I-HPMC izokwehlisa izinga lokushisa ngaliphi izinga?

I-Hydroxypropyl methylcellulose (HPMC) i-polymer encibilikayo emanzini esetshenziswa kabanzi kwezokwelapha, ukudla, ukwakha kanye neminye imikhakha. Inokusimama okuhle kwe-thermal, kodwa isengawohloka ngaphansi kwezinga lokushisa eliphezulu. Izinga lokushisa lokuwohloka kwe-HPMC lithintwa ikakhulukazi ukwakheka kwayo kwamangqamuzana, izimo zemvelo (njengomswakama, inani le-pH) kanye nesikhathi sokushisisa.

Izinga lokushisa lokuwohloka kwe-HPMC

Ukuwohloka kokushisa kwe-HPMC kuvame ukuvela ngaphezu kwama-200℃, futhi ukubola okusobala kuzokwenzeka phakathi kuka-250℃-300℃. Ngokuqondile:

Ngaphansi kwe-100℃: I-HPMC ikhombisa ngokuyinhloko ukuhwamuka kwamanzi kanye nezinguquko ezimpahleni ezibonakalayo, futhi akukho ukuwohloka okwenzekayo.

100℃-200℃: I-HPMC ingase ibangele i-oxidation ingxenye ngenxa yokwenyuka kwezinga lokushisa lendawo, kodwa izinzile kukonke.

200℃-250℃: I-HPMC kancane kancane ibonisa ukuwohloka kokushisa, okubonakaliswa ngokuyinhloko njengokuphuka kwesakhiwo nokukhululwa kwama-volatiles amancane amangqamuzana.

250℃-300℃: I-HPMC idlula ukubola okusobala, umbala uba mnyama, ama-molecule amancane afana namanzi, i-methanol, i-acetic acid ayakhululwa, bese kwenzeka i-carbonization.

Ngaphezu kuka-300℃: I-HPMC incipha ngokushesha futhi i-carbonize, futhi ezinye izinto ezingaphili zisala ekugcineni.

Izinto ezithinta ukucekelwa phansi kwe-HPMC

Isisindo samangqamuzana nezinga lokushintsha

Uma isisindo samangqamuzana e-HPMC sikhulu, ukumelana nokushisa kwawo kuvame ukuba phezulu.

Izinga lokushintshwa kwamaqembu e-methoxy kanye ne-hydroxypropoxy lizothinta ukuzinza kwawo okushisayo. I-HPMC enezinga eliphezulu lokushintshwa yonakala kalula emazingeni okushisa aphezulu.

Izici zemvelo

Umswakamo: I-HPMC ine-hygroscopicity eqinile, futhi umswakama ungase usheshise ukuwohloka kwawo emazingeni okushisa aphezulu.

Inani le-pH: I-HPMC isengozini yokuthola i-hydrolysis kanye nokuwohloka ngaphansi kwezimo ze-asidi eqinile noma i-alkali.

Isikhathi sokushisa

Ukushisa kufika ku-250℃isikhathi esifushane kungase kungaboli ngokuphelele, kuyilapho ukugcina izinga lokushisa eliphezulu isikhathi eside kuzosheshisa inqubo yokuwohloka.

Imikhiqizo yokuwohloka ye-HPMC

I-HPMC itholakala ikakhulukazi ku-cellulose, futhi imikhiqizo yayo yokuwohloka ifana ne-cellulose. Phakathi nenqubo yokushisisa, okulandelayo kungakhululwa:

Umhwamuko wamanzi (kusuka emaqenjini e-hydroxyl)

I-Methanol, i-ethanol (kusuka kumaqembu e-methoxy kanye ne-hydroxypropoxy)

I-acetic acid (kusuka emikhiqizweni yokubola)

I-carbon oxides (CO, CO₂, ekhiqizwa ukushiswa kwezinto eziphilayo)

Inani elincane lensalela ye-coke

Isicelo sokumelana nokushisa kwe-HPMC

Nakuba i-HPMC izokwehlisa kancane kancane ngaphezu kwama-200℃, ngokuvamile ayivezwa emazingeni okushisa aphezulu kangako ezinhlelweni zokusebenza zangempela. Ngokwesibonelo:

Imboni yezemithi: I-HPMC isetshenziselwa kakhulu ukuhlanganisa amaphilisi nama-ejenti akhipha isikhathi eside, ngokuvamile asebenza kuma-60.℃-80℃, ephansi kakhulu kunezinga lokushisa layo lokuwohloka.

Imboni yokudla: I-HPMC ingasetshenziswa njenge-thickener noma i-emulsifier, futhi izinga lokushisa elivamile lokusetshenziswa ngokuvamile alikho ngaphezu kwe-100.℃.

Imboni yezokwakha: I-HPMC isetshenziswa njengosimende nokuqina kodaka, futhi izinga lokushisa lokwakha ngokuvamile alidluli ama-80.℃, futhi akukho ukucekelwa phansi okuzokwenzeka.

I-HPMC iqala ukwehla ngokushisa ngaphezu kwama-200℃, ibola kakhulu phakathi kwama-250℃-300℃, futhi i-carbonizes ngokushesha ngaphezu kuka-300℃. Ezisetshenziswa ezingokoqobo, ukuchayeka isikhathi eside endaweni yokushisa okuphezulu kufanele kugwenywe ukuze kugcinwe ukusebenza kwayo okuzinzile.