Ikhiqizwa kanjani i-Hydroxypropyl Methylcellulose (HPMC)?

IHydroxypropyl methylcellulose (HPMC) i-semi-synthetic water-soluble polymer evame ukusetshenziswa ezimbonini zemithi, zokwakha nezokudla, phakathi kokunye. Itholakala ku-cellulose, i-polymer yemvelo etholakala ezindongeni zamaseli ezitshalo. Okulandelayo ukubuka kabanzi kwenqubo yokukhiqiza ye-HPMC:

Umthombo we-cellulose:

Impahla yokusetshenziswa eyinhloko yokukhiqizwa kwe-HPMC i-cellulose, engatholakala ku-pulp yezinkuni noma ama-cotton linters. I-Wood pulp iwumthombo ovamile ngoba inala futhi iyabiza.

Ukwelashwa kwe-alkali:

I-Cellulose iphathwa nge-alkali (imvamisa i-sodium hydroxide) ukususa ukungcola kanye ne-hemicellulose. Le nqubo, ebizwa ngokuthi i-mercerization, ikhiqiza i-cellulose ehlanzekile.

I-Etherification:

I-cellulose ehlanzekile ibe isingaphansi kwe-etherification, ukusabela kwamakhemikhali okwethula amaqembu e-ether kumgogodla we-cellulose. Ku-HPMC, womabili amaqembu e-hydroxypropyl kanye ne-methyl ethulwa ku-molecule ye-cellulose.

I-Hydroxypropylation:

I-Propylene oxide isetshenziselwa ukwethula amaqembu e-hydroxypropyl ku-cellulose. Lesi sinyathelo sihilela ukusabela kwe-propylene oxide ne-cellulose phambi kwe-catalyst.

I-Methylation:

Amaqembu e-methyl afakwa ku-cellulose ye-hydroxypropylated kusetshenziswa i-methyl chloride noma i-dimethyl sulfate. Lesi sinyathelo sibizwa nge-methylation.

Ukungathathi hlangothi nokugeza:

Ngemuva kokusabela kwe-etherification, umkhiqizo uyekwa ukuze kukhishwe noma yisiphi isisekelo esisele. I-HPMC ewumphumela ibe-ke igezwa ukuze kukhishwe imikhiqizo engasasebenzi kanye namakhemikhali angaphenduliwe.

ukomisa:

Isinyathelo sokugcina sibandakanya ukomisa i-HPMC ukuze kukhishwe amanzi amaningi futhi uthole umkhiqizo owufunayo ngempushana noma ifomu eliyimbudumbudu.

Kubalulekile ukuqaphela ukuthi imininingwane ethile yenqubo yokukhiqiza ingase yehluke phakathi kwabakhiqizi, futhi bangasebenzisa izimo ezihlukene, ama-catalyst, nama-reagents ukufeza ukusebenza okufunayo kwe-HPMC. Ukwengeza, izinyathelo zokulawula ikhwalithi zisetshenziswa kuyo yonke inqubo yokukhiqiza ukuze kuqinisekiswe ukuhambisana nokuhlanzeka komkhiqizo wokugcina.