Preparation And Properties Of PA6/MXD6/Clay Barrier Packaging Materials

In the Packaging industry, the plastic film has the advantages of low cost, flexible, transparent, non-toxic food contact and easy to transport. Nylon films have high strength, good impact resistance, resistance to puncture ability and excellent gas barrier of organic and inorganic among them. In order to improve the uniformity of clay dispersed in nylon matrix, PA6/clay composites (named: Nano Nylon) were prepared by in-situ intercalation polymerization, and then the PA6/MXD6/clay composites film were prepared by mechanical blending and blow molding, respectively. The influences of the MXD6 and clay on the crystallization, melting behavior, mechanical properities and blocking performance of the PA6 were studied to provide the theory basis of the MXD6 nylon composites packaging materials.The study of the PA6/clay nanocomposites shows that the addition of clay increases PA6 characteristic viscosity and sticky molecular weight. XRD analysis shows that the PA6 molecular chain insert into the clay layer and making the layer spacing of clay increases greatly. Clay layer dispersing in the PA6 matrix uniformly and forming the exfoliating PA6/clay nanocomposites. DSC analysis shows PA6 exhibits the characteristics of two crystal forms of a and y for the adding of layered clay, and showing heterogeneous nucleation in the crystallization process of PA6. TG analysis shows that the thermal stability of nylon material also improved for the adding of clay. Studied on the properities of PA6/MXD6 nylon blend material shows that the MXD6 has a good compatibility of PA6. The grains of PA6 are refined after blending with the MXD6. The increase of MXD6 content is beneficial to increase the mechanical properties of PA6/MXD6 composites. The PA6/MXD6/clay blending films were prepared by blowing process. The effects of clay and MXD6 on the rheological properties, crystallization behavior, mechanical properties and barrier properties of the PA6 films were studied. The results show that, PA6 exhibits the pseudo plastic behavior when added the clay and MXD6.The addition of the clay in the blend increased its sensitivity to shear, and the addition of the MXD6 in the blend increased its sensitivity to the temperature. The tensile strength increased gradually with increasing the amount of MXD6 and the elongation at break is negatively correlated with the degree of crystallinity. The a crystal form in PA6 tends to convert into y crystal form when MXD6 and clay were added, and the barrier properties of PA6 were also improved when adding the clay and MXD6 because the y crystal form has the better barrier properties, and the barrier ability to dimethylbenzene increases greatly just adding a small amount of clays.