Nazari akan Ingantacciyar Kula da Hydroxypropyl Methyl Cellulose

Bisa ga halin da ake ciki na samar da HPMC a cikin ƙasata, an yi nazarin abubuwan da suka shafi ingancin hydroxypropyl methylcellulose, kuma a kan wannan, yadda za a inganta darajar hydroxypropyl methylcellulose an tattauna kuma an yi nazari, ta yadda za a samar da shi.

Mabuɗin kalmomi:hydroxypropyl methylcellulose; inganci; sarrafawa; bincike

Hydroxypropyl methylcellulose (HPMC) shine cellulose maras ionic ruwa mai narkewa, gauraye ether da aka yi daga auduga, itace, da etherified tare da propylene oxide da methyl chloride bayan kumburin alkali. Cellulose gauraye ether shine gyare-gyaren da aka samu na madaidaicin ether guda ɗaya yana da kyawawan kaddarori na musamman fiye da ainihin monoether, kuma yana iya kunna aikin ether ɗin cellulose sosai kuma daidai. Daga cikin yawancin ethers masu gauraye, hydroxypropyl methylcellulose shine mafi mahimmanci. Hanyar shiri ita ce ƙara propylene oxide zuwa alkaline cellulose. Ana iya kwatanta HPMC na masana'antu a matsayin samfur na duniya. Matsayin maye gurbin ƙungiyar methyl (ƙimar DS) shine 1.3 zuwa 2.2, kuma ma'aunin maye gurbin molar hydroxypropyl shine 0.1 zuwa 0.8. Ana iya gani daga bayanan da ke sama cewa abun ciki da kaddarorin methyl da hydroxypropyl a cikin HPMC sun bambanta, wanda ya haifar da ɗankowar samfurin ƙarshe da Bambanci a cikin daidaituwa yana haifar da haɓakar ingancin samfuran ƙãre na masana'antar samarwa daban-daban.

Hydroxypropyl methylcellulose yana samar da abubuwan ether ta hanyar halayen sinadarai, waɗanda ke da manyan canje-canje a cikin abun da ke ciki, tsari da kaddarorinsa, musamman ma solubility na cellulose, wanda za'a iya bambanta bisa ga nau'i da adadin alkyl da aka gabatar. Sami abubuwan da aka samo asali na ether mai narkewa a cikin ruwa, maganin alkali mai narkewa, maganin polar (kamar ethanol, propanol) da sauran kaushi na kwayoyin halitta marasa iyaka (kamar benzene, ether), wanda ke faɗaɗa nau'ikan nau'ikan nau'ikan da aikace-aikacen abubuwan da suka samo asali na cellulose.

1. Tasirin tsarin alkalization na hydroxypropyl methylcellulose akan inganci

Tsarin alkalization shine mataki na farko a matakin mayar da martani na samar da HPMC, kuma yana ɗaya daga cikin matakai masu mahimmanci. Halin ingancin samfuran HPMC an ƙaddara shi ta hanyar tsarin alkalization, ba tsarin etherification ba, saboda tasirin alkalization kai tsaye yana shafar tasirin etherification.

Hydroxypropyl methylcellulose yana hulɗa tare da maganin alkaline don samar da alkali cellulose, wanda yake da tasiri sosai. A cikin etherification dauki, babban dauki na etherification wakili zuwa kumburi, shigar azzakari cikin farji, da etherification na cellulose da The rate of gefen halayen, da uniformity na dauki da kuma kaddarorin na karshe samfurin duk suna da alaka da samuwar da abun da ke ciki na alkali cellulose, don haka tsari da sinadarai Properties na alkali cellulose su ne muhimman bincike abubuwa a cikin samar da cellulose ether.

2. Sakamakon zafin jiki akan ingancin hydroxypropyl methylcellulose

A cikin wani takamaiman taro na KOH mai ruwa bayani, adadin adsorption da digiri na kumburi na hydroxypropyl methylcellulose zuwa alkali yana ƙaruwa tare da rage yawan zafin jiki. Misali, fitowar alkali cellulose ya bambanta tare da maida hankali na KOH: 15%, 8% a 10.°C, da 4.2% a 5°C. Tsarin wannan yanayin shine cewa samuwar alkali cellulose wani tsari ne na exothermic dauki. Yayin da zafin jiki ya tashi, adsorption na hydroxypropyl methylcellulose akan alkali Adadin ya ragu, amma yanayin hydrolysis na alkali cellulose yana karuwa sosai, wanda ba shi da kyau ga samuwar alkali cellulose. Ana iya gani daga sama cewa rage yawan zafin jiki na alkalization yana taimakawa wajen samar da alkali cellulose kuma yana hana aikin hydrolysis.

3. Sakamakon additives akan ingancin hydroxypropyl methylcellulose

A cikin cellulose-KOH-ruwa tsarin, da ƙari-gishiri yana da babban tasiri akan samuwar alkali cellulose. Lokacin da maida hankali na KOH bayani ya kasance ƙasa da 13%, adsorption na cellulose zuwa alkali ba ya shafar ƙarar potassium chloride gishiri. Lokacin da maida hankali na maganin lye ya fi 13%, bayan ƙara potassium chloride, bayyanar da ƙwayar cellulose zuwa alkali Adsorption yana ƙaruwa tare da maida hankali na potassium chloride, amma jimlar adsorption yana raguwa, kuma tallan ruwa yana ƙaruwa sosai, don haka Bugu da ƙari na gishiri gabaɗaya ba shi da kyau ga alkalization da kumburin cellulose, amma gishiri na iya hana hydrolysis da daidaita tsarin Tsarin ruwa na kyauta don haka yana inganta tasirin alkalization da etherification.

4. Tasirin tsarin samarwa akan ingancin hydroxypropyl methylcellulose

A halin yanzu, masana'antun samar da hydroxypropyl methylcellulose a cikin ƙasata galibi suna ɗaukar tsarin samar da ƙarfi. Shirye-shiryen da tsarin etherification na alkali cellulose duk ana yin su ne a cikin wani kaushi mai ƙarancin ƙarfi, don haka albarkatun da aka tace auduga yana buƙatar tarwatsawa don samun yanki mai girma da kuma sake kunnawa don tabbatar da ingancin samfurin da aka gama.

Add da pulverized cellulose, Organic sauran ƙarfi da alkali bayani a cikin reactor, da kuma amfani da iko inji stirring a wani zafin jiki da kuma lokaci don samun alkali cellulose tare da uniform alkalization da kasa lalacewa. Organic dilution kaushi (isopropanol, toluene, da dai sauransu) suna da wani inertness, wanda ya sa hydroxypropyl methylcellulose emit uniform zafi a lokacin samuwar tsari, yana nuna wani stepwise saki ci gaba, yayin da rage hydrolysis dauki alkali cellulose a gaban shugabanci Don samun high- ingancin alkali cellulose, yawanci maida hankali na lye amfani da wannan mahada ya kai 50%.

Bayan an jika cellulose a cikin lemun tsami, an sami cikakkiyar kumbura kuma daidai da alkalized alkali cellulose. Lye osmotically yana kumbura cellulose mafi kyau, yana kafa tushe mai kyau don halayen etherification na gaba. Hankula diluents yafi hada da isopropanol, acetone, toluene, da dai sauransu The solubility na lye, irin diluent da stirring yanayi su ne manyan abubuwan da suka shafi abun da ke ciki na alkali cellulose. Ana yin manyan yadudduka na sama da na ƙasa lokacin haɗuwa. Babban Layer yana kunshe da isopropanol da ruwa, kuma ƙananan Layer ya ƙunshi alkali da ƙananan adadin isopropanol. The cellulose tarwatsa a cikin tsarin ne cikakken a lamba tare da babba da ƙananan ruwa yadudduka karkashin inji stirring. Alkali a cikin tsarin Ma'aunin ruwa yana motsawa har sai an kafa cellulose.

Kamar yadda wani hali cellulose non-ionic gauraye ether, abun ciki na hydroxypropyl methylcellulose kungiyoyin ne a kan daban-daban macromolecular sarƙoƙi, wato, rarraba rabo na methyl da hydroxypropyl kungiyoyin daban a kan C na kowane glucose zobe matsayi. Yana da mafi girman tarwatsawa da bazuwar, yana sa ya yi wahala a ba da garantin ingancin ingancin samfurin.