改性剂种类对蒙脱土结构和性能的影响

为增加蒙脱土(montmorillonite,MMT)和有机物的相容性和研究插层剂种类对MMT结构和性能的影响,采用Cu,Co和Ni无机金属阳离子,十二烷基磺酸钠、十二烷基硫酸钠、α-烯烃磺酸盐和十二烷基苯磺酸钠等有机阴离子表面活性剂及十六烷基氯化吡啶、十六烷基三甲基溴化铵、十二烷基三甲基溴化铵等有机阳离子表面活性剂作为改性剂,对蒙脱土进行一次改性和二次改性,制备出一系列改性蒙脱土.研究了改性剂种类、插层方式、插层次序对插层效果的影响.X射线衍射分析表明:一次改性时,插层剂均能进入蒙脱土的层间,改性土的层间距由1.04nm增加到1.7～3.52nm;二次改性时,先阳离子后阴离子的插层顺序有利于层间距增大(4.14nm),还可利用配位作用将二次改性剂引入金属离子一次改性MMT中,使层间距增大.改性机理研究认为:阳离子改性机理为层间离子交换,而阴离子改性机理是改性剂和MMT表面形成了氢键.沉降实验表明一次改性土和二次改性土在有机溶剂中分散能力有所增强.

INFLUENCE OF MODIFIED AGENT STYLE ON STUCTURE AND PERFORMANCE OF MONTMORILLONITE

To ensure good compatibility between polymer and montmorillonite(MMT),and investigate the influence of the intercala-tion agent style on the structure and performance of MMT,a series of organophilic montmorillonite(MMT)were prepared by ion exchange between Cu,Co,Ni inorganic metal cation and/or cetylpyridinium chloride,cetyl trimethylammonium bromide,dodecyl trimethyl ammonium bromide etc.organic cationic or sodium dodecyl sulfate,sodium lauryl sulfate,alpha-olefin sulphonate,dodecyl benzene sulphonate etc.anionic surfactants as intercalation agents with the interlayer ions of MMT.The influence of modifying agent style,insertion method insert layer on the modification effect were studied.The results of X-ray diffraction show that the modified reagents are all intercalated into the layers of MMT when it was first inserted,and the spacing of MMT layers increases from 1.04 nm to values between 1.7 and 3.52 nm.When the anion-cation was used to modify MMT a second time,the optimal insertion order is to insert the cation first and then the anion.This increases the d-spacing(to 4.14 nm).The results also show that metal ions have the function of coordinating MMT modification first,and this function of coordination can be used to import the second insertion modi-fier to increase the d-spacing.According to the experimental results,the reaction mechanism for cation modification is ion exchange and for anion insertion,it is the formation of a hydrogen bond between the surface of the modifier and MMT.The results of the sedi-mentation experiment show that the organic MMT had better dispersibility.