Hydroxyethyl Cellulose (HEC) yakajairika mvura-inonyungudika polima inoshandiswa zvakanyanya mumakemikari ezuva nezuva, kuvaka, machira, mushonga, chikafu uye mamwe maindasitiri. Iyo isiri-ionic cellulose ether yakagadzirwa nekemikari inogadzirisa cellulose chaiyo. Nzira yekugadzira hydroxyethyl cellulose inosanganisira maitiro emakemikari akaoma, kusanganisira cellulose extraction, alkalization treatment, etherification reaction, etc. Izvi zvinotevera sumo yakadzama yekugadzirwa kwayo.
1. Kusarudzwa kwezvinhu zvakasvibiswa uye kubudiswa kwe cellulose
Iyo yakakosha zvinhu zve hydroxyethyl cellulose ndeye yakasikwa cellulose, iyo inonyanya kubva muhuni, donje kana mamwe mafiber echirimwa. Iyo cellulose yemukati muchirimwa sero madziro yakakwira, uye yakachena cellulose inogona kutorwa kubva kune izvi zvechisikigo zvinhu nemakanika kana makemikari nzira. Nzira yekubvisa inosanganisira kupwanya, kubvisa tsvina (yakadai se lignin, hemicellulose), bleaching uye mamwe matanho.
Cellulose extraction: Natural cellulose inowanzobatwa nemagetsi kana kemikari kubvisa zvinhu zvisiri-cellulose kuti uwane high-purity cellulose. Faibha yedonje, pulp yehuni, zvichingodaro zvese zvinogona kuve zvakajairika manyuko ezvigadzirwa. Munguva yekurapa, alkali (yakadai sesodium hydroxide) inoshandiswa kubatsira kunyungudutsa zvisiri-cellulose zvikamu, uye zvakasara zvakanyanya cellulose.
2. Alkalization kurapwa
Iyo yakacheneswa cellulose inofanira kutanga yave alkaliized. Iyi nhanho ndeyekuita kuti mapoka ehydroxyl ari pa cellulose molecular chain ashande zvakanyanya kuitira kuti agone kuita zviri nyore ne etherifying agent. Matanho makuru ekurapa alkalization ndeaya anotevera:
Kuita kwe cellulose nealkali: cellulose inosanganiswa nealkali yakasimba (kazhinji sodium hydroxide) kugadzira alkali cellulose (Alkali Cellulose). Iyi nzira inowanzoitwa mune aqueous medium. Alkali cellulose ndiyo inoitwa chigadzirwa che cellulose uye sodium hydroxide. Ichi chinhu chine looser chimiro uye yakakwirira reactivity, iyo inobatsira kune inotevera etherification reaction.
Iyo alkalization process inonyanya kuitika pakudziya kwakakodzera uye hunyoro, kazhinji muhupamhi hwe20 ℃ ~ 30 ℃ kwemaawa akati wandei kuona kuti mapoka ehydroxyl ari mumamorekuru ecellulose akaitwa zvizere.
3. Etherification reaction
Etherification inhanho yakakosha mukugadzirwa kwehydroxyethyl cellulose. Hydroxyethyl cellulose inogadzirwa nekuita alkali cellulose ine ethylene oxide kuunza hydroxyethyl mapoka. Matanho chaiwo ndeaya anotevera:
Reaction with ethylene oxide: Alkali cellulose inopindirana neimwe huwandu hweethylene oxide pasi pehumwe tembiricha uye kumanikidzwa kwemamiriro. Chimiro chemhete muethylene oxide chinovhura kuita chisungo cheether, chinopindirana nemapoka ehydroxyl mumamorekuru ecellulose, uye chinounza mapoka ehydroxyethyl (-CH2CH2OH). Iyi nzira inogona kugadzirisa dhigirii re etherification nekudzora maitiro ekuita (senge tembiricha, kudzvanywa, uye nguva).
Kuita kunowanzoitwa munzvimbo ine alkaline kuti ive nechokwadi chekushanda kwe etherification. The reaction tembiricha kazhinji 50 ℃ ~ 100 ℃, uye kuita nguva maawa akati wandei. Nekugadzirisa huwandu hweethylene oxide, chiyero chekutsiviwa kwechigadzirwa chekupedzisira chinogona kudzorwa, ndiko kuti, mangani mapoka e hydroxyl mu cellulose molecules anotsiviwa nemapoka ehydroxyethyl.
4. Neutralization uye kugeza
Mushure mekuita kwe etherification kwapera, zvinhu zve alkaline mumaitiro ekuita zvinoda kuderedzwa. Inowanzoshandiswa neutralizers zvinhu zvine acidic, zvakadai seacetic acid kana hydrochloric acid. Iyo neutralization maitiro ichaita kuti iyo yakawandisa alkali iite munyu, izvo zvisingazokanganisa kuita kwechigadzirwa.
Neutralization reaction: Bvisa chigadzirwa kubva mu reactor uye wedzera huwandu hwakakodzera hweasidhi yekusagadzikana kusvika iyo pH kukosha muhurongwa yasvika kwayakarerekera. Iyi nzira haingobvisi yakasara alkali, asi zvakare inoderedza kukanganisa kwekuita ne-zvigadzirwa pakuita kwehydroxyethyl cellulose.
Kugeza uye kupera mvura mumuviri: Chigadzirwa chisina kucheneswa chinoda kugezwa kakawanda, kazhinji nemvura kana ethanol nezvimwe zvinonyungudutsa kuti zvisuke tsvina yasara uye nezvinogadzirwa. Chigadzirwa chakagezwa chinobviswa mvura ne centrifugation, kusefa kudzvanya nedzimwe nzira dzekudzikisa hunyoro.
5. Kuomesa nekupwanya
Mushure mekugeza uye kupera mvura, iyo hydroxyethyl cellulose ichine humwe hunyoro hwehunyoro uye inoda kuomeswa zvakare. Iyo yekuomesa inogona kuitwa nekuomeswa nemhepo kana vacuum kuomeswa kuve nechokwadi chekuti chigadzirwa chine kugadzikana kwakanaka panguva yekuchengetedza uye kushandiswa.
Kuomesa: Pukuta chigadzirwa pane imwe tembiricha (kazhinji iri pasi pe60°C) kubvisa hunyoro hwasara. Iyo tembiricha yekuomesa haifanirwe kunge yakanyanya kukwirira, kana zvisina kudaro inogona kukonzera kuparara kwechigadzirwa uye kukanganisa kushanda kwayo.
Kupwanya uye kuongorora: Iyo yakaomeswa hydroxyethyl cellulose kazhinji inowanikwa mumabhuraki kana mapundu, uye inofanirwa kupwanywa kuti iwane hupfu hwakatsetseka. Iyo yakapwanyika chigadzirwa inodawo kuongororwa kuti iwane particle size yekugovera iyo inosangana nezvinodiwa kuti ive nechokwadi chekunyungudika kwayo uye kupararira kwayo mukushandisa zvinoshanda.
6. Kuedzwa uye kurongedza kwekupedzisira zvigadzirwa
Mushure mekugadzira, hydroxyethyl cellulose inoda kuongororwa mhando kuti ive nechokwadi chekuti zviratidzo zvekuita kwayo zvinosangana nezvinodiwa. Kuedza zvinhu zvinowanzo sanganisira:
Viscosity kuyerwa: Iyo viscosity yehydroxyethyl cellulose mushure mekunyungudika mumvura chiratidzo chakakosha chemhando, iyo inokanganisa kushandiswa kwayo mukupfeka, kuvaka, makemikari ezuva nezuva uye mamwe minda.
Hunyoro hwemukati: Edza hunyoro hwechigadzirwa kuti uone kugadzikana kwekuchengetedza.
Degree of substitution (DS) uye molar substitution (MS): Sarudza dhigirii rekutsinhanisa uye kutsiva molar muchigadzirwa kuburikidza nekuongorora kemikari kuti uve nechokwadi chekuita kwe etherification reaction.
Mushure mekupasa bvunzo, hydroxyethyl cellulose inoiswa muhupfu kana zvigadzirwa zvegranular, kazhinji mumabhegi epurasitiki anodzivirira hunyoro kana masaga emapepa kudzivirira kuti isanyorovese kana kusvibiswa.
Iyo yekugadzira maitiro ehydroxyethyl cellulose inonyanya kusanganisira matanho ekubvisa cellulose, alkalization kurapwa, etherification reaction, neutralization uye kugeza, kuomesa uye kupwanya. Maitiro ese anoenderana nealkalization uye etherification mumakemikari reaction, uye cellulose inopihwa yakanaka solubility yemvura uye thickening zvivakwa nekuunza hydroxyethyl mapoka. Hydroxyethyl cellulose inoshandiswa zvakanyanya mumaindasitiri mazhinji, senge thickener yekuputira, mvura-inochengetedza mumiriri wezvivakwa zvekuvaka, stabilizer muzvigadzirwa zvemakemikari zvemazuva ese, nezvimwe. zvechigadzirwa.
Nguva yekutumira: Oct-25-2024