Preparation Of Cyclodextrin Inclusion Complexes And Their Applications In Modification Of Waterborne Polyurethane

The waterborne polyurethane (WPU), which has the advantages of non-toxic, non-pollution and so on, is a kind of new environmental-friendly material, taking the water as the dispersion medium. As the growth of applications in coatings processing, the antibacterial and flame-retardant functional requirements of the WPU materials are also increasing. Therefore, it is of importance to research and develop new advanced antibacterial and flame-retardant functional WPU materials.With hydrophilic exterior and hydrophobic cavity, the cyclodextrin (CD) can form inclusion complexes with appropriate molecules. The particular molecular structure of CD can be widely used to improve the physicochemical properties of the guest molecules, such as stability, volatility, solubility and so on. In this paper, an antibacterial β-CD inclusion silver nanoparticles and a flame-retardant p-CD inclusion ammonium polyphosphate (APP) have been prepared. The main contributions are as follows:(1) The preparation conditions of P-CD inclusions, such as, the ratio of reactants, the temperature of reaction, and the time of reaction, have been investigated. The optimum conditions of the preparation of β-CD inclusion silver nanoparticles is:the molar ratio of β-CD to silver nanoparticles is 1:1 at the temperature of 60℃; The optimum conditions of the preparation of 拾-CD inclusion APP is:the molar ratio of 拾-CD to APP is 1:1 at the temperature of 60℃for 3h.The structure of the 拾-CD inclusion complexes have been characterized by X-ray diffraction(XRD), polarizing microscope, field emission scanning electron microscopy(SEM), thermo-gravimetric analysis(TGA) and element analysis. Meanwhile, the forming mechanism of β-CD inclusion complexes have been discussed.(2)The β-CD inclusion silver nanoparticles have been blended with the WPU to make the films. The structure and properties of the films have been analyzed by FT-IR spectrum, SEM, dynamic mechanical analysis, TGA and antibacterial test. Results show that P-CD inclusion silver nanoparticles are dispersed well in the WPU matrix. When the content of β-CD inclusion silver nanoparticles is less than 2.5wt%, the mechanical properties of the films are enhanced. Antibacterial tests show that the WPU films containing β-CD inclusion silver nanoparticles have the good anti-bacterial property, with the antibacterial ratio of 99.98%.(3)The β-CD inclusion APP are blended with the WPU to make the films. Results show that the β-CD inclusion function improves the compatibility between APP and WPU. When the content of the inclusion complex is less than 7.5wt%, the mechanical properties of the modified films are not much changed; however, the aggregation of the inclusion complex in the WPU matrix will happen when the content is more than 7.5wt%. At the same time, the introduction of β-CD inclusion APP improves the thermal decomposition temperature and carbon residue rate of the WPU films. Combustion tests show that the modified WPU films have the good flame-retardant property. The average combustion time of the modified WPU film is 3.7s.