Phunzirani pa Kuwongolera Ubwino wa Hydroxypropyl Methyl Cellulose

Malinga ndi momwe HPMC ikupangidwira m'dziko langa, zinthu zomwe zimakhudza ubwino wa hydroxypropyl methylcellulose zimawunikidwa, ndipo pazifukwa izi, momwe mungasinthire mulingo wa hydroxypropyl methylcellulose amakambidwa ndikuphunziridwa, kuti apange.

Mawu ofunikira:hydroxypropyl methylcellulose; khalidwe; kulamulira; kafukufuku

Hydroxypropyl methylcellulose (HPMC) ndi cellulose yosakanizidwa ndi madzi ya ionic yosakanikirana ndi thonje, nkhuni, ndi etherified ndi propylene oxide ndi methyl chloride pambuyo pa kutupa kwa alkali. Ma cellulose mix ether ndi Chochokera ku single substituent ether chili ndi zinthu zapadera kwambiri kuposa etha yoyambirira, ndipo imatha kusewera kachitidwe ka cellulose ether momveka bwino komanso mwangwiro. Pakati pa ma ether ambiri osakanikirana, hydroxypropyl methylcellulose ndiyofunikira kwambiri. Njira yokonzekera ndikuwonjezera propylene oxide ku cellulose yamchere. Industrial HPMC akhoza kufotokozedwa ngati mankhwala padziko lonse. Mlingo wolowa m'malo mwa gulu la methyl (DS mtengo) ndi 1.3 mpaka 2.2, ndipo digiri ya molar m'malo mwa hydroxypropyl ndi 0.1 mpaka 0.8. Zitha kuwoneka kuchokera kuzomwe zili pamwambazi kuti zomwe zili ndi methyl ndi hydroxypropyl mu HPMC ndizosiyana, zomwe zimapangitsa kuti zikhale zomaliza kukhuthala kwazinthu komanso Kusiyana kwa kufanana kumabweretsa kusinthasintha kwa zinthu zomalizidwa zamabizinesi osiyanasiyana opanga.

Hydroxypropyl methylcellulose imapanga zotumphukira za ether kudzera muzochita zamakina, zomwe zimasintha kwambiri pamapangidwe ake, kapangidwe kake ndi katundu, makamaka kusungunuka kwa cellulose, komwe kumatha kukhala kosiyanasiyana malinga ndi mtundu ndi kuchuluka kwa magulu a alkili. Pezani zotumphukira za etha zosungunuka m'madzi, sungunuka wa alkali, zosungunulira za polar (monga ethanol, propanol) ndi zosungunulira zopanda polar (monga benzene, ether), zomwe zimakulitsa kwambiri mitundu ndi ntchito za zotumphukira za cellulose.

1. Zotsatira za hydroxypropyl methylcellulose alkalization process paubwino

The alkalization ndondomeko ndi sitepe yoyamba mu anachita siteji ya HPMC kupanga, ndipo ndi chimodzi mwa zinthu zofunika kwambiri. The chibadidwe khalidwe la mankhwala HPMC makamaka anatsimikiza ndi alkalization ndondomeko, osati ndondomeko etherification, chifukwa alkalization zotsatira mwachindunji zimakhudza zotsatira za etherification.

Hydroxypropyl methylcellulose imalumikizana ndi njira ya alkaline kupanga alkali cellulose, yomwe imagwira ntchito kwambiri. Mu anachita etherification, anachita chachikulu cha wothandizila etherification kuti kutupa, malowedwe, ndi etherification wa mapadi ndi Mlingo wa mbali zimachitikira, yunifolomu anachita ndi katundu wa mankhwala chomaliza zonse zokhudzana ndi mapangidwe ndi zikuchokera Ma cellulose amchere, motero kapangidwe kake ndi kapangidwe kake ka cellulose ya alkali ndizofunikira zofufuza popanga cellulose ether.

2. Zotsatira za kutentha pa khalidwe la hydroxypropyl methylcellulose

Mu ndende ina ya yankho lamadzi la KOH, kuchuluka kwa adsorption ndi kuchuluka kwa kutupa kwa hydroxypropyl methylcellulose kupita ku zamchere kumawonjezeka ndi kuchepa kwa kutentha komwe kumachitika. Mwachitsanzo, kutulutsa kwa cellulose ya alkali kumasiyana malinga ndi kuchuluka kwa KOH: 15%, 8% pa 10.°C, ndi 4.2% pa 5°C. Limagwirira a mchitidwewu ndi mapangidwe alkali mapadi ndi exothermic anachita ndondomeko. Pamene kutentha kumakwera, kutsekemera kwa hydroxypropyl methylcellulose pa alkali Kuchuluka kumachepetsedwa, koma hydrolysis reaction ya alkali cellulose ikuwonjezeka kwambiri, zomwe sizikugwirizana ndi mapangidwe a alkali cellulose. Zitha kuwonedwa kuchokera pamwambapa kuti kutsitsa kutentha kwa alkalization kumathandizira kubadwa kwa cellulose yamchere ndipo kumalepheretsa hydrolysis reaction.

3. Zotsatira za zowonjezera pa khalidwe la hydroxypropyl methylcellulose

Mu cellulose-KOH-madzi dongosolo, zowonjezera-mchere umakhudza kwambiri mapangidwe alkali mapadi. Kuchuluka kwa yankho la KOH kumakhala kotsika kuposa 13%, kuyamwa kwa cellulose kukhala alkali sikukhudzidwa ndi kuwonjezera mchere wa potaziyamu chloride. Pamene ndende ya lye yankho ndi apamwamba kuposa 13%, pambuyo powonjezera potaziyamu kolorayidi, zikuoneka adsorption wa mapadi kuti alkali The adsorption kumawonjezera ndende ya potaziyamu kolorayidi, koma okwana adsorption mphamvu amachepetsa, ndi madzi mazenera ukuwonjezeka kwambiri, kotero Kuwonjezera mchere zambiri zoipa kwa alkalization ndi kutupa mapadi, koma mchere ziletsa hydrolysis ndi kulamulira dongosolo The ufulu madzi zili motero bwino zotsatira za alkalization ndi etherification.

4. Mphamvu ya njira yopangira pa khalidwe la hydroxypropyl methylcellulose

Pakadali pano, mabizinesi opanga hydroxypropyl methylcellulose m'dziko langa amatengera njira yopangira zosungunulira. Kukonzekera ndi etherification ya cellulose ya alkali zonse zimachitika mu inert organic solvent, kotero kuti thonje woyengedwa bwino ayenera kupukutidwa kuti apeze malo okulirapo a Surface ndi reactivity kuti atsimikizire mtundu wa chinthu chomalizidwa.

Add pulverized mapadi, organic zosungunulira ndi soda njira mu riyakitala, ndi ntchito amphamvu makina oyambitsa pa kutentha ndi nthawi kupeza zamchere mapadi ndi yunifolomu alkalization ndi zochepa kuwonongeka. Organic dilution solvents (isopropanol, toluene, etc.) ali ndi inertness, zomwe zimapangitsa hydroxypropyl methylcellulose emit kutentha yunifolomu pa mapangidwe ndondomeko, kusonyeza stepwise kumasulidwa patsogolo, pamene kuchepetsa hydrolysis anachita za alkali mapadi mu njira ina Kupeza mkulu- ulalo wabwino wa alkali cellulose, nthawi zambiri kuchuluka kwa sopo komwe kumagwiritsidwa ntchito pa ulalowu kumakhala kokwera mpaka 50%.

Pambuyo pa cellulose yoviikidwa mu sopo, cellulose yotupa komanso yofanana ndi alkali imapezeka. Lie osmotically imatupa cellulose bwino, kuyika maziko abwino a etherification reaction. Chiyerekezo diluents makamaka monga isopropanol, acetone, toluene, etc. The solubility wa lye, mtundu wa diluent ndi yogwira mtima zinthu ndi zikuluzikulu zimene zimakhudza zikuchokera zamchere mapadi. Zapamwamba ndi zapansi zimapangidwira posakaniza. Kumtunda kwapamwamba kumapangidwa ndi isopropanol ndi madzi, ndipo kumunsi kwapansi kumapangidwa ndi alkali ndi pang'ono isopropanol. The mapadi omwazika mu dongosolo mokwanira kukhudzana ndi chapamwamba ndi m'munsi madzi zigawo pansi makina yogwira mtima. The alkali mu dongosolo Mlingo wa madzi umasuntha mpaka cellulose atapangidwa.

Monga cellulose non-ionic mix mix ether, zomwe zili m'magulu a hydroxypropyl methylcellulose zili pamaketani osiyanasiyana a macromolecular, ndiye kuti, chiŵerengero chamagulu a methyl ndi hydroxypropyl ndi chosiyana pa C pa malo aliwonse a glucose. Ili ndi kubalalikana kwakukulu komanso kusasinthika, zomwe zimapangitsa kuti zikhale zovuta kutsimikizira kukhazikika kwa chinthucho.