(A) study on the preparation and properties of polyamide66/clay nanocomposites via melt intercalation

Abstract

Polyamide66(PA66) is a kind of important engineering plastic. Despite the fact that polyamide6 and polyamidel2/clay nanocomposites have been investigated, there were few studies on PA66/clay nanocomposites. Inspired by epoxide compound as the partially cross-linked agent of polyamide, we intended to prepare the co-intercalation clay which absorbs epoxide compound between the silicate layers. In this thesis, a new type of organophilic montmorillonites, co-treated by by methyl tallow bis-2-hydroxyethyl quaternary ammonium and epoxy resin (which can form a strong interaction with polyamide66 matrix) were prepared and applied in the preparing PA66/Clay Nanocomposites(PA66CN) via melt compounding method. To study the effect of epoxy resin in PA66CN, three different types of organic clay were used; CL-30B-E00, CL30B-E12, and CL30B-E23. The effects of the organoclays on the properties of the nanocomposites such as the morphology, dynamic mechanical properties, crystal structure and crystallization behavior, glass transition temperature, thermal stability, and tensile properties were investigated and analyzed. In this nanocomposite system, most of the silicate layers were exfoliated to individual layers or some thin stacks containing a few layers. PA66CX-E00 and PA66CXE12 had nearly exfoliated structures in agreement with the SAXS results, while PA66CX-E23 revealed a mixture of intercalated and exfoliated structures. The elastic storage modulus(E) of PA66 nanocomposites was higher than the neat PA66 in the whole range of temperature tested. On the other hand, the magnitude of the loss tangent peak in a or R transition region was decreased gradually with an increase in the clay loading. Multiple melting behavior in PA66 was also observed. Glass transition temperature changed little with clay loading. Thermal stability was more or less decreased with an increasing inorganic content. Young``s modulus and Tensile strength were enhanced by introducing organoclay. Among thre...