Synthesis And Characterization Of Supramolecular Waterborne Polyurethane With Quadruple Hydrogen Bonds Via Ureidotriazine

Supramolecular polymers have great development prospects in the preparation of functional polymers due to the reversibility and responsiveness of non-covalent interactions.Among them,the quadruple hydrogen bonds system has become an ideal structural unit for supramolecular polymers due to its strong bonding strength,high degree of directivity,and dynamic reversibility.The quadruple hydrogen bonds via ureido triazine structure have a great value in practical applications due to the higher binding constant and the cheap and easy-to-obtain triazine raw materials.By rationally designing the structure of ureido triazine,supramolecular polymers can be endowed with excellent mechanical properties and self-healing properties.Polyurethane is a widely used polymer.In recent years,with the enhancement of environmental protection awareness,the development of waterborne polyurethane with excellent performance is a work of practical significance.In this paper,a supramolecular waterborne polyurethane with excellent mechanical properties and self-healing properties was synthesized by introducing ureido triazine structural units into the polyurethane molecular chain.Firstly,2,4-diamino-6-undecyl triazine(DAUTA)monomer was synthesized by the addition reaction of dicyandiamide and dodecanenitrile.Then,Poly(ethylene-butylene adipate)glycol(PEBA-2000),isophorone diisocyanate(IPDI),2,4-diamino-6-undecyl triazine,Sodium2-[(2-aminoethyl)amino]ethanesulphonate(AAS-Na)and isophorondiamine(IPDA)were used as raw materials,and a series of supramolecular waterborne polyurethanes with quadruple hydrogen bonds via ureido triazine structure were synthesized by the acetone method.The effects of three variables,DAUTA addition amount(DAUTAC),hard segment content(HSC)and hydrophilic monomer addition amount(HGC)on the emulsion performance and film performance of supramolecular waterborne polyurethane were studied.The solid product of the reaction of dicyandiamide and dodecanenitrile and the supramolecular waterborne polyurethanes were analyzed by infrared spectroscopy(FT-IR)and proton nuclear magnetic resonance spectroscopy(~1H NMR),which proved to be the target product,and the ureidotriazine structure was formed quadruple hydrogen bonds in polyurethane.The synthesized supramolecular waterborne polyurethane emulsions’solid content is about 45%and has good stability.The particle size and viscosity test results of the emulsions show that the particle size of most emulsions does not exceed 300 nm.With the increase of DAUTAC and HSC,the particle size of the emulsion increases,and the viscosity of the emulsion gradually decreases;when the HGC increases,the particle size of the emulsion decreases and the viscosity shows an increasing trend.The TEM test showed that the prepared emulsion particles exhibited regular spherical shapes with different sizes.The water resistance test of the supramolecular waterborne polyurethane films shows that the water absorption rates of most of the films except the C5 group are less than 10%,and the water resistance is excellent.The TGA test shows that the film begins to decompose at about260°C,and is almost completely decomposed at 450°C,and has a great heat resistance.DSC test results show that with the increase of DAUTAC and HSC,the glass transition temperature(Tg)of the film will increase.The DMA and tensile tests of the film showed that the addition of DAUTA significantly improved the mechanical properties of the waterborne polyurethane.The tensile strength increased from 18.31 MPa(A1)to 33.85 MPa(A4),an increase of 84.9%.Self-healing tests show that the addition of DAUTA can significantly improve the self-healing performance of waterborne polyurethane.Compared with the self-healing efficiency of the blank additive A1 group film of 58.55%,the self-healing efficiency of the DAUTA additive A4group film can be as high as 90.52%.