Iyiphi indima edlalwa i-cellulose ether odakeni olomile oluxubile?

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 enekhono lokuphendula, futhi i-cellulose ether yatholakala ngokusabela kwe-etherifying agent - iqembu le-OH - NOMA iqembu.

Izici zama-cellulose ethers zincike ohlotsheni, inombolo kanye nokusatshalaliswa kwama-substituents.Ukuhlukaniswa kwe-cellulose ether kusekelwe futhi ohlotsheni lwezinye izingxenye, 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 ye-glucose cellulose yemvelo 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 ingxenye. ye-methoxide ishintshiwe, enye ingxenye yomkhiqizo oshintshiwe we-hydroxypropyl, Ifomula yesakhiwo ithi [C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X kanye ne-hydroxyethyl methyl cellulose ether HEmc, esetshenziswa kabanzi futhi idayiswe 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 yokwakha 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 weketango, 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, indawo engaphezulu iyancibilika ngokushesha futhi yakha ijeli ukugoqa izinto ukuvimbela ama-molecule amanzi ukuthi aqhubeke nokungena, ngezinye izikhathi isikhathi eside esinyakazayo asikwazi ukuhlakazwa ngokulinganayo, ukwakheka kwesisombululo esinodaka noma i-flocculent solution. 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 kuhlanganiswe isixazululo se-viscosity ephansi ye-MC ne-HPmc ingalungiswa i-10% -15% isisombululo sokuhlushwa, i-viscosity ephakathi kwe-MC ne-HPmc ingalungiswa isixazululo esingu-5% -10% kanye ne-viscosity ephezulu ye-MC ne-HPmc ingalungiswa kuphela 2% -3% isisombululo, futhi ngokuvamile i-viscosity ye-cellulose ether nayo ihlelwe ngesisombululo esingu-1% -2%.Isisindo esiphezulu se-cellulose ether thickener ukusebenza kahle, ukuhlushwa okufanayo kwesisombululo, ama-polymers esisindo samangqamuzana ahlukene ane-viscosity ehlukene, i-viscosity nesisindo samangqamuzana kungavezwa kanje, [η]=2.92×10-2 (DPn) 0.905, i-DPn isilinganiso i-polymerization degree ephezulu.Isisindo esiphansi se-cellulose ether ukwengeza okwengeziwe ukuze kuzuzwe i-viscosity ehlosiwe.I-viscosity yayo ayincikile kangako ku-shear rate, i-viscosity ephezulu ukufeza 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 liye lancipha 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 okuphuca.I-Pseudoplasticity iyanda ngokukhula kwesisindo sengqamuzana noma ukugcwala kwe-cellulose ether futhi izimele ohlotsheni oluhlukile neziqu.Ngakho-ke, ama-cellulose ethers webanga elifanayo le-viscosity, kungakhathaliseki ukuthi i-MC, i-HPmc noma i-HEmc, ahlala ebonisa izici ezifanayo ze-rheological inqobo nje uma ukugxila nokushisa kuhlala kungashintshi.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 lejeli.Lesi sakhiwo sinenzuzo enkulu ekwakhiweni kodaka lwesakhiwo ukulungisa ukugeleza nokugeleza kwendawo elengayo.Kudingeka kuchazwe lapha ukuthi ukuphakama kwe-viscosity ye-cellulose ether, kungcono ukugcina amanzi, kodwa ukuphakama kwe-viscosity, ukuphakama kwesisindo se-cellulose ether, ukuncipha okuhambisanayo kokuncibilika kwayo, okunomthelela omubi ukugxila kodaka 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