Nanocomposites based on ethylene vinyl acetate (EVA) and montmorillonite (MMT) were prepared using melt mixing of the two components and an intercalation agent hexadecyl trimethyl ammonium bromide(CTAB).The struc ture and properties of EVA/clay nanoco mposites were characterized by XRD,TGA,Molau and mechanical properties tests.The results showed that EVA could be intercalated into the galleries of layered sil icates in these samples,and the distance between layers of MMT in the EVA matrix was 4.09 nm.Interface adhesion between the components in the EVA/MMT (95/5) nan ocomposites was improved because the contact area between MMT layers and EVA mat rix increased and there was a great deal of active sites on the surface of MMT l ayers,which could bind tightly with the EVA matrix.Compared with those of EVA/MM T (95/5) composites without CTAB,the tensile strength,the Young’modulus and the tear strength of EVA/MMT (95/5) nanocomposites prepared in this work increased b y about 20 2%,43 3% and 17 1%,respectively.The thermal behavior of the compos ites was examined on a thermobalance in nitrogen.For the EVA/MMT (95/5) nanocomp osites,the acceleration of EVA deacylation and the deceleration of thermal degra dation were observed.
A kind of polyurethane/organically modified montmorillonite (PU/OMMT) nanocomposite based on poly(propylene glycol), 1,4 butanediol and 4,4 diphenylmethane diisocyanate was prepared by solution intercalation technology.The results of wide angle X ray diffraction and TEM showed that the gallery distance of OMMT in the PU matrix was 3～4?nm.As the hard segment content increased,the molecular chains of PU had difficulty in diffusing into the silicate layer galleries for intercalation.Transmission electron microscopy photographs showed that OMMT layers were dispersed well into the PU matrix on the nanometer scale,and an ordered intercalation structure was obtained.Compared with those of pure PU,the tensile strength,the tear strength and the elongation at break increased by about 43%,28% and 18% for PU/OMMT(92/8),respectively.The water absorption decreased with increasing the amount of OMMT.Thermogravimetric analysis showed that the PU/OMMT nanocomposites displayed a little higher thermal resistance than that of pure PU in the second pyrolysis stage.
