Ko te Hydroxyethyl cellulose (HEC) he pūmua kore-ionic, wairewa-wai i ahu mai i te cellulose, he pūmua tūturu e kitea ana i roto i ngā pakitara pūtau o ngā tipu. He whānuitia te whakamahinga i roto i ngā momo ahumahi, tae atu ki ngā rongoā, ngā mea whakapaipai, ngā peita, me ngā piripiri, nā te mea he pai rawa atu tōna whakamātotoru, tōna hanga kiriata, me ōna āhuatanga rheological. Ko te whakarite i te hydroxyethyl cellulose ko te whakaetere i te cellulose me te ethylene oxide i raro i ngā āhuatanga kawakore. Ka taea te wehewehe i tēnei tukanga ki ētahi mahi matua: te purenga cellulose, te whakakawakore, te whakaetere, te whakakore, te horoi, me te whakamaroke.
1. Te Whakamaemaetanga o te Cellulose
Ko te taahiraa tuatahi i roto i te whakarite i te hydroxyethyl cellulose ko te purenga o te cellulose, e ahu mai ana i te penupenu rakau, i ngā miro rānei. Kei roto i te cellulose mata ngā poke pēnei i te lignin, te hemicellulose, me ētahi atu mea tango me tango atu kia whiwhi ai i te cellulose tino parakore e tika ana mō te whakarerekētanga matū.
Ngā mahi e whai wāhi ana:
Te Tukatuka Ā-Mīhini: Ka tukatukahia te cellulose mata mā te ā-mīhini hei whakaiti i tōna rahi me te whakanui i tōna horahanga mata, hei whakahaere i ngā maimoatanga matū e whai ake nei.
Maimoatanga Matū: Ka maimoatia te cellulose ki ngā matū pēnei i te konutai hauwai (NaOH) me te konutai whanariki (Na2SO3) hei wawahi i te lignin me te hemicellulose, ā, muri iho ka horoia me te whakamaia hei tango i ngā paru toenga, kia puta ai he cellulose mā, he muka te āhua.
2. Te Whakapūngao
Kātahi ka whakahāngaihia te cellulose kua purea kia whakahohehia ai mō te tauhohenga etherification. Ko te tikanga o tēnei ko te rongoā i te cellulose ki te wai o te konutai hauwai.
Tauhohenga:
Cellulose+NaOH→Serulose kawakore
Tukanga:
Ka tārewa te cellulose i roto i te wai, ā, ka tāpirihia te wairewa konutai hauwai. Ko te kukū o te NaOH kei waenganui i te 10-30%, ā, ka mahia te tauhohenga i ngā pāmahana i waenganui i te 20-40°C.
Ka whakaohokia te ranunga kia mimiti ōrite te kawakore, ka hua ake te hanganga o te cellulose kawakore. He nui ake te tauhohenga o tēnei takawaenga ki te waikura etilena, ka āwhina i te tukanga whakaetere.
3. Whakapūtanga
Ko te taahiraa matua i roto i te whakarite i te hydroxyethyl cellulose ko te whakaetere i te cellulose alkali ki te ethylene oxide. Mā tēnei tauhohenga ka whakaurua ngā rōpū hydroxyethyl (-CH2CH2OH) ki roto i te anga o te cellulose, ka wairewa ki te wai.
Tauhohenga:
Pūmua kawakore+Waikura Ethylene→Pūmua Hydroxyethyl+NaOH
Tukanga:
Ka tāpirihia te waikura ethylene ki te cellulose alkali, i roto i te tukanga puranga, i te tukanga tonu rānei. Ko te tikanga ka whakahaerehia te tauhohenga i roto i te autoclave, i te tauhohenga pēhanga rānei.
Ko ngā āhuatanga tauhohenga, tae atu ki te pāmahana (50-100°C) me te pēhanga (1-5 atm), ka āta whakahaeretia kia pai ai te whakakapinga o ngā rōpū hydroxyethyl. Ko te nui o te whakakapinga (DS) me te whakakapinga molar (MS) he tawhā nui e pā ana ki ngā āhuatanga o te hua whakamutunga.
4. Whakakorenga
I muri i te tauhohenga etherification, kei roto i te ranunga te hydroxyethyl cellulose me te toenga konutai hauwai. Ko te taahiraa e whai ake nei ko te neutralization, te wāhi e whakakorengia ai te kawakore nui mā te whakamahi i te waikawa, ko te waikawa acetic (CH3COOH) te waikawa hydrochloric (HCl rānei).
Tauhohenga:NaOH+HCl→NaCl+H2O
Tukanga:
Ka tāpirihia mārire te waikawa ki te ranunga tauhohenga i raro i ngā tikanga whakahaere hei karo i te wera nui, hei ārai hoki i te pirau o te hydroxyethyl cellulose.
Kātahi ka whakatikatikaina te pH o te ranunga kua whakakorengia kia mau tonu ai te pH e hiahiatia ana, arā, tata ki te pH kūpapa (6-8).
5. Te horoi
Whai muri i te whakakorenga, me horoi te hua hei tango i ngā tote me ētahi atu hua taha. He mea nui tēnei taahiraa hei whiwhi i te hydroxyethyl cellulose parakore.
Tukanga:
Ka waimeha te ranunga tauhohenga ki te wai, kātahi ka wehea te hydroxyethyl cellulose mā te tātari, te centrifugation rānei.
Ka horoia tonutia te hydroxyethyl cellulose kua wehea ki te wai whakakore iona hei tango i ngā tote me ngā poke toenga. Ka haere tonu te tukanga horoi kia tae rā anō te wai horoi ki tētahi kawe hiko kua tohua, e tohu ana kua tangohia ngā poke wairewa.
6. Te whakamaroke
Ko te whakamaroke te taahiraa whakamutunga o te whakarite i te hydroxyethyl cellulose. Mā tēnei taahiraa ka tangohia te wai nui, ka puta he paura maroke e tika ana mō ngā momo whakamahinga.
Tukanga:
Ka horahia te hydroxyethyl cellulose kua horoia ki runga i ngā paepae whakamaroke, ka haria rānei mā roto i tētahi kauhanga whakamaroke. Ka āta whakahaeretia te pāmahana whakamaroke kia kore ai e heke te pāmahana, mai i te 50-80°C te nuinga.
Heoi anō, ka taea te whakamahi i te whakamaroke rehu hei whakamaroke tere, hei whakamaroke whai hua hoki. I roto i te whakamaroke rehu, ka whakakorikoria te wai hydroxyethyl cellulose kia rite ki ngā pata iti, ka whakamarokehia ki te hau wera, ka hua ake he paura iti.
Kātahi ka mirahia te hua maroke ki te rahi e hiahiatia ana, kātahi ka tākaihia mō te penapena me te tohatoha.
Te Mana Kounga me ngā Taupānga
I roto i te tukanga whakarite, ka whakatinanahia ngā mahi whakahaere kounga pakari hei whakarite i te ōritetanga me te kounga o te hydroxyethyl cellulose. Ka aro turukihia tonutia ngā tawhā matua pēnei i te matotoru, te nui o te whakakapinga, te nui o te makuku, me te rahi o te matūriki.
Ngā tono:
Rongoā: Whakamahia hei whakamātotoru, hei here, hei whakaū i roto i ngā whakatakotoranga pēnei i ngā papa, ngā whakatārewatanga, me ngā hinu whakahinuhinu.
Ngā mea whakapaipai: Ka whakarato i te matotoru me te kakano ki ngā hua pēnei i ngā kirīmi, ngā hinu kiri, me ngā hopi horoi makawe.
Ngā Peita me ngā Paninga: Ka mahi hei whakamātotoru me te whakarerekē i te reo o ngā peita, ka whakapai ake i ngā āhuatanga tono me te pumau o ngā peita.
Ahumahi Kai: He mea whakamātotoru, he mea whakaū, he mea whakaemulsifier hoki i roto i ngā momo hua kai.
Ko te whakarite i te hydroxyethyl cellulose he raupapa o ngā tukanga matū me ngā tukanga miihini kua tautuhia pai e aro ana ki te whakarerekē i te cellulose hei whakauru i ngā rōpū hydroxyethyl. He mea nui ia taahiraa, mai i te purenga cellulose ki te whakamaroke, hei whakatau i te kounga me te mahi o te hua whakamutunga. Nā ngā āhuatanga maha o te Hydroxyethyl cellulose, he mea tino nui tēnei hei whakauru i roto i ngā ahumahi maha, e whakaatu ana i te hiranga o ngā mahi hanga tika hei whakatutuki i ngā whakaritenga motuhake o ngā tono rerekē.
Wā tuku: Mei-28-2024