Preparation And Characterization Of Waterborne Polyurethane

In this paper,the waterborne polyurethane(WPU)dispersion was prepared successfully by using PCDL,PCL and IPDI as the main raw materials.The effect of different content for DMPA and R(NCO/OH molar ratio)on the properties of waterborne polyurethane dispersion and film were investigated.The synthesis of polyurethane prepolymer and film were characterized by fourier transform infrared spectroscopy(FT-IR),respectively.The morphology of waterborne polyurethane dispersion was measured by transmission electron microscope(TEM).The thermal decomposition temperature and glass transition temperature of waterborne polyurethane dispersion film was determined by thermogravimetric analysis(TGA)and dynamic mechanical analysis(DMA),respectively.The mechanical properties of waterborne polyurethane films were characterized by microcomputer control electronic universal testing machine.The synthetic process of PU prepolymer was trailed by fourier transform infrared spectroscopy(FT-IR).The effects of different DMPA content and R on the morphology and properties of WPU films were investigated by transmission electron microscope(TEM),thermogravimetric analysis(TGA)and dynamic mechanical analysis(DMA),tensile test,water and solvent resistance test.TEM images showed that the particle size of all waterborne PU dispersions ranged from 10nm to 20nm and was of uniform particle size distribution.With an increase in DMPA content,the glass transition temperature(T_g),mechanical strength and thermal decomposition temperature of loss5wt%(T_d5)increased firstly and then decreased,while water resistance decreased.The PCDL-WPU,PCL and PCDL/PCL WPU films with the maximum value of T_g,mechanical strength and T_d5 corresponded to 6.2%,6.1%and 6.1%of DMPA content,respectively.With the increase in R,the mechanical strength of the all films increased.The results showed that the addition of crosslinker into PU restricted the motion of PU molecules,indicating a relatively high cross-link network structure in the PU films,and resulted in the improvement of mechanical strength,water resistance,solvent resistance and cross-linking degree of all WPU films.The foundings also showed that the properties of PCDL-based WPU films performed better than that of PCL-based or PCDL-PCL WPU films.