1.Structure iyo mabda'a diyaarinta ether cellulose
Jaantuska 1 wuxuu muujinayaa qaabka caadiga ah ee ethers cellulose. Unug kasta oo bD-anhydroglucose (cutubka soo noqnoqda ee cellulose) wuxuu beddelaa hal koox oo ah C (2), C (3) iyo C (6), taas oo ah, waxaa jiri kara ilaa saddex kooxood oo ether ah. Sababo la xiriira silsiladda intra-silsiladda iyo isku xidhka hydrogen eemacromolecules cellulose, way adagtahay in lagu milmo biyaha iyo ku dhawaad dhammaan dareerayaasha organic. Soo bandhigida kooxaha ether-ka iyada oo loo marayo etherification waxay burburisaa curaarta hydrogen intramolecular iyo intermolecular, waxay wanaajisaa hydrophilicity, waxayna si weyn u wanaajisaa milmaheeda warbaahinta biyaha.
Beddelaadaha caadiga ah ee etherified waa kooxo alkoksy ah oo miisaankoodu yar yahay (1 ilaa 4 atomi kaarboon) ama kooxaha hydroxyalkyl, kuwaas oo markaa lagu bedeli karo kooxaha kale ee shaqeeya sida karboxyl, hydroxyl ama kooxaha amino. Ku-beddelayaashu waxay noqon karaan hal, laba ama ka badan oo kala duwan. Silsiladda makromolecular ee cellulose, kooxaha hydroxyl ee ku yaal boosaska C (2), C (3) iyo C (6) ee unug kasta oo gulukoos ayaa lagu beddelayaa qaybo kala duwan. Si adag u hadla, ether cellulose guud ahaan ma laha qaab-dhismeedka kiimikada qeexan, marka laga reebo kuwa alaabooyinka si buuxda u bedelay hal nooc oo koox ah (dhammaan saddexda kooxood ee hydroxyl waa la bedelay). Alaabooyinkan waxa kaliya oo loo isticmaali karaa falanqaynta shaybaadhka iyo cilmi-baadhista, mana laha qiimo ganacsi.
(a) Qaab dhismeedka guud ee laba unug oo anhydroglucose ah oo ah silsiladda unugyada ether cellulose, R1 ~ R6=H, ama beddelka organic;
(b) Qayb silsilad molikula ah oo karboxymethyl ahhydroxyethyl cellulose, heerka beddelka karboxymethyl waa 0.5, heerka beddelka hydroxyethyl waa 2.0, heerka beddelka molarkuna waa 3.0. Qaab dhismeedkani waxa uu ka dhigan yahay celceliska heerka beddelka ee kooxaha la kala saaray, laakiin beddelayaashu run ahaantii waa rankh.
Ku-beddele kasta, wadarta qaddarka etherification waxaa lagu muujiyey heerka beddelka qiimaha DS. Baaxadda DS waa 0 ~ 3, taas oo u dhiganta celceliska tirada kooxaha hydroxyl ee lagu beddelay kooxaha etherification ee cutub kasta oo anhydroglucose ah.
Ethers-ka hydroxyalkyl cellulose, falcelinta beddelka ayaa ka bilaabi doonta etherification kooxaha cusub ee hydroxyl lacag la'aan ah, iyo heerka beddelka waxaa lagu qiyaasi karaa qiimaha MS, taas oo ah, heerka molar ee beddelka. Waxay ka dhigan tahay celceliska tirada moles ee falceliyeyaasha etherifying ee lagu daray unug kasta oo anhydroglucose ah. Dareen-celinta caadiga ah waa ethylene oxide alaabtuna waxay leedahay beddelka hydroxyethyl. Jaantuska 1, qiimaha MS ee alaabtu waa 3.0.
Aragti ahaan, ma jiro xadka sare ee qiimaha MS. Haddii qiimaha DS ee heerka beddelka ee koox kasta oo giraanta gulukoosta la yaqaan, celceliska dhererka silsiladda dhinaca etherka Qaar ka mid ah wax soo saareyaasha ayaa sidoo kale inta badan adeegsada jajabka tirada badan (wt%) ee kooxaha etherification kala duwan (sida -OCH3 ama -OC2H4OH) si loo matalo heerka beddelka iyo shahaado beddelka DS iyo qiyamka MS. Jajabka tirada koox kasta iyo qiimaheeda DS ama MS waxa lagu beddeli karaa xisaab fudud.
Inta badan ether-ka cellulose waa polymers-ka biyaha-milmi kara, qaarna waxay sidoo kale qayb ahaan ku milmaan dareerayaasha organic. Cellulose ether waxay leedahay sifooyinka waxtarka sare leh, qiimo jaban, habayn sahlan, sun yar iyo noocyo kala duwan, iyo baahida iyo goobaha codsiga ayaa weli sii kordhaya. Sida wakiil caawiye ah, ether cellulose waxay leedahay awood codsi oo weyn dhinacyada kala duwan ee warshadaha. waxaa heli kara MS/DS.
Ether-ka Cellulose waxa loo kala saaray si waafaqsan qaab dhismeedka kiimikaad ee beddelayaasha oo loo kala qaybiyo anionic, cationic iyo ethers nonionic. Ether-ka nonionic waxa loo qaybin karaa alaab biyo-milmi leh iyo saliid-milmi.
Alaabooyinka la warshadeeyay waxay ku taxan yihiin qaybta sare ee Shaxda 1. Qaybta hoose ee Shaxda 1 waxay liis garaysaa qaar ka mid ah kooxaha etherification ee la yaqaan, kuwaas oo aan weli noqon alaab ganacsi oo muhiim ah.
Amarka soo gaabinta ee beddelka ether-ka isku dhafan waxaa lagu magacaabi karaa iyadoo loo eegayo habka alifbeetada ama heerka DS (MS), tusaale ahaan, 2-hydroxyethyl methylcellulose, soo gaabinta waa HEMC, waxaana sidoo kale loo qori karaa sida MHEC muuji beddelka methyl.
Kooxaha hydroxyl ee ku jira cellulose si sahal ah uma heli karaan wakiilada etherification, habka etherification waxaa badanaa lagu fuliyaa xaaladaha alkaline, guud ahaan iyadoo la isticmaalayo qadar gaar ah oo NaOH aqueous. Cellulose-ku waxa uu marka hore u samaysmaa alkali cellulose oo bararsan oo leh NaOH xal aqueous ah, ka dibna waxa la mariyaa falcelinta etherification ee wakiilka etherification. Inta lagu guda jiro wax soo saarka iyo diyaarinta ethers isku dhafan, noocyada kala duwan ee wakiilada etherification waa in la isticmaalaa isla waqti isku mid ah, ama etherification waa in lagu fuliyaa tallaabo tallaabo ah quudin joogto ah (haddii loo baahdo). Waxaa jira afar nooc oo falcelin ah oo ku jira etherification of cellulose, kuwaas oo lagu soo koobay qaacidada falcelinta (cellulosic waxaa lagu beddelay Cell-OH) sida soo socota:
Isla'egta (1) waxay qeexaysaa falcelinta etherification Williamson. RX waa ester aashitada inorganic, iyo X waa halogen Br, Cl ama sulfuric acid ester. Chloride R-Cl guud ahaan waxaa loo isticmaalaa warshadaha, tusaale ahaan, methyl chloride, ethyl chloride ama chloroacetic acid. Qiyaasta stoichiometric ee saldhiga ayaa la cunaa falcelintan oo kale. Alaabooyinka ether-ka cellulose ee warshadaysan ee methyl cellulose, ethyl cellulose iyo carboxymethyl cellulose waa badeecadaha falcelinta etherification Williamson.
Habka falcelinta (2) waa falcelinta dheeriga ah ee epoxides-catalyzed (sida R=H, CH3, ama C2H5) iyo kooxaha hydroxyl ee molecules cellulose iyada oo aan la isticmaalin saldhigga. Dareen-celintani waxay u badan tahay inay sii socoto maaddaama kooxo cusub oo hydroxyl ah ay soo baxaan inta lagu jiro falcelinta, taasoo horseedaysa samaynta silsiladaha dhinaca oligoalkylethylene oxide: falcelin la mid ah 1-aziridine (aziridine) waxay samayn doontaa aminoethyl ether: Cell-O-CH2-CH2-NH2 . Alaabooyinka ay ka midka yihiin hydroxyethyl cellulose, hydroxypropyl cellulose iyo hydroxybutyl cellulose waa dhammaan badeecooyinka epioxidation sal-catalyzed.
Qaaciddada falcelinta (3) waa falcelinta u dhaxaysa Cell-OH iyo xeryahooda organic ka kooban labanlaab bonds firfircoon ee dhexdhexaad ah alkaline, Y waa koox elektaroonik ah-saarid, sida CN, CONH2, ama SO3-Na+. Maanta falcelinta noocan ah marar dhif ah ayaa warshad ahaan loo isticmaalaa.
Habka falcelinta (4), etherification with diazoalkane wali lama warshadayn.
- Noocyada ethers cellulose
Ether-ka Cellulose wuxuu noqon karaa monoether ama ether isku dhafan, alaabtiisuna way ka duwan tahay. Waxaa jira kooxo hydrophilic ah oo hooseeya oo ku jira macromolecule cellulose, sida kooxaha hydroxyethyl, kuwaas oo ku siin kara badeecada heer gaar ah oo biyo ah, halka kooxaha hydrophobic, sida methyl, ethyl, iwm., kaliya beddelaad dhexdhexaad ah oo heer sare ah ayaa kara sii sheyga xoogaa biyo ah oo milmaya, iyo sheyga hoose ee la bedelay kaliya waxa uu barara biyaha ama waxa lagu milmi karaa xalalka alkali ee milan. Iyada oo si qoto dheer cilmi baaris ku saabsan sifooyinka ethers cellulose, ethers cellulose cusub iyo beerahooda codsiga si joogto ah loo horumarin doonaa oo la soo saari doonaa, iyo xoog wadista ugu weyn waa suuqa codsiga ballaaran oo joogto ah la safeeyey.
Sharciga guud ee saameynta kooxaha ethers-ka isku dhafan ee guryaha milmay waa:
1) Kordhi waxyaabaha ku jira kooxaha hydrophobic ee alaabta si ay u kordhiyaan hydrophobicity ee ether iyo hoos u dhig barta gel;
2) Kordhi waxa ku jira kooxaha hydrophilic (sida kooxaha hydroxyethyl) si ay u kordhiso dhibicdeeda gel;
3) Kooxda hydroxypropyl waa mid gaar ah, iyo hydroxypropylation saxda ah waxay hoos u dhigi kartaa heerkulka jel ee alaabta, iyo heerkulka jel ee alaabta hydroxypropylated dhexdhexaad ah ayaa mar kale kici doona, laakiin heer sare oo beddelaad ah ayaa hoos u dhigi doona dhibicdeeda gel; Sababta ayaa sabab u ah qaabka dhererka silsiladda carbon ee gaarka ah ee kooxda hydroxypropyl, heerka hoose ee hydroxypropylation, curaarta hydrogen daciifka ah ee gudaha iyo inta u dhaxaysa molecules ee macromolecule cellulose, iyo kooxaha hydrophilic hydroxyl ee silsiladaha laanta. Biyaha ayaa ugu badan. Dhanka kale, haddii beddelku sarreeyo, waxaa jiri doona polymerization kooxda dhinaca, nuxurka qaraabada ee kooxda hydroxyl ayaa hoos u dhici doonta, hydrophobicity-ku wuu kordhi doonaa, iyo milanka ayaa hoos u dhigi doona halkii.
Wax soo saarka iyo cilmi-baarista eeether celluloseleh taariikh dheer. Sannadkii 1905, Suida ayaa markii ugu horreysay sheegtay etherification of cellulose, kaas oo ahaa methylated leh dimethyl sulfate. Nonionic alkyl ethers waxaa shati u siyay Lilienfeld (1912), Dreyfus (1914) iyo Leuchs (1920) ee ethers-cellulose-ka biyo-milmi ama saliid-milmi, siday u kala horreeyaan. Buchler iyo Gomberg waxay soo saareen benzyl cellulose 1921, carboxymethyl cellulose waxaa markii ugu horeysay soo saaray Jansen 1918, Hubert wuxuu soo saaray hydroxyethyl cellulose 1920. Horraantii 1920-meeyadii, karboxymethylcellulose waxaa lagu ganacsan jiray Jarmalka. Laga soo bilaabo 1937 ilaa 1938, wax soo saarka warshadaha ee MC iyo HEC ayaa laga xaqiiqsaday Maraykanka. Iswidhan waxa ay bilaawday soosaarka EHEC ee biyaha lagu milmo sanadii 1945. Kadib 1945, wax soo saarka ether-ka cellulose ayaa si xawli ah ugu fiday Galbeedka Yurub, Maraykanka iyo Japan. Dhammaadkii 1957kii, Shiinaha CMC ayaa markii ugu horreysay la geliyay wax soo saarka warshadda Celluloid ee Shanghai. Marka la gaaro 2004, awoodda wax-soo-saarka dalkaygu waxay noqon doontaa 30,000 tan oo eter ionic ah iyo 10,000 tan oo eter-ka ionic ah. Marka la gaaro 2007, waxay gaari doontaa 100,000 tan oo eter ionic ah iyo 40,000 tan oo eter Nonionic ah. Shirkadaha tignoolajiyada wadajirka ah ee gudaha iyo dibedda ayaa sidoo kale si joogto ah u soo baxaya, iyo awoodda wax soo saarka ether-ka Shiinaha ee cellulose iyo heerka farsamada ayaa si joogto ah u soo hagaagaya.
Sanadihii la soo dhaafay, monoethers badan oo cellulose iyo ethers isku dhafan oo leh qiyam kala duwan DS, viscosities, daahirsanaanta iyo sifooyinka rheological ayaa si joogto ah loo horumariyay. Waqtigan xaadirka ah, diiradda horumarinta berrinkii ethers cellulose waa in la qaato tignoolajiyada wax soo saarka sare, tignoolajiyada diyaarinta cusub, qalab cusub, Badeecooyin cusub, alaab tayo sare leh, iyo alaabooyin nidaamsan waa in si farsamo ah loo baaro.
Waqtiga boostada: Abriil-28-2024