Study On Preparation And Foaming Properties Of Pp/pa6/ommt Nanocomposites

Polypropylene (PP) foams have excellent physical and mechanical properties, they are widely used in food, cosmetics, packaging of electronic products and the inner parts of the cars, sound and heat insulation fittings. However, the melt viscosity and melting strength of general PP were sharply decline after melting, which lead to bubble combination, gas escape and cell collapse, so that the foamability of PP is poor and difficult to be processed to foam products with good cellular structure. While, Nylon 6 possesses a serious of super properties, such as toughness, vibration resistance, high crystallization, high mechanical intension and heat resistance, high impact strength, high melting point, perfect processing properties and so on. In this article, PA6 is blended with PP to improve its melting strength and mechanical properties. For the incompatibility between PP and PA6, how to solve the compatibility of PP/PA6 blend is the critical problem to improve the blend's properties. In this article, using the homemade effective compatibilizer and nano-OMMT to enhance the compatibility of blends, therefore, the melting strength and mechanical properties can be enhanced.In this paper, the initiators of DCP and BPO were used to prepare Composite initiator firstly, and then the excellent PP-g-MAH as compatibilizer was prepare with the composite initiator. The optimization of composite formulation and process conditions were studied during the preparation of PP-g-MAH. The experimental results show that the composite initiator could effectively prepare PP-g-MAH with the high grafting rate and high melt strength. After melting blend with the homemade PP-g-MAH as compatibilizer, PP, PA6, and OMMT, the excellent performance of PP/PA6/PP-g-MAH/OMMT composites were prepared. Compared with the performance of pure PP, PP/PA6/PP-g-MAH/OMMT composites prepared under the optimization formulation, the impact strength of composite materials was increased by 41%, the tensile strength was increased by 8.4% and the melt strength by 132%.In addition, the effect of processing conditions on the properties of the PP/PA6/PP-g-MAH/OMMT composite foams such as foaming temperature, shear rate and the vibration force field were also studied in this article. The experimental results show that the optimal foaming conditions are temperature (165°C), shear speed (65rpm) and the vibration intensity (5Hz/100um). Under these conditions, the composite foams with the average diameter of about 40um, and the cell density of 3.0 x 10 cell/cm were made. All these results showed that during the processing of composite materials foams, the shear stress field with the vibration force field, help to improve the cell shape (tend to polygon), uniformization ofthe cell distribution, and increase of cell density.