Preparation and Properties of Eco-friendly Polyurethane Nanocomposites Using Cellulose Nanocrystals with Amino Group as Fillers

In this study, a polyol mixture of bio-polyol and petroleum-polyol in a mass ratio of 3:7 was reacted with 4,4'-methylenebis(phenyl isocyanate) (MDI) to prepare an eco-friendly polyurethane (PU) nanocomposite. Also, using 3-aminopropyltriethoxysilane (APS) silane coupling agent, -NH2 group was grafted onto the cellulose nanocrystals (CNCs) surfaces, which was used as fillers. We studied the effects of surface modified CNC fillers on the mechanical properties of PU nanocomposites using thermogravimetric analysis (TGA), universal testing machine (UTM) and dynamic mechanical analyzer (DMA). The -NH2 groups grafted on the CNC surface can form urea bonds with -NCO groups of MDI at the interface, which increased the tensile strength and modulus of PU nanocomposites more than those of the pristine CNC as fillers.