I-sodium carboxymethyl cellulose, ebizwa ngokuba yi-carboxymethyl cellulose (CMC) luhlobo lwe-polymer fiber ether elungiswe ngokuguqulwa kweekhemikhali zeselulosi yendalo. Ubume bayo ubukhulu becala yiyunithi ye-D-glucose nge-β (1→4) Izitshixo zidityaniswe kunye.
I-CMC imhlophe okanye i-milky white fibrous powder okanye iigranules, kunye noxinano lwe-0.5-0.7 g/cm3, phantse ayinavumba, ayinancasa, kunye ne-hygroscopic. Ukusasazwa ngokulula emanzini ukwenza isisombululo se-colloidal esicacileyo, esinganyibilikiyo kwizinyibilikisi zezinto eziphilayo ezifana ne-ethanol. I-pH ye-1% yesisombululo se-aqueous yi-6.5-8.5, xa i-pH> 10 okanye i-<5, i-viscosity ye-mucilage iyancipha kakhulu, kwaye ukusebenza kuhle kakhulu xa i-pH = 7. Uzinzile kubushushu, i-viscosity inyuka ngokukhawuleza ngaphantsi kwe-20 ° C, kwaye itshintsha kancinane kwi-45 ° C. Ukufudumala kwexesha elide ngaphezu kwe-80 ° C kunokunciphisa i-colloid kwaye kunciphise kakhulu i-viscosity kunye nokusebenza. Inyibilika ngokulula emanzini kwaye isisombululo siyabonakala; izinzile kakhulu kwisisombululo se-alkaline, kodwa i-hydrolyzed ngokulula xa idibana ne-asidi, kwaye iya kudlula xa ixabiso le-pH liyi-2-3, kwaye liya kusabela ngeetyuwa zetsimbi ezininzi.
Ifomula yolwakhiwo: C6H7(OH)2OCH2COONA Ifomula yemolekyuli: C8H11O5Na
Ukusabela okuphambili kukuba: i-cellulose yendalo iqala i-alkalinization reaction kunye ne-NaOH, kunye nokongezwa kwe-chloroacetic acid, i-hydrogen kwiqela le-hydroxyl kwiyunithi ye-glucose ithatha indawo yokuphendula kunye neqela le-carboxymethyl kwi-chloroacetic acid. Inokubonwa kwifomula yesakhiwo ukuba kukho amaqela amathathu e-hydroxyl kwiyunithi nganye ye-glucose, oko kukuthi, i-C2, i-C3, kunye ne-C6 amaqela e-hydroxyl. I-hydrogen kwiqela ngalinye le-hydroxyl ithathelwa indawo yi-carboxymethyl, echazwa njengeqondo lokutshintshwa kwe-3. Iqondo lokutshintshwa kwe-CMC lichaphazela ngokuthe ngqo ukunyibilika, i-emulsification, ukuqina, ukuzinza, ukuxhathisa kwe-asidi kunye nokuxhatshazwa kwetyuwa.CMC .
Ngokuqhelekileyo kukholelwa ukuba xa i-degree of substitution ijikeleze i-0.6-0.7, ukusebenza kwe-emulsifying kungcono, kwaye ngokunyuka kweqondo lokutshintshwa, ezinye iipropati ziphuculwa ngokufanelekileyo. Xa iqondo lokutshintshwa lingaphezulu kwe-0.8, ukuxhathisa kwayo kwe-asidi kunye nokumelana netyuwa kuphuculwe kakhulu. .
Ukongezelela, kukhankanywe ngasentla ukuba kukho amaqela amathathu e-hydroxyl kwiyunithi nganye, oko kukuthi, amaqela e-hydroxyl yesibini ye-C2 kunye ne-C3 kunye neqela eliphambili le-hydroxyl ye-C6. Kwithiyori, umsebenzi weqela eliphambili le-hydroxyl mkhulu kuneqela lesibini le-hydroxyl, kodwa ngokwesiphumo se-isotopic se-C, iqela -OH kwi-C2 I-acidic ngakumbi, ngakumbi kwindawo ye-alkali enamandla, umsebenzi wayo. inamandla kune-C3 kunye ne-C6, ngoko ke ilungele ukuphendulwa kwe-substitution, ilandelwa yi-C6, kunye ne-C3 iyona buthathaka.
Enyanisweni, ukusebenza kwe-CMC akuhambelani kuphela neqondo lokutshintshwa, kodwa kunye nokufana kokusasazwa kwamaqela e-carboxymethyl kuyo yonke i-molecule ye-cellulose kunye nokutshintshwa kwamaqela e-hydroxymethyl kwiyunithi nganye nge-C2, i-C3, kunye ne-C6 molekyuli nganye. ezinxulumene nokufana. Kuba i-CMC iyikhompawundi yomgca enepolymerized kakhulu, kwaye iqela layo le-carboxymethyl line-inhomogeneous substitution kwi-molekyuli, iimolekyuli zineendlela ezahlukeneyo zokuqhelaniswa xa isisombululo sishiywe simile, kwaye ubude bemolekyuli yomgca bahlukile xa kukho amandla okucheba kwisisombululo. . I-axis inomdla wokujika kwi-flow direction, kwaye olu tyekelo luba luqilima ngokunyuka kwezinga lokucheba kude kube yilapho ulungelelwaniso lokugqibela lucwangciswe ngokupheleleyo. Olu phawu lweCMC lubizwa ngokuba yipseudoplasticity. I-pseudoplasticity ye-CMC inceda kwi-homogenization kunye nokuthuthwa kwemibhobho, kwaye ayiyi kungcamla igreasy kakhulu kubisi olulwelo, olunceda ukukhutshwa kwevumba lobisi. .
Ukusebenzisa iimveliso ze-CMC, kufuneka sibe nokuqonda kakuhle kweeparamitha eziphambili ezifana nokuzinza, i-viscosity, ukumelana ne-asidi, kunye ne-viscosity. Yazi indlela esikhetha ngayo imveliso efanelekileyo.
Iimveliso ze-CMC ezine-viscosity ephantsi zinencasa ehlaziyayo, i-viscosity ephantsi, kwaye phantse akukho mvakalelo engqindilili. Zisetyenziswa ikakhulu kwiisosi ezikhethekileyo kunye neziselo. Ulwelo lomlomo lwezempilo lukwayinto elungileyo.
Medium-viscosity iimveliso ze-CMC zisetyenziswa ikakhulu kwiziselo eziqinileyo, iziselo zeprotheyini eziqhelekileyo kunye neejusi zeziqhamo. Indlela yokukhetha ixhomekeke kwimikhwa yobuqu yeenjineli. Kuzinzo lweziselo zobisi, i-CMC ibe negalelo elikhulu.
Iimveliso ze-CMC ezinobukhulu obuphezulu zinendawo enkulu yesicelo. Xa kuthelekiswa nesitatshi, i-guar gum, i-xanthan gum kunye nezinye iimveliso, ukuzinza kwe-CMC kusabonakala ngokucacileyo, ngakumbi kwiimveliso zenyama, inzuzo yokugcina amanzi ye-CMC ibonakala ngakumbi! Phakathi kwezizinzi ezifana ne-ayisikrimu, i-CMC ikwalukhetho oluhle.
Ezona zalathisi ziphambili zokulinganisa umgangatho we-CMC sisidanga sokutshintshwa (DS) kunye nobunyulu. Ngokubanzi, iimpawu ze-CMC zahlukile ukuba i-DS yahlukile; iqondo eliphezulu lokutshintshwa, lomelele ukunyibilika, kwaye ngcono ukungafihli kunye nokuzinza kwesisombululo. Ngokutsho kweengxelo, ukucaca kwe-CMC kungcono xa i-degree of substitution i-0.7-1.2, kunye ne-viscosity yesisombululo sayo samanzi sikhulu xa ixabiso le-pH li-6-9.
Ukuze kuqinisekiswe umgangatho wayo, ukongeza ekukhetheni iarhente etherification, ezinye izinto ezichaphazela iqondo endaweni kunye nobunyulu kufuneka kwakhona ziqwalaselwe, ezifana ubudlelwane phakathi isixa alkali kunye nearhente etherification, ixesha etherification, umxholo wamanzi kwi. inkqubo, ubushushu, ixabiso leDH, isisombululo sokuNxibelela kunye netyuwa njl.
Umgangatho weemveliso ezigqityiweyo zeCMC ikakhulu zixhomekeke kwisisombululo semveliso. Ukuba isisombululo semveliso sicacile, kukho iinqununu ezimbalwa ze-gel, iifayili zamahhala, kunye namabala amnyama okungcola, ngokuqinisekileyo kuqinisekiswa ukuba umgangatho we-CMC ulungile. Ukuba isisombululo sishiywe iintsuku ezimbalwa, isisombululo asibonakali. Imhlophe okanye i-turbid, kodwa icace kakhulu, leyo yimveliso engcono!
Ixesha lokuposa: Dec-14-2022