1. Te hanganga me te kaupapa whakarite o te cellulose ether
E whakaatu ana te Pikitia 1 i te hanganga noa o ngā etera cellulose. Ka whakakapia e ia waeine bD-anhydroglucose (te waeine tāruarua o te cellulose) tētahi rōpū i ngā tūranga C (2), C (3) me C (6), arā, ka taea te whai rōpū etera tae atu ki te toru. Nā ngā here hauwai i roto i te mekameka me te mekameka i waenga i ngā mekameka ongā macromolecules cellulose, he uaua ki te rewa i roto i te wai, me te nuinga o ngā whakarewa waro. Mā te whakaurunga o ngā rōpū etera mā te whakaetera ka whakangaro i ngā here hauwai ā-roto me ā-waenga ngota ngota, ka whakapai ake i tōna hiranga wai, ā, ka tino whakapai ake i tōna wairewatanga i roto i te wai.
Ko ngā whakakapinga etherified noa he rōpū alkoxy taumaha ngota iti (1 ki te 4 ngota waro) he rōpū hydroxyalkyl rānei, ka taea te whakakapi i ēnei ki ētahi atu rōpū mahi pēnei i te carboxyl, hydroxyl, amino rānei. Tērā pea he momo rerekē ngā whakakapinga. I te mekameka macromolecular cellulose, ka whakakapia ngā rōpū hydroxyl i ngā tūranga C(2), C(3) me C(6) o ia waeine glucose ki ngā ōwehenga rerekē. Ko te tikanga, kāore he hanganga matū tuturu o te cellulose ether, engari ko ngā hua kua whakakapia katoatia e te momo rōpū kotahi (kua whakakapia ngā rōpū hydroxyl e toru). Ka taea anake te whakamahi i ēnei hua mō te tātari taiwhanga me te rangahau, ā, kāore he uara arumoni.
(a) Te hanganga whānui o ngā waeine anhydroglucose e rua o te mekameka ngota cellulose ether, R1~R6=H, he whakakapinga waro rānei;
(b) He wāhanga mekameka ngota o te carboxymethylte hauwaitoiretiri pūtau, ko te nekehanga o te whakakapinga o te carboxymethyl he 0.5, ko te nekehanga o te whakakapinga o te hydroxyethyl he 2.0, ā, ko te nekehanga o te whakakapinga o te molar he 3.0. Ko tēnei hanganga e tohu ana i te taumata whakakapinga toharite o ngā rōpū etherified, engari he matapōkere ngā whakakapinga.
Mō ia whakakapinga, ko te nui katoa o te etherification e whakaatuhia ana e te uara DS o te whakakapinga. Ko te whānuitanga o te DS he 0~3, he rite ki te maha toharite o ngā rōpū hydroxyl kua whakakapia e ngā rōpū etherification i runga i ia waeine anhydroglucose.
Mō ngā etera hydroxyalkyl cellulose, ka tīmata te tauhohenga whakakapinga i te etherification mai i ngā rōpū hydroxyl kore utu hou, ā, ka taea te ine i te nui o te whakakapinga mā te uara MS, arā, te nui o te molar o te whakakapinga. E tohu ana i te maha toharite o ngā mole o te matū etherifying tauhohenga i tāpirihia ki ia wae anhydroglucose. Ko te matū tauhohenga noa ko te ethylene oxide, ā, he matū hydroxyethyl kei roto i te hua. I te Pikitia 1, ko te uara MS o te hua ko te 3.0.
I roto i te ariā, kāore he rohe mōrahi mō te uara MS. Mena ka mōhiotia te uara DS o te tohu whakakapinga i runga i ia rōpū mowhiti huka, ko te roa mekameka toharite o te mekameka taha etera. Ka whakamahia hoki e ētahi kaihanga te wāhanga papatipu (wt%) o ngā rōpū etera rerekē (pēnei i te -OCH3, i te -OC2H4OH rānei) hei tohu i te taumata whakakapinga me te tohu hei utu mō ngā uara DS me MS. Ka taea te huri i te wāhanga papatipu o ia rōpū me tōna uara DS, MS rānei mā te tatau ngāwari.
Ko te nuinga o ngā etera cellulose he pūmua wairewa-wai, ā, ko ētahi he wairewa-wāhanga ki ngā whakarewa waro. Ko ngā āhuatanga o te etera cellulose he tino whai hua, he iti te utu, he ngāwari te tukatuka, he iti te paitini me te whānuitanga o ngā momo, ā, kei te whānui tonu te tono me ngā mara tono. Hei kaihoko āwhina, he nui te kaha tono o te etera cellulose i roto i ngā momo mara ahumahi. Ka taea te tiki mā te MS/DS.
E ai ki te hanganga matū o ngā whakakapinga, ka whakarōpūtia ngā etera cellulose ki ngā etera anionic, cationic me te nonionic. Ka taea te wehewehe i ngā etera nonionic ki ngā hua wairewa-wai me ngā hua wairewa-hinu.
Kei te wāhanga o runga o te Ripanga 1 ngā hua kua ahumahihia. Kei te wāhanga o raro o te Ripanga 1 ētahi rōpū whakapūngao e mōhiotia ana, kāore anō kia waiho hei hua arumoni nui.
Ka taea te whakaingoa i te raupapa whakarāpopototanga o ngā whakakapinga etera whakauru kia rite ki te raupapa pīpāpā, ki te taumata rānei o te DS (MS), hei tauira, mō te 2-hydroxyethyl methylcellulose, ko te whakarāpopototanga ko HEMC, ā, ka taea hoki te tuhi hei MHEC hei whakanui i te whakakapinga methyl.
Kāore e ngāwari te uru atu o ngā rōpū hydroxyl i runga i te cellulose mā ngā kaihoko etherification, ā, ko te tukanga etherification ka mahia i raro i ngā āhuatanga kawakore, mā te whakamahi i tētahi kukū wai NaOH. Ka hangaia tuatahitia te cellulose hei cellulose kawakore pupuhi me te wai NaOH, kātahi ka pāngia e te tauhohenga etherification me te kaihoko etherification. I te wā e hanga ana, e whakarite ana hoki i ngā ethers whakaranu, me whakamahi ngā momo kaihoko etherification rerekē i te wā kotahi, me whakahaere rānei te etherification i ia taahiraa mā te whāngai wā poto (mēnā e tika ana). E whā ngā momo tauhohenga i roto i te etherification o te cellulose, e whakarāpopototia ana e te tauira tauhohenga (ka whakakapia te cellulosic ki te Cell-OH) penei:
E whakaahua ana te whārite (1) i te tauhohenga etherification Williamson. Ko te RX he ester waikawa inorganic, ā, ko te X he halogen Br, Cl, he ester waikawa whanariki rānei. Ko te chloride R-Cl e whakamahia whānuitia ana i roto i te ahumahi, hei tauira, te methyl chloride, te ethyl chloride, te waikawa chloroacetic rānei. He nui te nui o te turanga ka pau i roto i ēnei tauhohenga. Ko ngā hua cellulose ether ahumahi ko te methyl cellulose, te ethyl cellulose me te carboxymethyl cellulose, ko ngā hua o te tauhohenga etherification Williamson.
Ko te tātai tauhohenga (2) ko te tauhohenga tāpiri o ngā epoxide kua whakakorikoria e te turanga (pērā i te R=H, CH3, C2H5 rānei) me ngā rōpū hydroxyl ki runga i ngā ngota cellulose me te kore e pau te turanga. Tērā pea ka haere tonu tēnei tauhohenga i te mea ka puta ake ngā rōpū hydroxyl hou i te wā o te tauhohenga, ka arahi ki te hanganga o ngā mekameka taha o te oligoalkylethylene oxide: Ka puta he aminoethyl ether i tētahi tauhohenga rite ki te 1-aziridine (aziridine): Cell-O-CH2-CH2-NH2. Ko ngā hua pēnei i te hydroxyethyl cellulose, te hydroxypropyl cellulose me te hydroxybutyl cellulose he hua katoa o te epoxidation kua whakakorikoria e te turanga.
Ko te tātai tauhohenga (3) ko te tauhohenga i waenga i te Cell-OH me ngā matū waro kei roto ngā hononga takirua hohe i roto i te reo kawakore, ko Y he rōpū tango-irahiko, pērā i te CN, CONH2, SO3-Na+ rānei. I ēnei rā, kāore i te tino whakamahia tēnei momo tauhohenga i roto i ngā ahumahi.
Kāore anō kia whakawhanakehia te tauira tauhohenga (4), te whakaeteretanga me te diazoalkane.
- Ngā momo etera cellulose
Ka taea te whakamahi i te monoether, i te ether whakauru rānei, ā, he rerekē ōna āhuatanga. He iti te whakakapinga o ngā rōpū hydrophilic i runga i te macromolecule cellulose, pērā i ngā rōpū hydroxyethyl, ka taea te whakawhiwhi i te hua ki tētahi taumata wairewatanga wai, engari mō ngā rōpū hydrophobic, pērā i te methyl, ethyl, me ētahi atu, ko te whakakapinga ngawari anake ka taea te whakawhiwhi i te hua ki tētahi taumata wairewatanga wai, ā, ko te hua iti te whakakapinga ka pupuhi noa i roto i te wai, ka taea rānei te whakarewa i roto i te otinga alkali waimeha. Mā te rangahau hohonu mō ngā āhuatanga o ngā cellulose ether, ka whanake tonu, ka whakaputahia hoki ngā cellulose ether hou me ō rātou mara tono, ā, ko te kaha nui rawa atu ko te mākete tono whānui me te whakapai tonu.
Ko te ture whānui o te awe o ngā rōpū i roto i ngā etera whakauru ki ngā āhuatanga wairewa ko:
1) Whakanuia te ihirangi o ngā rōpū hydrophobic i roto i te hua hei whakanui ake i te hydrophobicity o te ether me te whakaheke i te ira gel;
2) Whakanuia te ihirangi o ngā rōpū hydrophilic (pērā i ngā rōpū hydroxyethyl) hei whakanui ake i tōna ira gel;
3) He motuhake te rōpū hydroxypropyl, ā, mā te hydroxypropylation tika ka taea te whakaheke i te pāmahana tiēre o te hua, ā, ka piki anō te pāmahana tiēre o te hua hydroxypropylated reo, engari mā te taumata teitei o te whakakapinga ka whakaiti i tōna ira tiēre; Ko te take he hanganga mekameka waro motuhake o te rōpū hydroxypropyl, he iti te taumata o te hydroxypropylation, he ngoikore ngā here hauwai i roto, i waenganui hoki i ngā ngota i roto i te macromolecule cellulose, me ngā rōpū hydroxyl hydrophilic i runga i ngā mekameka peka. Ko te wai te mea matua. I tētahi atu taha, ki te teitei te whakakapinga, ka polymerization te rōpū taha, ka heke te ihirangi whanaunga o te rōpū hydroxyl, ka piki ake te hydrophobicity, ā, ka heke te wairewa.
Te whakaputa me te rangahau ote etera celluloseHe roa te hītori o tēnei. I te tau 1905, i tuatahi te pūrongo a Suida mō te whakaetere o te cellulose, i whakametilahia ki te dimethyl sulfate. I patenthia ngā nonionic alkyl ethers e Lilienfeld (1912), Dreyfus (1914) me Leuchs (1920) mō ngā cellulose ethers wairewa-wai, wairewa-hinu rānei. I hangaia e Buchler rāua ko Gomberg te benzyl cellulose i te tau 1921, i hangaia tuatahitia te carboxymethyl cellulose e Jansen i te tau 1918, ā, i hangaia e Hubert te hydroxyethyl cellulose i te tau 1920. I ngā tau tōmua o te tekau tau atu i 1920, i hokohokohia te carboxymethylcellulose i Tiamana. Mai i te tau 1937 ki te 1938, i whakatinanahia te hanga ahumahi o te MC me te HEC i te United States. I tīmata a Sweden ki te hanga i te EHEC wairewa-wai i te tau 1945. I muri i te tau 1945, i tere te horapa o te hanga o te cellulose ether i Uropi ki te Hauāuru, te United States me Hapani. I te mutunga o te tau 1957, i tīmata te hanga o te China CMC i te Shanghai Celluloid Factory. I te tau 2004, ko te kaha whakaputa o tōku whenua ka eke ki te 30,000 tāne o te ionic ether me te 10,000 tāne o te non-ionic ether. I te tau 2007, ka eke ki te 100,000 tāne o te ionic ether me te 40,000 tāne o te non-ionic ether. Kei te puta tonu mai hoki ngā kamupene hangarau tahi i te kāinga me tāwāhi, ā, kei te piki haere tonu te kaha whakaputa cellulose ether me te taumata hangarau o Haina.
I ngā tau tata nei, he maha ngā monoether cellulose me ngā ether whakauru me ngā uara DS rerekē, ngā matotoru, te parakore me ngā āhuatanga rheological rerekē kua whanakehia tonutia. I tēnei wā, ko te arotahi o te whanaketanga i roto i te mara o ngā ether cellulose ko te whakamahi i te hangarau whakaputa matatau, te hangarau whakarite hou, ngā taputapu hou, ngā hua hou, ngā hua kounga teitei, me ngā hua pūnaha me rangahau hangarau.
Wā tuku: 28 Paenga-whāwhā 2024