I-Cellulose ether iyi-polymer yokwenziwa eyenziwe nge-cellulose yemvelo ngokuguqulwa kwamakhemikhali.I-Cellulose ether iphuma ku-cellulose yemvelo.Ukukhiqizwa kwe-cellulose ether kuhlukile kuma-polymers okwenziwa.Impahla yayo eyisisekelo i-cellulose, isakhi se-polymer yemvelo.Ngenxa yemininingwane yesakhiwo se-cellulose yemvelo, i-cellulose ngokwayo ayinalo ikhono lokusabela nge-etherification agents.Kodwa-ke, ngemva kokwelashwa kwe-ejenti yokuvuvukala, izibopho eziqinile ze-hydrogen phakathi kwamaketanga amangqamuzana namaketanga ziyabhujiswa, futhi ukukhululwa okusebenzayo kweqembu le-hydroxyl kuba i-alkali cellulose esebenzayo.Thola i-cellulose ether.
Izici zama-cellulose ethers zincike ohlotsheni, inombolo nokusatshalaliswa kwezinto ezibambele.Ukuhlukaniswa kwe-cellulose ethers futhi kusekelwe ohlotsheni lwama-substitute, izinga le-etherification, ukuncibilika kanye nezakhiwo zesicelo ezihlobene.Ngokuya kohlobo lwama-substituent ochungechungeni lwemolekyuli, ingahlukaniswa ibe i-monoether ne-ether exutshiwe.Ngokuvamile sisebenzisa i-mc njenge-monoether, ne-HPmc njenge-ether exubile.I-Methyl cellulose ether mc iwumkhiqizo ngemuva kokuthi iqembu le-hydroxyl kuyunithi ye-glucose ye-cellulose yemvelo lithathelwe indawo yiqembu le-methoxy.Kungumkhiqizo otholwe ngokufaka esikhundleni ingxenye yeqembu le-hydroxyl kuyunithi neqembu le-methoxy kanye nengxenye neqembu le-hydroxypropyl.Ifomula yesakhiwo ithi [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEmc, lezi yizinhlobo eziyinhloko ezisetshenziswa kakhulu futhi ezithengiswa emakethe.
Ngokuya nge-solubility, ingahlukaniswa ibe yi-ionic ne-non-ionic.Ama-ether e-non-ionic cellulose ancibilika emanzini akhiwa ikakhulukazi uchungechunge olubili lwama-alkyl ether nama-hydroxyalkyl ether.I-Ionic Cmc isetshenziswa kakhulu ezintweni zokwenziwa zokuhlanza, ukuphrinta izindwangu nokudaya, ukuhlola ukudla nowoyela.I-non-ionic mc, i-HPmc, i-HEmc, njll. isetshenziswa kakhulu ezintweni zokwakha, i-latex coatings, imithi, amakhemikhali ansuku zonke, njll. Isetshenziswa njenge-thickener, i-ejenti yokugcina amanzi, i-stabilizer, i-dispersant kanye ne-ejenti yokwakha ifilimu.
Ukugcinwa kwamanzi kwe-cellulose ether
Ekukhiqizeni izinto zokwakha, ikakhulukazi udaka oluxutshwe okomile, i-cellulose ether idlala indima engenakushintshwa, ikakhulukazi ekukhiqizeni udaka olukhethekile (udaka oluguquliwe), luyingxenye ebalulekile futhi ebalulekile.
Indima ebalulekile ye-ether ye-cellulose encibilikayo emanzini ikakhulukazi inezici ezintathu, eyodwa iwumthamo omuhle kakhulu wokugcinwa kwamanzi, enye ithonya lokungaguquguquki kanye ne-thixotropy yodaka, kanti okwesithathu ukuxhumana nosimende.
Umphumela wokugcina amanzi we-cellulose ether uncike ekumunceni kwamanzi kwesendlalelo sesisekelo, ukwakheka kodaka, ukujiya kongqimba lodaka, isidingo samanzi sodaka, kanye nesikhathi sokusetha sendawo yokusetha.Ukugcinwa kwamanzi kwe-cellulose ether ngokwayo kuvela ekuncibilikeni nasekuphelelweni kwamanzi emzimbeni kwe-cellulose ether ngokwayo.Njengoba sonke sazi, nakuba iketanga lamangqamuzana e-cellulose liqukethe inani elikhulu lamaqembu e-OH ane-hydratable, ayincibiliki emanzini, ngoba isakhiwo se-cellulose sinezinga eliphezulu le-crystallinity.Amandla okukhipha amanzi emaqenjini e-hydroxyl ewodwa akwanele ukumboza amabhondi e-hydrogen aqinile namandla e-van der Waals phakathi kwama-molecule.Ngakho-ke, iyavuvukala kuphela kodwa ayincibiliki emanzini.Lapho enye indawo yethulwa ochungechungeni lwamangqamuzana, akugcini nje kuphela ukuthi okungene esikhundleni kucekela phansi iketango le-hydrogen, kodwa futhi isibopho se-hydrogen se-interchain siyabhujiswa ngenxa yokuhlangana kwento ebambele phakathi kwamaketanga aseduze.Uma i-substitute inkulu, ibanga eliphakathi kwama-molecule liba likhulu.Ibanga elikhulu.Umphumela omkhulu wokucekela phansi izibopho ze-hydrogen, i-cellulose ether iyancibilika emanzini ngemva kokuba i-cellulose lattice yanda futhi isisombululo singena, sakha isisombululo se-viscosity ephezulu.Lapho izinga lokushisa likhuphuka, i-hydration ye-polymer iba buthaka, futhi amanzi phakathi kwamaketanga axoshwa.Lapho umphumela wokuphelelwa amanzi emzimbeni wanele, ama-molecule aqala ukuhlanganisa, enze ijeli yesakhiwo senethiwekhi enezinhlangothi ezintathu futhi ahlanganiswe.Izinto ezithinta ukugcinwa kwamanzi kodaka zihlanganisa i-viscosity ye-cellulose ether, inani elingeziwe, ukucoleka kwezinhlayiya kanye nezinga lokushisa lokusetshenziswa.
Ukuphakama kwe-viscosity ye-cellulose ether, ngcono ukusebenza kokugcinwa kwamanzi, futhi kukhuphuka i-viscosity yesisombululo se-polymer.Ngokuya ngesisindo samangqamuzana (i-polymerization degree) ye-polymer, futhi kunqunywa ubude beketanga lesakhiwo samangqamuzana kanye nokuma kweketango, futhi ukusatshalaliswa kwezinhlobo nenani labasekeli nakho kuthinta ngqo uhla lwayo lwe-viscosity.[η]=Kmα
[η] I-viscosity yangaphakathi yesixazululo se-polymer
m polymer isisindo samangqamuzana
α polymer isici njalo
K i-viscosity solution coefficient
I-viscosity yesisombululo se-polymer incike esisindweni samangqamuzana e-polymer.I-viscosity kanye nokugxila kwesisombululo se-cellulose ether kuhlobene nokusetshenziswa emikhakheni ehlukahlukene.Ngakho-ke, i-cellulose ether ngayinye inezincazelo eziningi ezihlukahlukene ze-viscosity, futhi ukulungiswa kwe-viscosity kubonakala ikakhulukazi ngokuwohloka kwe-alkali cellulose, okungukuthi, ukugqashuka kwamaketanga e-cellulose yamangqamuzana.
Uma sikhulu inani le-cellulose ether engezwe odakeni, ngcono ukusebenza kokugcinwa kwamanzi, futhi lapho ukuphakama kwe-viscosity, kuba ngcono ukusebenza kokugcinwa kwamanzi.
Ngosayizi wezinhlayiyana, ukucoleka kwezinhlayiyana, kuba ngcono nokugcinwa kwamanzi (bheka uMdwebo 3).Ngemva kokuba izinhlayiya ezinkulu ze-cellulose ether zihlangana namanzi, indawo engaphezulu iyancibilika ngokushesha futhi yakhe ijeli ukuze igoqe into ukuvimbela ama-molecule amanzi ukuthi angaqhubeki nokungena.Kwesinye isikhathi ayikwazi ukuhlakazwa ngokufanayo futhi incibilike ngisho nangemva kokunyakaziswa kwesikhathi eside, kwakheka isixazululo esinamafu esigelezayo noma i-agglomeration.Kuthinta kakhulu ukugcinwa kwamanzi kwe-cellulose ether, futhi ukuncibilika kungenye yezici zokukhetha i-cellulose ether.
Ukuqina kanye Thixotropy yeCellulose Ether
Umsebenzi wesibili we-cellulose ether - ukuqina kuncike: izinga le-polymerization ye-cellulose ether, ukuhlushwa kwesisombululo, izinga le-shear, izinga lokushisa nezinye izimo.Impahla ye-gelling yesixazululo ihlukile ku-alkyl cellulose kanye nokuphuma kwayo okuguquliwe.Izakhiwo ze-gelation zihlobene nezinga lokushintshwa, ukugxila kwesisombululo kanye nezithasiselo.Kokuphuma kokunye okuguquliwe kwe-hydroxyalkyl, izakhiwo zejeli nazo zihlobene nezinga lokuguqulwa le-hydroxyalkyl.Ku-mc ne-HPmc ene-viscosity ephansi, isisombululo sokuhlushwa esingu-10% -15% singalungiselelwa, isisombululo se-5% -10% singalungiselelwa i-viscosity ephakathi mc ne-HPmc, kanti isisombululo se-2% -3% singalungiselelwa i-viscosity mc ephezulu futhi I-HPmc, futhi ngokuvamile Ukuhlukaniswa kwe-viscosity ye-cellulose ether nakho kuhlelwe ngesisombululo esingu-1% -2%.I-high molecular weight cellulose ether ine-high thickening ukusebenza kahle.Esixazululweni esifanayo sokuhlushwa, ama-polymer anesisindo samangqamuzana ahlukene anama-viscosity ahlukene.Izinga eliphezulu.I-viscosity ehlosiwe ingafinyelelwa kuphela ngokungeza inani elikhulu lesisindo esiphansi se-cellulose ether.I-viscosity yayo inokwencika okuncane kuzinga lokugunda, futhi i-viscosity ephezulu ifinyelela i-viscosity ehlosiwe, futhi inani elidingekayo lokwengeza lincane, futhi 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 lejeli lesisombululo liphinde linciphise ngokuhambisana nokwanda kokuhlushwa kwesisombululo, nama-gel ekamelweni lokushisa ngemva kokufinyelela ekugxilweni okuthile.I-gelation concentration ye-HPmc iphakeme kumazinga okushisa asekamereni.
Ukuvumelana kungabuye kulungiswe ngokukhetha usayizi wezinhlayiyana nokukhetha ama-cellulose ether anamazinga ahlukene okuguqulwa.Lokhu okubizwa ngokuthi ukuguqulwa ukwethula izinga elithile lokushintshwa kwamaqembu e-hydroxyalkyl esakhiweni samathambo e-mc.Ngokushintsha amanani ashintshile ahlobene ezinto ezimbili ezibambele, okungukuthi, i-DS kanye ne-ms amanani okushintsha ahlobene weqembu le-methoxy ne-hydroxyalkyl esivame ukukusho.Izidingo zokusebenza ezihlukahlukene ze-cellulose ether zingatholwa ngokushintsha amanani ashintshile ahlobene walezi zingxenye ezimbili.
Ama-cellulose ethers asetshenziswa ezintweni zokwakha eziyimpuphu kufanele ahlakazeke ngokushesha emanzini abandayo futhi anikeze ukuhambisana okufanele kwesistimu.Uma inikezwa izinga elithile lokugunda, isala iphenduka i-flocculent futhi i-colloidal block, okuwumkhiqizo osezingeni eliphansi noma ompofu.
Kuphinde kube nobudlelwano obuhle bomugqa phakathi kokuvumelana kokunamathisela usimende kanye nomthamo we-cellulose ether.I-cellulose ether ingakhuphula kakhulu i-viscosity yodaka.Uma umthamo umkhulu, umphumela uba sobala kakhulu, bheka uMfanekiso 6
Isixazululo se-aqueous cellulose cellulose ether esine-high-viscosity sine-thixotropy ephezulu, ephinde ibe yisici esikhulu se-cellulose ether.Izixazululo ezinamanzi zama-polymers ohlobo lwe-Mc zivame ukuba ne-pseudoplastic kanye ne-non-thixotropic fluidity ngaphansi kwezinga lokushisa lejeli, kodwa izakhiwo zokugeleza kwe-Newtonian ngamanani aphansi e-shear.I-Pseudoplasticity iyanda ngesisindo se-molecular noma ukugxila kwe-cellulose ether, kungakhathaliseki ukuthi hlobo luni lwe-substitute kanye nezinga lokushintsha.Ngakho-ke, ama-cellulose ethers webanga elifanayo le-viscosity, kungakhathaliseki ukuthi i-mc, i-HPmc, i-HEmc, izohlale ibonisa izici ezifanayo ze-rheological inqobo nje uma ukugxila nokushisa kugcinwa njalo.Ama-gel esakhiwo akhiwa lapho izinga lokushisa liphakanyiswa, futhi ukugeleza kwe-thixotropic kakhulu kwenzeka.I-concentration ephezulu kanye ne-viscosity ephansi ye-cellulose ethers ibonisa i-thixotropy ngisho nangaphansi kwezinga lokushisa le-gel.Lesi sakhiwo sinenzuzo enkulu ekulungisweni kokulinganisa nokuwohloka ekwakhiweni kodaka lokwakha.Kudingeka kuchazwe lapha ukuthi ukuphakama kwe-viscosity ye-cellulose ether, ukugcinwa kwamanzi kangcono, kodwa ukuphakama kwe-viscosity, ukuphakama kwesisindo se-cellulose ether, kanye nokwehla okuhambisanayo kokuncibilika kwayo, okunomthelela omubi. ekugxilweni kodaka nokusebenza kokwakhiwa.Ukuphakama kwe-viscosity, kusobala kakhulu umphumela wokuqina odongeni, kodwa awulingani ngokuphelele.I-viscosity ethile emaphakathi nephansi, kodwa i-cellulose ether eshintshiwe inokusebenza okungcono ekuthuthukiseni amandla esakhiwo sodaka olumanzi.Ngokukhula kwe-viscosity, ukugcinwa kwamanzi kwe-cellulose ether kuyathuthuka.
Isikhathi sokuthumela: Nov-22-2022