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The clay-reinforced epoxy nanocomposite was prepared by the polymerization method. The effect of clay addition on the mechanical properties of epoxy/clay nanocomposites was studied through tensile, flexural, impact strength, and fracture toughness tests. The morphology and tribology behavior of epoxy/clay nanocomposites were determined by X-ray diffraction (XRD) and wear test, respectively. The wear test was performed to determine the specific abrasion of the nanocomposites. In addition, the water absorption characteristic of the nanocomposites was also investigated in this study. XRD analysis indicated that the exfoliation structure was observed in the epoxy nanocomposites with 3 wt% of clay, while the intercalated structure was shown at 6 wt% of clay. It was found that the addition of clay up to 3 wt% increased the tensile strength, flexural strength, impact strength, and the fracture toughness. On the contrary, the presence of above 3 wt% of clay produced a reverse effect. It could be concluded that the best properties in mechanical, wear resistance, and water resistance were obtained for the epoxy nanocomposites containing 3 wt% of clay.

The water absorption behavior of different types of organophilic montmorillonite (OMMT)-filled polyamide 6/polypropylene nanocomposites with and without compatibilizers (maleated PP or PP-g-MA and maleated styreneethylene/butylene-styrene or SEBS-g-MA) was evaluated. Four different types of OMMT, i.e., dodecylamine-modified MMT (D-MMT), 12 aminolauric acid-modified MMT (A-MMT), stearylamine-modified MMT (S-MMT), and commercial organo-MMT (C-MMT) were used as reinforcement. The water absorption response of the nanocomposites was studied and analyzed by tensile test and morphology assessment by scanning electron microscopy (SEM). The kinetics of water absorption of the nanocomposites conforms to Fick's law. The M m and D are dependent on the types of OMMT and compatibilizers. The equilibrium water content and diffusivity of PA6/PP blend were increased by the addition of OMMT but decreased in the presence of compatibilizers. On water absorption, both strength and stiffness of the nanocomposites were drastically decreased, but the ductility was remarkably increased. Both PP-g-MA and SEBS-g-MA played an effective role as compatibilizers for the nanocomposites. This was manifested by their higher retention ability in strength and stiffness (in the wet and re-dried states), reduced the equilibrium water content, and diffusivity of the nanocomposites.

Abstract. Nanocomposites based on polyamide 6/polypropylene (PA6/PP = 70/30) blend containing organophilic montmorillonite (OMMT) and maleated polypropylene (PP-g-MA) as compatibilizer were prepared by melt compounding followed by injection molding. Modification of montmorillonite (MMT) with dodecyalmine was successfully performed. The morphological and mechanical properties of nanocomposites were investigated by using x-ray diffraction (XRD), transmission electron microscopy (TEM), tensile, flexural, and impact tests. The thermal stability of nanocomposites was characterized by using thermogravimetric analysis (TGA) and heat distortion temperature (HDT). XRD and TEM results indicated that the intercalated structure was obtained for PA6/PP/MMT composite, a mixture of intercalated and exfoliated structures for PA6/PP/OMMT nanocomposite, and exfoliated structure for PP-g-MA compatibilized PA6/PP/OMMT nancomposite. Thermal stability and HDT of PA6/PP matrix were improved by the addition of both MMT and OMMT. The introduction of PP-g-MA into the PA6/PP/OMMT nanocomposite enhanced the properties such as stiffness, strength, ductility, impact strength, and HDT. This was attributed to the compatibilizing effect of PP-g-MA which improved interfacial adhesion between OMMT with PA6/PP matrix and also promoted the degree of exfoliation of silicate layers in the PA6/PP matrix.

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