I-Cellulose ether iyi-polymer yokwenziwa eyenziwe nge-cellulose yemvelo njengempahla eluhlaza ngokuguqulwa kwamakhemikhali. I-Cellulose ether iphuma ku-cellulose yemvelo, ukukhiqizwa kwe-cellulose ether kanye ne-polymer yokwenziwa kwehlukile, impahla yayo eyisisekelo i-cellulose, izinhlanganisela ze-polymer zemvelo. Ngenxa yemininingwane yesakhiwo se-cellulose yemvelo, i-cellulose ngokwayo ayinawo amandla okusabela nge-ejenti etherifying. Kodwa ngemva kokwelashwa kwe-ejenti yokuvuvukala, izibopho eziqinile ze-hydrogen phakathi kwamaketanga amangqamuzana namaketanga zabhujiswa, futhi umsebenzi weqembu le-hydroxyl wakhululwa ku-alkali cellulose ngekhono lokuphendula, kanye ne-cellulose ether yatholwa ngokusabela kwe-etherifying agent - iqembu le-OH libe - NOMA iqembu.
Izici zama-cellulose ethers zincike ohlotsheni, inombolo nokusatshalaliswa kwezinto ezibambele. Ukuhlukaniswa kwe-cellulose ether kusekelwe futhi ohlotsheni lwama-substitute, izinga le-etherification, ukunyibilika kanye nokusetshenziswa okuhlobene kungahlukaniswa. Ngokohlobo lwama-substituent ochungechungeni lwemolekyuli, ingahlukaniswa ibe i-ether eyodwa ne-ether exutshiwe. I-MC ivamise ukusetshenziswa njenge-ether eyodwa, kuyilapho i-HPmc iyi-ether exubile. I-Methyl cellulose ether MC iyiyunithi yemvelo ye-cellulose glucose ku-hydroxyl i-methoxide ithathelwa indawo ifomula yesakhiwo somkhiqizo [CO H7O2 (OH) 3-H (OCH3) H] X, i-hydroxypropyl methyl cellulose ether HPmc iyiyunithi ku-hydroxyl iyingxenye ye-methoxide eshintshwayo, enye ingxenye ye-hydroxypropyl [C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X kanye ne-hydroxyethyl methyl cellulose ether HEmc, esetshenziswa kakhulu futhi idayiswa emakethe.
Kusukela ku-solubility ingahlukaniswa ngohlobo lwe-ionic kanye nohlobo olungezona i-ionic. I-ether ye-cellulose engeyona i-ionic encibilikayo emanzini yakhiwa ikakhulukazi i-alkyl ether kanye ne-hydroxyl alkyl ether yochungechunge olubili lwezinhlobo. I-Ionic Cmc isetshenziswa kakhulu okokuhlanza okokwenziwa, izindwangu, ukuphrinta, ukudla kanye nokuxhashazwa kwe-petroleum. I-Non-ionic MC, i-HPmc, i-HEmc nezinye ezisetshenziswa kakhulu ezintweni zokwakha, i-latex coatings, imithi, i-chemistry yansuku zonke nezinye izici. Njenge-ejenti yokuqina, i-ejenti yokugcina amanzi, i-stabilizer, i-dispersant, i-ejenti eyenza ifilimu.
Ukugcinwa kwamanzi e-Cellulose ether
Ekukhiqizeni izinto zokwakha, ikakhulukazi udaka olomile oluxubile, i-cellulose ether idlala indima engenakushintshwa, ikakhulukazi ekukhiqizeni udaka olukhethekile (udaka oluguquliwe), luyingxenye ebalulekile.
Indima ebalulekile ye-ether ye-cellulose encibilikayo emanzini ikakhulukazi inezici ezintathu, eyodwa ikhono elihle kakhulu lokugcina amanzi, okwesibili ithonya lokungaguquguquki kodaka kanye ne-thixotropy, kanti okwesithathu ukuxhumana nosimende.
Ukugcinwa kwamanzi e-cellulose ether, kuncike esisekelweni se-hydroscopicity, ukwakheka kodaka, ugqinsi lwengqimba yodaka, isidingo samanzi odaka, isikhathi sokufingqa sento yokufingqa. Ukugcinwa kwamanzi kwe-cellulose ether kuvela ekuncibilikeni nasekuphelelweni kwamanzi emzimbeni kwe-cellulose ether ngokwayo. Kuyaziwa ukuthi amaketanga e-cellulose yamangqamuzana, nakuba aqukethe inani elikhulu lamaqembu e-OH ane-hydrated kakhulu, awancibiliki emanzini ngenxa yesakhiwo sawo esicwebezelayo. Amandla okukhipha amanzi emaqenjini e-hydroxyl ewodwa akwanele ukukhokhela amabhondi e-hydrogen e-intermolecular aqinile namandla e-van der Waals. Lapho okushintshiwe kwethulwa ochungechungeni lwamangqamuzana, akuzona kuphela ezinye ezibhubhisa iketango le-hydrogen, kodwa futhi amabhondi e-hydrogen e-interchain ayaphulwa ngenxa yokugaxana kwezakhi phakathi kwamaketanga aseduze. Uma ama-substituent emakhulu, ibanga eliphakathi kwama-molecule likhulu. Ukubhujiswa okukhulu komphumela we-hydrogen bond, ukunwetshwa kwe-cellulose lattice, isixazululo ku-ether cellulose siba encibilikayo emanzini, ukwakheka kwesisombululo se-viscosity ephezulu. Njengoba izinga lokushisa likhuphuka, i-hydration ye-polymer iyancipha futhi amanzi phakathi kwamaketanga akhishwe. Lapho umphumela wokukhipha amanzi emzimbeni wanele, ama-molecule aqala ukuhlangana futhi ijeli igoqeka kunethiwekhi ye-three-dimensional. Izici ezithinta ukugcinwa kwamanzi kodaka zihlanganisa i-cellulose ether viscosity, umthamo, ukuqina kwezinhlayiyana kanye nezinga lokushisa lesevisi.
Ubukhulu be-viscosity ye-cellulose ether, ngcono ukusebenza kokugcinwa kwamanzi, i-viscosity yesisombululo se-polymer. Isisindo samangqamuzana (idigri ye-polymerization) ye-polymer futhi inqunywa ubude ne-morphology yesakhiwo samangqamuzana eketango, futhi ukusatshalaliswa kwenombolo yezingxenye ezihlukile kuthinta ngokuqondile ububanzi be-viscosity. [eta] = Km alpha
I-viscosity yangaphakathi yezixazululo ze-polymer
Isisindo samangqamuzana esingu-M polymer
α polymer isici njalo
K i-viscosity solution coefficient
I-viscosity yesisombululo se-polymer incike esisindweni samangqamuzana e-polymer. I-viscosity kanye nokugxila kwezixazululo ze-cellulose ether kuhlobene nezinhlelo zokusebenza ezihlukahlukene. Ngakho-ke, i-cellulose ether ngayinye inezincazelo eziningi ezihlukahlukene ze-viscosity, ukulawulwa kwe-viscosity futhi ikakhulukazi ngokucekelwa phansi kwe-alkali cellulose, okungukuthi ukuphuka kweketango lamangqamuzana e-cellulose ukuze kuzuzwe.
Ngosayizi wezinhlayiyana, ukucoleka kwezinhlayiyana, kuba ngcono nokugcinwa kwamanzi. Izinhlayiya ezinkulu ze-cellulose ether ezithintana namanzi, i-surface iyancibilika ngokushesha futhi yakha ijeli ukugoqa izinto ukuvimbela ama-molecule wamanzi ukuthi aqhubeke nokungena, ngezinye izikhathi isikhathi eside esishukumisayo asikwazi ukuhlakazwa ngokulinganayo, ukwakheka kwesisombululo se-flocculent esinodaka noma i-agglomerate. Ukunyibilika kwe-cellulose ether kungenye yezinto zokukhetha i-cellulose ether.
Ukuqina kanye ne-thixotropy ye-cellulose ether
Umphumela wesibili we-cellulose ether - ukuqina kuncike: i-cellulose ether polymerization degree, ukuhlushwa kwesisombululo, izinga le-shear, izinga lokushisa nezinye izimo. Impahla ye-gelation yesisombululo ihlukile ku-alkyl cellulose kanye nokuphuma kwayo okuguquliwe. Izici ze-Gelation zihlobene nezinga lokushintshwa, ukugxila kwesisombululo kanye nezithasiselo. Kokuphuma kokunye okuguquliwe kwe-hydroxyl alkyl, izakhiwo zejeli nazo zihlobene nezinga lokuguqulwa kwe-hydroxyl alkyl. Ukuze uthole ukuhlushwa kwesisombululo se-viscosity ephansi ye-MC ne-HPmc ingalungiswa 10% -15% isixazululo sokuhlushwa, i-viscosity ephakathi kwe-MC ne-HPmc ingalungiswa i-5% -10% isixazululo kanye ne-viscosity ephezulu ye-MC ne-HPmc ingalungiswa kuphela i-2% -3% isixazululo, futhi ngokuvamile i-viscosity ye-cellulose ether ibuye ihlelwe nge-2% isixazululo se-2%. Isisindo esiphezulu se-cellulose ether thickener ukusebenza kahle, ukuhlushwa okufanayo kwesisombululo, ama-polymers ahlukene esisindo samangqamuzana ane-viscosity ehlukene, i-viscosity nesisindo samangqamuzana singavezwa kanje, [η] = 2.92 × 10-2 (DPn) 0.905, i-DPn yizinga elijwayelekile le-polymerization eliphezulu. Isisindo esiphansi se-cellulose ether ukwengeza okwengeziwe ukuze kuzuzwe i-viscosity ehlosiwe. I-viscosity yayo ayincikile kangako ku-shear rate, i-viscosity ephezulu ukuze kuzuzwe i-viscosity ehlosiwe, inani elidingekayo ukuze wengeze kancane, i-viscosity incike ekusebenzeni kahle kokuqina. Ngakho-ke, ukuze kuzuzwe ukuvumelana okuthile, inani elithile le-cellulose ether (ukugxila kwesisombululo) kanye ne-viscosity yesisombululo kufanele kuqinisekiswe. Izinga lokushisa le-gelation lesisombululo lehla ngokuhambisana nokwanda kokugxila kwesisombululo, futhi i-gelation yenzeke ekamelweni lokushisa ngemva kokufinyelela ekugxilweni okuthile. I-HPmc inokugxila okuphezulu kwe-gelation kuthempelesha yekamelo.
Ukuvumelana kungabuye kulungiswe ngokukhetha usayizi wezinhlayiyana nama-cellulose ether anamazinga ahlukene okuguqulwa. Okubizwa ngokuthi ukuguqulwa ukwethulwa kweqembu le-hydroxyl alkyl ngezinga elithile lokushintsha esakhiweni samathambo e-MC. Ngokushintsha amanani ashintshile ahlobene ezinto ezimbili ezibambele, okungukuthi, amanani ashintshile ahlobene we-DS ne-MS weqembu le-methoxy ne-hydroxyl. Izakhiwo ezihlukahlukene ze-cellulose ether ziyadingeka ngokushintsha amanani ashintshile ahlobene ezinhlobo ezimbili zama-substitutes.
ubudlelwano phakathi kokuvumelana nokuguqulwa. Emfanekisweni wesi-5, ukungezwa kwe-cellulose ether kuthinta ukusetshenziswa kwamanzi kodaka futhi kushintsha isilinganiso se-water-binder samanzi nosimende, okuwumphumela wokuqina. Lapho umthamo uphakeme, ukusetshenziswa kwamanzi kuyanda.
Ama-cellulose ether asetshenziswa ezintweni zokwakha eziyimpuphu kufanele ahlakazeke ngokushesha emanzini abandayo futhi anikeze isistimu ukuvumelana okulungile. Uma izinga lokugunda elinikeziwe lisalokhu linyakaza futhi liyi-colloidal liwumkhiqizo osezingeni eliphansi noma wekhwalithi ephansi.
Kukhona futhi ubudlelwano obuhle bomugqa phakathi kokungaguquguquki kwe-slurry kasimende kanye nesilinganiso se-cellulose ether, i-cellulose ether ingakhuphula kakhulu i-viscosity yodaka, umthamo omkhulu, umphumela osobala kakhulu.
Isixazululo samanzi se-cellulose ether esine-viscosity ephezulu sine-thixotropy ephezulu, okungenye yezici ze-cellulose ether. Izixazululo ezinamanzi zama-polymers ohlobo lwe-Mc ngokuvamile zine-pseudoplastic, non-thixotropic fluidity ngaphansi kwezinga lokushisa lejeli, kodwa izakhiwo zokugeleza kwe-Newtonian ngamanani aphansi e-shear. I-Pseudoplasticity iyanda ngokukhula kwesisindo sengqamuzana noma ukuhlangana kwe-cellulose ether futhi izimele ohlotsheni oluhlukile neziqu. Ngakho-ke, i-cellulose ethers yebanga elifanayo le-viscosity, kungakhathaliseki ukuthi i-MC, i-HPmc noma i-HEmc, ihlale ibonisa izici ezifanayo ze-rheological inqobo nje uma ukugxila kanye nezinga lokushisa lihlala lingashintshi. Lapho izinga lokushisa likhuphuka, i-gel yesakhiwo iyakhiwa futhi ukugeleza okuphezulu kwe-thixotropic kwenzeka. Ama-cellulose ethers ane-concentration ephezulu kanye ne-viscosity ephansi abonisa i-thixotropy ngisho nangaphansi kwezinga lokushisa le-gel. Lesi sakhiwo sinenzuzo enkulu ekwakhiweni kodaka lwesakhiwo ukulungisa ukugeleza nokugeleza kwendawo elengayo. Kudingeka kuchazwe lapha ukuthi ukuphakama kwe-viscosity ye-cellulose ether, ukugcinwa kwamanzi kangcono, kodwa ukuphakama kwe-viscosity, ukuphakama kwesisindo samangqamuzana e-cellulose ether, ukuncipha okuhambisanayo kokuncibilika kwayo, okunomthelela omubi ekugxilweni kodaka kanye nokusebenza kokwakhiwa. Ukuphakama kwe-viscosity, kusobala kakhulu umphumela wokujiya wodaka, kodwa akuwona ubudlelwano obuphelele bokulinganisa. I-viscosity ethile ephansi, kodwa i-cellulose ether eguquliwe ekuthuthukiseni amandla esakhiwo sodaka olumanzi inokusebenza okuhle kakhulu, ngokunyuka kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuyathuthukiswa.
Isikhathi sokuthumela: Mar-30-2022