Water Absorption Behavior of Different Types of Organophilic Montmorillonite-Filled Polyamide 6/Polypropylene Nanocomposites

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 styrene-ethylene/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 (AMMT), 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 Mm 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. POLYM. COMPOS., 31:195-202 2010. (C) 2009 Society of Plastics Engineers