Focus on Cellulose ethers

Isiphumo se-hydroxyethyl methylcellulose kudaka lwesamente

Impembelelo yezinto ezifana nokutshintsha kwe-viscosity ye-hydroxyethyl methylcellulose (HEMC), nokuba iguqulwe okanye ayikho, kwaye umxholo wokutshintsha kwingcinezelo yesivuno kunye ne-viscosity yeplastiki ye-samente entsha yodaka yafundwa. Kwi-HEMC engalungiswanga, i-viscosity ephezulu, iphantsi kwengcinezelo yesivuno kunye ne-plastiki viscosity yomdaka; impembelelo yenguqu ye-viscosity ye-HEMC elungisiweyo kwiipropati ze-rheological zodaka zibuthathaka; kungakhathaliseki ukuba iguqulwe okanye ayikho, i-viscosity ephezulu ye-HEMC, ephantsi Isiphumo sokunciphisa uxinzelelo lwesivuno kunye nokuphuhliswa kweplastiki ye-viscosity yomdaka kubonakala ngakumbi. Xa umxholo we-HEMC ukhulu kune-0.3%, uxinzelelo lwesivuno kunye ne-viscosity yeplastiki yokunyuka komdaka kunye nokunyuka komxholo; xa umxholo we-HEMC ukhulu, uxinzelelo lwesivuno somdaka luyancipha ngexesha, kwaye uluhlu lwe-viscosity yeplastiki lwanda ngexesha.

Amagama aphambili: i-hydroxyethyl methylcellulose, udaka olutsha, iipropathi zerheological, uxinzelelo lwesivuno, viscosity yeplastiki

I. Intshayelelo

Ngophuhliso lobugcisa bokwakha udaka, ingqwalasela engakumbi ihlawulwe kulwakhiwo lomatshini. Ukuthuthwa komgama omde ngokuthe nkqo kubeka phambili iimfuno ezintsha zodaka olumponthiweyo: ulwelo olulungileyo kufuneka lugcinwe kuyo yonke inkqubo yokumpompa. Oku kufuna ukufunda izinto ezichaphazelayo kunye neemeko ezithintelayo zodaka, kwaye indlela eqhelekileyo kukuqwalasela i-rheological parameters of mortar.

Iimpawu ze-rheological zodaka ikakhulu zixhomekeke kwindalo kunye nobungakanani bezinto eziluhlaza. I-Cellulose ether yi-admixture esetyenziswa ngokubanzi kwi-industrial mortar, enempembelelo enkulu kwiipropati ze-rheological zodaka, ngoko abaphengululi basekhaya nakwamanye amazwe baye benza uphando malunga nalo. Isishwankathelo, ezi zigqibo zilandelayo zinokuthi zenziwe: ukunyuka kwexabiso le-cellulose ether kuya kukhokelela ekunyuseni kwe-torque yokuqala yodaka, kodwa emva kwexesha lokuvuselela, ukuchasana kokuhamba komdaka kuya kuncipha endaweni (1) ; xa i-fluidity yokuqala ifana ngokusisiseko, ubumanzi bodaka buya kulahleka kuqala. ukwanda emva kokuncipha (2); amandla esivuno kunye ne-viscosity yeplastiki yodaka yabonisa indlela yokunciphisa kuqala kwaye yanda, kwaye i-cellulose ether ikhuthaza ukutshatyalaliswa kwesakhiwo sodaka kwaye yandisa ixesha ukusuka kwintshabalalo ukuya ekwakhiweni kwakhona (3); I-Ether kunye ne-powder edibeneyo ine-viscosity ephezulu kunye nokuzinza njl. (4). Nangona kunjalo, ezi zifundo zingentla zineentsilelo:

Imigangatho yokulinganisa kunye neenkqubo zabaphengululi abahlukeneyo azifani, kwaye iziphumo zovavanyo azikwazi ukuthelekiswa ngokuchanekileyo; uluhlu lovavanyo lwesixhobo lulinganiselwe, kwaye i-rheological parameters yodaka olulinganisiweyo lunoluhlu oluncinci lokuhluka, olungamelanga ngokubanzi; kukho ukungabikho kweemvavanyo zokuthelekisa kwi-cellulose ethers kunye ne-viscosities eyahlukeneyo; Zininzi izinto ezinempembelelo, kwaye ukuphindaphinda akulunganga. Kwiminyaka yakutshanje, ukubonakala kwe-rheometer yodaka lwe-Viskomat XL ibonelele ngokulula kakhulu ukuzimisela okuchanekileyo kweempawu ze-rheological zodaka. Ineenzuzo zenqanaba eliphezulu lolawulo oluzenzekelayo, umthamo omkhulu, uluhlu olubanzi lovavanyo, kunye neziphumo zovavanyo ngakumbi ngokuhambelana neemeko zokwenyani. Kweli phepha, ngokusekwe ekusetyenzisweni kolu hlobo lwesixhobo, iziphumo zophando zabaphengululi abakhoyo ziyadityaniswa, kwaye inkqubo yovavanyo yenzelwe ukufunda isiphumo seentlobo ezahlukeneyo kunye ne-viscosities ye-hydroxyethyl methylcellulose (HEMC) kwi-rheology yodaka kwi. uluhlu lwedosi enkulu. impembelelo yokusebenza.

2. Imodeli ye-Rheological yodaka lwesamente entsha

Ekubeni i-rheology yaziswa kwisamente kunye nesayensi yekhonkrithi, inani elikhulu lezifundo libonise ukuba ikhonkrithi entsha kunye nodaka lunokuthi luthathwe njenge-Bingham fluid, kwaye i-Banfill yachaza ngakumbi ukuba nokwenzeka kokusebenzisa imodeli ye-Bingham ukuchaza iimpawu ze-rheological zodaka (5). Kwi-rheological equation τ=τ0+μγ yomzekelo we-Bingham, τ luxinzelelo lokucheba, τ0 luxinzelelo lwesivuno, μ yi-viscosity yeplastiki, kwaye γ yireyithi yokucheba. Phakathi kwazo, τ0 kunye no μ zezona parameters zibalulekileyo: τ0 bubuncinane boxinzelelo lokucheba olunokwenza udaka lwesamente luhambe, kwaye kuphela xa τ>τ0 isebenza kudaka, udaka lunokuhamba; μ ibonisa ukuxhathisa kwe-viscous xa udaka luhamba Ubukhulu be-μ, buhamba kancinci udaka [3]. Kwimeko apho zombini u-τ0 kunye no-μ zingaziwa, uxinzelelo lokucheba kufuneka lulinganiswe ubuncinane kwiireyithi ezimbini ezahlukeneyo zokucheba phambi kokuba zibalwe (6).

Kwi-rheometer yodaka olunikiweyo, ijika le-NT elifunyenwe ngokumisela isantya sokujikeleza kwe-blade N kunye nokulinganisa i-torque T eveliswa yi-hear resistance of the mortar ingasetyenziselwa ukubala enye i-equation T = g+ ehambelana nemodeli ye-Bingham Iiparamitha ezimbini. g kunye neh yeNh. g ilingana noxinzelelo lwesivuno τ0, h ilingana neplastiki viscosity μ, kunye τ0 = (K/G) g, μ = ( l / G ) h , apho uG ehlala enxulumene nesixhobo, kunye no-K ukugqithiswa ngendlela eyaziwayo Ifunyanwa ngokulungisa ulwelo oluneempawu eziguqukayo ngesantya sokucheba[7]. Ukuze kube lula, eli phepha lixubusha ngokuthe ngqo u-g kunye no-h, kwaye lisebenzisa umthetho oguqukayo we-g kunye no-h ukubonisa umthetho oguqukayo woxinzelelo lwesivuno kunye ne-viscosity yeplastiki yodaka.

3. Uvavanyo

3.1 Iimathiriyeli ekrwada

3.2 isanti

Isanti yequartz: isanti erhabaxa yi 20-40 mesh, isanti ephakathi yi 40-70 mesh, isanti ecolekileyo yi 70-100 mesh, kwaye ezi zintathu zixutywe kumlinganiselo we 2:2:1.

3.3 Iselulosi ether

IHydroxyethyl methylcellulose HEMC20 (viscosity 20000 mPa s), HEMC25 (viscosity 25000 mPa s), HEMC40 (viscosity 40000 mPa s), kunye HEMC45 (viscosity 45000 mPa s), apho HEMC525 i-modified cellulosether.

3.4 Ukuxuba amanzi

amanzi etephu.

3.5 Isicwangciso sovavanyo

Umlinganiselo we-lime-sand ngu-1: 2.5, ukusetyenziswa kwamanzi kugxininiswe kwi-60% yokusetyenziswa kwe-samente, kwaye umxholo we-HEMC ngu-0-1.2% wokusetyenziswa kwe-cement.

Okokuqala xuba i-samente elinganiswe ngokuchanekileyo, i-HEMC kunye nesanti ye-quartz ngokulinganayo, uze udibanise amanzi okuxuba ngokuhambelana ne-GB / T17671-1999 kwaye ugxobhoze, kwaye usebenzise i-rheometer yodaka lwe-Viskomat XL ukuvavanya. Inkqubo yovavanyo yile: isantya sandiswa ngokukhawuleza ukusuka ku-0 ukuya ku-80rpm kwi-0 ~ 5min, i-60rpm kwi-5 ~ 7min, i-40rpm kwi-7 ~ 9min, i-20rpm kwi-9 ~ 11min, i-10rpm kwi-11 ~ 13min, kunye ne-5rpm kwi-13 ~ 15min , I-15 ~ 30min, isantya ngu-0rpm, kwaye emva koko ujikeleze kanye nge-30min ngokwenkqubo engentla, kwaye ixesha lokuvavanya lilonke li-120min.

4. Iziphumo kunye nengxoxo

4.1 Impembelelo ye-HEMC yenguqu ye-viscosity kwiipropati ze-rheological ze-cement mortar

(Isixa se-HEMC yi-0.5% ye-cement mass), ngokuhambelanayo kubonakalisa umthetho wokuhluka koxinzelelo lwesivuno kunye ne-viscosity yeplastiki yodaka. Ingabonwa ukuba nangona i-viscosity ye-HEMC40 iphezulu kune-HEMC20, uxinzelelo lwesivuno kunye ne-viscosity yeplastiki yodaka oluxutywe ne-HEMC40 lungaphantsi kunelo lodaka oluxutywe ne-HEMC20; nangona i-viscosity ye-HEMC45 i-80% ephezulu kune-HEMC25, uxinzelelo lwesivuno somdaka luncinci, kwaye i-viscosity yeplastiki iphakathi Emva kwemizuzu engama-90 kukho ukwanda. Oku kungenxa yokuba i-viscosity ephezulu ye-cellulose ether, iyacotha izinga lokuchithwa, kwaye kuthatha ixesha elide ukuba udaka olulungiswe nalo lufikelele kwi-viscosity yokugqibela [8]. Ukongezelela, ngexesha elifanayo kuvavanyo, ubuninzi bodaka oluxutywe ne-HEMC40 lwalungaphantsi kunodaka oluxutywe ne-HEMC20, kwaye udaka oluxutywe ne-HEMC45 lwalungaphantsi kunodaka oluxutywe ne-HEMC25, ebonisa ukuba i-HEMC40 kunye ne-HEMC45 zazisa amaqamza omoya amaninzi, kwaye amaqamza omoya kudaka ane ""ibhola" isiphumo, esikwanciphisa ukuxhathisa kokuhamba kodaka.

Emva kokongeza i-HEMC40, uxinzelelo lwesivuno somdaka lwalulingana emva kwemizuzu engama-60, kwaye i-viscosity yeplastiki yanda; emva kokongeza i-HEMC20, uxinzelelo lwesivuno sodaka lwafikelela ekulinganeni emva kwemizuzu engama-30, kwaye i-viscosity yeplastiki yanda. Ibonisa ukuba i-HEMC40 inempembelelo enkulu yokunciphisa uphuhliso loxinzelelo lwesivuno sodaka kunye ne-viscosity yeplastiki kune-HEMC20, kwaye ithatha ixesha elide ukufikelela kwi-viscosity yokugqibela.

Uxinzelelo lwesivuno somdaka oxutywe ne-HEMC45 wehla ukusuka kwi-0 ukuya kwi-120 imizuzu, kwaye i-viscosity yeplastiki yanda emva kwemizuzu engama-90; ngelixa uxinzelelo lwesivuno sodaka oluxutywe ne-HEMC25 lwanda emva kwemizuzu engama-90, kwaye i-viscosity yeplastiki yanda emva kwemizuzu engama-60. Ibonisa ukuba i-HEMC45 inempembelelo enkulu yokunciphisa ukuphuhliswa koxinzelelo lwemveliso yodaka kunye ne-viscosity yeplastiki kune-HEMC25, kwaye ixesha elifunekayo ukufikelela kwi-viscosity yokugqibela lide.

4.2 Isiphumo somxholo we-HEMC kuxinzelelo lwesivuno sodaka lwesamente

Ngexesha lovavanyo, izinto ezichaphazela uxinzelelo lwesivuno sodaka zezi: i-delamination yodaka kunye nokopha, ukonakala kwesakhiwo ngokuvuselela, ukubunjwa kweemveliso ze-hydration, ukunciphisa ukufuma okukhululekile kwidaka, kunye nesiphumo sokunciphisa i-cellulose ether. Ngesiphumo esibambekayo se-cellulose ether, imbono eyamkelekileyo ngokubanzi kukuyichaza nge-adsorption ye-admixtures.

Ingabonwa ukuba xa i-HEMC40 yongezwa kwaye umxholo wayo ungaphantsi kwe-0.3%, uxinzelelo lwesivuno somdaka luyancipha ngokuthe ngcembe ngokunyuka komxholo we-HEMC40; xa umxholo we-HEMC40 umkhulu kune-0.3%, uxinzelelo lwesivuno sodaka lukhula ngokuthe ngcembe. Ngenxa yokopha kunye ne-delamination yodaka ngaphandle kwe-ether ye-cellulose, akukho ntlama yesamente eyaneleyo phakathi kwee-aggregates ukuthambisa, okubangela ukwanda koxinzelelo lwesivuno kunye nobunzima bokuhamba. Ukongezwa ngokufanelekileyo kwe-cellulose ether kunokuphucula ngokufanelekileyo i-mortar delamination phenomenon, kunye neebhubhu zomoya eziveziweyo zilingana "neebhola" ezincinci, ezinokunciphisa uxinzelelo lwesivuno sodaka kwaye zenze kube lula ukuhamba. Njengoko umxholo we-cellulose ether usanda, isiqulatho sawo sokufuma esingatshintshiyo nawo uyenyuka kancinci. Xa umxholo we-cellulose ether udlula ixabiso elithile, impembelelo yokunciphisa umswakama okhululekile iqala ukudlala indima ehamba phambili, kwaye uxinzelelo lwesivuno somdaka lukhula ngokuthe ngcembe.

Xa isixa se-HEMC40 singaphantsi kwe-0.3%, uxinzelelo lwesivuno sodaka luyehla ngokuthe ngcembe ngaphakathi kwe-0-120min, nto leyo inxulumene ikakhulu nokwanda koxinzelelo olukhulu lodaka, kuba kukho umgama othile phakathi kwencakuba kunye nezantsi. isixhobo, kunye ne-aggregate emva kokutshona kwe-delamination ukuya ezantsi, ukuchasana okuphezulu kuba kuncinci; xa umxholo we-HEMC40 u-0.3%, udaka aluyi kutshabalalisa, i-adsorption ye-cellulose ether iyancipha, i-hydration ilawula, kwaye uxinzelelo lwesivuno lunokwanda okuthile; umxholo we-HEMC40 ngu-Xa umxholo we-cellulose ether yi-0.5% -0.7%, i-adsorption ye-cellulose ether iyanda ngokuthe ngcembe, izinga le-hydration liyancipha, kwaye ukuphuhliswa koxinzelelo lwesivuno sodaka luqala ukutshintsha; Phezulu, umlinganiselo we-hydration uphantsi kwaye uxinzelelo lwesivuno sodaka luyancipha ngokuhamba kwexesha.

4.3 Impembelelo yomxholo we-HEMC kwi-viscosity yeplastiki yodaka lwesamente

Inokubonwa ukuba emva kokongeza i-HEMC40, i-viscosity yeplastiki yodaka inyuka ngokuthe ngcembe ngokunyuka komxholo we-HEMC40. Oku kungenxa yokuba i-ether ye-cellulose inesiphumo sokuqina, esinokunyusa i-viscosity yolwelo, kwaye ubukhulu bedosi, ubukhulu be-viscosity yodaka. Isizathu sokuba i-viscosity yeplastiki yodaka iyancipha emva kokongeza i-0.1% HEMC40 nayo ngenxa yempembelelo "yebhola" yokuqaliswa kweebhola zomoya, kunye nokunciphisa ukopha kunye nokuchithwa kodaka.

I-viscosity yeplastiki yodaka oluqhelekileyo ngaphandle kokongeza i-cellulose ether ngokuthe ngcembe iyancipha ngokuhamba kwexesha, ekwanxulumene noxinaniso olusezantsi lwenxalenye ephezulu ebangelwa kukubekwa kodaka; xa umxholo we-HEMC40 ngu-0.1% -0.5%, isakhiwo sodaka silingana, kwaye isakhiwo sodaka silingana emva kwemizuzu engama-30. I-viscosity yeplastiki ayitshintshi kakhulu. Ngeli xesha, ikakhulu ibonisa i-viscosity effect ye-cellulose ether ngokwayo; emva kokuba umxholo we-HEMC40 ungaphezulu kwe-0.7%, i-viscosity yeplastiki yodaka ikhula ngokuthe ngcembe ngokunyuka kwexesha, kuba i-viscosity yodaka nayo ihambelana ne-ether cellulose. I-viscosity yesisombululo se-cellulose ether iyanda ngokuthe ngcembe emva kwexesha elithile emva kokuqala kokuxuba. Okukhona idosi inkulu, kokukhona isiphumo sokunyuka sibaluleke ngakumbi ngokuhamba kwexesha.

V. Isiphelo

Izinto ezifana nokuguqulwa kwe-viscosity ye-HEMC, nokuba itshintshile okanye ayikho, kwaye ukutshintshwa kwemilinganiselo kuya kuchaphazela kakhulu iipropati ze-rheological zodaka, ezinokubonakaliswa yimilinganiselo emibini yoxinzelelo lwesivuno kunye ne-viscosity yeplastiki.

Kwi-HEMC engalungiswanga, i-viscosity enkulu, iyancipha uxinzelelo lwesivuno kunye ne-plastiki viscosity yomdaka ngaphakathi kwe-0-120min; impembelelo yenguqu ye-viscosity ye-HEMC eguquliweyo kwiipropati ze-rheological zodaka ibuthathaka kune-HEMC engaguqukiyo; kungakhathaliseki ukuba ukuguqulwa Kungakhathaliseki ukuba isigxina okanye ayikho, i-viscosity enkulu ye-HEMC, eyona nto ibaluleke kakhulu umphumo wokulibaziseka ekuphuhliseni uxinzelelo lwemveliso yodaka kunye ne-viscosity yeplastiki.

Xa udibanisa i-HEMC40 kunye ne-viscosity ye-40000mPa·s kunye nomxholo wayo mkhulu kune-0.3%, uxinzelelo lwesivuno sodaka lwanda ngokuthe ngcembe; xa umxholo udlula i-0.9%, uxinzelelo lwesivuno sodaka luqala ukubonisa umkhwa wokunciphisa ngokuthe ngcembe ngexesha; I-viscosity yeplastiki iyanda ngokunyuka komxholo we-HEMC40. Xa umxholo ungaphezu kwe-0.7%, i-viscosity yeplastiki yodaka iqala ukubonisa umkhwa wokunyuka ngokuthe ngcembe kunye nexesha.


Ixesha lokuposa: Nov-24-2022
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