Pehea ka hana ʻana o ka hydroxyethyl cellulose?

ʻO ka Hydroxyethyl Cellulose (HEC) he polymer wai-soluble maʻamau i hoʻohana nui ʻia i nā kemika o kēlā me kēia lā, ke kūkulu ʻana, nā uhi, nā lāʻau lapaʻau, nā meaʻai a me nā ʻoihana ʻē aʻe. ʻO ia kahi etera cellulose non-ionic i hana ʻia e ka hoʻololi ʻana i ka cellulose kūlohelohe. ʻO ke kaʻina hana o ka hydroxyethyl cellulose e pili ana i nā hopena kemika paʻakikī, e like me ka wehe ʻana o cellulose, ka mālama alkalization, ka etherification reaction, a me nā mea ʻē aʻe.

1. Ke kohoʻana i nā mea maka a me ka unuhiʻana o ka cellulose
ʻO ke kumu kumu o ka hydroxyethyl cellulose he cellulose maoli, ka mea nui mai ka lāʻau, ka pulupulu a me nā mea kanu ʻē aʻe. He kiʻekiʻe ka maʻiʻo cellulose i loko o nā paia o nā mea kanu, a hiki ke kiʻi ʻia ka cellulose maʻemaʻe mai kēia mau mea kūlohelohe ma ke ʻano mechanical a i ʻole kemika. ʻO ke kaʻina hana e hoʻoneʻe ʻia me ka ʻoki ʻana, ka wehe ʻana i nā mea haumia (e like me ka lignin, hemicellulose), bleaching a me nā pae ʻē aʻe.

ʻO ka unuhi ʻana o ka cellulose: Hoʻohana pinepine ʻia ka cellulose kūlohelohe i ka mechanically a i ʻole ke kemika e wehe i nā mea cellulose non-cellulose e loaʻa ai ka cellulose maʻemaʻe kiʻekiʻe. ʻO ka pulupulu pulupulu, ka pulupulu lāʻau, a me nā mea ʻē aʻe hiki ke lilo i kumu maʻamau o nā mea maka. I ka wā o ka mālama ʻana, hoʻohana ʻia ka alkali (e like me ka sodium hydroxide) e kōkua i ka hoʻoheheʻe ʻana i nā ʻāpana non-cellulose, a ʻo ke koena ka cellulose.
2. Lapaʻau Alkalization
Pono e hoʻomaʻemaʻe mua ʻia ka cellulose i hoʻomaʻemaʻe ʻia. ʻO kēia kaʻina hana e hoʻoikaika i nā pūʻulu hydroxyl ma ke kaulahao molekula cellulose i hiki iā lākou ke hana maʻalahi me ka mea hoʻoheheʻe. ʻO nā ʻanuʻu nui o ka mālama ʻana i ka alkaliization penei:

ʻO ka pane o ka cellulose me ka alkali: ua hui pū ʻia ka cellulose me kahi alkali ikaika (maʻamau ka sodium hydroxide) e hana i ka cellulose alkali (Alkali Cellulose). Hana ʻia kēia hana ma kahi ʻano wai. ʻO Alkali cellulose ka hopena hopena o ka cellulose a me ka sodium hydroxide. Loaʻa i kēia mea i kahi ʻano looser a me ka reactivity kiʻekiʻe, i kūpono i ka hopena etherification ma hope.
Hana ʻia ke kaʻina hana alkalization i ka mahana kūpono a me ka haʻahaʻa, ma ke ʻano he 20 ℃ ~ 30 ℃ no kekahi mau hola e hōʻoia i ka hoʻoikaika piha ʻana o nā pūʻulu hydroxyl i loko o nā molekole cellulose.

3. Etherification pane
ʻO ka Etherification kahi hana nui i ka hana ʻana o ka hydroxyethyl cellulose. Hoʻokumu ʻia ka Hydroxyethyl cellulose e ka hoʻopili ʻana i ka cellulose alkali me ka ethylene oxide e hoʻolauna i nā hui hydroxyethyl. ʻO nā ʻanuʻu kikoʻī penei:

ʻO ka pane me ka ethylene oxide: Hoʻopili ʻo Alkali cellulose me kahi nui o ka ethylene oxide ma lalo o kekahi mau kūlana wela a me ke kaomi. Wehe ʻia ke apo i loko o ka ethylene oxide e hana i kahi paʻa etera, hoʻopili me nā pūʻulu hydroxyl i loko o nā molekole cellulose, a hoʻokomo i nā pūʻulu hydroxyethyl (–CH2CH2OH). Hiki i kēia kaʻina hana ke hoʻololi i ke kiʻekiʻe o ka etherification ma ke kāohi ʻana i nā kūlana hopena (e like me ka mahana, kaomi, a me ka manawa).
Hoʻokō pinepine ʻia ka hopena ma kahi ʻano alkaline e hōʻoia i ka pono o ka etherification. ʻO ka mahana o ka hopena he 50 ℃ ~ 100 ℃, a he mau hola ka manawa hoʻonā. Ma ka hoʻoponopono ʻana i ka nui o ka ethylene oxide, hiki ke hoʻomalu ʻia ke degere o ka hoʻololi ʻana o ka huahana hope, ʻo ia hoʻi, ehia mau pūʻulu hydroxyl i loko o nā molekule cellulose i hoʻololi ʻia e nā hui hydroxyethyl.

4. Neutralization a holoi
Ma hope o ka pau ʻana o ka hopena etherification, pono e hoʻokaʻawale ʻia nā mea alkaline i ka ʻōnaehana hopena. ʻO nā mea hoʻokuʻu maʻamau i hoʻohana ʻia he mau mea ʻakika, e like me ka acetic acid a i ʻole hydrochloric acid. ʻO ke kaʻina hana neutralization e hoʻopau i ka alkali nui i loko o nā paʻakai, ʻaʻole ia e pili i ka hana o ka huahana.

Pane hoʻoneʻe: E lawe i ka huahana mai loko aʻe o ka reactor a hoʻohui i ka nui kūpono o ka waika no ka hoʻohaʻahaʻa ʻana a hiki i ka waiwai pH o ka ʻōnaehana ke kū ʻole. ʻAʻole kēia kaʻina hana e wehe wale i ke koena alkali, akā e hōʻemi hoʻi i ka hopena o ka hopena o nā huahana i ka hana o ka hydroxyethyl cellulose.

Holoi a maloʻo: Pono e holoi pinepine ʻia ka huahana neutralized, maʻamau me ka wai a i ʻole ethanol a me nā mea hoʻoheheʻe ʻē aʻe e holoi i ke koena o nā haumia a me nā huahana. Hoʻomaʻemaʻe ʻia ka huahana i holoi ʻia e ka centrifugation, kānana kaomi ʻana a me nā ʻano hana ʻē aʻe e hōʻemi ai i ka maʻa.

5. ʻO ka maloʻo a me kaʻokiʻana
Ma hope o ka holoi ʻana a me ka maloʻo ʻana, aia ka hydroxyethyl cellulose i kahi nui o ka wai a pono e hoʻomaloʻo hou ʻia. Hiki ke hana ʻia ke kaʻina hoʻomaloʻo ma ka hoʻomaloʻo ʻana i ka ea a i ʻole ka maloʻo maloʻo e hōʻoia i ka paʻa maikaʻi o ka huahana i ka wā mālama a hoʻohana.

Hoʻomaloʻo: E hoʻomaloʻo i ka huahana ma kahi mahana (ma lalo o 60°C) e wehe i ke koena o ka wai. ʻAʻole pono ke kiʻekiʻe loa ka mahana maloʻo, inā ʻaʻole ia e hōʻino i ka huahana a pili i kāna hana.

Ka ʻohi ʻana a me ka nānā ʻana: Aia ka hydroxyethyl cellulose maloʻo i loko o nā poloka a i ʻole nā ​​puʻupuʻu, a pono e ʻoki ʻia no ka loaʻa ʻana o ka pauda maikaʻi. Pono e nānā ʻia ka huahana i ʻoki ʻia no ka loaʻa ʻana o kahi puʻupuʻu nui e kū ai i nā koi e hōʻoia i kona solubility a me ka dispersibility i nā noi kūpono.

6. ʻO ka hoʻāʻo ʻana a me ka hoʻopili ʻana i nā huahana hope loa
Ma hope o ka hana ʻana, pono e hoʻāʻo ʻia ka hydroxyethyl cellulose no ka maikaʻi e hōʻoia i ka hoʻokō ʻana o kāna mau hōʻailona hana i nā koi maʻamau. Hoʻokomo pinepine ʻia nā mea hoʻāʻo:

Ana Viscosity: ʻO ka viscosity o ka hydroxyethyl cellulose ma hope o ka hoʻoheheʻe ʻana i loko o ka wai he hōʻailona koʻikoʻi koʻikoʻi, e pili ana i kona hoʻohana ʻana i nā uhi, ke kūkulu ʻana, nā kemika o kēlā me kēia lā a me nā māla ʻē aʻe.
ʻAno wai: E hoʻāʻo i ka makū o ka huahana e hōʻoia i ka paʻa o kona waihona.
Degree of substitution (DS) and molar substitution (MS): E hoʻoholo i ke kiʻekiʻe o ka hoʻololi ʻana a me ka hoʻololi ʻana i ka molar i loko o ka huahana ma o ka loiloi kemika e hōʻoia i ka hopena o ka hopena etherification.
Ma hope o ka hala ʻana i ka hoʻāʻo, e hoʻopili ʻia ka hydroxyethyl cellulose i loko o ka pauka a i ʻole nā ​​​​huahana granular, maʻamau i loko o nā ʻeke pepa a i ʻole nā ​​​​ʻeke pepa e pale ai i ka pulu a i ʻole ka haumia.

ʻO ke kaʻina hana o ka hydroxyethyl cellulose ka nui o nā ʻanuʻu o ka lawe ʻana i ka cellulose, ka mālama ʻana i ka alkalization, ka hopena etherification, ka neutralization a me ka holoi ʻana, ka maloʻo a me ka wāwahi. ʻO ke kaʻina holoʻokoʻa e pili ana i ka alkalization a me ka etherification i ka hopena kemika, a hāʻawi ʻia ka cellulose i ka wai solubility maikaʻi a me nā waiwai mānoanoa ma ka hoʻokomo ʻana i nā hui hydroxyethyl. Hoʻohana nui ʻia ka hydroxyethyl cellulose i nā ʻoihana he nui, e like me ka mānoanoa no ka uhi ʻana, ka mea mālama wai no nā mea kūkulu hale, stabilizer i nā huahana kemika i kēlā me kēia lā, a me nā mea ʻē aʻe. o ka huahana.