高岭石的结晶有序度及其对纸张涂布粘浓度的影响

粘浓度是纸张涂布的一项重要指标,测定的变化范围从46.4—72％。用Hinckley方法测定了高岭石的结晶度指数,从0.57变化至1.40。当粘浓度>67％时,结晶度指数>1。粘浓度<67％,结晶度指数<1,有序高岭石有利于粘浓度提高。随着结构无序化,晶粒变小,晶片变薄,比表面增加,晶体边缘和角易破损,使粘浓度降低。结构无序化破坏了颗粒的均匀性,使颗粒长/厚比增加,粘浓度降低。高岭石八面体中Fe~(3+)的存在一定程度上影响了有序度。

THE CRYSTALLINITY OF KAOLINITE AND ITS EFFECT ON THE VISCOSITY CONCENTRATION OF PAPER COATING

The viscosity concentration (VC)and crystallinity of different kaolinites from 18 samples were measured, and the VC varies from 46.4% to 72% and the Hinckley indices (HI) have a range of variation from 0.57 to 1.40. It is interesting to note that HI are all greater than unity in the samples with VC>67% and HI<1 in the samples with VC<67%. It is evident that wellordered kaolinites play a major role in the increase of VC. The study shows that the crystal size decreases, the plate becomes thinner and the specific surface area increases with increasing degree of structure disorder of kaolinite. As a result, the individual edges and corners are easy to break and the VC tends to decrease.