The Synthesis and Properties Research of High Hydrophilic Polyurethane
|School||East China University of Science and Technology|
|Keywords||Hydrophilic chain extender polyethylene glycol polyurethane elastomers microphase separation|
Hydrophilic chain extender and the synthesis and properties of polyurethane elastomer were mainly discussed in this artical. Hydrophilic polyurethane elastomer by prepolymerization was synthesized and the analysis of their structures and performances were made. The work consists two parts:(1) The anionic hydrophilic chain extender containing carboxyl using maleic anhydride and diethanolamine as the raw materials was prepared, studying the synthesis conditions and characterizing their structure. (2)Synthesized a series of hydrophilic polyurethane elastomer by prepolymer method and made relevant characterization and performance tests in order to get PU elastomers with good mechanical and hydrophilic performances.Maleic anhydride and diethanolamine both have high reactivity, and their reaction is simple and rapid. So the reaction time, reaction temperature and molar ratio have to be controlled in order to get the right product. In this paper, a lot of experiments about the reaction conditions had been done and finally the optimum reaction conditions were determined. The product named single maleic amide acid. And also its molecular structure has been characterized.Using the different polyether with the same molecular weight, PU elestomers samples have been synthesized. The more ether oxygen bond contained in the molecule, the higher their hydrophilic properties will be, but the worse their mechanical properties are correspondingly. With the increase content of ether oxygen bond in the soft segment, the soft segment Tg of the PU elastomers will increase.PU elastomer samples with the polyethylene glycol of different molecular weight were synthesized. With the molecular weight increasing, the hydrophilic properties of the PU elastomers increase correspondingly and the mechanical properties was supposed to decrease. However, the PU elastomer synthesized by polyethylene glycol 2000 shows a higher tensile strength owe to the molecular structure regularity degree and the ability to crystallize at room temperature of polyethylene glycol 2000. Therefore, the order of mechanical properties is PU-2000>PU-400>PU-1000.