Morphology, thermal, and mechanical properties of polyamide 66/clay nanocomposites with epoxy-modified organoclay

Abstract

A new kind of organophilic clay, cotreated by methyl tallow bis-2-hydroxyethyl quaternary ammonium and epoxy resin into sodium montmorillonite (to form a strong interaction with polyamide 66 matrix), was prepared and used in. preparing PA66/clay nanocomposites (PA66CN) via melt-compounding method. Three different types of organic clays, CL30B-E00, CL30B-E12, and CL30B-E23, were used to study the effect of epoxy resin in PA66CN. The morphological, mechanical, and thermal properties have been studied using X-ray diffraction, transmission electron microscopy (TEM), mechanical, and thermal analysis, respectively. TEM analysis of the nanocomposites shows that most of the silicate layers were exfoliated to individual layers and to some thin stacks containing a few layers. PA66CX-E00 and PA66CX-E12 had nearly exfoliated structures in agreement with the SAXS results, while PA66CX-E23 shows a coexistence of intercalated and exfoliated structures. The storage modulus of PA66 nanocomposites was I higher than that of the neat PA66 in the whole range of tested temperature. On the other hand, the magnitude of the loss tangent peak in alpha- or beta-transition region decreased gradually with the increase in the clay loading. Multiple melting behavior in PA66 was also observed. Thermal stability more or less decreased with an increasing inorganic content. Young's modulus and tensile strength were enhanced by introducing organoclay. Among the three types of nanocomposites prepared, PA66CX-E12 showed the highest improvement in properties, while PA66CX-E23 showed properties inferior to that of PA66CX-E00 without epoxy resin. In conclusion, an optimum amount of epoxy resin is required to form the strong interaction with the amide group of PA66. (c) 2006 Wiley Periodicals, Inc.