Structure and mechanical properties of newly modified clay/epoxy nanocomposites prepared by ball milling

A novel kind of organic montmorillonite (MMT II), modified with the combination of dodecyl benzyl dimethyl ammonium chloride (DBDA) and meta-xylylenediamine (MXDA), was prepared by a newly designed modification method, and finely exfoliated MMT II/epoxy nanocomposites were achieved by the aid of shearing force of ball milling. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structure of MMT II and the corresponding nanocomposites. The mechanical properties were tested. The results show that large agglomerates of MMT II can not be homogeneously dispersed by general stirring, which only induces an intercalated or partially exfoliated structure of MMT II in epoxy matrix at most. Whereas the exfoliation of the retained intercalation structure or agglomerates can be promoted by external shearing force of ball milling, which induces homogeneously dispersed nano-sheets of MMT II and enhances mechanical properties. Impact strength can be increased up from 32.1 kJ/m² to 48.1 kJ/m², which is about 50% higher than that of pristine matrix, and the flexural strength can also be increased by about 8%.