Preparation And Properties Of PA6/kaolin Nanocomposites

PA6/kaolin nanocomposites usually combine the advantages of the polymer materials and the inorganic materials. But it is not only the simple addition of their properties. The nanocomposites exhibited more excellent properties. In order to increase using of PA6, and make it to high property and function development, the scientists developed a series of PA6 composites with a lot of depth experiments. But still have more shortages about difficult of preparation, complex methods and the low performance filler. To overcome these questions, we developed a new kind of PA6/kaolin nanocomposites. In the present investigation, nano-kaolin and PA6 were used to prepare PA6/kaolin nanocomposties by melt intercalation. Besides study on mechanical properties, we investigated its rheological behavior, melt and crystallization behavior.1. Preparation and characterization of PA6/kaolin nanocomposites:The PA6/kaolin nanocomposites were prepared by melt intercalation of nano-kaolin and PA6 in twin screw extruder. The PA6 and PA6/kaolin nanocomposites were characterized by Fourier transform IR(FTIR)spectroscopy; The morphological structure of nanocomposites was characterize by wide angle X-ray diffraction(WAXD) and scanned electron microscope(SEM); After add to nano-kaolin, It is indicated the strength and tenacity of PA6/kaolin nanocomposites were increased together.2. Investigation on the rheological behaviors of PA6/kaolin nanocomposites:The experimental results showed that both PA6 and PA6/kaolin nanocomposites were pseudoplastic and exhibited shear-thinning behavior. At a constant shearing rate , there was a similar influence of kalin loading on the shearing stress and apparent viscosity. The reduction of the viscous activation energy with the increment of shearing stress indicated that nanocomosites can be processed over a wider temperature at a constant shearing stress.3. Investigation on the melt and crystallization behaviors of PA6/kaolin nanocomposites:It is found that although kaolin acts as the nucleating agent of the PA6 in the systems, it changes theγcrystalline form toαform of PA6 matrix, which is different with PA6/montmorillonite nanocomposites reported in literatures. The melt and crystallization behaviors of nanocomposites were also investigated, and calculated its equilibrium melting temperature. The crystallization kinetics of PA6 and its nanocomposites were analysized using the classical crystallization kinetics equation. It was demonstrated the Avrami equation was suitable to describe the isothermal crystallization of PA6 and its nanocomposites. The Ozawa equation and the Avrami equation modified by Jeziorny were not suitable to described the nonisothermal crystallization kinetics, but the Mo's metheod described well. Some important parameters for the crystallization kinetics were obtained. Additionally, the activation energy of nonisothermal crystallization for nanocompotites were calculated from Hoffmann -Lauritzen theory.