Table 2. Physical Properties of WPU According to NCO/OH Ratio and EDA Content

Sample	Particle size (nm)	Viscosity (cP)	Appearances
WPU_1.0	112	29	Blue light
WPU_1.2	118	26	Blue light & Milky white
WPU_1.4	121	25	Blue light & Milky white
WPU_1.6	134	21	Milky white
WPU_1.8	142	19	Milky white & partially precipitate