Research On The Post-chain Extension Of Waterborne Polyurethane Under The Different Emulsion

In this paper, the main research is the three different types of emulsifying method of expanding chain:general method of emulsifying chain extension, synchronous chain extension emulsification method and reverse chain extension method. Change the temperature in the process of post-chain extension and the content of DMPA in the process of compounding the prepolymers to compound a series of waterborne polyurethane. And then use a more accurate method to determine the subsequent chain extension efficiency. Residual amino can be measured by reacting with ninhydrin which can make amino color. The basement of the absorption peaks can be measured by UV-Vis. Then the influence of the particle size and post-chain temperature on the chain extension efficiency can be discussed.(1) In the post-chain extension process using the general method of expanding chain to compound waterborne polyurethane under different temperature and different content of DMPA.The main research on the process of the synthesis of waterborne polyurethane, the residual NH2 changes with the temperature changing, the particle size changes and the residual NH2 changes with the particle size changing. Then the sample emulsions react with ninhydrin, under the uv-visible spectra, measure the ultraviolet-visible absorption peaks. At the same time, we also measure the particle size, infrared detection, and solid content.This chapter studies show that:when add the same content of DMPA at the different temperature, the chain extension efficiency is high at 20℃,30℃ and 40℃, low at high temperature and low temperature. Research on the reaction condition of the same content of DMPA and different temperature, we find that with the temperature changing, the particle size changes irregular. Research on the reaction condition of the same temperature and different content of DMPA, we find that with the content of DMPA rising, the particle size rises.Research on the relationship of the residual NH2 groups and the particle size, we find that with the particle size decreasing, the residual NH2 decreases, the chain extension efficiency rises at the temperature lower than 40℃. When the temperature higher than 40℃, the conclusion is just opposite. Repeat the experiment, all get the same result.(2) In the process of chain extension, change the chain extension method, by adopting the method of synchronous extender chain. The method is that mix the ethanediamine and water and pour into the emulsifying barrels to synthetic water-based polyurethane under different temperature and different DMPA content.The main research on the process of the synthesis of waterborne polyurethane, the residual NH2 changes with the temperature changing, the particle size changes and the residual NH2 changes with the particle size changing. Then the sample emulsions react with ninhydrin, under the uv-visible spectra, measure the ultraviolet-visible absorption peaks. At the same time, we also measure the particle size, infrared detection, and solid content.This chapter studies show that:when add the same content of DMPA at the different temperature, we find that with the temperature rising, the residual NH2 decreases, the chain extension efficiency rises. Research on the reaction condition of the same content of DMPA and different temperature, we find that with the temperature changing, the particle size changes irregular. Research on the reaction condition of the same temperature and different content of DMPA, we find that with the content of DMPA rising, the particle size rises. Research on the relationship of the residual NH2 groups and the particle size, we find that with the particle size increasing, the residual NH2 decreases, the chain extension efficiency increases at the temperature lower than 40℃. When the temperature higher than 40℃,the conclusion is just opposite. Repeat the experiment, all get the same result.(3) In the process of chain extension, change the chain extension method, adopt the method of inverse emulsion, pouring synthetic prepolymers slowly into the mixed triethylamine (TEA), water and ethyl diamine. Then research on the synthesised waterborne polyurethane under the different temperature and different content of DMPA.The main research on the process of the synthesis of waterborne polyurethane, the residual NH2 changes with the temperature changing, the particle size changes and the residual NH2 changes with the particle size changing. Then the sample emulsions react with ninhydrin, under the uv-visible spectra, measure the ultraviolet-visible absorption peaks. At the same time, we also measure the particle size, infrared detection, and solid content.This chapter studies show that:when add the same content of DMPA at the different temperature, we find that the chain extension efficiency is low at the low temperature and high at high temperature. Research on the reaction condition of the same content of DMPA and different temperature, we find that with the temperature changing, the particle size changes irregular. Research on the reaction condition of the same temperature and different content of DMPA, we find that with the content of DMPA rising, the particle size rises. Research on the relationship of the residual NH2 groups and the particle size, we find that with the particle size decreasing, the residual NH2 decreases, the chain extension efficiency increases at the temperature lower than 40℃.When the temperature higher than 40℃,the conclusion is just opposite.⑤. Research on the waterborne polyurethane under the different emulsion and same temperature, we find that when the temperature is lower than 30℃, the chain extension is high under the common way and low under the reverse emulsion way. When the temperature is higher than 30℃, the result is just different. Repeat the experiment, all get the same result.