev daws teeb meem sib xyaw ua ke uas muaj cov cellulose ethers sib txawv kuj tau txais kev saib xyuas ntawm tib neeg. Piv txwv li, sodium carboxymethyl cellulose (NACMC) thiab hydroxyethyl cellulose (HEC) yog siv los ua cov neeg sawv cev hloov roj hauv cov teb roj, uas muaj qhov zoo ntawm kev tiv taus shear muaj zog, cov khoom siv raw ntau thiab tsawg dua kev ua qias tuaj ib puag ncig, tab sis qhov cuam tshuam ntawm kev siv lawv ib leeg tsis zoo tagnrho. Txawm hais tias tus thawj muaj viscosity zoo, nws yooj yim cuam tshuam los ntawm qhov kub thiab salinity ntawm lub pas dej; txawm hais tias tus tom kawg muaj qhov kub thiab ntsev zoo tiv taus, nws lub peev xwm thickening tsis zoo thiab qhov ntau npaum li cas yog qhov loj heev. Cov kws tshawb fawb sib xyaw ob qho kev daws teeb meem thiab pom tias qhov viscosity ntawm cov tshuaj sib xyaw ua ke tau loj dua, qhov kub thiab ntsev tiv taus tau zoo dua rau qee qhov, thiab qhov cuam tshuam ntawm daim ntawv thov tau txhim kho. Verica Sovilj et al. tau kawm txog tus cwj pwm rheological ntawm cov tshuaj ntawm cov txheej txheem sib xyaw ua ke uas muaj HPMC thiab NACMC thiab anionic surfactant nrog lub rotational viscometer. Tus cwj pwm rheological ntawm lub kaw lus nyob ntawm HPMC-NACMC, HPMC-SDS thiab NACMC- (HPMC-SDS) cov teebmeem sib txawv tshwm sim ntawm.
Cov khoom rheological ntawm cellulose ether cov kev daws teeb meem kuj raug cuam tshuam los ntawm ntau yam, xws li cov khoom ntxiv, lub zog sab nraud thiab kub. Tomoaki Hino et al. kawm txog qhov cuam tshuam ntawm kev ntxiv nicotine rau cov khoom rheological ntawm hydroxypropyl methylcellulose. Ntawm 25C thiab qhov concentration qis dua 3%, HPMC tau pom tus cwj pwm Newtonian kua. Thaum ntxiv nicotine, qhov viscosity nce ntxiv, uas qhia tau tias nicotine ua rau muaj kev sib txuas ntawmHPMCcov molecule. Nicotine ntawm no qhia txog cov nyhuv ntsev uas ua rau lub gel point thiab pos huab ntawm HPMC nce. Lub zog tshuab xws li lub zog shear kuj tseem yuav muaj qee yam cuam tshuam rau cov khoom ntawm cellulose ether aqueous kua. Siv rheological turbidimeter thiab lub kaum sab xis me me lub teeb scattering cuab yeej, nws pom tias nyob rau hauv semi-dilute kua, ua rau kom tus nqi shear nce, vim yog shear sib xyaw, qhov kub hloov pauv ntawm pos huab yuav nce.
Lub sijhawm tshaj tawm: Plaub Hlis-28-2024