Hydroxypropyl methylcellulose (HPMC) wani ether ne wanda ba na ionic cellulose ba wanda ake amfani dashi sosai a cikin magani, abinci, gini da sauran fagage, musamman a cikin allunan ci gaba da sakin magunguna da kayan gini. Nazarin lalatawar zafi na HPMC ba kawai mahimmanci bane don fahimtar canje-canjen aikin da za'a iya fuskanta yayin sarrafawa, har ma yana da mahimmanci don haɓaka sabbin kayan aiki da haɓaka rayuwar sabis da amincin samfuran.
Halayen lalatawar thermal na HPMC
Lalacewar thermal na hydroxypropyl methylcellulose ya fi shafar tsarinsa na ƙwayoyin cuta, zafin zafi da yanayin muhallinsa (kamar yanayi, zafi, da sauransu). Tsarin kwayoyin halittarsa ya ƙunshi babban adadin ƙungiyoyin hydroxyl da ether bonds, don haka yana da haɗari ga halayen sinadarai irin su oxidation da bazuwar a yanayin zafi.
Tsarin lalatawar thermal na HPMC yawanci ana raba shi zuwa matakai da yawa. Na farko, a ƙananan zafin jiki (kimanin 50-150 ° C), HPMC na iya samun asarar jama'a saboda asarar ruwa kyauta da ruwa mai laushi, amma wannan tsari ba ya haɗa da karya haɗin sinadarai, kawai canje-canje na jiki. Yayin da zafin jiki ya ƙara ƙaruwa (sama da 150 ° C), ether bonds da ƙungiyoyin hydroxyl a cikin tsarin HPMC sun fara karyewa, wanda ya haifar da rushewar sarkar kwayoyin da canje-canje a cikin tsarin. Musamman, lokacin da HPMC ya kasance mai zafi zuwa kimanin 200-300 ° C, yana farawa da bazuwar thermal, a lokacin ne ƙungiyoyin hydroxyl da sarƙoƙi na gefe irin su methoxy ko hydroxypropyl a cikin kwayar halitta a hankali suna bazuwa don samar da ƙananan ƙwayoyin ƙwayoyin cuta kamar methanol, formic. acid da ƙananan adadin hydrocarbons.
Tsarin lalata thermal
Tsarin lalata yanayin zafi na HPMC yana da ɗan rikitarwa kuma ya ƙunshi matakai da yawa. Za a iya taƙaita tsarin lalacewarsa kamar haka: yayin da zafin jiki ya tashi, ether bonds a cikin HPMC a hankali ya karye don samar da ƙananan gutsuttsuran kwayoyin halitta, wanda daga nan ya kara lalacewa don sakin kayan gas kamar ruwa, carbon dioxide, da carbon monoxide. Babban hanyoyin lalata yanayin zafinta sun haɗa da matakai masu zuwa:
Tsarin bushewar ruwa: HPMC yana asarar ruwa na jiki da kuma ɗan ƙaramin ruwa mai ɗaure a ƙananan zafin jiki, kuma wannan tsari ba ya lalata tsarin sinadarai.
Rushewar ƙungiyoyin hydroxyl: A cikin kewayon zafin jiki na kusan 200-300 ° C, ƙungiyoyin hydroxyl akan sarkar kwayoyin halitta na HPMC sun fara pyrolyze, samar da ruwa da radicals hydroxyl. A wannan lokacin, sassan sassan methoxy da hydroxypropyl suma sannu a hankali suna raguwa don samar da ƙananan ƙwayoyin cuta kamar methanol, formic acid, da sauransu.
Babban karyewar sarkar: Lokacin da aka ƙara yawan zafin jiki zuwa 300-400 ° C, haɗin β-1,4-glycosidic na babban sarkar cellulose zai fuskanci pyrolysis don samar da ƙananan samfurori masu canzawa da ragowar carbon.
Kara fashewa: Lokacin da zafin jiki ya haura sama da 400°C, ragowar hydrocarbons da wasu gurɓatattun ɓangarorin cellulose da ba su cika ba za su ƙara fashewa don samar da CO2, CO da wasu ƙananan ƙwayoyin ƙwayoyin cuta.
Abubuwan da ke shafar lalatawar thermal
Lalacewar thermal na HPMC yana shafar abubuwa da yawa, galibi gami da abubuwa masu zuwa:
Zazzabi: Matsakaicin ƙima da ƙarancin ƙarancin zafi suna da alaƙa da yanayin zafi. Gabaɗaya, mafi girman zafin jiki, saurin haɓakar halayen lalacewa kuma mafi girman matakin lalacewa. A aikace-aikace masu amfani, yadda ake sarrafa zafin sarrafawa don guje wa lalatawar zafi mai yawa na HPMC batu ne da ke buƙatar kulawa.
Yanayin yanayi: Halin lalata yanayin zafi na HPMC a cikin yanayi daban-daban shima ya bambanta. A cikin iska ko yanayin iskar oxygen, HPMC yana da sauƙin oxidize, yana samar da ƙarin samfuran gas da ragowar carbon, yayin da a cikin yanayi mara kyau (kamar nitrogen), tsarin lalata yana bayyana a matsayin pyrolysis, yana haifar da ƙaramin adadin ragowar carbon.
Nauyin kwayoyin halitta: Nauyin kwayoyin halitta na HPMC kuma yana rinjayar yanayin lalata yanayin zafi. Mafi girman nauyin kwayoyin halitta, mafi girma yawan zafin jiki na farawa na lalatawar thermal. Wannan shi ne saboda babban nauyin kwayoyin HPMC yana da sarƙoƙi na kwayoyin da suka fi tsayi da kuma mafi tsayayyen sifofi, kuma yana buƙatar makamashi mafi girma don karya igiyoyin kwayoyin halitta.
Abun dash: Abubuwan da ke cikin danshi a cikin HPMC shima yana shafar lalatawar zafi. Danshi na iya rage yawan zafin jiki na bazuwar sa, yana barin lalacewa ya faru a ƙananan yanayin zafi.
Tasirin aikace-aikacen lalatawar thermal
Halayen lalatawar thermal na HPMC suna da tasiri mai mahimmanci akan aikace-aikacen sa. Misali, a cikin shirye-shiryen magunguna, ana yawan amfani da HPMC azaman kayan ci gaba mai dorewa don sarrafa ƙimar sakin ƙwayoyi. Duk da haka, yayin sarrafa miyagun ƙwayoyi, yanayin zafi mai zafi zai shafi tsarin HPMC, ta haka yana canza aikin saki na miyagun ƙwayoyi. Sabili da haka, nazarin yanayin lalata yanayin zafi yana da matukar mahimmanci don inganta sarrafa magunguna da tabbatar da kwanciyar hankali.
A cikin kayan gini, ana amfani da HPMC galibi a cikin samfuran gini kamar su siminti da gypsum don taka rawa wajen yin kauri da riƙe ruwa. Tunda kayan gini yawanci suna buƙatar samun yanayin yanayin zafin jiki lokacin amfani da su, kwanciyar hankali na thermal na HPMC shima muhimmin abin la'akari ne don zaɓin kayan. A yanayin zafi mai zafi, lalatawar thermal na HPMC zai haifar da raguwar aikin kayan aiki, don haka lokacin zaɓar da amfani da shi, ana la'akari da aikin sa a yanayin zafi daban-daban.
Tsarin lalatawar thermal na hydroxypropyl methylcellulose (HPMC) ya haɗa da matakai da yawa, wanda yawancin zafin jiki ya shafa, yanayi, nauyin kwayoyin halitta da abun ciki na danshi. Tsarin lalata yanayin zafi ya haɗa da bushewa, bazuwar hydroxyl da sarƙoƙi na gefe, da tsagewar babban sarkar. Halayen lalatawar thermal na HPMC suna da mahimmancin aikace-aikacen aikace-aikacen a cikin fagagen shirye-shiryen magunguna, kayan gini, da sauransu. Saboda haka, zurfin fahimtar yanayin lalata yanayin zafi yana da mahimmanci don haɓaka ƙirar tsari da haɓaka aikin samfur. A cikin bincike na gaba, ana iya inganta kwanciyar hankali na thermal na HPMC ta hanyar gyare-gyare, ƙara stabilizers, da dai sauransu, don haka fadada filin aikace-aikacensa.
Lokacin aikawa: Oktoba-25-2024