Hydroxypropyl methylcellulose (HPMC) isiri-ionic cellulose ether inoshandiswa zvakanyanya mukurapa, chikafu, kuvaka uye mamwe minda, kunyanya mumishonga inoburitswa-inoburitsa mahwendefa uye zvekuvaka. Chidzidzo chekudzikira kwekupisa kweHPMC hakuna kukosha chete pakunzwisisa shanduko yekushanda inogona kusangana panguva yekugadziriswa, asi zvakare yakakosha zvikuru pakugadzira zvinhu zvitsva nekuvandudza hupenyu hwesevhisi uye kuchengetedzeka kwezvigadzirwa.
Thermal degradation maitiro eHPMC
Kupisa kwekupisa kwehydroxypropyl methylcellulose kunonyanya kukanganiswa neyakaomesesa chimiro, tembiricha yekudziya uye mamiriro ezvakatipoteredza (semhepo, humidity, nezvimwewo). Chimiro chayo chemorekuru chine huwandu hukuru hwemapoka e-hydroxyl uye ether bond, saka inotarisana nekuchinja kwemakemikari senge oxidation uye kuora pakupisa kwakanyanya.
Iyo yekupisa yekushatisa maitiro eHPMC inowanzo kukamurwa kuita akati wandei matanho. Kutanga, pakudzika kwakadzika (anenge 50-150 ° C), HPMC inogona kurasikirwa nehuwandu nekuda kwekurasikirwa kwemvura yakasununguka uye adsorbed mvura, asi izvi hazvibatanidzi kuputswa kwemakemikari zvisungo, kuchinja kwemuviri chete. Sezvo tembiricha ichikwira mberi (pamusoro pe150 ° C), ether zvisungo uye mapoka ehydroxyl muchimiro cheHPMC anotanga kutyoka, zvichikonzera kuputsika kweketani yemamorekuru uye shanduko muchimiro. Kunyanya, kana HPMC ichipisa kusvika pa200-300 ° C, inotanga kuparara kwekupisa, panguva iyo mapoka ehydroxyl nemacheni epadivi senge methoxy kana hydroxypropyl mumorekuru anoora zvishoma nezvishoma kugadzira zvigadzirwa zvidiki zvemamorekuru senge methanol, formic. asidhi uye shoma shoma yemahydrocarbon.
Thermal degradation mechanism
Iyo yekupisa yekupisa nzira yeHPMC yakaoma uye inosanganisira akawanda matanho. Maitiro ayo ekushatisa anogona kungopfupikiswa sezvizvi: sezvo tembiricha inokwira, ether zvisungo muHPMC zvishoma nezvishoma zvinotyoka kuti ibudise zvimedu zvidiki zvemamorekuru, izvo zvinobva zvawedzera kuora kuburitsa zvigadzirwa zvegasi semvura, kabhoni dhaibhoni, uye kabhoni monoxide. Nzira dzayo huru dzekupisa kupisa dzinosanganisira matanho anotevera:
Dehydration process: HPMC inorasikirwa nemuviri adsorbed mvura uye shoma shoma yemvura yakasungwa pane yakaderera tembiricha, uye iyi nzira haiparadzi chimiro chayo chemakemikari.
Kushatiswa kwemapoka ehydroxyl: Mutembiricha yeanenge 200-300 ° C, mapoka ehydroxyl ari paHPMC molecular chain anotanga kuita pyrolyze, achigadzira mvura uye hydroxyl radicals. Panguva ino, methoxy uye hydroxypropyl epadivi cheni zvakare inowora zvishoma nezvishoma kugadzira mamorekuru akadai se methanol, formic acid, nezvimwe.
Main chain breakage: Kana tembiricha ichiwedzerwa kusvika 300-400 ° C, iyo β-1,4-glycosidic bond of cellulose main chain ichaitwa pyrolysis kugadzira zvigadzirwa zvidiki zvinoputika uye kabhoni masara.
Kuwedzera kutsemuka: Kana tembiricha yakwira kusvika pamusoro pe400°C, mahydrocarbon akasara uye zvimwe zvimedu zveselulosi zvisina kucheneswa zvichawedzera kutsemuka kugadzira CO2, CO uye mamwe mamorekuru madiki.
Zvinhu zvinokanganisa kupisa kwemafuta
Kushatisa kwekupisa kweHPMC kunokanganisa nezvakawanda zvinhu, kunyanya kusanganisira zvinotevera zvinhu:
Tembiricha: Chiyero uye dhigirii rekupisa kwekupisa zvine hukama nekushisa. Kazhinji, kukwirisa tembiricha, ndiko kukurumidza kwemaitiro ekudzikira uye kuwedzera dhigirii yekudzikira. Mumashandisirwo anoshanda, maitiro ekudzora tembiricha yekugadzira kudzivirira zvakanyanya kupisa kweHPMC inyaya inoda kutariswa.
Atmosphere: Hunhu hwekupisa hwekupisa kweHPMC mumhepo dzakasiyana siyana zvakare. Mumhepo kana okisijeni nharaunda, HPMC iri nyore kuita oxidize, ichigadzira mamwe gasi zvigadzirwa uye kabhoni zvakasara, nepo mune inert mhepo (yakadai senitrogen), iyo degradation maitiro anonyanya kuratidzwa se pyrolysis, ichigadzira diki diki masara ekabhoni.
Molecular huremu: Huremu hwemamorekuru hweHPMC hunokanganisawo maitiro ayo ekudzikisira kupisa. Kukwira kwehuremu hwema molecular, ndiko kuwedzera kwekushisa kwekutanga kwekupisa kwekupisa. Izvi zvinodaro nekuti yakakwira molecular uremu HPMC ine macheni akareba mamorekuru uye zvimiro zvakatsiga, uye inoda simba repamusoro kutyora mabhondi ayo.
Hunyoro hwemukati: Hunyoro hwemukati muHPMC hunokanganisawo kupisa kwayo. Hunyoro hunogona kudzikisira tembiricha yekuora kwayo, zvichibvumira kudzikira kuti kuitike pakudzika kwakadzika.
Kushandisa kukanganisa kwekupisa kwekupisa
Hunhu hwekupisa hwekupisa kweHPMC hune chekuita kwakakosha pakushandisa kwayo kunoshanda. Semuenzaniso, mukugadzirira kwemishonga, HPMC inowanzo shandiswa seyakagadziriswa-yakaburitswa zvinhu kudzora kuburitswa kwemishonga. Nekudaro, panguva yekugadzira zvinodhaka, tembiricha yepamusoro inokanganisa chimiro cheHPMC, nekudaro ichichinja kuburitswa kwemushonga. Naizvozvo, kudzidza maitiro ayo ekudzikisira kupisa kwakakosha zvikuru pakugadzirisa kugadzirwa kwezvinodhaka uye kuve nechokwadi chekugadzikana kwezvinodhaka.
Muzvivakwa zvekuvaka, HPMC inonyanya kushandiswa mukuvaka zvigadzirwa senge simende uye gypsum kuita basa mukukora uye kuchengetedza mvura. Sezvo zvivakwa zvekuvaka zvinowanzoda kusangana nemamiriro ekushisa akanyanya kana aiswa, kugadzikana kwekupisa kweHPMC zvakare kwakakosha kufunga nezvekusarudza zvinhu. Pakupisa kwepamusoro, kupisa kwekupisa kweHPMC kunotungamirira mukuderera kwekushanda kwezvinhu, saka kana uchisarudza uye uchiishandisa, kushanda kwayo pakupisa kwakasiyana kunowanzoonekwa.
Iyo thermal degradation process yehydroxypropyl methylcellulose (HPMC) inosanganisira akawanda matanho, ayo anonyanya kukanganiswa nekupisa, mhepo, molecular huremu uye hunyoro hwemukati. Iyo yekupisa kwayo yekupisa maitiro inosanganisira kupera mvura mumuviri, kuparara kwehydroxyl nemacheni eparutivi, uye kutsemuka kweketani huru. Hunhu hwekudzikisira kupisa kweHPMC hune kukosha kwekushandiswa kwakakosha muminda yekugadzirira mishonga, zvekuvakisa, nezvimwewo. Naizvozvo, kunzwisisa kwakadzama kwemaitiro ayo ekudzikisira kupisa kwakakosha pakugadzirisa dhizaini nekuvandudza mashandiro echigadzirwa. Mukutsvagisa kweramangwana, kugadzikana kwekupisa kweHPMC kunogona kuvandudzwa nekugadzirisa, nekuwedzera zvigadziriso, nezvimwe, nekudaro ichiwedzera nzvimbo yayo yekushandisa.
Nguva yekutumira: Oct-25-2024