Izakhiwo zamakhemikhali ze-HPMC

I-Hydroxypropyl Methylcellulose (HPMC)iyi-non-ionic cellulose ether, okuwumkhiqizo oguqulwe ngamakhemikhali owakhiwe ukusabela kwe-cellulose yemvelo nge-propylene oxide kanye ne-methyl chloride ngemva kokuhlanganiswa kwe-alkali. I-HPMC izinzile kahle ngokomzimba nangokwekhemikhali futhi isetshenziswa kabanzi kwezemithi, izinto zokwakha, ukudla, izimonyo nakweminye imikhakha. Izakhiwo zayo zamakhemikhali yilezi ezilandelayo:

1. Izici zesakhiwo sama-molecule

Uhlaka oluyisisekelo lwe-HPMC luvela ku-cellulose yemvelo, eyakhiwa amayunithi e-glucose axhunywe yizibopho ze-β-1,4-glycosidic ukwakha uchungechunge lwe-macromolecular oluqondile. Ukwethulwa kwamaqembu e-hydroxypropyl kanye ne-methoxy kuthatha indawo yamaqembu e-hydroxyl (-OH) kuchungechunge lwe-cellulose molecular, ngaleyo ndlela luyinike izakhiwo ezihlukile. Leli zinga lokushintshana (okungukuthi, izinga lokushintshana kwamaqembu e-methoxy kanye ne-hydroxypropyl) linethonya elibalulekile ekuncibilikeni, izakhiwo zejeli kanye nokuzinza kwe-HPMC.

2. Ukuncibilika

I-HPMC iyi-polymer ejwayelekile engeyona i-ionic encibilikayo emanzini engavuvukala ngokushesha emanzini abandayo futhi yakhe isixazululo se-colloidal esibonakalayo noma esikhanyayo. Kodwa-ke, emanzini ashisayo, i-HPMC akulula ukuyincibilikisa futhi izokwakha ijeli emazingeni okushisa aphezulu. Le mpahla yejeli eguquguqukayo ingenye yezakhiwo ezibalulekile zomzimba nezamakhemikhali ze-HPMC. Ngaphezu kwamanzi, i-HPMC ingancibilika nakwezinye izinyibilikisi eziphilayo ze-polar, njengesinyibilikisi esixubile se-ethanol namanzi, i-dimethylformamide, njll.

3. Ukuqina kokushisa kanye nokwakheka kwe-gel

I-HPMC inokuqina okuhle kakhulu kokushisa. Njengoba izinga lokushisa likhuphuka, amaketanga ama-molecule e-HPMC esixazululweni samanzi azohlangana nokuhlangana kokuphelelwa amanzi emzimbeni ukuze akhe isakhiwo senethiwekhi esinezinhlangothi ezintathu, futhi kuzokwenzeka ushintsho kusuka esixazululweni kuya ejelini. Izinga lokushisa le-gelation lincike kokuqukethwe kanye nesisindo sama-molecule wezinto ezithatha indawo. Ngokuvamile, i-HPMC enokuqukethwe okuphezulu kwe-hydroxypropyl inokushisa okuphezulu kwe-gelation, kuyilapho i-HPMC enokuqukethwe okuphezulu kwe-methoxy inokushisa okuphansi kwe-gelation.

I-Gelation iyaguqulwa, futhi ijeli izoncibilika ibuyele esimweni soketshezi ngemva kokupholisa. Le mpahla ye-thermogel eyingqayizivele yenza i-HPMC ivame ukusetshenziswa njengento ekhishwa njalo embonini yemithi futhi isetshenziswe embonini yezinto zokwakha ukuthuthukisa ukusebenza kokwakhiwa kwe-mortar.

4. Ukuqina kwe-pH

I-HPMC igcina ukuzinza okuhle ebangeni le-pH elingu-3 ~ 11. Lolu hlu olubanzi lokuzinza kwe-pH luvumela ukuthi lusetshenziswe ezindaweni ezahlukahlukene ngaphandle kokuwohloka noma imvula. Uma inani le-pH lingaphansi kuka-3 noma ngaphezulu kuka-11, isixazululo singase sonakale noma sinciphe ngenxa yokugxila okuphezulu kwama-ion e-hydrogen noma ama-ion e-hydroxide, okuholela ekusebenzeni okunciphile.

5. Ukusabela Kwamakhemikhali

Ngenxa yokuba khona kwamaqembu e-hydroxyl angashintshiwe ku-molecule ye-HPMC, isagcina umsebenzi othile wamakhemikhali futhi ingabhekana nokusabela okulandelayo:

Ukusabela kwe-esterification: Ngaphansi kwezimo ezifanele, i-HPMC ingasabela nama-acyl chloride, ama-anhydride, njll. ukuze yakhe ama-ester;

Ukusabela kwe-Etherification: Amaqembu e-hydroxyl asele angaqhubeka nokusabela nama-etherifying agents (njenge-epoxides) ukuze ashintshe izinga lokushintsha kanye nokusebenza kwe-HPMC;

Ukusabela kwe-oxidation: Uma kukhona ama-oxidant aqinile (njenge-potassium permanganate, i-sodium hypochlorite), uchungechunge lwama-molecule lwe-HPMC lungaphuka, okuholela ekunciphiseni i-viscosity;

Ukusabela kwe-Hydrolysis: Ngaphansi kwesenzo sama-acid aqinile noma izisekelo eziqinile, amaketanga aseceleni e-hydroxypropyl kanye ne-methoxy angase afakwe i-hydrolyzed, okubangela izinguquko esakhiweni sama-molecule kanye nokuwohloka kokusebenza.

Ngokuvamile, ngaphansi kwezimo ezijwayelekile zokusetshenziswa, izakhiwo zamakhemikhali ze-HPMC zizinzile.

6. Ukubola kwezitshalo

I-HPMC itholakala ku-cellulose yemvelo, ngakho-ke ingawohloka ibe ushukela omncane wama-molecule endaweni ethile yemvelo (njengangaphansi kwesenzo sezinto ezincane), bese ekugcineni iboliswe ibe yi-carbon dioxide namanzi. Lokhu kubola okuhle kwenza i-HPMC ihlangabezane nezidingo zezinto ezinobungani nemvelo.

7. Ukuhambisana nezinye izinto

Njenge-polymer engeyona i-ionic, i-HPMC ihambisana kahle nezithasiselo ezahlukahlukene ze-ionic noma ezingeyona i-ionic (njengezinye i-polymer, ama-surfactant, ama-thickeners, njll.). Ikakhulukazi ohlelweni lokwakheka, ingasebenza nezithako ezahlukahlukene zemithi, izakhamzimba, imibala, njll. ngaphandle kwemvula noma ukuhlukaniswa.

Ukuqina kwe-HPMC endaweni enama-electrolyte amaningi kuzothinteka, futhi usawoti omningi wezinto ezingaphili ungabangela ukuthi i-viscosity yesisombululo yehle noma ifinyelele ngisho.

8. Ukumelana nama-enzyme

Uma kuqhathaniswa ne-cellulose yemvelo,I-HPMCinokumelana okuthuthukisiwe ne-cellulase ngenxa yokufakwa esikhundleni kwamaqembu athile e-hydroxyl, futhi ayiboli kalula ngama-enzyme avamile. Lesi sici siyinika inzuzo yokukhululwa kwemithi okubambezelekile endaweni yokugaya ukudla.

I-Hydroxypropyl methylcellulose (HPMC) iyinto yemvelo ye-polymer eguqulwe ngamakhemikhali enokuncibilika kwamanzi okuhle, i-gelation yokushisa, ukuqina kwe-pH, ukuqina kwamakhemikhali kanye nokubola. Ngenxa yesakhiwo sayo esiyingqayizivele kanye nezakhiwo zamakhemikhali, i-HPMC isetshenziswa kabanzi emikhakheni yezokwelapha, izinto zokwakha, izembozo, ukudla, izimonyo, njll., ikakhulukazi ekwakhiweni okudinga ukuqina, ukukhululwa okulawulwayo, ukwakheka kwefilimu, ukumiswa, i-emulsification kanye neminye imisebenzi.