Cov nyhuv ntawm thickeningcellulose ethernyob ntawm: qib polymerization ntawm cellulose ether, kev daws teeb meem concentration, shear rate, kub thiab lwm yam mob. Lub zog gelling ntawm cov tshuaj yog tshwj xeeb rau alkyl cellulose thiab nws cov derivatives hloov kho. Cov khoom gelation muaj feem cuam tshuam nrog qib ntawm kev hloov pauv, kev daws teeb meem concentration thiab cov khoom ntxiv. Rau hydroxyalkyl hloov kho derivatives, cov khoom gel kuj muaj feem cuam tshuam nrog qib hloov kho ntawm hydroxyalkyl. Rau cov viscosity qis MC thiab HPMC, 10% -15% daws tuaj yeem npaj tau, nruab nrab viscosity MC thiab HPMC tuaj yeem npaj tau 5% -10% daws, thiab viscosity siab MC thiab HPMC tsuas yog tuaj yeem npaj 2% -3% daws, thiab feem ntau qhov kev faib tawm viscosity ntawm cellulose ether kuj tau muab qib nrog 1% -2% daws.
Cov cellulose ether uas muaj cov molecular hnyav ntau muaj cov thickening efficiency siab, thiab cov polymers uas muaj cov molecular hnyav sib txawv muaj cov viscosities sib txawv hauv tib qho kev daws teeb meem. Lub hom phiaj viscosity tsuas yog ua tiav los ntawm kev ntxiv ntau ntawm cov cellulose ether uas muaj molecular hnyav tsawg. Nws cov viscosity muaj kev vam khom me ntsis rau ntawm qhov shear rate, thiab cov viscosity siab ncav cuag lub hom phiaj viscosity, xav tau ntxiv tsawg dua, thiab cov viscosity nyob ntawm qhov thickening efficiency. Yog li ntawd, kom ua tiav qee qhov sib xws, qee qhov ntawm cellulose ether (kev sib xyaw ntawm cov tshuaj) thiab cov viscosity ntawm cov tshuaj yuav tsum tau lees paub. Qhov kub ntawm cov tshuaj gel kuj txo qis linearly nrog qhov nce ntawm qhov concentration ntawm cov tshuaj, thiab cov gels ntawm chav tsev kub tom qab ncav cuag qee qhov concentration. Qhov gelling concentration ntawm HPMC yog qhov siab heev ntawm chav tsev kub.
Kev sib xws kuj tseem tuaj yeem hloov kho los ntawm kev xaiv qhov loj me ntawm cov khoom me me thiab xaiv cov cellulose ethers nrog ntau qib kev hloov kho. Qhov kev hloov kho hu ua yog qhia txog qee qib ntawm kev hloov pauv ntawm cov pab pawg hydroxyalkyl ntawm cov qauv pob txha ntawm MC. Los ntawm kev hloov pauv cov nqi hloov pauv ntawm ob qho kev hloov pauv, uas yog, DS thiab MS cov nqi hloov pauv ntawm cov pab pawg methoxy thiab hydroxyalkyl uas peb feem ntau hais. Ntau yam kev ua tau zoo ntawm cellulose ether tuaj yeem tau txais los ntawm kev hloov pauv cov nqi hloov pauv ntawm ob qho kev hloov pauv.
Cov kua dej cellulose ether uas muaj viscosity siab muaj thixotropy siab, uas kuj yog ib qho tseem ceeb ntawm cellulose ether. Cov kua dej ntawm MC polymers feem ntau muaj pseudoplastic thiab non-thixotropic fluidity qis dua lawv qhov kub gel, tab sis Newtonian flow cov yam ntxwv ntawm qhov qis shear rates. Pseudoplasticity nce nrog qhov hnyav molecular lossis concentration ntawm cellulose ether, tsis hais hom substituent thiab qib ntawm kev hloov pauv. Yog li ntawd, cellulose ethers ntawm tib qib viscosity, tsis hais MC, HPMC, HEMC, yuav ib txwm qhia tib yam rheological khoom ntev li ntev tau qhov concentration thiab kub tau khaws cia tas li. Cov gels qauv tau tsim thaum qhov kub nce, thiab cov dej ntws thixotropic siab tshwm sim. Cov concentration siab thiab viscosity qis cellulose ethers qhia thixotropy txawm tias qis dua qhov kub gel. Cov yam ntxwv no yog qhov zoo rau kev kho qhov sib npaug thiab sagging hauv kev tsim kho ntawm cov mortar tsev.
Nws yuav tsum tau piav qhia ntawm no tias qhov siab dua ntawm viscosity ntawmcellulose ether, qhov zoo dua qhov kev khaws cia dej, tab sis qhov siab dua qhov viscosity, qhov siab dua qhov hnyav molecular ntawm cellulose ether, thiab qhov sib xws txo qis hauv nws cov solubility, uas muaj qhov cuam tshuam tsis zoo rau qhov concentration ntawm mortar thiab kev ua haujlwm ntawm kev tsim kho. Qhov siab dua qhov viscosity, qhov pom tseeb ntau dua qhov thickening effect ntawm mortar, tab sis nws tsis yog proportional tag nrho. Qee qhov nruab nrab thiab qis viscosity, tab sis cov cellulose ether hloov kho muaj kev ua tau zoo dua hauv kev txhim kho lub zog ntawm cov mortar ntub. Nrog rau kev nce ntawm viscosity, qhov kev khaws cia dej ntawm cellulose ether txhim kho.
Lub sijhawm tshaj tawm: Plaub Hlis-28-2024