I-Cellulose ether iyi-polymer yokwenziwa eyenziwe nge-cellulose yemvelo njengezinto zokusetshenziswa ngokuguqulwa kwamakhemikhali. I-Cellulose ether iyi-derivative ye-cellulose yemvelo, ukukhiqizwa kwe-cellulose ether kanye ne-polymer yokwenziwa kuhlukile, izinto zayo eziyisisekelo yi-cellulose, ama-polymer compounds emvelo. Ngenxa yokwakheka kwe-cellulose yemvelo, i-cellulose ngokwayo ayinawo amandla okusabela ne-etherifying agent. Kodwa ngemva kokwelashwa kwe-ejenti yokuvuvukala, izibopho ze-hydrogen ezinamandla phakathi kwamaketanga namaketanga e-molecule zabhujiswa, futhi umsebenzi weqembu le-hydroxyl wakhishwa waba yi-alkali cellulose enekhono lokusabela, kanti i-cellulose ether yatholakala ngokusabela kwe-etherifying agent — iqembu le-OH libe yi-OR.
Izakhiwo zama-ether e-cellulose zincike ohlotsheni, inombolo kanye nokusatshalaliswa kwezinto ezithatha indawo. Ukuhlukaniswa kwe-ether ye-cellulose kusekelwe ohlotsheni lwezinto ezithatha indawo, izinga lokushintshwa kwe-ether, ukuncibilika kanye nokusetshenziswa okuhlobene kungahlukaniswa. Ngokusho kohlobo lwezinto ezithatha indawo kuchungechunge lwama-molecule, ingahlukaniswa ibe yi-ether eyodwa kanye ne-ether exubile. I-MC ivame ukusetshenziswa njenge-ether eyodwa, kuyilapho i-HPmc iyi-ether exubile. I-Methyl cellulose ether MC iyiyunithi yemvelo ye-cellulose glucose ku-hydroxyl, i-methoxide ithathelwe indawo yifomula yesakhiwo somkhiqizo [CO H7O2 (OH) 3-H (OCH3) H] X, i-hydroxypropyl methyl cellulose ether HPmc iyiyunithi ku-hydroxyl iyingxenye ye-methoxide ethathelwe indawo, enye ingxenye yomkhiqizo othathelwe indawo yi-hydroxypropyl, ifomula yesakhiwo yi-[C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X kanye ne-hydroxyethyl methyl cellulose ether HEmc, esetshenziswa kabanzi futhi ithengiswa emakethe.
Kusukela ekuncibilikeni kungahlukaniswa kube uhlobo lwe-ionic kanye nohlobo olungeyona i-ionic. I-ether ye-cellulose engeyona i-ionic encibilikayo emanzini yakhiwe kakhulu yi-alkyl ether kanye ne-hydroxyl alkyl ether uchungechunge lwezinhlobo ezimbili. I-Cmc ye-Ionic isetshenziswa kakhulu ekuhlanzeni kokwenziwa, ezindwangu, ekunyatheliseni, ekudleni nasekusetshenzisweni kwephethiloli. I-MC engeyona i-ionic, i-HPmc, i-HEmc kanye nezinye ezisetshenziswa kakhulu ezintweni zokwakha, ezimbozweni ze-latex, kwezokwelapha, kwekhemistri yansuku zonke nakwezinye izici. Njenge-ejenti yokuqina, i-ejenti yokugcina amanzi, i-stabilizer, i-dispersant, i-ejenti yokwakha ifilimu.
Ukugcinwa kwamanzi e-cellulose ether
Ekukhiqizweni kwezinto zokwakha, ikakhulukazi udaka oluxubile olomile, i-cellulose ether idlala indima engenakuphikwa, ikakhulukazi ekukhiqizweni kodaka olukhethekile (udaka oluguquliwe), luyingxenye ebalulekile.
Indima ebalulekile ye-cellulose ether encibilikayo emanzini ku-mortar inezici ezintathu, eyodwa ikhono elihle kakhulu lokugcina amanzi, eyesibili ithonya lokuvumelana kwe-mortar kanye ne-thixotropy, kanti eyesithathu ukusebenzisana ne-samente.
Ukugcinwa kwamanzi e-cellulose ether, kuncike esisekelweni se-hydroscopicity, ukwakheka kwe-mortar, ubukhulu bengqimba ye-mortar, isidingo samanzi e-mortar, isikhathi sokuqiniswa kwezinto zokuqiniswa. Ukugcinwa kwamanzi e-cellulose ether kuvela ekuncibilikeni nasekuphelelweni kwamanzi kwe-cellulose ether uqobo. Kwaziwa kahle ukuthi izintambo zama-molecule e-cellulose, yize ziqukethe inani elikhulu lamaqembu e-OH anamanzi amaningi, azincibiliki emanzini ngenxa yesakhiwo sazo esicwebezelayo kakhulu. Amandla okufuthwa kwamanzi amaqembu e-hydroxyl kuphela awanele ukukhokhela izibopho ze-hydrogen eziphakathi kwama-molecule kanye namandla e-van der Waals. Lapho izintambo ezifakwayo zifakwa kuchungechunge lwama-molecule, akuzona nje izintambo ezibhubhisa uchungechunge lwe-hydrogen, kodwa futhi nezibopho ze-hydrogen eziphakathi ziyaphulwa ngenxa yokuhlangana kwezintambo eziseduze. Lapho izintambo ezikhona zikhulu, ibanga eliphakathi kwama-molecule likhulu. Lapho ukubhujiswa komphumela wesibopho se-hydrogen kukhulu, ukwanda kwe-cellulose lattice, isixazululo singene ku-cellulose ether siba manzi ancibilikayo, ukwakheka kwesisombululo se-viscosity ephezulu. Njengoba izinga lokushisa likhuphuka, ukumuncwa kwe-polymer kuyancipha futhi amanzi aphakathi kwamaketanga ayakhishwa. Uma umphumela wokuphelelwa amanzi emzimbeni wanele, ama-molecule aqala ukuhlangana futhi ijeli ligoqeka kunethiwekhi enezinhlangothi ezintathu. Izici ezithinta ukugcinwa kwamanzi kwe-mortar zifaka phakathi i-cellulose ether viscosity, umthamo, ubuncane bezinhlayiya kanye nokushisa kwesevisi.
Uma i-viscosity ye-cellulose ether inkulu, kulapho ukusebenza kokugcinwa kwamanzi kuba ngcono khona, i-viscosity yesisombululo se-polymer iba ngcono. Isisindo sama-molecule (izinga le-polymerization) se-polymer sinqunywa ubude kanye nesimo sesakhiwo sama-molecule se-chain, kanye nokusatshalaliswa kwenani lezinto ezithatha indawo kuthinta ngqo ububanzi be-viscosity. [eta] = Km alpha
Ukuqina kwangaphakathi kwezixazululo ze-polymer
Isisindo sama-molecule e-polymer engu-M
isici se-polymer ye-α
Isixazululo se-K viscosity coefficient
Ukuqina kwesisombululo se-polymer kuncike esisindweni sama-molecule se-polymer. Ukuqina kanye nokuhlushwa kwezixazululo ze-cellulose ether kuhlobene nezinhlelo zokusebenza ezahlukahlukene. Ngakho-ke, i-cellulose ether ngayinye inezincazelo eziningi ezahlukene ze-viscosity, ukulawulwa kwe-viscosity nakho kubangelwa ukuwohloka kwe-alkali cellulose, okungukuthi ukuqhekeka kwe-cellulose molecular chain ukuze kufezwe.
Ngosayizi wezinhlayiya, uma izinhlayiya zincane, kuba ngcono ukugcinwa kwamanzi. Izinhlayiya ezinkulu ze-cellulose ether zithintana namanzi, ubuso buncibilika ngokushesha bese benza ijeli yokugoqa izinto ukuze kuvinjelwe ama-molecule amanzi ukuthi angaqhubeki nokungena, ngezinye izikhathi ukuxubha isikhathi eside akukwazi ukuhlakazeka ngokulinganayo, ukwakheka kwesisombululo esinodaka esithambile noma i-agglomerate. Ukuncibilika kwe-cellulose ether kungenye yezinto ezibalulekile ukukhetha i-cellulose ether.
Ukuqina kanye ne-thixotropy ye-cellulose ether
Umphumela wesibili we-cellulose ether – ukuqina kuncike ku: izinga le-polymerization ye-cellulose ether, ukuhlushwa kwesisombululo, izinga lokugunda, izinga lokushisa nezinye izimo. Impahla ye-gelation yesisombululo ihlukile ku-alkyl cellulose kanye ne-derivatives yayo eguquliwe. Izici ze-gelation zihlobene nezinga lokushintsha, ukuhlushwa kwesisombululo kanye nezithasiselo. Kuma-derivatives aguquliwe e-hydroxyl alkyl, izakhiwo zejeli zihlobene nezinga lokuguqulwa kwe-hydroxyl alkyl. Ukuze kulungiswe ukuhlushwa kwesisombululo se-viscosity ephansi ye-MC kanye ne-HPmc kungalungiswa isixazululo sokuhlushwa esingu-10%-15%, i-viscosity ephakathi ye-MC kanye ne-HPmc kungalungiswa isixazululo esingu-5%-10% kanye ne-viscosity ephezulu ye-MC kanye ne-HPmc kungalungiswa isixazululo esingu-2%-3% kuphela, futhi ngokuvamile i-viscosity ye-cellulose ether nayo ihlelwa ngesisombululo esingu-1%-2%. Ukusebenza kahle kwe-cellulose ether thickener yesisindo sama-molecule aphezulu, ukuhlushwa okufanayo kwesisombululo, ama-polymer ahlukene anesisindo sama-molecule ane-viscosity ehlukile, i-viscosity kanye nesisindo sama-molecule kungavezwa kanje, [η]=2.92×10-2 (DPn) 0.905, i-DPn iyizinga eliphakathi le-polymerization eliphakeme. I-cellulose ether yesisindo sama-molecule esiphansi ukuze wengeze okwengeziwe ukuze kufezwe i-viscosity eqondiwe. I-viscosity yayo ayixhomekile kakhulu esilinganisweni sokushefa, i-viscosity ephezulu ukuze kufezwe i-viscosity eqondiwe, inani elidingekayo ukuze kwengezwe kancane, i-viscosity incike ekusebenzeni kahle kokujiya. Ngakho-ke, ukuze kufezwe ukuvumelana okuthile, inani elithile le-cellulose ether (ukuhlushwa kwesisombululo) kanye ne-viscosity yesisombululo kumele kuqinisekiswe. Izinga lokushisa le-gel yesisombululo lehle ngokuhambisana nokwanda kokuhlushwa kwesisombululo, futhi i-gelation yenzeka ekushiseni kwegumbi ngemuva kokufinyelela ukuhlushwa okuthile. I-HPmc ine-gelation ephezulu ekushiseni kwegumbi.
Ukuvumelana kungalungiswa futhi ngokukhetha usayizi wezinhlayiya kanye nama-ether e-cellulose anamazinga ahlukene okuguqulwa. Lokhu okubizwa ngokuthi ukuguqulwa ukungeniswa kweqembu le-hydroxyl alkyl ngezinga elithile lokushintsha isakhiwo se-skeleton se-MC. Ngokushintsha amanani okushintshana ahlobene ama-substituents amabili, okungukuthi, amanani okushintshana ahlobene e-DS kanye ne-MS amaqembu e-methoxy kanye ne-hydroxyl. Izakhiwo ezahlukahlukene ze-cellulose ether ziyadingeka ngokushintsha amanani okushintshana ahlobene ezinhlobo ezimbili zama-substituents.
ubudlelwano phakathi kokuvumelana nokuguqulwa. KuMfanekiso 5, ukungezwa kwe-cellulose ether kuthinta ukusetshenziswa kwamanzi kwe-mortar futhi kushintsha isilinganiso samanzi ne-water-binder samanzi ne-simende, okuwumphumela wokujiya. Uma umthamo uphakeme, ukusetshenziswa kwamanzi amaningi.
Ama-cellulose ether asetshenziswa ezintweni zokwakha eziwumpuphu kumele ancibilike ngokushesha emanzini abandayo futhi anikeze uhlelo ukuqina okufanele. Uma izinga lokugunda elinikeziwe lisalokhu lithambile futhi liyi-colloidal, kungumkhiqizo ongaphansi kwezinga noma wekhwalithi ephansi.
Kukhona futhi ubudlelwano obuhle obuqondile phakathi kokuvumelana kwe-slurry yesimende kanye nomthamo we-cellulose ether, i-cellulose ether ingakhulisa kakhulu i-viscosity yodaka, lapho umthamo ukhula, umphumela uba sobala kakhulu.
Isixazululo samanzi se-Cellulose ether esine-viscosity ephezulu sine-thixotropy ephezulu, okungenye yezici ze-cellulose ether. Izixazululo zamanzi zama-polymer ohlobo lwe-Mc zivame ukuba ne-pseudoplastic, i-non-thixotropic fluidity engaphansi kokushisa kwejeli yazo, kodwa izakhiwo zokugeleza kwe-Newtonian ngamanani aphansi okushefa. I-Pseudoplasticity iyanda ngokwanda kwesisindo sama-molecule noma ukuhlushwa kwe-cellulose ether futhi ayixhomekile kuhlobo nezinga elifanele. Ngakho-ke, ama-cellulose ethers ebanga elifanayo le-viscosity, kungaba yi-MC, i-HPmc noma i-HEmc, ahlala ebonisa izakhiwo ezifanayo ze-rheological inqobo nje uma ukuhlushwa kanye nokushisa kuhlala kungaguquki. Lapho izinga lokushisa likhuphuka, kwakheka ijeli yesakhiwo futhi kwenzeka ukugeleza okuphezulu kwe-thixotropic. Ama-cellulose ethers ane-viscosity ephezulu kanye ne-viscosity ephansi abonisa i-thixotropy ngisho nangaphansi kokushisa kwejeli. Le mpahla inenzuzo enkulu ekwakhiweni kwe-mortar yokwakha ukulungisa ukugeleza kwayo kanye nempahla yokulenga. Kudingeka kuchazwe lapha ukuthi uma i-viscosity ye-cellulose ether iphakeme, kuba ngcono ukugcinwa kwamanzi, kodwa uma i-viscosity iphakeme, kulapho isisindo sama-molecule se-cellulose ether siphakeme, kwehla ukuncibilika kwayo okuhambisanayo, okunomthelela omubi ekugxilweni kwe-mortar kanye nokusebenza kokwakhiwa. Uma i-viscosity iphakeme, kulapho umphumela wokujiya we-mortar ubonakala khona, kodwa akuyona ubuhlobo obuphelele obulinganayo. I-viscosity ephansi, kodwa eguquliwe ye-cellulose ether ekuthuthukiseni amandla esakhiwo se-mortar emanzi inokusebenza okuhle kakhulu, ngokwanda kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuthuthukisiwe.
Isikhathi sokuthunyelwe: Mashi-30-2022