Different processing methods such as magnetical stirring．high-speed emulsifying and homogenizing and ball milling

were used to homogenously disperse the clay agglomerates and facilitate their exfoliation in epoxy/clay nanocomposites．The mechanical properties and effect of external shearing force on the exfoliation of organic clay modified with organic amine

quaternary ammonium salts and the combination of quatemary ammonium salts and meta-xylylenedianfine (MXDA) were investigated It was found that

for the general stirring

only partially exfaliated stmcture for the small clay particles or the external layers of large clay agglomerates were obtained While the fine exfoliation for the external and central layers can be easily achieved by exerting vigorous shearing force

and the catalytic role of acid primary alkylammonium is not the key influencing the exfoliation of clay in epoxy matrix．The impact strength and flexural strength of epoxy/clay nanocomposites can be dramatically improved

which was about 50％ and 8％ higher that

those of the pristine epoxy．respectively．The degree of exfoiiation of clay particles will be substantially determined by the pulverization of the clay agglomerates The smaller the size of clay particles

the better the dispersion and exfoliation of clay layers ale

and a simultaneous outward shift of the extcrnal and central layers occurs．