Cellulose ether ke polymer ea maiketsetso e entsoeng ka selulose ea tlhaho ka phetoho ea lik'hemik'hale.Cellulose ether e tsoa ho cellulose ea tlhaho.Tlhahiso ea cellulose ether e fapane le li-polymers tsa maiketsetso.Thepa ea eona ea mantlha ke cellulose, motsoako oa tlhaho oa polymer.Ka lebaka la ho khetheha ha sebopeho sa cellulose ea tlhaho, selulose ka boeona ha e na bokhoni ba ho itšoara ka li-etherification agents.Leha ho le joalo, ka mor'a ho phekoloa ha moemeli oa ho ruruha, maqhama a matla a hydrogen pakeng tsa liketane tsa molek'hule le liketane li senyeha, 'me ho lokolloa ka mafolofolo ha sehlopha sa hydroxyl ho fetoha selulose e sebetsang ea alkali.Fumana ether ea cellulose.
Thepa ea cellulose ethers e itšetlehile ka mofuta, palo le kabo ea li-substituent.Ho hlophisoa ha cellulose ethers ho boetse ho ipapisitse le mofuta oa li-substituent, tekanyo ea etherification, solubility le thepa e amanang le kopo.Ho ea ka mofuta oa li-substituents ka ketane ea molek'hule, e ka aroloa ka monoether le ether e tsoakiloeng.Hangata re sebelisa mc joalo ka monoether, le HPmc joalo ka ether e tsoakiloeng.Methyl cellulose ether mc ke sehlahisoa ka mor'a hore sehlopha sa hydroxyl se karolong ea tsoekere ea cellulose ea tlhaho e nkeloe sebaka ke sehlopha sa methoxy.Ke sehlahisoa se fumanoang ka ho kenya karolo ea sehlopha sa hydroxyl sebakeng sa sehlopha ka sehlopha sa methoxy le karolo e 'ngoe ka sehlopha sa hydroxypropyl.Sebopeho sa sebopeho ke [C6H7O2(OH)3-mn(OCH3)m[OCH2CH(OH)CH3]n]x Hydroxyethyl methyl cellulose ether HEmc, ena ke mefuta e meholo e sebelisoang haholo le e rekisoang' marakeng.
Mabapi le solubility, e ka aroloa ka ionic le non-ionic.Li-ether tse qhibilihang ka metsing tseo e seng tsa ionic cellulose ethers haholo-holo li entsoe ka lihlopha tse peli tsa alkyl ethers le hydroxyalkyl ethers.Ionic Cmc e sebelisoa haholo ho li-detergents tsa maiketsetso, khatiso ea masela le ho daea, ho hlahloba lijo le oli.Non-ionic mc, HPmc, HEmc, joalo-joalo li sebelisoa haholo-holo ka thepa ea kaho, liaparo tsa latex, meriana, lik'hemik'hale tsa letsatsi le letsatsi, joalo-joalo E sebelisoa e le motenya, moemeli oa ho boloka metsi, stabilizer, dispersant le ho etsa filimi.
Ho boloka metsi a cellulose ether
Ha ho etsoa thepa ea mohaho, haholo-holo seretse se omeletseng, selulose ether e phetha karolo e ke keng ea nkeloa sebaka, haholo-holo tlhahiso ea seretse se khethehileng (seretse se fetotsoeng), ke karolo ea bohlokoa le ea bohlokoa.
Karolo ea bohlokoa ea selulose e qhibilihang ka metsing ka seretse e na le likarolo tse tharo, e 'ngoe ke bokhoni bo babatsehang ba ho boloka metsi, e' ngoe ke tšusumetso ea ho lumellana le thixotropy ea seretse, 'me ea boraro ke ho sebelisana le samente.
Phello ea ho boloka metsi ea cellulose ether e itšetlehile ka ho kenngoa ha metsi a lera la motheo, sebopeho sa seretse, botenya ba lera la seretse, tlhokahalo ea metsi ea seretse, le nako ea ho beha thepa.Ho boloka metsi a cellulose ether ka boeona ho tsoa ho solubility le dehydration ea cellulose ether ka boeona.Joalokaha bohle re tseba, le hoja ketane ea molek'hule ea cellulose e na le palo e kholo ea lihlopha tsa OH tse nang le metsi a mangata haholo, ha e qhibilihe ka metsing, hobane sebopeho sa cellulose se na le tekanyo e phahameng ea crystallinity.Bokhoni ba hydration ba lihlopha tsa hydroxyl feela ha boa lekana ho koahela litlamo tse matla tsa hydrogen le matla a van der Waals pakeng tsa limolek'hule.Ka hona, e ruruha feela empa ha e qhibilihe ka metsing.Ha substituent e hlahiswa ka ketane ea limolek'hule, e seng feela substituent timetsa ketane ea haedrojene, empa hape interchain hydrogen tlamo timetsoa ka lebaka la wedging ea substituent pakeng tsa liketane tse haufi.Ha sebaka se seng se le seholo, sebaka se pakeng tsa limolek'hule se ba seholoanyane.Bohole bo boholo.Phello e kholoanyane ea ho senya likamano tsa hydrogen, cellulose ether e fetoha metsi a qhibilihang ka mor'a hore lesela la cellulose le atolohe 'me tharollo e kene, e etsa tharollo e phahameng ea viscosity.Ha mocheso o phahama, hydration ea polymer e fokotseha, 'me metsi a pakeng tsa liketane a lelekoa.Ha phello ea ho felloa ke metsi e lekane, limolek'hule li qala ho bokellana, ho etsa gel ea sebopeho sa marang-rang a mararo le ho phuthoa.Lintlha tse amang ho bolokoa ha metsi ka seretse li kenyelletsa viscosity ea cellulose ether, chelete e ekelitsoeng, botle ba likaroloana le mocheso oa tšebeliso.
Ho phahama ha viscosity ea cellulose ether, ho ntlafatsa ts'ebetso ea ho boloka metsi, 'me ho phahamisa viscosity ea motsoako oa polymer.Ho ipapisitse le boima ba limolek'hule (tekanyo ea polymerization) ea polymer, e boetse e khethoa ke bolelele ba ketane ea sebopeho sa limolek'hule le sebopeho sa ketane, mme kabo ea mefuta le bongata ba li-substituent le tsona li ama ka kotloloho mofuta oa eona oa viscosity.[η]=Kmα
[η] Intrinsic viscosity ea tharollo ea polymer
m boima ba molek'hule ea polymer
α polymer tšobotsi kamehla
K viscosity tharollo coefficient
Viscosity ea tharollo ea polymer e itšetlehile ka boima ba limolek'hule tsa polymer.Viscosity le mahloriso a tharollo ea cellulose ether li amana le ts'ebeliso libakeng tse fapaneng.Ka hona, ether e 'ngoe le e' ngoe ea cellulose e na le litlhaloso tse ngata tse fapaneng tsa viscosity, 'me phetoho ea viscosity e hlokomeloa haholo ka ho senyeha ha cellulose ea alkali, ke hore, ho robeha ha liketane tsa cellulose limolek'hule.
Ha palo e kholo ea ether ea cellulose e kentsoeng seretseng, e ntlafatsa ts'ebetso ea ho boloka metsi, 'me ha ponahalo ea viscosity e phahame, e ntlafatsa ts'ebetso ea ho boloka metsi.
Bakeng sa boholo ba karoloana, ha karoloana e le ntle, ho boloka metsi ho molemo (sheba setšoantšo sa 3).Ka mor'a hore likaroloana tse kholo tsa cellulose ether li kopane le metsi, bokaholimo bo qhibiliha hang-hang 'me bo etse gel ho phuthela thepa ho thibela limolek'hule tsa metsi ho tsoela pele ho kenella.Ka nako e 'ngoe ha e khone ho qhalakanngoa le ho qhibiliha ka mokhoa o ts'oanang le ka mor'a ho sisinyeha ha nako e telele, ho etsa tharollo e koahetsoeng ke maru kapa agglomeration.E ama haholo ho boloka metsi a cellulose ether, 'me ho qhibiliha ke e' ngoe ea lintlha tsa ho khetha cellulose ether.
Thickening le Thixotropy ea Cellulose Ether
Mosebetsi oa bobeli oa cellulose ether - thickening e itšetlehile ka: tekanyo ea polymerization ea cellulose ether, mahloriso a tharollo, sekhahla sa ho kuta, mocheso le maemo a mang.Thepa ea gelling ea tharollo e ikhethile ho alkyl cellulose le lihlahisoa tsa eona tse fetotsoeng.Thepa ea gelation e amana le tekanyo ea ho fetola, mahloriso a tharollo le li-additives.Bakeng sa li-derivatives tse fetotsoeng tsa hydroxyalkyl, thepa ea gel e boetse e amana le boemo ba phetoho ea hydroxyalkyl.Bakeng sa mc le HPmc e nang le viscosity e tlaase, 10% -15% tharollo ea mahloriso e ka lokisoa, 5% -10% tharollo e ka lokisoa bakeng sa viscosity e bohareng mc le HPmc, 'me 2% -3% tharollo e ka lokisoa bakeng sa viscosity e phahameng mc le HPmc, 'me hangata The viscosity classification ea cellulose ether e boetse e hlophisoa ka tharollo ea 1% -2%.Limolek'hule tse phahameng tsa cellulose ether li na le bokhoni bo phahameng ba ho tiea.Tharollong e tšoanang ea mahloriso, li-polymer tse nang le boima bo fapaneng ba limolek'hule li na le li-viscosity tse fapaneng.Tekanyo e phahameng.Sepheo sa viscosity se ka finyelloa feela ka ho eketsa palo e kholo ea boima bo tlaase ba molek'hule cellulose ether.Viscosity ea eona ha e itšetlehe haholo ka sekhahla sa ho kuta, 'me viscosity e phahameng e fihla ho viscosity e reriloeng,' me palo e hlokahalang ea tlatsetso e nyane, 'me viscosity e ipapisitse le katleho e kholo.Ka hona, ho finyella ts'ebetso e itseng, palo e itseng ea cellulose ether (ho tsepamisa maikutlo ho tharollo) le viscosity ea tharollo e tlameha ho tiisetsoa.Mocheso oa mocheso oa gel oa tharollo o boetse o fokotseha ka mokhoa o ts'oanang le ho eketseha ha motsoako oa tharollo, le li-gel ka mocheso oa motsoako ka mor'a hore li fihle boemong bo itseng.Motsoako oa gelation oa HPmc o phahame mocheso oa kamore.
Ho lumellana ho ka boela ha fetoloa ka ho khetha boholo ba likaroloana le ho khetha li-cellulose ethers tse nang le likhato tse fapaneng tsa phetoho.Seo ho thoeng ke phetoho ke ho hlahisa tekanyo e itseng ea ho fetola lihlopha tsa hydroxyalkyl holim'a sebopeho sa skeleton sa mc.Ka ho fetola litekanyetso tse lekanyelitsoeng tsa phapanyetso ea li-substitute tse peli, ke hore, DS le ms e amanang le phapanyetso ea boleng ba lihlopha tsa methoxy le hydroxyalkyl tseo re li buang hangata.Litlhoko tse fapaneng tsa ts'ebetso ea cellulose ether li ka fumanoa ka ho fetola litekanyetso tse amanang le tse ling tse peli.
Li-cellulose ethers tse sebelisoang ka thepa ea mohaho ea phofo li tlameha ho qhibiliha ka potlako metsing a batang 'me li fane ka mokhoa o loketseng oa tsamaiso.Haeba ho fanoa ka sekhahla se itseng sa ho kuta, se ntse se fetoha flocculent le colloidal block, e leng sehlahisoa sa boleng bo tlaase kapa se tlaase.
Ho boetse ho na le kamano e ntle pakeng tsa ho lumellana ha pente ea samente le tekanyo ea cellulose ether.Cellulose ether e ka eketsa viscosity ea seretse haholo.Ha litekanyetso li le kholoanyane, phello e bonahala haholoanyane, bona setšoantšo sa 6
High-viscosity cellulose ether aqueous solution e na le thixotropy e phahameng, eo hape e leng tšobotsi e kholo ea cellulose ether.Litharollo tsa metsi tsa li-polymer tsa mofuta oa Mc hangata li na le pseudoplastic le non-thixotropic fluidity ka tlase ho mocheso oa tsona oa gel, empa thepa ea Newtonian e phallang ka litekanyetso tse tlaase tsa ho kuta.Pseudoplasticity e eketseha ka boima ba molek'hule kapa bongata ba cellulose ether, ho sa tsotelehe mofuta oa ntho e nkelang sebaka le tekanyo ea ho e nkela sebaka.Ka hona, li-cellulose ethers tsa sehlopha se tšoanang sa viscosity, ho sa tsotellehe hore na mc, HPmc, HEmc, li tla lula li bontša litšobotsi tse tšoanang tsa rheological hafeela mahloriso le mocheso li bolokiloe kamehla.Li-gels tsa mohaho li thehoa ha mocheso o phahama, 'me ho phalla haholo thixotropic ho etsahala.Mahloriso a phahameng le a tlaase a viscosity cellulose ethers a bontša thixotropy esita le ka tlase ho mocheso oa gel.Thepa ena e na le molemo o moholo ho lokisoeng ha maemo le ho putlama ha kaho ea seretse sa moaho.Hoa hlokahala ho hlalosa mona hore ho phahama ha viscosity ea cellulose ether, ho boloka metsi ho ntlafala, empa ho phahama ha viscosity, ho phahamisa boima ba molek'hule ea cellulose ether, le ho fokotseha ho tšoanang ha ho qhibiliha ha eona, ho nang le phello e mpe. ka mahloriso a seretse le ts'ebetso ea kaho.Ha li-viscosity li phahame, ho hlakile haholoanyane phello e teteaneng holim'a seretse, empa ha e lekane ka ho feletseng.Li-viscosity tse ling tse mahareng le tse tlase, empa cellulose ether e fetotsoeng e na le ts'ebetso e ntle ho ntlafatsa matla a sebopeho sa seretse se metsi.Ka ho eketseha ha viscosity, ho boloka metsi a cellulose ether ho ntlafala.
Nako ea poso: Nov-22-2022