Hydroxyethyl methyl cellulose (HEMC) isiri-ionic cellulose ether inoshandiswa zvakanyanya mukuvaka, machira, ceramics, mishonga, chikafu uye mamwe maindasitiri. HEMC ine mvura yakanaka solubility, thickening, kuchengetedza mvura, firimu-kuumba uye bonding properties, uye inoita basa rinokosha mumatope akaoma-akasanganiswa, latex pendi, detergent nemamwe minda.
1. Nzira yekugadzira
1.1 Kugadzirira kwezvinhu
HEMC inonyanya kugadzirirwa kubva kune yakasikwa chirimwa cellulose, methyl chloride (CH₃Cl), ethylene oxide (C₂H₄O), sodium hydroxide (NaOH) uye zvimwe zvigadzirwa.
Cellulose: Huni pulp kana donje pulp inowanzoshandiswa sechinhu chikuru mbishi zvinhu, izvo zvinoda kuchena kwepamusoro uye mashoma kusvibiswa kuve nechokwadi chemhando yechigadzirwa.
Alkalizer (NaOH): inoshandiswa kumisa cellulose uye kugadzirisa kuita basa.
Etherifying agent (CH₃Cl uye C₂H₄O): ipai methyl uye hydroxyethyl mapoka zvichiteerana, kuitira kuti cellulose ipinde panzvimbo yekutsiva, inovandudza kunyungudika kwemvura uye kushanda kwezvinhu.
Organic solvent (yakadai se isopropanol): inoshandiswa kunyungudutsa reactants, kudzora maitiro emamiriro ezvinhu uye kuderedza maitiro emativi.
1.2 Alkalization kurapwa
Mushure mekunge cellulose yapwanyika, huwandu hwakakodzera hwe sodium hydroxide solution inowedzerwa uye alkalization kurapwa kunoitwa pane imwe tembiricha uye kumanikidza, izvo zvinowanzotora 30-60 maminetsi. Chinangwa chikuru che alkalization ndechekuwedzera cellulose molecular chain uye kugadzirisa reactivity yayo ne etherifying agent. Iyi nzira inowanzoitwa mune yakavharwa reactor nekukurudzira kuti ive nechokwadi chekuti alkali solution inopinda mu cellulose zvakaenzana.
1.3 Etherification maitiro
Iyo alkalized cellulose inopindirana nemethylation uye hydroxyethylation reagents (CH₃Cl uye C₂H₄O) mune reactor kugadzira hydroxyethyl methyl cellulose. Reaction mamiriro anosanganisira:
Tembiricha: 60-90°C
Kudzvinyirira: 0.5-1.5 MPa
Nguva: 2-5 maawa
Munguva yekuita, methylation uye hydroxyethylation reactions inoenderera panguva imwe chete, kuitira kuti hydroxyl (-OH) chikamu che cellulose chinotsiviwa nemethyl (-OCH).₃) uye hydroxyethyl (-OCH₂CH₂OH), nekudaro ichishandura kunyungudika kwayo uye kukora zvivakwa. Kuti uvandudze dhigirii rekutsiva (DS uye MS kukosha), zvinowanzodikanwa kukwenenzvera kurongeka uye chikamu chekuwedzera etherification mumiriri.
1.4 Neutralization uye kugeza
Mushure mekuita kwapera, sisitimu ichine isingaite alkali, solvent uye ne-zvigadzirwa (seNaCl). Naizvozvo, neutralization uye kugeza zvinodiwa:
Neutralization: Shandisa asidhi (yakadai seacetic acid) kumisa alkali muhurongwa uye gadzirisa iyo pH kukosha ku6-8.
Washing: Shandisa mvura yakawanda inopisa kana ethanol aqueous solution kuti urambe uchigeza cellulose kuti ubvise zvinhu zvisingagadziriswi uye ne-zvigadzirwa, kuderedza kusvibiswa kwemukati, nekuvandudza kuchena kwechigadzirwa.
1.5 Kuomesa nekupwanya
Mushure mekugeza, HEMC ichine hunyoro hwepamusoro uye inoda kuomeswa. Nzira dzakajairika dzekuomesa ndeidzi:
Kuomeswa kwemhepo: kushandisa mhepo inopisa yekumhanya kuomesa HEMC yakanyorova, ine hunyanzvi hwepamusoro uye yakakodzera kugadzirwa kwakakura.
Vacuum kuomeswa: kupisa uye kuomeswa pasi pekumanikidzwa kwakadzika nharaunda, iyo inogona kunyatso kudzivirira kuparara kwe cellulose uye inokodzera zvigadzirwa zvemhando yepamusoro.
Mushure mekuoma, HEMC inopwanyika ne pulverizer uye saizi yechikamu inodzorwa nekuongorora kuti iwane kunaka kunodiwa kwechigadzirwa (kazhinji 80-120 mesh).
2. Kudzora kwehutano
HEMC yemhando yekudzora inonyanya kusanganisira zvinotevera zviratidzo:
Digree of substitution (DS neMS): inosarudza solubility uye viscosity, kazhinji DS iri pakati pe1.1-2.0 uye MS iri pakati pe0.1-0.5.
Hunyoro hwemukati: kazhinji hunodiwa kuve≤5%.
Viscosity: akasiyana viscosity mamakisi anodiwa kune akasiyana mashandisirwo minda (senge 400-100,000 mPa·s).
Kuchena: kunoda yakaderera madota, kubviswa kwezvakasara zvinonyungudutsa, uye kuona kuti hapana hwema.
3. Nzvimbo huru dzekushandisa
Zvivako zvekuvaka: zvinoshandiswa musimende dhaka, putty poda, tile inonamira, kuvandudza kuchengetwa kwemvura uye kuita kwekuvaka.
Indasitiri yekupfekedza: inoshandiswa mulatex pendi uye pendi, kupa yakanaka rheology uye anti-sagging kuita.
Mushonga uye chikafu: seyakakora uye emulsifier, zvinoenderana negiredhi rekudya kana pharmacopoeia zviyero.
TheHEMC maitiro ekugadzira anosanganisira alkalization, etherification, neutralization, kuwacha, kuomesa uye kupwanya. Kugadzirisa maparamendi uye kuvandudza dhigirii rekutsiva uye kuchena kwechigadzirwa ndiwo makiyi ekuvandudza mashandiro eHEMC. Nekuwedzera kwezvinodiwa zvekuchengetedzwa kwezvakatipoteredza uye kugadzirwa kwakasvibirira, HEMC kugadzirwa kuchabhadhara zvakanyanya kuchengetedza simba uye kuderedzwa kwekubuda uye kushandiswa kwegirinhi zvinonyungudutsa.
Nguva yekutumira: Chivabvu-08-2025