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.
Ka seretse se itokiselitseng, palo ea ho eketsoa ha cellulose ether e tlase haholo, empa e ka ntlafatsa haholo ts'ebetso ea seretse se metsi, 'me ke tlatsetso e kholo e amang ts'ebetso ea kaho ea seretse.Khetho e utloahalang ea li-cellulose ethers tsa mefuta e sa tšoaneng, li-viscosities tse fapaneng, boholo bo fapaneng ba likaroloana, likhato tse fapaneng tsa viscosity le chelete e eketsehileng e tla ba le phello e ntle ntlafatsong ea ts'ebetso ea seretse se omeletseng sa phofo.Hajoale, liretse tse ngata tsa masonry le plastering li na le ts'ebetso e mpe ea ho boloka metsi, 'me seretse sa metsi se tla arohana kamora metsotso e seng mekae ea ho ema.
Ho boloka metsi ke ts'ebetso ea bohlokoa ea methyl cellulose ether, hape ke ts'ebetso eo bahlahisi ba bangata ba seretse se ommeng malapeng, haholo-holo ba libakeng tse ka boroa tse nang le mocheso o phahameng, ba e ela hloko.Lintlha tse amang phello ea ho boloka metsi ea seretse sa motsoako o omileng li kenyelletsa palo ea MC e ekelitsoeng, viscosity ea MC, botle ba likaroloana le mocheso oa tikoloho ea tšebeliso.
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.MC eo re tloaetseng ho e sebelisa ke monoether, 'me HPMC ke 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 methoxy.Foromo ea sebopeho ke [COH7O2(OH)3-h(OCH3)h ]x.Karolo ea sehlopha sa hydroxyl ho yuniti e nkeloa sebaka ke sehlopha sa methoxy, 'me karolo e' ngoe e nkeloa sebaka ke sehlopha sa hydroxypropyl, foromo ea sebopeho ke [C6H7O2(OH) 3-mn(OCH3)m[OCH2CH(OH)CH3] n] x Ethyl methyl cellulose ether HEMC, tsena 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 mohaho, liphahlo 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 moemeli oa ho etsa filimi.
Ho boloka metsi a cellulose ether: Ha ho etsoa thepa ea mohaho, haholo-holo seretse sa phofo se omeletseng, cellulose 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 cellulose ether e qhibilihang ka metsing ka har'a seretse e na le likarolo tse tharo:
1. Bokhoni bo botle ba ho boloka metsi
2. Phello ea seretse ho tsitsisa le thixotropy
3. Tšebelisano 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.
Nako ea poso: Dec-06-2022