Study On The Preparation And Self-healing Performance Of UPy Modified Polyurethane

Polyurethane materials have been widely used in the field of engineering materials due to theirs various forms and excellent comprehensive performance.With the extensive use of polyurethane,the wear and damage caused by various factors have seriously affected the performance and service life.The development of self-healing materials have provided a feasible solution to this problem.Now the widely used hydrogen bond self-healing system is supramolecular system with four-fold hydrogen bond structure-UPy system.In this paper,the UPy structure was polymerized with polyether ternyl alcohol 330 N to prepare supramolecular polymer,and the supramolecular polymer was added into the polyurethane resin by physical blending to prepare polyurethane with self-healing properties.The amount of supramolecular fillers was controlled to study the performance of self-healing polyurethane.The main contents of this paper are as follows:First,Supramolecular polymer UPy-330 N was synthesized by UPy-NCO and 330 N.After optimizing the experimental conditions,a method of room temperature curing polyurethane was introduced.Under normal temperature conditions,self-healing polyurethane was prepared by UPy-330 N and polyurethane in a solution of chloroform and reactant ratio of 2:1,because the filler mixed more evenly and chloroform residue rarely.After curing more than 48 h,the self-healing polyurethane films were obtained with the supramolecular content of 3 %,5 %,8 %,10 %,15 %.The results of DSC test showed the glass transition temperature of the sample decreased with the increase of supramolecular content.The results of XRD and hardness test showed that the crystallinity of polyurethane decreased with the increase of supramolecular content.The results of tensile test showed that with the increase of supramolecular content,the tensile strength and elongation at break of the material increased significantly.Then,a series of self-healing polyurethane were prepared by MDI-100 polyurethane and supramolecular polymer.The scratch test was carried out on materials to explore the relationships between the healing efficiency and temperature,time and supramolecular content.The experimental results show that the longer time and the higher temperature provided the better self-healing performance of the material.With the increase of supramolecular content,the self-healing performance is improved greatly,and the final scratch repair efficiency can reach 96 %.After the material is cut and spliced,tensile test is conducted after the repair.The maximum strength of the material can be restored to the original strength of 86 %.Finally,a series of self-repairing polyurethane materials were prepared by MDI-50 polyurethane and supramolecular polymer.The self-healing properties of materials were studied,and the results showed that the self-healing properties of materials could be greatly improved by changing the type of isocyanate.The self-healing efficiency of materials could be higher than 90 %,and self-healing could be realized at room temperature.