Kusintha kwa cellulose etherification

01. Kuyambitsa cellulose

Cellulose ndi macromolecular polysaccharide yopangidwa ndi shuga. Insoluble m'madzi ndi organic solvents. Ndilo gawo lalikulu la khoma la cell cell, komanso ndi polysaccharide yofalitsidwa kwambiri komanso yochuluka kwambiri m'chilengedwe.

Cellulose ndiye chinthu chongowonjezedwanso chochulukirapo padziko lapansi, komanso ndi polima wachilengedwe wokhala ndi kuchuluka kwakukulu. Ili ndi maubwino ongowonjezedwanso, osawonongeka kwathunthu, komanso kuyanjana kwabwino.

02. Zifukwa zosinthira mapadi

Ma cellulose macromolecules ali ndi magulu ambiri -OH. Chifukwa cha mphamvu ya ma hydrogen bond, mphamvu yapakati pa macromolecules imakhala yayikulu, zomwe zimapangitsa kuti enthalpy isungunuke △H; Komano, pali mphete mu cellulose macromolecules. Monga momwe zimakhalira, kulimba kwa unyolo wa maselo ndikokulirapo, zomwe zingayambitse kusintha kwa entropy kocheperako ΔS. Zifukwa ziwirizi zimapangitsa kutentha kwa cellulose yosungunuka (= △H / △S ) kudzakhala kokwera, ndipo kutentha kwa cellulose kumakhala kochepa. Choncho, pamene cellulose imatenthedwa ndi kutentha kwina, ulusi udzawonekera Chodabwitsa chakuti cellulose yawonongeka isanayambe kusungunuka, choncho, kukonza zinthu za cellulose sikungathe kutengera njira yoyamba kusungunuka ndiyeno kuumba.

03. Kufunika kwa kusintha kwa cellulose

Chifukwa cha kuchepa kwapang'onopang'ono kwa zinthu zakuthambo komanso mavuto azachilengedwe omwe akuchulukirachulukira chifukwa cha zinyalala zopangidwa ndi nsalu za fiber, kupanga ndi kugwiritsa ntchito zinthu zachilengedwe zongowonjezwdwanso zakhala malo amodzi omwe anthu amawaganizira kwambiri. Cellulose ndiye chiwongola dzanja chochuluka kwambiri m'chilengedwe. Ili ndi zinthu zabwino kwambiri monga hygroscopicity yabwino, antistatic, mphamvu yamphamvu ya mpweya, utoto wabwino, kuvala bwino, kukonza nsalu kosavuta, komanso kuwonongeka kwachilengedwe. Lili ndi makhalidwe omwe sangafanane ndi ulusi wamankhwala. .

Maselo a cellulose ali ndi magulu ambiri a hydroxyl, omwe ndi osavuta kupanga ma intramolecular ndi intermolecular hydrogen bonds, ndipo amawola pa kutentha kwakukulu popanda kusungunuka. Komabe, mapadi amakhala ndi reactivity yabwino, ndipo chomangira chake cha haidrojeni chikhoza kuwonongedwa ndi kusintha kwa mankhwala kapena kumezanitsa, zomwe zimatha kuchepetsa kusungunuka kwake. Monga zinthu zosiyanasiyana zamafakitale, zimagwiritsidwa ntchito kwambiri muzovala, kupatukana kwa membrane, mapulasitiki, fodya ndi zokutira.

04. Kusintha kwa cellulose etherification

Cellulose ether ndi mtundu wa cellulose yochokera ku cellulose yomwe imapezeka mwa kusintha kwa etherification kwa cellulose. Amagwiritsidwa ntchito kwambiri chifukwa cha kukhuthala kwake, emulsification, kuyimitsidwa, kupanga filimu, colloid yoteteza, kusunga chinyezi, ndi zomatira. Amagwiritsidwa ntchito muzakudya, mankhwala, kupanga mapepala, utoto, zomangira, etc.

Etherification wa cellulose ndi mndandanda wa zotumphukira zomwe zimapangidwa ndi momwe magulu a hydroxyl amachitira pa cellulose cell chain ndi alkylating agents pansi pamikhalidwe yamchere. Kugwiritsa ntchito magulu a hydroxyl kumachepetsa kuchuluka kwa ma intermolecular hydrogen zomangira kuchepetsa mphamvu za intermolecular, potero Kupititsa patsogolo kukhazikika kwamafuta a cellulose, kukonza magwiridwe antchito azinthu, komanso kuchepetsa kusungunuka kwa cellulose.

Zitsanzo za zotsatira za etherification kusinthidwa pa ntchito zina za cellulose:

Pogwiritsa ntchito thonje woyengedwa ngati zopangira zopangira, ofufuzawo adagwiritsa ntchito njira imodzi yopangira etherification kuti akonzekere carboxymethyl hydroxypropyl cellulose ether complex reaction, high viscosity, kukana bwino kwa asidi ndi kukana mchere kudzera mu alkalization ndi etherification reaction. Pogwiritsa ntchito gawo limodzi la etherification, cellulose yopangidwa ndi carboxymethyl hydroxypropyl imakhala ndi kukana kwa mchere wabwino, kukana kwa asidi komanso kusungunuka. Posintha kuchuluka kwa propylene oxide ndi chloroacetic acid, zinthu zomwe zili ndi carboxymethyl ndi hydroxypropyl zosiyanasiyana zimatha kukonzedwa. Zotsatira zoyeserera zikuwonetsa kuti cellulose ya carboxymethyl hydroxypropyl yopangidwa ndi njira imodzi imakhala ndi kadulidwe kakang'ono kakupanga, kugwiritsa ntchito zosungunulira zochepa, ndipo mankhwalawa amakana kwambiri mchere wonyezimira komanso wa divalent komanso kukana kwa asidi wabwino.

05. Chiyembekezo cha kusintha kwa cellulose etherification

Cellulose ndi chinthu chofunikira chamankhwala komanso mankhwala omwe ali ndi zinthu zambiri, zobiriwira komanso zachilengedwe, komanso zongowonjezwdwa. Zomwe zimachokera ku kusinthidwa kwa cellulose etherification zimakhala ndi ntchito zabwino kwambiri, zogwiritsidwa ntchito zosiyanasiyana komanso zotsatira zabwino kwambiri zogwiritsira ntchito, ndikukwaniritsa zosowa za chuma cha dziko lonse. Ndipo zosowa za chitukuko cha anthu, ndi kupita patsogolo kwaukadaulo kopitilira patsogolo komanso kukwaniritsidwa kwa malonda m'tsogolomu, ngati zida zopangira ndi njira zopangira zotumphukira za cellulose zitha kukhala zamakampani, zidzagwiritsidwa ntchito mokwanira ndikuzindikira ntchito zambiri. . Mtengo