Preparation and Properties of Eco-friendly Polyurethane Composites Using Microcrystalline Cellulose with Secondary Amino Group as Fillers

To synthesize polyurethane (PU) composites with high biodegradability, we prepared MCC-TPPI filler first by modifying biodegradable microcrystalline cellulose (MCC) powder with a silane coupling agent, trimethoxysilylpropyl modified polyethylenimine (TPPI). We studied effects of the polyol mixing ratios of bio-polyol (B-2466, MCNC) and poly(tetrahydrofuran) (PTHF, Mw = similar to 1000 g/mol) and the use of MCC and MCC-TPPI fillers on thermal stability and mechanical properties of polyurethane composites using thermogravimetric analysis (TGA), scanning electron microscope (SEM) and universal testing machine (UTM). The tensile strength, elongation at break and Young's modulus of PU composites with MCC-TPPI filler were increased more compared to the composites with pristine MCC filler by 1.51, 3.67 and 1.12 times, due to generation of stronger urea bond at the interface of polyurethane (PU) matrix and the MCC-TPPI filler. The bio-based PU composites synthesized in this study have excellent mechanical properties, therefore, they are expected to replace petroleum-based PU, which is widely used to make automotive sheet, carpet and headliner.