Focus on Cellulose ethers

Menene Hydroxypropyl Methylcellulose Daga

Menene Hydroxypropyl Methylcellulose Daga

Hydroxypropyl methylcellulose (HPMC) polymer semisynthetic ne wanda ake amfani dashi a cikin masana'antu da yawa, gami da gini, abinci, magunguna, da samfuran kulawa na sirri. Yana da daraja don iyawarta don inganta rheological Properties na formulations, kazalika da jituwa tare da sauran sinadaran da ƙananan guba. Don fahimtar yadda ake yin HPMC, yana da mahimmanci a fara fahimtar tsari da kaddarorin cellulose.

Cellulose doguwar sarkar glucose ce da ake samu a bangon tantanin halitta. Kwayoyin glucose suna haɗe tare da beta-1,4-glycosidic bonds, suna samar da sarkar layi. Sa'an nan kuma an haɗa sarƙoƙin tare da haɗin gwiwar hydrogen da sojojin Van der Waals don samar da ƙarfi, sifofi masu ƙarfi. Cellulose ita ce mafi yawan abubuwan halitta a duniya, kuma ana amfani da ita a aikace-aikace iri-iri, gami da takarda, yadi, da kayan gini.

Yayin da cellulose yana da kaddarorin masu amfani da yawa, sau da yawa yana da ƙarfi sosai kuma ba zai iya narkewa don amfani da shi a cikin tsari da yawa. Don shawo kan waɗannan iyakoki, masana kimiyya sun ƙirƙira wasu abubuwan da aka gyara na cellulose, gami da HPMC. Ana yin HPMC ta hanyar gyara cellulose na halitta ta hanyar jerin halayen sinadarai.

Mataki na farko na yin HPMC shine samun kayan farawa cellulose. Ana iya yin haka ta hanyar hako cellulose daga tushen shuka kamar ɓangaren itace, auduga, ko bamboo. Sannan ana bi da cellulose tare da maganin alkaline, irin su sodium hydroxide ko potassium hydroxide, don cire ƙazanta kuma a wargaza zaruruwan cellulose zuwa ƙananan barbashi. Wannan tsari ana kiransa da mercerization, kuma yana sa cellulose ya fi ƙarfin aiki da sauƙi don gyarawa.

Bayan hayar, ana mayar da cellulose tare da cakuda propylene oxide da methyl chloride don gabatar da hydroxypropyl da kungiyoyin methyl akan kashin bayan cellulose. Ana ƙara ƙungiyoyin hydroxypropyl don haɓaka haɓakar solubility da abubuwan riƙewar ruwa na cellulose, yayin da ƙungiyoyin methyl an ƙara su don haɓaka kwanciyar hankali da rage haɓakawar cellulose. Yawanci ana yin sa ne a gaban mai kara kuzari, kamar sodium hydroxide ko potassium hydroxide, kuma ƙarƙashin yanayin sarrafawa na zafin jiki, matsa lamba, da lokacin amsawa.

Matsayin maye gurbin (DS) na HPMC yana nufin adadin hydroxypropyl da ƙungiyoyin methyl waɗanda aka gabatar akan kashin bayan cellulose. DS na iya bambanta dangane da abubuwan da ake so na HPMC da takamaiman aikace-aikacen da ake amfani da shi. Gabaɗaya, ƙimar DS mafi girma suna haifar da HPMC tare da ƙananan danko da ƙimar rushewar sauri, yayin da ƙananan ƙimar DS ke haifar da HPMC tare da mafi girman danko da rage saurin rushewa.

Bayan an gama amsawa, samfurin da aka samu yana tsarkakewa kuma an bushe shi don ƙirƙirar foda HPMC. Tsarin tsarkakewa ya haɗa da cire duk wani sinadari da ba a yi amfani da shi ba, sauran kaushi, da sauran ƙazanta daga HPMC. Ana yin wannan yawanci ta hanyar haɗaɗɗun matakan wankewa, tacewa, da bushewa.

Samfurin ƙarshe shine fari zuwa fari-fari wanda ba shi da wari kuma mara daɗi. HPMC yana narkewa a cikin ruwa da yawancin kaushi na halitta, kuma yana iya samar da gels, fina-finai, da sauran sifofi dangane da yanayin amfani. Shi polymer wanda ba na ionic ba, ma'ana cewa baya ɗaukar wani cajin lantarki, kuma ana ɗaukarsa gabaɗaya ba mai guba bane kuma yana da aminci don amfani a aikace-aikace da yawa.

Ana amfani da HPMC a cikin nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan nau'ikan iri, gami da fenti, adhesives, sealants, magunguna, da samfuran abinci. A cikin aikace-aikacen gini, ana amfani da HPMC sau da yawa azaman mai kauri, ɗaure, da tsohon fim a cikin samfuran siminti da samfuran gypsum, irin su turmi, grouts, da mahadi na haɗin gwiwa.


Lokacin aikawa: Afrilu-22-2023
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