Hydroxyethyl cellulose (HEC) ke polima e se nang ionic, e qhibilihang ka metsing e tsoang ho cellulose, polima ea tlhaho e fumanehang maboteng a lisele tsa limela. E sebelisoa haholo liindastering tse fapaneng, ho kenyelletsa le tsa meriana, litlolo, lipente le likhomaretsi, ka lebaka la botenya ba eona bo botle, ho etsa lifilimi le thepa ea rheological. Ho lokisoa ha hydroxyethyl cellulose ho kenyelletsa etherification ea selulose ka ethylene oxide tlas'a maemo a alkaline. Ts'ebetso ena e ka aroloa ka mehato e 'maloa ea bohlokoa: ho hloekisa cellulose, alkalization, etherification, neutralization, ho hlatsoa le ho omisa.
1. Ho Hloekisa Cellulose
Mohato oa pele oa ho lokisoa ha hydroxyethyl cellulose ke tlhoekiso ea selulose, eo hangata e tsoang ho makhasi a lehong kapa lithareng tsa k'hothone. Selulose e tala e na le litšila tse kang lignin, hemicellulose, le li-extractive tse ling tse lokelang ho tlosoa ho fumana selulose e hloekileng e loketseng phetoho ea lik'hemik'hale.
Mehato e amehang:
Mechanical Processing: Selulose e tala e sebetsoa ka mochine ho fokotsa boholo ba eona le ho eketsa sebaka sa eona sa holimo, ho nolofatsa phekolo ea lik'hemik'hale tse latelang.
Kalafo ea Lik'hemik'hale: Selulose e tšoaroa ka lik'hemik'hale tse kang sodium hydroxide (NaOH) le sodium sulfite (Na2SO3) ho senya lignin le hemicellulose, e lateloa ke ho hlatsoa le ho soeufala ho tlosa litšila tse setseng le ho fumana selulose e tšoeu, e nang le fibrous.
2. Alkalization
Selulose e hloekisitsoeng e ntan'o etsoa alkali ho e kenya tšebetsong bakeng sa karabelo ea etherification. Sena se kenyelletsa ho phekola selulose ka tharollo e nang le metsi a sodium hydroxide.
Maikutlo:
Cellulose+NaOH→Alkali selulose
Mokhoa:
Selulose e emisoa ka metsing, 'me tharollo ea sodium hydroxide e eketsoa. Khatello ea NaOH hangata e tloha ho 10-30%, 'me karabelo e etsoa ka mocheso o pakeng tsa 20-40 ° C.
Motsoako o hlohlelletsoa ho etsa bonnete ba ho monya ka mokhoa o ts'oanang oa alkali, e lebisang ho thehoeng ha selulose ea alkali. Sebaka sena se bohareng se sebetsa haholoanyane ho ethylene oxide, se nolofalletsa ts'ebetso ea etherification.
3. Etherification
Mohato o ka sehloohong oa ho lokisa hydroxyethyl cellulose ke etherification ea alkali cellulose ka ethylene oxide. Karabelo ena e hlahisa lihlopha tsa hydroxyethyl (-CH2CH2OH) ka har'a mokokotlo oa cellulose, e etsa hore e qhibilihe ka metsing.
Maikutlo:
Alkali cellulose+Ethylene oxide→Hydroxyethyl cellulose+NaOH
Mokhoa:
Ethylene oxide e kenngoa ho selulose ea alkali, ebang ke ka batch kapa ts'ebetso e tsoelang pele. Hangata karabelo e etsoa ka "autoclave" kapa "pressure reactor".
Maemo a karabelo, ho kenyeletsoa mocheso (50-100 ° C) le khatello (1-5 atm), li laoloa ka hloko ho etsa bonnete ba hore ho na le sebaka se nepahetseng sa lihlopha tsa hydroxyethyl. The degree of substitution (DS) le molar substitution (MS) ke liparamente tsa bohlokoa tse susumetsang thepa ea sehlahisoa sa ho qetela.
4. Ho se nke lehlakore
Kamora karabelo ea etherification, motsoako o na le hydroxyethyl cellulose le masala a sodium hydroxide. Mohato o latelang ke ho se nke lehlakore, moo alkali e feteletseng e fokotsoang ka ho sebelisa asiti, hangata acetic acid (CH3COOH) kapa hydrochloric acid (HCl).
Karabelo:NaOH+HCl→NaCl+H2O
Mokhoa:
Asiti e kenngoa butle-butle ho motsoako oa karabelo tlas'a maemo a laoloang ho qoba mocheso o feteletseng le ho thibela ho senyeha ha hydroxyethyl cellulose.
Motsoako o sa nke lehlakore o beoa tokiso ea pH ho netefatsa hore o ka har'a sebaka se lakatsehang, hangata ho pota pH e sa nke lehlakore (6-8).
5. Ho hlatsoa
Ka mor'a ho se nke lehlakore, sehlahisoa se tlameha ho hlatsuoa ho tlosa letsoai le lihlahisoa tse ling. Mohato ona o bohlokoa bakeng sa ho fumana cellulose e hloekileng ea hydroxyethyl.
Mokhoa:
Motsoako oa karabelo o hlapolotsoe ka metsi, 'me cellulose ea hydroxyethyl e arohanngoa ke ho hloekisa kapa centrifugation.
Selulose se arohaneng sa hydroxyethyl se hlatsuoa khafetsa ka metsi a senyehileng ho tlosa matsoai a setseng le litšila. Mokhoa oa ho hlatsoa o tsoela pele ho fihlela metsi a hlatsoang a fihla ho conductivity e boletsoeng, e bontšang ho tlosoa ha litšila tse qhibilihisang.
6. Ho omisa
Mohato oa ho qetela oa ho lokisa cellulose ea hydroxyethyl ke ho omisa. Mohato ona o tlosa metsi a feteletseng, o fana ka sehlahisoa se omileng, se phofshoana se loketseng lits'ebetso tse fapaneng.
Mokhoa:
Hydroxyethyl cellulose e hlatsoitsoeng e aloa holim'a literei tse omisang kapa e fetisoa ka kotopo ea ho omisa. Thempereichara ea ho omisa e laoloa ka hloko ho qoba ho senyeha ha mocheso, hangata ho tloha ho 50-80 ° C.
Ntle le moo, ho omisa ka spray ho ka sebelisoa bakeng sa ho omisa ka potlako le ka katleho. Nakong ea ho omisa, tharollo ea aqueous hydroxyethyl cellulose e kenngoa ka athomo hore e be marotholi a matle ebe e omisoa moeeng o chesang, e leng se hlahisang phofo e ntle.
Sehlahisoa se omisitsoeng se tšeloa ho isa tekanyong e lakatsehang ebe se pakela ho bolokoa le ho ajoa.
Taolo ea Boleng le Likopo
Ho pholletsa le ts'ebetso ea ho lokisa, mehato e matla ea taolo ea boleng e kengoa ts'ebetsong ho netefatsa botsitso le boleng ba hydroxyethyl cellulose. Lintlha tsa bohlokoa tse kang viscosity, degree of substitution, mongobo, le boholo ba likaroloana li lula li behiloe leihlo.
Lisebelisoa:
Meriana ea Meriana: E sebelisoa e le sekontiri se teteaneng, se tlamang, le se tsitsitseng linthong tse kang matlapa, li-suspensions le litlolo.
Litlolo: E fana ka viscosity le sebopeho ho lihlahisoa tse kang litlolo, litlolo le li-shampoo.
Lipente le Liaparo: E sebetsa e le mofetoleli o teteaneng le oa rheology, ho ntlafatsa thepa ea kopo le botsitso ba lipente.
Indasteri ea Lijo: E sebetsa e le seteifatsi, se tsitsitseng, le emulsifier lihlahisoa tse fapaneng tsa lijo.
Tokisetso ea hydroxyethyl cellulose e kenyelletsa letoto la lits'ebetso tse hlalositsoeng hantle tsa lik'hemik'hale le tsa mochini tse reretsoeng ho fetola selulose ho hlahisa lihlopha tsa hydroxyethyl. Mohato o mong le o mong, ho tloha ho tlhoekiso ea selulose ho isa ho omisoang, ke oa bohlokoa ho khethollang boleng le tšebetso ea sehlahisoa sa ho qetela. Thepa ea Hydroxyethyl cellulose e etsa hore e be motsoako oa bohlokoa liindastering tse ngata, e totobatsa bohlokoa ba mekhoa e nepahetseng ea tlhahiso ho fihlela litlhoko tse ikhethang tsa lits'ebetso tse fapaneng.
Nako ea poso: May-28-2024