A Novel Process Of Rapidly Delaminating Urea-Intercalated Kaolinite

Kaolinite[Al₂Si₂O₅(OH)₄]is a kind of layered silicate material.The thickness,specific surface area,brightness and structure of kaolinite particles significantly affect their dispersibility,agglomeration and rheological properties,whenever kaolinite is used as a coating,pigment paper,ceramics,rubber,refractory materials or polymers etc.Therefore, the rapid delamination of kaolinite is very important,which will result in the industrial innovation and produce good economic benefits.This work presents a combined method of sonication and acid-dipping to delaminate kaolinite rapidly.It is found that the combined treatment with sonication and acid-dipping procedure can delaminate kaolinite more effectively in a short time.And the thickness decreases to 12 nm from 40 nm for raw kaolinite.Study on the changes of functional groups and thermal decomposition behavior were investigated.The combined treatment with sonication and acid-dipping procedure caused the loss of some OH groups due to the prototropy.The TG curve shows a two-step weight loss(100～400℃and＞400℃).The initial dehydroxylation temperature also decreases to 400℃from 450℃and the total mass loss also increases to 15.8%from 11.3%.The research of factors affecting the delamination also had been carried out.The thickness of kaolinite decreases with the increase of intercalation ratio.The specific surface area also increases with the increase of sonication time and increases more on the earlier stage of sonication than later.