Focus on Cellulose ethers

Umgangatho we-cellulose hpmc umisela umgangatho wodaka

Umgangatho we-cellulose hpmc umisela umgangatho wodaka

Kwi-dry-mixed mortar, inani elongezelelweyo le-hydroxypropyl methylcellulose HPMC liphantsi kakhulu, kodwa linokuphucula kakhulu ukusebenza kodaka olumanzi, kwaye iyona nto yokongeza echaphazela ukwakhiwa kodaka. I-cellulose ethers eneedigri ezahlukeneyo ze-viscosity kunye nezongezelelo zinefuthe elihle ekusebenzeni kodaka olumileyo lwepowder. Okwangoku, udaka oluninzi lwe-masonry kunye ne-plastering lunokusebenza okungahambi kakuhle kokugcinwa kwamanzi, kwaye i-slurry yamanzi iya kwahlula emva kwemizuzu embalwa yokuma. Ukugcinwa kwamanzi ngumsebenzi obalulekileyo we-methyl cellulose ether, kwaye ikwayintsebenzo eyenziwa ngabavelisi abaninzi basekhaya abaxubene nodaka, ngakumbi abo bakwiingingqi ezisemazantsi ezinobushushu obuphezulu, banikele ingqalelo kuyo. Izinto ezichaphazela umphumo wokugcinwa kwamanzi kwi-powder mortar eyomileyo ziquka inani le-HPMC eyongeziweyo, i-viscosity ye-HPMC, i-fineness of particles kunye nokushisa kwendawo yokusetyenziswa.

1. Ingcamango: I-ether ye-Cellulose yi-polymer yokwenziwa eyenziwe kwi-cellulose yendalo ngokuguqulwa kweekhemikhali. I-ether ye-cellulose iphuma kwi-cellulose yendalo. Ukuveliswa kwe-cellulose ether kuyahluka kwiipolymers zokwenziwa. Izinto zayo ezisisiseko ziyi-cellulose, i-polymer compound yendalo. Ngenxa yobungcali besakhiwo se-cellulose yendalo, i-cellulose ngokwayo ayinakho ukusabela kunye nee-etherification agents. Nangona kunjalo, emva kokunyangwa kwe-ejenti yokuvuvukala, iibhondi ze-hydrogen ezomeleleyo phakathi kwamatyathanga e-molecular kunye namatyathanga atshatyalaliswa, kwaye ukukhutshwa okusebenzayo kweqela le-hydroxyl kuba yi-alkali cellulose esebenzayo. Fumana i-ether cellulose. Iimpawu ze-cellulose ethers zixhomekeke kuhlobo, inani kunye nokuhanjiswa kwezinto ezithatha indawo. Ulwahlulo lwe-cellulose ethers lukwasekelwe kuhlobo lwabaxumi, i-degree of etherification, i-solubility kunye neepropati ezinxulumene nesicelo. Ngokohlobo lwababambeleyo kwitsheyini yemolekyuli, inokwahlulwa ibe yi-monoether kunye ne-ether edibeneyo. I-HPMC esidla ngokuyisebenzisa ixutywe iether. IHydroxypropyl methylcellulose ether I-HPMC yimveliso efunyenwe ngokufaka endaweni yeqela le-hydroxyl kwiqela le-methoxy kunye nenye inxalenye eneqela le-hydroxypropyl. Ifomula yolwakhiwo ithi [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)) CH3] n] x

I-HPMC isetyenziswa ikakhulu kwizinto zokwakha, iingubo zelatex, amayeza, iikhemikhali zemihla ngemihla, njl njl. Isetyenziswa njenge-thickener, i-arhente yokugcina amanzi, i-stabilizer, i-dispersant kunye ne-agent yokwenza ifilimu.

2. Ukugcinwa kwamanzi kwi-ether ye-cellulose: Ukuveliswa kwezinto zokwakha, ngokukodwa udaka lomgubo owomileyo, i-cellulose ether idlala indima engenakulinganiswa, ngakumbi ekuveliseni udaka olukhethekileyo (udaka olulungisiweyo), luyimfuneko kwaye lubalulekile. Indima ebalulekileyo ye-ether ye-cellulose e-soluble yamanzi kwi-mortar ikakhulu inemiba emithathu, enye inamandla okugcina amanzi, enye yimpembelelo ehambelanayo kunye ne-thixotropy yodaka, kwaye okwesithathu kukusebenzisana nesamente. Ukugcinwa kwamanzi kwi-ether ye-cellulose kuxhomekeke ekufunjweni kwamanzi kwinqanaba lesiseko, ukubunjwa kodaka, ubukhulu bodaka lodaka, imfuno yamanzi yodaka, kunye nexesha lokumisela izinto zokumisela. Ukugcinwa kwamanzi kwe-cellulose ether ngokwayo kuvela kwi-solubility kunye nokuphelelwa ngamanzi kwe-cellulose ether ngokwayo. Njengoko sonke sisazi, nangona i-cellulose i-molecular chain iqulethe inani elikhulu lamaqela e-OH anamandla, ayinyibiliki emanzini, kuba isakhiwo se-cellulose sinezinga eliphezulu le-crystallinity. Isakhono se-hydration samaqela e-hydroxyl iyodwa akwanelanga ukugubungela iibhondi ze-hydrogen ezomeleleyo kunye ne-van der Waals phakathi kwee-molecule. Ngoko ke, idumba kuphela kodwa ayinyibiliki emanzini. Xa i-substituent ingeniswa kwitsheyina le-molecular, kungekhona nje i-substituent etshabalalisa ikhonkco le-hydrogen, kodwa kunye ne-interchain ye-hydrogen bond iyatshatyalaliswa ngenxa yokutshatyalaliswa kwe-substituent phakathi kwamatyathanga akufutshane. Ubukhulu be-substitute, umgama omkhulu phakathi kweemolekyuli. Umgama mkhulu. Umphumo omkhulu wokutshabalalisa iibhondi ze-hydrogen, i-ether ye-cellulose iba yi-soluble yamanzi emva kokuba i-cellulose lattice yanda kwaye isisombululo singena, senza isisombululo esiphezulu se-viscosity. Xa izinga lokushisa liphakama, i-hydration ye-polymer iyancipha, kwaye amanzi phakathi kwamaketanga akhutshwa ngaphandle. Xa isiphumo sokuchithwa kwamanzi sanele, iamolekyu ziqala ukudibanisa, zenza i-gel yesakhiwo senethiwekhi ye-dimensional emithathu kwaye ihlanganiswe ngaphandle. Izinto ezichaphazela ukugcinwa kwamanzi kwi-mortar ziquka i-viscosity ye-cellulose ether, inani elongezelelweyo, ukucocwa kweengqungquthela kunye nokushisa kokusetyenziswa. Ubukhulu be-viscosity ye-cellulose ether, ngcono ukugcinwa kwamanzi ukusebenza. Ngokuqhelekileyo, okukhona i-viscosity iphezulu, ingcono isiphumo sokugcina amanzi. Ukuphakama kwe-viscosity, kuyabonakala ngakumbi umphumo wokuqina kumdaka, kodwa awuhambelani ngokuthe ngqo. Ukuphakama kwe-viscosity, i-viscous ngakumbi i-mortar emanzi iya kuba, oko kukuthi, ngexesha lokwakha, kubonakaliswa njengokunamathela kwi-scraper kunye nokunamathela okuphezulu kwi-substrate. Kodwa akuncedi ukunyusa amandla esakhiwo sodaka olumanzi ngokwalo. Ngexesha lokwakha, ukusebenza kwe-anti-sag akubonakali. Ubuninzi be-ether ye-cellulose eyongeziweyo kwidaka, ngcono ukugcinwa kwamanzi, kunye nokuphakama kwe-viscosity, ngcono ukugcinwa kwamanzi. Ngokuphathelele ubungakanani bamasuntswana, incinci incinci, ngcono ukugcinwa kwamanzi. Emva kokuba amasuntswana amakhulu e-cellulose ether adibane namanzi, umphezulu uyanyibilika ngokukhawuleza kwaye wenze ijeli ukusonga izinto zokuthintela iimolekyuli zamanzi ukuba zingaqhubeki nokungena. Ngamanye amaxesha ayinakuchithwa ngokulinganayo kwaye inyibilikiswe nasemva kwexesha elide, ukwenza isisombululo esinamafu okanye i-agglomeration. Ichaphazela kakhulu ukugcinwa kwamanzi kwe-cellulose ether, kunye ne-solubility yenye yezinto zokukhetha i-cellulose ether. Ukulunga kukwayisalathisi sokusebenza esibalulekileyo se-methyl cellulose ether. I-HPMC esetyenziselwa udaka lwepowder eyomileyo iyadingeka ukuba ibe ngumgubo, kunye nomxholo wamanzi aphantsi, kunye nokulungiswa kwakhona kufuna i-20% ~ 60% ye-particle size ibe ngaphantsi kwe-63um. Ukucoleka kuchaphazela ukunyibilika kwe-methyl cellulose ether. I-coarse MC idla ngokuba yigranular, kwaye kulula ukuyinyibilika emanzini ngaphandle kwe-agglomeration, kodwa izinga lokuchithwa licotha kakhulu, ngoko ke ayifanelekanga ukusetyenziswa kwidaka elomileyo lomgubo. Kwipowder eyomileyo yodaka, i-MC ihlakazekile phakathi kwezinto zesamente ezifana ne-aggregate, i-fine filler kunye nesamente, kwaye kuphela umgubo ococekileyo owaneleyo unokunqanda i-methyl cellulose ether agglomeration xa ixutywa namanzi. Xa HPMC idityaniswe ngamanzi ukunyibilikisa agglomerate, kuba nzima kakhulu ukuchithachitha kwaye ukunyibilika. Ngodaka olutshiziweyo olunokwakhiwa ngoomatshini, imfuno yokucoca iphezulu ngenxa yexesha elifutshane lokuxuba. Ukucoleka kwe-HPMC nako kunempembelelo ethile kugcino lwamanzi. Ngokubanzi, kwi-methyl cellulose ethers ezineviscosity efanayo kodwa ukucoleka okwahlukileyo, phantsi komyinge wokongeza ofanayo, kokukhona ucoleka kokukhona kungcono ugcino lwamanzi. Ukugcinwa kwamanzi kwe-HPMC kukwanxulumene nobushushu obusetyenzisiweyo, kwaye ukugcinwa kwamanzi kwe-methyl cellulose ether kuncipha ngokunyuka kwamaqondo obushushu. Nangona kunjalo, kwizinto ezisetyenziswayo, udaka olomileyo lomgubo luhlala lusetyenziswa kwiindawo ezishushu kumaqondo obushushu aphezulu (angaphezulu kwama-40 degrees) kwiindawo ezininzi, ezinje ngodonga lwangaphandle lokutyatyekwa phantsi kwelanga ehlotyeni, oluhlala lukhawulezisa Ukunyangwa kwesamente kunye nokuqina kwesamente. udaka olomileyo lomgubo. Ukwehla kwezinga lokugcinwa kwamanzi kukhokelela kwimvakalelo ecacileyo yokuba zombini ukusebenza kunye nokumelana nokuqhekeka kuchaphazeleka, kwaye kubaluleke kakhulu ukunciphisa impembelelo yobushushu phantsi kwesi simo.

3. Ukuqina kunye ne-thixotropy ye-cellulose ether: Umsebenzi wesibini we-cellulose ether-i-thickening effect ixhomekeke kwi: iqondo le-polymerization ye-cellulose ether, i-concentration concentration, iqondo lokushisa kunye nezinye iimeko. Ipropati ye-gelling yesisombululo iyingqayizivele kwi-alkyl cellulose kunye ne-derivatives yayo eguqulwayo. Iimpawu ze-gelation zihambelana neqondo lokutshintshwa, ukugxininiswa kwesisombululo kunye nezongezo. Kwizinto ze-hydroxyalkyl eziguqulweyo, iipropathi zejeli nazo zihambelana neqondo lokuguqulwa kwe-hydroxyalkyl. Kwisisombululo se-HPMC esine-viscosity ephantsi, isisombululo soxinaniso se-10% -15% sinokulungiswa, i-medium-viscosity HPMC ingalungiswa isisombululo se-5% -10%, kunye ne-high-viscosity HPMC inokulungiselela kuphela isisombululo se-2% -3%, kunye ne-viscosity. ye-cellulose ether idla ngokuba uHlelo lukwahlelwa ngesisombululo se-1% -2%. Ubunzima bemolekyuli ephezulu ye-cellulose ether inokuqina okuphezulu. Iipolymers ezinobunzima beemolekyuli ezahlukeneyo zinee-viscosity ezahlukeneyo kwisisombululo esifanayo soxinaniso. Iqondo eliphezulu lepolymerization. I-viscosity ekujoliswe kuyo inokufezekiswa kuphela ngokongeza inani elikhulu le-ether ye-cellulose ephantsi ye-molecular weight. I-viscosity yayo inokuxhomekeka okuncinci kwireyithi yokucheba, kwaye i-viscosity ephezulu ifikelela kwi-viscosity ekujoliswe kuyo, kwaye inani elifunekayo lokongeza lincinci, kwaye i-viscosity ixhomekeke ekusebenzeni kakuhle. Ngoko ke, ukufezekisa ukuhambelana okuthile, inani elithile le-cellulose ether (ukugxilwa kwesisombululo) kunye ne-viscosity yesisombululo kufuneka kuqinisekiswe. Iqondo lokushisa le-gel yesisombululo liyancipha ngokuhambelana nokunyuka koxinzelelo lwesisombululo, kunye neegels kwiqondo lokushisa emva kokufikelela kwinqanaba elithile. Uxinzelelo lwe-gelling lwe-HPMC luphezulu ngokwentelekiso kwiqondo lobushushu begumbi. Ukuhambelana kungalungiswa ngokukhetha ubungakanani besuntswana kunye nokukhetha i-cellulose ethers ngeedigri ezahlukeneyo zokuguqulwa. Into ebizwa ngokuba yinguquko kukwazisa iqondo elithile lokutshintshwa kwamaqela e-hydroxyalkyl kwisakhiwo samathambo e-MC. Ngokutshintsha amaxabiso ahambelanayo atshintshileyo amabini abambeleyo, oko kukuthi, i-DS kunye ne-ms ehambelanayo amaxabiso e-methoxy kunye ne-hydroxyalkyl esihlala siyithetha. Iimfuno ezahlukeneyo zokusebenza ze-cellulose ether zinokufunyanwa ngokutshintsha amaxabiso ahambelanayo ahambelanayo amabini abambeleyo. Ubudlelwane phakathi kokuhambelana kunye nokuguqulwa: ukongezwa kwe-cellulose ether kuchaphazela ukusetyenziswa kwamanzi kwi-mortar, ukutshintsha umlinganiselo we-binder yamanzi wamanzi kunye ne-samente yimpembelelo yokuqina, i-dosage ephezulu, ngakumbi ukusetyenziswa kwamanzi. I-cellulose ethers esetyenziswe kwizinto zokwakha ezinomgubo kufuneka ichithe ngokukhawuleza emanzini abandayo kwaye inikeze ukuhambelana okufanelekileyo kwesistim. Kukwakho nobudlelwane obuhle bomgca phakathi kokungaguquguquki kwentlama yesamente kunye nedosi ye-cellulose ether. I-ether ye-cellulose inokunyusa kakhulu i-viscosity yodaka. Ubukhulu bedosi, kokukhona isiphumo esicacileyo. I-high-viscosity cellulose ether isisombululo samanzi sine-thixotropy ephezulu, ekwayimpawu enkulu ye-cellulose ether. Ngoko ke, ii-cellulose ethers zebakala elifanayo le-viscosity zihlala zibonisa iimpawu ezifanayo ze-rheological nje ukuba ugxininiso kunye nobushushu bugcinwa rhoqo. Iigels zesakhiwo zenziwe xa ubushushu buphakanyisiwe, kwaye ukuhamba okuphezulu kwe-thixotropic kwenzeka. Uxinzelelo oluphezulu kunye ne-viscosity ephantsi ye-cellulose ethers ibonisa i-thixotropy nangaphantsi kweqondo lokushisa le-gel. Lo mhlaba unenzuzo enkulu kuhlengahlengiso lomgangatho kunye nokuncipha kulwakhiwo lodaka lwesakhiwo. Kufuneka kucaciswe apha ukuba i-viscosity ephezulu ye-ether ye-cellulose, ngcono ukugcinwa kwamanzi, kodwa ukuphakama kwe-viscosity, ukuphakama kwe-molecular weight ye-cellulose ether, kunye nokuncipha okuhambelanayo kwi-solubility yayo, enefuthe elibi. kugxininiso lodaka kunye nokusebenza kolwakhiwo. Ukuphakama kwe-viscosity, kuyabonakala ngakumbi umphumo wokuqina kumdaka, kodwa awulingani ngokupheleleyo. Enye i-viscosity ephakathi kunye nephantsi, kodwa i-ether ye-cellulose eguqulwayo inomsebenzi ongcono ekuphuculeni amandla okwakhiwa kodaka olumanzi. Ngokunyuka kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuphucula.

4. Ukunciphisa i-cellulose ether: Umsebenzi wesithathu we-cellulose ether kukulibazisa inkqubo ye-hydration yesamente. I-Cellulose ether inika udaka oluneepropati ezahlukeneyo eziluncedo, kwaye inciphisa kwakhona ubushushu bokuqala be-hydration yesamente kwaye ilibazise inkqubo ye-hydration eguquguqukayo yesamente. Oku akulunganga ukusetyenziswa kodaka kwiindawo ezibandayo. Esi siphumo sokubuyisela sibangelwa yi-adsorption ye-cellulose ether molecules kwiimveliso ze-hydration ezifana ne-CSH kunye ne-ca (OH) i-2. Ngenxa yokunyuka kwe-viscosity yesisombululo se-pore, i-ether ye-cellulose iyanciphisa ukuhamba kwe-ion kwisisombululo, ngaloo ndlela ilibazise inkqubo ye-hydration. Ukuphakama koxinzelelo lwe-cellulose ether kwizinto ze-mineral gel, isiphumo esicacileyo sokulibaziseka kwe-hydration. I-ether ye-cellulose ayilibazisi nje ukubeka, kodwa iphinda ilibazise inkqubo yokuqina kwenkqubo yodaka lwesamente. Umphumo wokunciphisa i-cellulose ether ayixhomekanga kuphela ekugxininiseni kwayo kwinkqubo ye-gel mineral, kodwa nakwisakhiwo samachiza. Okukhona isiphumo sokubabaza se-cellulose ether, kokukhona sinamandla isiphumo sokubambezela ukutshintshwa kwe-hydrophilic kunokutshintsha amanzi. Nangona kunjalo, i-viscosity ye-cellulose ether inefuthe elincinci kwi-cement hydration kinetics. Ngokunyuka komxholo we-cellulose ether, ixesha lokumisela udaka landa kakhulu. Kukho ukulungelelaniswa okuhle okungahambi kakuhle phakathi kwexesha lokuqala lokumisela lodaka kunye nomxholo we-cellulose ether, kunye nokulungelelaniswa kakuhle komgca phakathi kwexesha lokugqibela lokumisela kunye nomxholo we-cellulose ether. Sinokulawula ixesha lokusebenza lodaka ngokutshintsha inani le-cellulose ether. Ukushwankathela, kwi-mortar esele ixutywe, i-cellulose ether idlala indima yokugcina amanzi, ukuqina, ukulibazisa amandla e-cement hydration, kunye nokuphucula ukusebenza kokwakhiwa. Umthamo olungileyo wokugcinwa kwamanzi wenza i-samente i-hydration igqibeke ngakumbi, inokuphucula i-viscosity emanzi yodaka olumanzi, ukwandisa amandla okubopha udaka, kunye nokulungelelanisa ixesha. Ukongeza i-cellulose ether kumatshini wokutshiza udaka kunokuphucula ukutshiza okanye ukumpompa ukusebenza kunye namandla okwakhiwa kodaka. Ngoko ke, i-cellulose ether isetyenziswa ngokubanzi njengesongezo esibalulekileyo kwi-mortar esele ixutywe.


Ixesha lokuposa: Jan-23-2023
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