Preparation And Properties Of Waterborne Polyurethane-based Nanocomposites

With the increasing awareness of environmental protection and health,waterborne polyurethane(WPU),as a non-toxic and harmless new environment-friendly material,has been widely used in packaging,printing and textile fields due to its excellent comprehensive properties.The purpose of this project is to use variety nano-fillers to enhance the thermal properties and mechanical properties of water-based polyurethane materials,so that it can be better applied in the field of printing and packaging.However,the mechanical properties and thermal properties of the waterborne polyurethane films synthesized in the laboratory are insufficient,which used as film materials is greatly limited.Therefore,further modification of waterborne polyurethane materials is needed.At the same time,parts of the nano-fillers are derived from recyclable waste,which can realize the preparation of polyurethane composites and the utilization of waste resources.The modification method is mainly to improve the comprehensive properties of polymer by adding fillers into the polymer by physical blending,which provides a new way for the enhancement of polymer composites by nanomaterials.This experimental is divided into two parts:In the first part,a method to enhance waterbased polyurethane by using alcoholysis of waste PET bottles as organic micro and nano materials was proposed,and the recycling process of degradation of waste PET bottles was studied.Using waterbased polyurethane dispersions as polymer matrix,organic micro-nano materials/water-based polyurethane composites were prepared by using the alcoholysis of discarded PET bottles as organic micro-nano modified materials with the same gradient mass ratio.The microstructure and properties of the composites were investigated.The results show that the organic micro-nano materials are successfully dispersed in the WPU matrix and have no obvious effect on the amorphous structure of the WPU.The thermogravimetric analysis showed that the addition of organic micro and nano materials reduced the thermal stability of polyurethane and made the composite film decompose more easily.At the same time,the mechanical analysis shows that the organic micro-nano modified material has a significant effect on the energy storage modulus of waterborne polyurethane film,which enhances the stiffness of the composite film.Among them,the mechanical properties of the composite with 0.75wt%organic micro/nano material were improved most obviously.In the second part,a variety of organic/inorganic nanomaterials were established to strengthen the polyurethane acrylic(PUA)matrix.Nanomaterials/polyurethane acrylic composites were prepared by using carbon nanotubes(CNTs),nano-crystalline cellulose(CNCs)and nano-alumina(Al2O3)as modifiers,and their microstructure and application properties were studied.The results show that different kinds of nano-fillers can disperse evenly in the polyurethane acrylic matrix,which indicates that the polyurethane acrylic matrix has physical inclusion.The addition of CNTs and CNCs significantly improved the thermal stability of the composite films.Among them,the composite film filled with CNCs has the most obvious stiffness improvement,and the film is not easy to deform.In addition,CNTs significantly increased the elongation of polyurethane acrylic films to 127.29%and provided the highest dielectric response.